Chapter 18: Parkinson's Disease

Parkinson's disease (PD) is a progressive disorder of the central nervous system (CNS) with both motor and nonmotor symptoms. Motor symptoms include the cardinal features of rigidity, bradykinesia, tremor, and, in later stages, postural instability. Non-motor symptoms may precede the onset of motor symptoms by years. Early symptoms can include loss of sense of smell, constipation, rapid eye movement (REM) sleep behavior disorder, mood disorders, and orthostatic hypotension. Other nonmotor symptoms include altered bladder function, excessive saliva, integumentary changes, difficulty speaking and swallowing, and cognitive problems (slowed thinking, confusion, and in some cases dementia). Onset is insidious with a slow rate of progression. Disruptions in daily functions, roles, and activities, as well as depression, are common in individuals with PD.

PD is a common disease that affects an estimated 1 million Americans and an estimated 7 to 10 million people worldwide. More than 2% of people older than 65 years of age have PD, second only to Alzheimer's disease among neurodegenerative disorders. The prevalence of the disease is expected to increase substantially in the coming years due to the aging of the population. The average age of onset is 50 to 60 years. Only 4% to 10% of patients are diagnosed with early-onset PD (less than 40 years of age). Young-onset PD is classified as beginning between 21 and 40 years of age, and juvenile-onset PD affects individuals less than 21 years of age. Men are affected 1.2 to 1.5 times more frequently than women.^1,2

The term parkinsonism is a generic term used to describe a group of disorders with primary disturbances in the dopamine systems of basal ganglia (BG). Both genetic and environmental influences have been identified. Parkinson's disease, or idiopathic parkinsonism, is the most common form, affecting approximately 78% of patients. Secondary parkinsonism results from a number of different identifiable causes, including viruses, toxins, drugs, tumors, and so forth (Box 18.1). The term parkinsonism-plus syndromes refers to those conditions that mimic PD in some respects, but the symptoms are caused by other neurodegenerative disorders.³

Parkinson's Disease

Parkinson's disease was first described as "the shaking palsy" by James Parkinson in 1817⁴ and refers to those cases where the etiology is idiopathic (unknown) or genetically determined. Two distinct clinical subgroups have been identified. One group includes individuals whose dominant symptoms include postural instability and gait disturbances (postural instability gait disturbed [PIGD]). Another group includes individuals with tremor as the main feature (tremor predominant). Patients who are tremor predominant typically demonstrate few problems with bradykinesia or postural instability.³

Genetic forms of PD represent less than 10% of cases overall. In a small number of families, several gene mutations have been identified (e.g., PARK1, PINK1, LRRK2, DJ-1, and glucocerebrosidase, among others).¹ Genes have been grouped into two categories: (1) causal genes, which actually produce the disease; and (2) associated genes that do not cause PD but increase the risk of developing it.

Secondary Parkinsonim

Postencephalitic Parkinsonism

The influenza epidemics of encephalitis lethargica that occurred from 1917 to 1926 affected large numbers of individuals. The onset of parkinsonian symptoms typically occurred after many years, giving rise to the theory that a slow virus infected the brain. In the absence of a recent outbreak, this type of parkinsonism is no longer seen. Moving case histories are portrayed in the book Awakenings by Oliver Sacks.⁵

Toxic Parkinsonism

Parkinsonian symptoms occur in individuals exposed to certain environmental toxins, including pesticides (e.g., permethrin, beta-HCH, paraquat, maneb, Agent Orange) and industrial chemicals (e.g., manganese, carbon disulfide, carbon monoxide, cyanide, methanol). The most common of these toxins is manganese, which represents a serious occupational hazard to many miners from prolonged exposure.^6,7 Severe and permanent parkinsonism has been inadvertently produced in individuals who injected a synthetic heroin containing the chemical MPTP (1-methyl-4-phenyl-1,2,3,6- tetra/hydropyridine).⁸ It is important to note that simple exposure is never enough to cause the disease.

Drug-Induced Parkinsonism (DIP)

A variety of drugs can produce extrapyramidal dysfunction that mimics the signs of PD. These drugs are thought to interfere with dopaminergic mechanisms either presy-naptically or postsynaptically. They include (1) neuroleptic drugs such as chlorpromazine (Thorazine), haloperidol (Haldol), thioridazine (Mellaril), and thiothixene (Navane); (2) antidepressant drugs such as amitriptyline (Triavil), amoxapine (Asendin), and trazodone (Desyrel); and (3) antihypertensive drugs such as methyldopa (Aldomet) and reserpine. High doses of these medications are particularly problematic in the elderly. Withdrawal of these agents usually reverses the symptoms within a few weeks, although in some cases the effects can persist and may be related to subclinical PD.⁹

Parkinsonism can be caused in rare cases by metabolic conditions, including disorders of calcium metabolism that result in BG calcification. These include hypothyroidism, hyperparathyroidism, hypoparathyroidism, and Wilson's disease.⁹

Parkinson-Plus Syndromes

A group of neurodegenerative diseases can affect the substantia nigra and produce parkinsonian symptoms along with other neurological signs. These diseases include striatonigral degeneration (SND), Shy-Drager syndrome, progressive supranuclear palsy (PSPO), olivopontocerebellar atrophy (OPCA), and cortical– basal ganglionic degeneration (CBGD). In addition, parkinsonian symptoms can be exhibited in patients with multi-infarct vascular disease, Alzheimer's disease, diffuse Lewy body disease (DLBD), normal pressure hydrocephalus (NPH), Creutzfeldt-Jakob disease (CJD), Wilson's disease (WD), and juvenile Huntington's disease. Many of these conditions are rare and affect relatively small numbers of individuals. Early in their course, these diseases may present with rigidity and bradykinesia indistinguishable from PD. However, other diagnostic symptoms eventually appear (e.g., cognitive impairment in Alzheimer's disease). Another diagnostic feature is that Parkinson-plus syndromes typically do not show measurable improvement from the administration of anti-Parkinson medications such as levodopa (L-dopa) therapy (termed the apomorphine test). ⁹

The BG is a network of subcortical nuclei consisting of the caudate nucleus, the putamen, the globus pallidus, and the subthalamic nucleus along with the substantia nigra. The caudate and the putamen together are called the striatum (Fig. 18.1). The BG engages in a number of parallel circuits or loops, only a few of which are motor. The direct motor loop through the BG consists of signals transmitted from the cortex to putamen to globus pallidus, to ventrolateral (VL) nucleus of the thalamus, and back to cortex (supplementary motor area [SMA]) (Fig. 18.2). This VL-SMA connection is excitatory and facilitates discharge of cells in the SMA. The BG thus serves to activate the cortex via a positive-feedback loop and assists in the initiation of voluntary movement. Inhibition of the thalamus by the BG is thought to underlie the hypokinesia seen in PD. An indirect loop through the BG involves the subthalamic nucleus, the globus pallidus interna, and substantia nigra pars reticulata to the superior colliculus and midbrain tegmentum (Fig. 18.3). This indirect loop serves to decrease thalamocortical activation. The BG projection to the superior colliculus assists in regulation of saccadic eye movements. The BG projection to the reticular formation assists in the regulation of trunk and limb musculature (via extrapyramidal pathways), sleep and wakefulness, and arousal. Other circuits in the BG are involved with memory and cognitive functions.¹⁰

Parkinson's disease is defined by (1) degeneration of dopaminergic neurons in the BG in the pars compactus of the substantia nigra that produce dopamine and (2) as the disease progresses and neurons degenerate, the presence of cytoplasmic inclusion bodies, called Lewy bodies. Substantial neurodegeneration occurs in PD before the onset of motor symptoms with clinical signs emerging at 30% to 60% degeneration of neurons. Loss of the melanin-containing neurons produces characteristic changes in depigmentation in the substantia nigra with a characteristic pallor.¹¹

Postmortem studies by Braak and colleagues have yielded evidence supporting the view that PD is a widely dispersed neurodegenerative disease that demonstrates a progression through different stages. Early on (stage 1) lesions are found in the medulla oblongata (dorsal IX/X nucleus or intermediate reticular zone). In stage 2, pathology is expanded to involve lesions of the caudal raphe nuclei, the gigantocellular reticular nucleus, and coeruleus-subcoeruleus complex. In stage 3, involvement of the nigrostriatal system is apparent (pars compacta of the substantia nigra). In stage 4, lesions are also found in the cortex (temporal mesocortex and allocortex). In stage 5, pathology is extended to involve the sensory association areas of the neocortex and pre-frontal neocortex. In stage 6, pathology is extended to involve the sensory association areas of the neocortex and premotor areas.^12,13,14

Primary Motor Symptoms

Rigidity

Rigidity is one of the clinical hallmarks of PD and is defined as increased resistance to passive motion. Patients frequently complain of "heaviness" and "stiffness" of their limbs. It is felt uniformly in both agonist and antagonist muscles and in movements in both directions. Spinal stretch reflexes are normal. Rigidity is fairly constant regardless of the task, amplitude, or speed of movement. Two types are identified: cogwheel or lead pipe. Cogwheel rigidity is a jerky, ratchet-like resistance to passive movement as muscles alternately tense and relax. It occurs when tremor coexists with rigidity. Lead pipe rigidity is a sustained resistance to passive movement, with no fluctuations. Rigidity is often asymmetrical, especially in the early stages of PD. It typically affects proximal muscles first, especially the shoulders and neck, and it progresses to involve muscles of the face and extremities. Rigidity may initially affect the left or right side, eventually spreading to involve the whole body. As the disease progresses, rigidity becomes more severe. Rigidity decreases the ability to move easily. For example, loss of bed mobility or lack of reciprocal arm swing during gait is often related to the degree of truncal rigidity. Active movement, mental concentration, or emotional stress may all increase rigidity. Prolonged rigidity results in decreased range of motion (ROM) and serious secondary complications of contracture and postural deformity. Rigidity also has a direct impact on increasing resting energy expenditure and fatigue levels.^9,10

Bradykinesia

Bradykinesia refers to slowness of movement and is one of the cardinal features of PD. Weakness, tremor, and rigidity may contribute to bradykinesia but do not fully explain it. The principle deficit is the result of insufficient recruitment of muscle force during initiation of movement. Patients underscale movement commands in internally generated movements. The introduction of external cues (e.g., vision, sound) can partially ameliorate this and is used in treatment to guide movement. It is one of the most disabling symptoms of PD, with prolonged movement and reaction times resulting in increased time on task and dependence in daily activities. Slowness of thought, bradyphrenia, can contribute to bradykinesia.¹⁵

Akinesia refers to a poverty of spontaneous movement. For example, the patient with PD demonstrates hypomimia or masked facial expression, with significant social consequences. The absence of associated movements (e.g., arm swing during walking) or freezing (e.g., sudden stops in movement as in freezing of gait [FOG]) are other examples. Freezing episodes can be triggered by confrontation of competing stimuli. For example, the patient slows and stops walking (FOG) when exposed to a narrowed space or an obstacle. Freezing episodes are typically short-lived and usually can be overcome by attentional strategies or "behavioral tricks" using external cues (e.g., dropping a tissue initiates a stepping response). Stress can exacerbate freezing episodes. In advanced PD, freezing episodes can severely limit function and increase risk of falling. Akinesia can be influenced by the degree of rigidity, as well as stage of disease, fluctuations in drug action, and disturbances in attention and depression. ⁹

Hypokinesia refers to slowed and reduced movements and can also be seen in PD. For example, patients with moderate or severe PD typically present with handwriting that may start out strong but becomes smaller and smaller as writing proceeds (micrographia). During walking, rotational movements of the trunk with arm swing may also start out strong and decrease over time.

Tremor

Tremor, a third cardinal feature of PD, involves involuntary shaking or oscillating movement of a part or parts of the body resulting from contractions of opposing muscles. In the early stages of the disease, about 70% of patients experience a slight tremor of the hand or foot on one side of the body, or less commonly in the jaw or tongue. It tends to be mild and occurs for only short periods. The tremor is known as a resting tremor because it is present at rest, suppressed briefly by voluntary movement, and disappears with sleep. Tremor in the lower limbs is most apparent while the patient is supine. Tremor of the head and trunk, postural tremor, can be seen when muscles are used to maintain an upright posture against gravity. Action tremor, tremor that continues with movement, can occur in patients with advanced disease. Tremor tends to be less severe when the patient is relaxed and unoccupied. It is aggravated by emotional stress or excitement. In later stages tremor can become severe, spread to the other side, and interfere with activities of daily living (ADL). Fluctuations in frequency and intensity are common.⁹

Postural Instability

Individuals with PD demonstrate abnormalities of posture and balance, resulting in postural instability. These changes are rare in the early years (i.e., the first 5 years after diagnosis). As the disease progresses, a number of problems become evident across a broad spectrum of movement control. Patients demonstrate abnormal and inflexible postural responses controlling their center of mass (COM) within their base of support (BOS). Narrowing of the BOS (tandem stance or single-limb stance) or competing attentional demands (divided attention situations) increases postural instability. Patients also experience increased difficulty during dynamic destabilizing activities such as self-initiated movements (e.g., functional reach, walking, turning) and perform poorly under conditions of perturbed balance.¹⁶ The response to instability is an abnormal pattern of coactivation, resulting in a rigid body and an inability to utilize normal postural synergies to recover balance.^17,18 Patients also demonstrate difficulty in regulating feed-forward, anticipatory adjustments of postural muscles during voluntary movements. Sensorimotor integration is impaired as evidenced by difficulty in adapting movement strategies to changing sensory conditions.¹⁷ Visuospatial impairment has been identified in patients with advanced PD and correlates with lower scores in mobility.¹⁹ Some patients are unable to perceive the upright or vertical position, which may indicate an abnormality in processing of vestibular, visual, and proprioceptive information contributing to balance. Contributing factors to postural instability include rigidity, decreased muscle torque production and weakness, loss of available ROM particularly of trunk motions, and axial rigidity. Medication side effects (e.g., postural hypotension and dyskinesias) also contribute.

Progressive development of postural deformity occurs. Weakness of antigravity muscles contributes to the adoption of a flexed, stooped posture with increased flexion of the neck, trunk, hips, and knees.²⁰ This results in a significant change in the center-of-alignment position, positioning the individual at the forward limits of stability. In the lower extremities (LEs), contractures develop in hip and knee flexors, hip rotators and adductors, and plantarflexors. In the spine, dorsal spine and neck flexors are involved, and in the upper extremities (UEs), shoulder adductors and internal rotators and elbow flexors are involved. Function becomes progressively more limited by these musculoskeletal constraints. Older individuals with reduced activity levels and poor diet are likely to develop osteoporosis.

Frequent falls and fall injury are the result of progressive disease. Falls are initially absent early in the disease, then become increasingly prevalent during the middle portion of disease progression, and as the patient becomes progressively immobile, disappear during late disease. About 70% of patients with PD report experiencing falls within the past year and 50% report recurrent falls. The rate of fall injury is about 40%. Although most injuries are not severe, some lead to hospitalization. Within 10 years of diagnosis, approximately 25% of patients will have developed a hip fracture. Disease severity, postural instability, and gait impairment including freezing are clearly linked to increased risk for falls.²¹ Other risk factors include dementia, depression, postural hypotension, and involuntary movements associated with long-term use of anti-parkinsonian medication (dyskinesias).²² Falls can lead to "fear of falling" with increasing levels of immobility and dependency with a deteriorating quality of life.²³

Secondary Motor Symptoms

Muscle Performance

A reduction in strength is evident in patients with PD. Torque production is decreased at all speeds resulting in activity limitations and muscle weakness.^24,25,26 Changes in strength may be dopamine related as patients on dopamine replacement ("on" state) demonstrate increases in strength when compared to testing the same muscles during an "off" state.²⁷ Electromyography (EMG) studies reveal that motor unit recruitment is delayed with under-recruitment of muscles. Once initiated, contraction is characterized by multiple bursts and asynchronization, that is, pauses and an inability to smoothly increase firing rate as contraction continues.^28,29 These difficulties are compounded during the production of complex movements. As the disease progresses, disuse weakness evolves from inactivity and increases movement difficulties.

In patients with PD, fatigue is among the most common symptoms reported. The patient has difficulty in sustaining activity and experiences increasing weakness and lethargy as the day progresses. Repetitive motor acts may start out strong but decrease in strength and amplitude as the activity progresses. Performance decreases dramatically with great physical effort or stress. Rest or sleep may restore mobility. When L-dopa therapy is initiated, the patient may notice a dramatic improvement initially and feel significantly less fatigued. In long-standing disease and drug therapy, fatigue typically reappears. A common perception among patients is an increased sense of effort associated with movement that is manifested by difficulty activating and sustaining responses.

Motor Function

The striatum of the BG (caudate nucleus, putamen, and nucleus accumbens) receive input from all cortical areas and project throughout the thalamus to frontal lobe areas (prefrontal, premotor, and supplementary motor areas) concerned with motor planning. In PD, motor planning deficits are evident, involving a loss regulatory control of both automatic and voluntary movement responses directed through the pyramidal system.³⁰ Paucity of movement occurs with less accurate movements overall. This deficit in accuracy becomes more pronounced as the patient attempts to increase the speed of movement (speed-accuracy trade-off). This is a commonly observed problem in the elderly in general. Patients experience difficulty performing complex, sequential, or simultaneous movements (dual-task control). The difficulties combining tasks or shifting attentional sets from one to another can also be seen with cognitive tasks or when combining cognitive and motor tasks. Movement preparation (i.e., the when, where, and how to initiate movement) is significantly prolonged (a finding also seen with advancing age). This start hesitation is especially evident as the disease progresses.³¹ For example, the patient is slow and hesitant in initiating movement during a transfer sequence.

Motor learning deficits are seen in patients with PD but are not universal. Learning of a new motor skills and fine-tuning of skills are intact at the early stage of PD for non-demented, medicated individuals. Retention tests may yield poorer performance but this is most likely due to problems in motor initiation than in actual retention. Deficits in motor skill learning have been demonstrated in advanced disease and for complex and sequential tasks. Thus, the processing requirements of the procedural task are critical in determining the degree of expected learning. Learning is impaired with random presentations of stimulus conditions (random practice order) whereas blocked practice order reduces learning difficulty. Thus context interference degrades learning in patients with PD. Learning deficits can be expected to be severe if multiple motor programs are required either simultaneously or sequentially (i.e., switching among tasks). For example, the patient freezes up when asked to carry out another motor task while walking (dual tasking). Compounding variables that degrade learning include the severity of disease, dementia, and visual–perceptual deficits. Differences in learning can also be expected based on medication levels as motor learning is degraded when patients are in the "off" state of medication.^{31,32,33,34,35}

Gait

Approximately 13% to 33% of patients present with postural instability and gait disturbances as their initial motor symptom and comprise a PIGD group. Gait disturbances are also a common feature of late-onset or advanced PD.³⁶ The patient with PD demonstrates a number of significant gait changes resulting from impoverished movement. There is a reduction in arm swing with asymmetry. An abnormal stooped posture contributes to development of a festinating gait pattern, characterized by a progressive increase in speed with a shortening of stride. Thus, the patient takes multiple short steps to catch up with his or her COM to avoid falling, and may eventually break into a run or trot. Gait can be anteropulsive (a forward festinating gait) or less commonly retropulsive (a backward festinating gait). Some patients are able to stop only when they come in contact with an object or a wall. Patients who are toe-walkers owing to plantarflexion contractures exhibit an additional postural instability from narrowing of their BOS. Turning or changing direction is particularly difficult and typically accomplished by taking multiple small steps. Problems with controlling posture and balance limit independence, community ambulation, and safety.^{37,38,39,40,41} In early disease FOG is generally short in duration and rarely leads to falls. With disease progression FOG becomes more common and disabling, often leading to falls. Patients who are in the "off" state experience increased FOG and deterioration in gait performance whereas gait patterns improve when peak medication prevails.⁴² Most patients with mild gait deficits can compensate at least partially using external cues and attentional strategies.

Nonmotor Symptoms

Sensory Symptoms

Patients with PD do not suffer from primary sensory loss. However, as many as 50% experience paresthesias and pain, including sensations of numbness, tingling, cold, aching pain, and burning. Pain may be due to the disease's effect on central nociception. Symptoms are typically intermittent, and vary in intensity and location. Some patients report their pain is linked to the motor fluctuations experienced during L-dopa therapy (e.g., pain is more intense in an "off" state). Pain may also be increased in patients experiencing depression.⁴³ It is also important to remember that some of the discomfort and pain can result from postural stress syndrome secondary to faulty posture, ligamentous strain, lack of movement, and muscle rigidity. For example, back pain may accompany a prolonged, stooped, kyphotic posture.

Proprioceptive regulation of voluntary movement may also be impaired. Patients with PD perform significantly worse than control subjects on tests of kinesthesia and proprioceptive position sense. Without visual guidance, patients demonstrate increased difficulty in accurately perceiving the extent of movement, consistently underscaling their movements. Deficits in visuospatial skills may also occur. Patients demonstrate significantly more errors than normal on visual perception tasks involving spatial organization.^44,45

Olfactory dysfunction is common, with some studies showing up to 100% of patients affected. Most patients with PD report a decline or loss of sense of smell (anosmia), often years before motor symptoms develop. Loss of smell therefore has important implications for diagnosis of early disease. It also increases the difficulty individuals have in maintaining a healthy diet and adequate nutrition.⁴⁶

Conventional drugs (e.g., anticholinergic drugs) used in PD can cause visual disturbances (e.g., blurred vision and sensitivity to light [photophobia]). These drugs can also worsen the normal visual changes associated with aging (presbyopia). Conjugate gaze and saccadic eye movements may also be impaired. Eye pursuit movements may have a jerky, cogwheeling quality. Decreased blinking can produce bloodshot, irritated eyes that burn and itch.

Dysphagia

Dysphagia, impaired swallowing, is present in as many as 95% of patients and is the result of rigidity, reduced mobility, and restricted range of movement.⁴⁷ It is often an early symptom of the disease though it is present in all stages. Individuals with PD experience problems in all four phases of swallowing: oral preparatory, oral, pharyngeal, and esophageal. Thus, the patient demonstrates abnormal tongue control and problems with chewing, bolus formation, delayed swallow response, and peristalsis. Dysphagia can lead to choking or aspiration pneumonia and impaired nutrition with significant weight loss. Nutritional inadequacy can contribute to the fatigue and exhaustion typically experienced by patients with PD.⁴⁸ Patients also typically experience excessive drooling (sialorrhea) as a result of increased saliva production and decreased spontaneous swallowing. Drooling is particularly problematic while sleeping or initiating speech and in advanced cases increases the risk of aspiration. Excessive drooling has important negative social implications.

Speech Disorders

Speech is impaired in 75% to 89% of patients and is the result of primary symptoms of PD (rigidity, bradykinesia, hypokinesia, and tremor).⁴⁷ Patients with PD experience hypokinetic dysarthria, which is characterized by decreased voice volume, monotone/monopitch speech, imprecise or distorted articulation, and uncontrolled speech rate. Vocal quality is degraded with speech described as hoarse, breathy, and harsh. In addition, patients experience timing difficulty of vocal onsets and offsets. Reduced mobility, restricted range, and uncontrolled rate of movement of muscles controlling respiration, phonation, resonation, and articulation are present. Reduced vital capacity results in reduced air expended during phonation. In advanced cases, the patient may speak in whispers or not at all, demonstrating mutism. Sensory problems may also contribute to speech difficulties. Patients who are instructed to upscale their speech sounds to produce increased volume consistently describe their speech as "too loud." Speech difficulties contribute to social isolation and impaired activity participation.^47,48

Cognitive Dysfunction

Impairments in cognitive function can be mild (e.g., mildly impaired memory) or severe (e.g., psychosis). PD dementia occurs in approximately 20% to 40% of the patients. Older patients appear to be at greatest risk for dementia, with reported rates 4.4 times higher for individuals 80 years of age or older.⁴⁹ Dementia is associated with increased mortality rates. Coexisting Alzheimer's disease and multi-infarct dementia secondary to atherosclerotic disease are also common in the elderly and may be contributory factors in some patients. Dementia associated with PD is characterized by loss of executive functions (planning, reasoning, abstract thinking, judgment, and so forth) and changes in visuospatial skills, memory, and verbal fluency. Bradyphrenia, slowed thinking, is seen in patients with PD and may be one of the early nonspecific features of the disease. Cognitive performance is degraded in the "off" state. Hallucinations, delusions, and psychosis are common complications owing to L-dopa toxicity.

Depression and Anxiety

Depression is common in patients with PD. Major depression is reported to occur in approximately 40% of patients.⁵⁰ A significant number of patients develop depression before or just after onset of motor symptoms, suggesting an endogenous cause that may be related to underlying deficiencies of dopamine, serotonin, and norepinephrine. Patients demonstrate a variety of symptoms, including feelings of guilt, hopelessness, and worthlessness; loss of energy; poor concentration; deficits in short-term memory; loss of ambition or enthusiasm; and disturbances in appetite and sleep. Suicidal thoughts may also be present. Hypomimia, a reduction in facial expressiveness, can give the appearance of depression. Patients can also demonstrate dysthymic disorder characterized by chronic depression and dysphoric mood, resulting in poor appetite or overeating, insomnia or hypersomnia, low energy, low self-esteem, and poor concentration.

Anxiety is a common symptom in PD, occurring in up to 38% of patients. Clinically patients may present with symptoms of a panic attack (e.g., palpitations, sweating, trembling, shortness of breath, and so forth) as well as social phobia (social withdrawal), agoraphobia, obsessive-compulsive disorder, or panic disorder. Anxiety symptoms may not be simply related to the psychological or social difficulties patients experience, but due to specific neurobiological processes associated with the disease. Patients who are in the "off" medication state experience significant worsening of depression and anxiety.⁵¹

Autonomic Dysfunction

Autonomic dysfunction occurs with PD and is a direct manifestation of the disease, as evidenced by the presence of Lewy bodies found in the autonomic nervous system.⁵² Thermoregulatory dysfunction includes excessive sweating and abnormal or uncomfortable sensations of warmth and coldness. Patients in the "off" state experience impaired peripheral vasodilation with difficulty dissipating body heat. Seborrhea (increased oil secretion of the sebaceous glands of the skin) and seborrheic dermatitis (oily, chafing, and reddened skin) are also common. Patients with PD exhibit abnormally slow pupillary responses to light and pain and reduced overall response to changes in light.⁵³

Gastrointestinal disorders include poor motility, changes in appetite, inadequate hydration, sialorrhea, and weight loss. Constipation is a common problem for most patients and typically occurs early in PD. Urinary incontinence occurs with associated symptoms of urinary frequency, urgency, and nocturia. Many of these problems occur in the aging population in general and in men with benign prostatic hypertrophy. Erectile dysfunction is often present in males, including impotence and reduced rates of sexual activity.⁵³

Early and progressive sympathetic denervation of the heart occurs in the majority of patients with PD. This results in diminished heart function, which may be a contributory factor to the fatigue that most patients experience.⁵³ Patients with advanced PD exhibit altered heart rate (HR) and blood pressure (BP) during exercise with decreased exercise efficiency.⁵⁴ Patients with mild to moderate PD do not appear to demonstrate significantly different exercise capacity (maximal HR, maximal oxygen consumption) when compared to age-matched controls. However, these patients did demonstrate decreased peak power and higher submaximal HRs and oxygen consumption rates than controls.^55,56,57

Orthostatic hypotension (OH) is common in middle and late PD and is caused by a sharp drop in BP that occurs with position changes (e.g., supine-to-sit or sit-to-stand). Typical symptoms include lightheadedness or dizziness. Patients can also experience pallor, diaphoresis, weakness, trembling, nausea, difficulty thinking, or syncope. The condition puts individuals at risk for loss of balance, falls, and fall injury. Medications (e.g., levodopa/carbidopa, bromocriptine) can contribute to orthostatic hypotension.⁵³

Patients with PD demonstrate respiratory impairments, reported in as many as 84% of patients. Airway obstruction (e.g., air trapping, lung insufflation) is the most frequently reported pulmonary problem and has been linked to episodes of pulmonary failure. The etiology remains unknown but may be linked to bradykinetic disorganization of respiratory movements. Restrictive lung dysfunction is common and is linked to the decreased chest expansion that occurs as a result of rigidity of the trunk muscles, loss of musculoskeletal flexibility, and kyphotic posture. Patients with PD demonstrate lower forced vital capacity (FVC), lower forced expiratory volume in 1 second (FEV₁), and higher residual volume (RV) and residual airway resistance (RAW) values when compared to age-matched controls. Daily function and activity participation are reduced in patients with pulmonary dysfunction.^58,59 A sedentary lifestyle with decreased activity levels contributes to cardiopulmonary deconditioning.

In long-standing disease, the LEs may exhibit circulatory changes owing to venous pooling as a result of decreased mobility and prolonged sitting. Thus, patients can present with mild to moderate edema of the feet and ankles, which usually subsides during sleep.

Sleep Disorders

Individuals with PD can experience excessive daytime somnolence (sleepiness). At night, insomnia (disturbed sleep pattern) may occur. This includes problems in falling asleep, staying asleep, and good quality of sleep. REM sleep behavior disorder (RBD) occurs early in PD and affects as many as 50% to 60% of patients. In a person with RBD, the paralysis that normally occurs during REM sleep is incomplete or absent, allowing the person to "act out" his or her dreams that are vivid, intense, and violent. Dream-enacting behaviors include agitation and physical activity during sleep (e.g., talking, yelling, punching, kicking, arm flailing, and grabbing).^60,61 Box 18.2 provides a summary of the cardinal features and clinical manifestations of PD.

Diagnosis at onset of PD is difficult with accurate diagnosis possible only with continued observation of evolving clinical signs and symptoms. There is no single definitive test or group of tests used to diagnose the disease. The diagnosis is made on the basis of history and clinical examination.

Handwriting samples, speech analysis, interview questions that focus on developing symptoms, and physical examination are used. In the preclinical stage, nonmotor symptoms predominate. There is an increasing focus on use of questionnaires and tests (e.g., olfactory testing, imaging of cardiac sympathetic innervation) that focus on emerging nonmotor symptoms.^62,63,64 Often symptoms of loss of smell, sleep disturbances, vivid dreams with REM alterations, foot dystonia and foot cramping similar to restless legs syndrome, orthostatic hypotension, and constipation are symptoms that are present many years before an official diagnoses of PD is made. A diagnosis of PD is typically made if at least two of the four cardinal motor features are present. Exclusion of Parkinson-plus syndromes is necessary. The presence of extrapyramidal signs that are bilaterally symmetrical and do not respond to L-dopa and dopamine agonists (apomorphine test) is suggestive of these syndromes, not PD. Imaging can be used to rule out other pathologies. In vivo functional imaging (magnetic resonance imaging [MRI]) using chemical markers to identify dopaminergic deficits in PD and related disorders identifies dopamine deficiency but does not discriminate between PD and other causes of parkinsonism.⁶⁵

The disease is progressive, with a long subclinical period (without apparent clinical manifestations) estimated to be at least 5 years. Mean PD duration is approximately 13 years. There is variability of the rate of progression. Patients with a young age at onset or who are tremor predominant typically demonstrate a more benign progression. Patients with PD who present with postural instability and gait disturbances (the PIGD group) tend to have more pronounced deterioration with a more rapid disease progression. Neurobehavioral disturbances and dementia are also more common in this group. With L-dopa therapy, progression is generally slower with an overall improvement in mortality rates. The most common causes of death are cardiovascular disease and pneumonia.⁶⁵

Hoehn-Yahr Classification of Disability Scale

An estimate of the stage and severity of the disease can be made using a staging scale. The most widely used in clinical practice and research trials is the Hoehn-Yahr Classification of Disability Scale (Table 18.1).⁶⁶ It provides a broad measure for charting the progression of the disease using motor signs and elements of functional status. Stage I is used to indicate minimal disease involvement, whereas stage V is indicative of severe deterioration in which the patient is confined to bed or a wheelchair.⁶⁷

Unified Parkinson's Disease Rating Scale (UPDRS)

The Unified Parkinson's Disease Rating Scale (UPDRS) has been the "gold standard" for measuring the progression of PD since 1987.⁶⁸ The original UPDRS was composed of four parts: Part I, Mentation, Behavior, and Mood; Part II, Activities of Daily Living; Part III, Motor Examination; and Part IV, Complications of Therapy. Goetz and colleagues reported on a modification of this scale renamed the Movement Disorder Society–sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS).^69,70,71 The goals of the revision were to improve ability to detect slower and smaller changes in mildly disabled patients and increase focus on nonmotor symptoms. It retains the 4-part structure with substantial reworking of questions and an additional 6 items (most on nonmotor aspects of PD), bringing the total to 48. A four-point scale is used for all items (as opposed to some items graded as 0, no, or 1, yes, in the original scale). A score of 0 means normal or no problems; 1, minimal problems; 2, mild problems; 3, moderate problems; and 4, severe problems. Descriptors are added for each question. Parts I and II have been renamed: Part I is now Non-motor Aspects of Experiences of Daily Living and Part II is now Motor Experiences of Daily Living. Part III is Motor Examination (same title) and Part IV is renamed Motor Complications.⁷⁰ The total time to administer the test is an estimated 30 minutes, with Parts I and II designed to be self-administered by the patient. See Appendix 18.A.

Medical management is directed at slowing disease progression using neuroprotective strategies, and symptomatic treatment of motor and nonmotor symptoms. Management becomes increasingly more challenging over time for patients with moderate and advanced disease (i.e., Stage III or higher on the Hoehn-Yahr Classification of Disability Scale).^{72,73,74,75,76}

Pharmacological Management

A number of agents are available as first-line neuroprotective and symptomatic therapy. Selection is individualized according to the patient's characteristics with the benefits and risks of adverse side effects carefully weighed. Starting medication early has been shown to be beneficial in slowing the progression of the disease. Drug delivery should be as close to constant as possible to avoid large peaks and valleys. The importance of taking the medication on a fixed schedule should be stressed to patients, family members, and caregivers. When patients with PD are hospitalized it is important that they continue to receive their medication on schedule.⁷⁷ Currently three out of four patients with PD do not receive their medications on time when they are in a hospital setting. Sixty-one percent of patients who did not receive their medications on time had serious complications.⁷⁸ The Aware in Care kit from the National Parkinson Foundation can be helpful in avoiding these complications (www.awareincare.org).

Levodopa/Carbidopa

Levodopa/carbidopa (Sinemet) is the gold standard drug therapy for PD. Levodopa (L-dopa) was first introduced in 1961 as an experimental drug and came into widespread clinical use in the late 1960s. It is a dopamine precursor that is metabolized to dopamine in the brain. Thus, administration of the drug represents an attempt to correct the essential neurochemical imbalance. Most of L-dopa (almost 99%) is metabolized before reaching the brain, requiring administration of high doses that can produce numerous side effects. Today, L-dopa is commonly administered with carbidopa, a decarboxylase inhibitor that allows a higher percentage of L-dopa to enter the brain. Thus, lower doses of L-dopa can be used with fewer adverse side effects. Sinemet is available in immediate-release (IR) and controlled-release (CR) formulations. The IR form has a short half-life requiring multiple oral dosing throughout the day. The CR form is a long-acting, sustained-release preparation. Both are equally effective.^79,80

The primary benefits of dopamine replacement include controlling the PD motor symptoms of bradykinesia and rigidity. Increased movement velocity, initial burst of motor activity, and increased strength are all positive outcomes.⁸⁰ The effects on reduction of tremor are more varied. Some individuals demonstrate little or no response whereas others demonstrate a positive reduction in tremor amplitude. It does not appear to have a direct impact on postural instability. The decision about when to start levodopa/carbidopa is determined by the neurologist and is different for every person. Initial dosing improves low levels of levodopa often with dramatic improvements in functional status. This is sometimes referred to as the honeymoon period, in which there is clear-cut drug effectiveness.

There are numerous adverse effects of dopamine replacement therapy. For many patients the typical therapeutic window is 4 to 6 years before optimal benefit wears off (termed wearing-off state). At this point, a significant number of patients experience disabling dyskinesias, dystonia, and motor fluctuations. Dyskinesias are dynamic uncontrolled or involuntary movements that occur typically at peak L-dopa dose or when the patient is transitioning between "on" and "off" states. The movements are choreo-athetotic in quality and may initially appear as facial grimacing with twitching of the lips and tongue protrusion. With time the involuntary movements become more prevalent, vigorous, and more extensive, involving the limbs, trunk, and neck. Dyskinesias are estimated to develop and increase at a rate of 10% per year following start of dopamine therapy. Dystonia, a prolonged involuntary contraction that causes twisting or torsion of body segments, can also occur. The patient typically complains of clawing of the toes or fingers, or cramping of the calf, neck, face, or paraspinal muscles. Dystonia is associated with pain and occurs typically during "off' periods. Motor fluctuations include both the "on–off" phenomenon and wearing-off. The term "on–off" phenomenon refers to abrupt, random fluctuations in motor performance and responses. Production of movement errors is common. Wearing-off refers to end-of-dose deterioration, a worsening of symptoms toward the end of the expected timeframe of medication effectiveness.⁷⁹ Patients may experience akathisia, a motor restlessness. In general, they experience an intolerance of inactivity (sitting still) and experience significant disruptions in sleep and relaxation. This affects as many as 25% of patients and is relieved with movement (e.g., walking). Akathisia is associated with advanced PD and is more commonly seen in the "off" state.

Deprenyl can be administered with levodopa/carbidopa to control mild wearing-off phenomena. Unsupervised reduction or sudden discontinuation of levodopa/carbidopa is contraindicated and may produce dangerous, life-threatening adverse effects. Adverse interactions can occur with several medications, including antacids, antiseizure drugs, antihypertensives, and antidepressants.⁸⁰

Patients may also experience other changes that are dose related and may indicate the need for drug modification. These include (1) disabling psychiatric toxicity (visual hallucinations, delusions, and paranoia); (2) depression; (3) gastrointestinal changes (nausea, dry mouth); (4) cardiovascular changes (hypotension, dizziness, arrhythmias); (5) genitourinary changes (dysuria); and (6) sleep disturbances (insomnia, sleep fragmentation).^79,80

Dopamine Agonists

Dopamine agonists (DAs) are a class of drugs designed to directly stimulate postsynaptic dopamine receptors. They are administered alone as a first-line monotherapy or along with levodopa/carbidopa, allowing lower doses to be administered with prolonged effectiveness (i.e., L-dopa–sparing therapy). Patients with moderate to advanced PD who demonstrate declining responses to levodopa/carbidopa therapy may benefit. The most commonly prescribed DA drugs include ropinirole (Requip) and pramipexole (Mirapex); bromocriptine (Parlodel) is less commonly used. The greatest benefit of these drugs is reducing rigidity, bradykinesia, and motor fluctuations. Adverse effects are similar to those of L-dopa with nausea, sedation, dizziness, constipation, and hallucinations being the most common. These medications have also been linked to an increased risk of impulse control disorders (e.g., pathological gambling, compulsive shopping, hypersexuality, overeating).⁸⁰

Anticholinergics

Anticholinergic agents may be used in early PD or as an adjunct for patients on carbidopa/levodopa. They block cholinergic function and have the most benefit moderating tremor and the dystonia that may accompany the wearing-off; they have little or no effect on other PD symptoms. The drugs commonly prescribed in this group include trihexyphenidyl (Artane) and benztropine mesylate (Cogentin). Anticholinergic adverse effects include blurred vision, dry mouth, dizziness, and urinary retention. Central toxicity is indicated by impaired memory, confusion, hallucinations, and delusions.⁸⁰

Monoamine Oxidase B Inhibitors

Monoamine oxidase B (MAO-B) is the major enzyme that acts to degrade dopamine in the brain. MAO-B inhibitors include selegiline, also called deprenyl (Eldepryl) and rasagiline (Azilect). Patients in the early stages of PD may be given MAO-B inhibitors to enhance levels of dopamine. Clinically, early monotherapy treatment with selegiline has been shown to have a modest effect in slowing, but not halting, disease progression. Once L-dopa therapy is started, selegiline in combination improves symptom control and permits a lower dose to be used. MAO-B inhibitors have a low risk of dyskinesias. There are few adverse effects, including mild nausea, dry mouth, dizziness, orthostatic hypotension, confusion, hallucinations, and insomnia.⁸⁰

Implications for the Physical Therapist

The therapist needs to be fully aware of each of the medications the patient is taking and potential adverse effects. It is important to remember that patients on dopamine replacement will develop motor complications at some point. Optimal performance can be expected at peak dosage whereas worsening performance is associated with end-of-dose cycle and medication depletion.⁸¹ Timing of physical therapy examination and intervention should be consistent and occur whenever possible during optimal dosing cycle. Therapists are involved in monitoring drug effectiveness on motor performance, function, and activity participation. As the disease progresses, patients may develop an intolerance for a particular medication, necessitating a change in prescription. Often, it is the therapist who first notices a change in functional status as the patient's system adapts to either the amount or type of drug prescribed. Accurate observation, examination, and reporting of these changes greatly assists the physician in modifying a drug prescription. Therapists may also be involved with clinical drug trials as new medications or combinations are developed. Table 18.2 presents an overview of the pharmacology of PD.

Nutritional Management

A high-protein diet can block the effectiveness of L-dopa. The dietary amino acids in protein compete with L-dopa absorption. This is particularly problematic in patients with chronic disease who exhibit fluctuations in motor performance. Thus, patients are generally advised to follow a high-calorie, low-protein diet. Generally no more than 15% of calories should come from protein. Dietary recommendations may also include shifting the intake of daily protein to the evening meal when patients are less active. These modifications minimize motor fluctuations and maximize responsiveness to L-dopa therapy. The patient is encouraged to eat a variety of foods and may be advised to take dietary supplements to ensure adequate intake of vitamins and minerals. Patients are also advised to increase their daily intake of water and dietary fiber to help control problems of constipation.⁷⁶

Rigidity and bradykinesia can limit upright posture and UE feeding movements. Learned motor plans, for example, using a cup or eating utensils, may also be difficult. Occupational therapy intervention to improve feeding and recommend adaptive eating devices is of considerable importance in helping to maintain nutrition and general health status. The speech-language pathologist also has an important role in the evaluation of dysphagia and the recommendation of strategies to assist with swallowing dysfunction. Patient, family, and caregiver education should focus on the importance of maintaining good nutritional intake. Percutaneous endoscopic gastrostomy (PEG) is reserved for advanced disease when all other strategies for dysphagia fail.

Deep Brain Stimulation

Deep brain stimulation (DBS) involves the implantation of electrodes into the brain where they block nerve signals that cause symptoms. Brain electrodes are placed in the subthalamic nucleus (STN) or less frequently the globus pallidus (GPi). An impulse generator (IPG), similar to a pacemaker, is implanted in the subclavicular area and a thin wire goes under the skin to connect to the brain electrodes. High-frequency stimulation is provided. The patient can control the pacemaker's "on–off" switch using a controller while the physician determines the amount of stimulation it delivers, tailoring it to the individual's needs.⁸²

DBS is effective for the treatment of advanced PD. Improvement of tremor that is refractory to pharmacological therapy is seen in approximately 90% of patients with one-third to one-half of patients experiencing total suppression with DBS of the STN. DBS has been shown to successfully control PD symptoms of motor overactivity (dyskinesias), substantially increase "on" time, and improve ADL scores. DBS has also been shown to reduce the medication requirements and is a treatment of choice in patients with medication-resistant motor fluctuations and dyskinesia. Other motor symptoms of akinesia, rigidity, weakness, and reduced walking speed may improve with DBS though the responses are more variable. Possible adverse effects include confusion, headache, speech problems, gait disturbances, and falling. Most of the complications are temporary and resolve within 6 months. Surgical risks (intracerebral hemorrhage, infection) and mechanical problems with the device (lead breakage, generator malfunction) are also possible. Deep brain stimulation has largely replaced stereotaxic surgical procedures of the brain (thalamotomy and pallidotomy).^{82,83,84,85,86}

Rehabilitation has an important role in reducing activity limitations while promoting activity participation and independence. In addition, known complications of PD can be reduced or prevented while quality of life is promoted. Optimal management involves a coordinated interdisciplinary team to oversee a comprehensive plan of care to address the patient's individual clinical problems, concerns, and needs. The team typically includes the physician, nurse, physical therapist, occupational therapist, speech-language pathologist, and social worker. Referral to other specialists may also be necessary, for example, psychologist, nutritionist, gastroenterologist, urologist, pulmonologist, and so forth. As with any team, the patient is the central figure with family and caregivers being key members.

The ideal rehabilitation program considers the patient's disease history, course, and symptoms, together with impairments, activity limitations, and participation restrictions. Of equal importance are the patient's abilities (assets), priorities, and resources, including family, home, and community resources. Deterioration of condition and medication-induced fluctuations in performance should be expected. Depression and anxiety are common and should be carefully monitored. The overall focus is on long-range planning, with anticipated episodes of care including hospital-based, outpatient, and home/community-based care.

Therapeutic Care Continuum

A therapeutic care continuum based on disease stage (early, middle, late) is an effective way to organize care. Interventions are restorative (aimed at improving impairments, activity limitations, and participation restrictions), preventative (aimed at minimizing potential complications and indirect impairments), and compensatory (aimed at modifying the task, activity, or environment to improve function) (see discussion in Chapter 1). It is critical for the whole team to provide a supportive environment to assist patients and their family members in the difficult adjustment to living with a chronic and progressive disease.

In the early stage of the disease, patients are functional and independent with minimal impairments. A referral for physical therapy is often delayed at this stage, although benefits could clearly be obtained in improving fitness levels and delaying or preventing indirect impairments. Patients are typically seen on an outpatient basis.

During the middle stage of the disease, symptoms are more readily apparent and activity limitations emerge. The patient may still be independent in gait and ADL, although performance is slowed and less efficient. Some assistance may be required. The patient may be seen as an outpatient, during home care, or during a brief inpatient admission. There are numerous benefits to rehabilitation services. Exercise training programs have been shown to be effective for patients with mild to moderate PD in improving motor performance.^{87,88,89,90,91,92,93} Perceived quality of life and subjective well-being are also improved.⁹⁴ Family and caregiver instruction is intensified to assist the patient in remaining as functionally independent as possible.

In the late stage, disease progression leads to increased and more severe impairments and complications. Patients are dependent in many or most of their daily functional mobility skills and ADL and are typically wheelchair bound or bedridden. Family and community resources are vital in maintaining the patient in the home. Some patients may require placement in a chronic care facility. These changes can be a source of great anxiety and frustration to the patient and family. Goals need to be restructured. The therapist needs to focus on preventative care to avoid secondary complications that may be life threatening (e.g., pneumonia, pressure ulcers, and so forth). Compensatory training focuses on maintaining function, including being upright and out of bed as much as possible. Safety for both the caregiver and the patient becomes a primary concern as maximal assist dependent transfers become the norm. Often, environmental adaptations may mean the difference between total dependence and modified dependence. The rehabilitation team should be supportive of the patient's efforts no matter how small they may be. Patients in late-stage PD demonstrate extremely limited skills to interact with their environment, with increasing social isolation and withdrawal. Families also suffer from the increasing demands of care, burnout, and social isolation. Therapists need to maximize psychosocial support and be readily available for consultation. Table 18.3 presents an overview of Parkinson's disease stages and intervention strategies.

The preferred practice pattern for patients with PD from the Guide to Physical Therapist Practice is 5E, Impaired Motor Function and Sensory Integrity Associated with Progressive Disorders of the Central Nervous System— Acquired in Adolescence or Adulthood.^{97, p. 375} In this document the reader will find relevant information on patient/client diagnostic classification; ICD-9-CM codes; examination components; considerations for evaluation, diagnosis, and prognosis; and suggested interventions. Thus, the Guide to Physical Therapist Practice serves as a primary resource in designing an appropriate plan of care (POC) and documenting the services provided and outcomes achieved.

A comprehensive examination is required to determine the level of impairments and degree of function. Subsequent reexamination at specified intervals is used to distinguish change in status as well as effects of treatment. Data are obtained from the history, systems review, and relevant tests and measures (Box 18.3).⁹⁷ The selection of examination procedures and instruments is determined by the patient's unique status. The severity of problems, stage of disease, age, phase and setting of rehabilitation, and other factors must all be taken into account in structuring the examination and evaluating data. During the early and middle stages of PD, measures of impairment and physical performance are relatively stable. During late stages of the disease and under conditions of fluctuating symptoms with pharmacological instability, measures can be expected to be less stable.⁹⁸

This section presents strategies for examination as well as relevant tests and measures. Complete descriptions of many of the tests and measures identified are provided in earlier chapters focusing on examination.

Cognitive Function

Memory, orientation, conceptual reasoning, problem solving, and judgment should be examined. Speed of information processing, attention, and concentration are particularly important to determine if bradyphrenia is suspected. A brief screen of cognitive function can be obtained using the Mini-Mental Status Examination (MMSE).⁹⁹

Psychosocial Function

The therapist should determine overall levels of depression, stress and anxiety, and available coping strategies. It is important to ask the patient about the presence of depressive symptoms such as sadness, apathy, passivity, insomnia, anorexia, weight loss, inactivity and dependency, inability to concentrate and impaired memory, or suicidal ideation. Useful instruments include the Geriatric Depression Scale¹⁰⁰ and the Beck Depression Inventory.¹⁰¹ Anxiety is prevalent and disabling in this patient population. The Hospital Anxiety and Depression Scale is reliable in detecting and grading the severity of depression and anxiety in the hospital setting.^102,103

Sensory Function

A screening examination of sensation is indicated (superficial and deep sensations, combined cortical sensations). Sensory changes can be expected with aging (blunting of touch sensations and proprioception with greater losses in LEs than UEs, and distal more than proximal). Specific areas of sensory loss may be indicative of co-morbid pathology, for example, stroke, diabetic neuropathy, and so forth. The patient with PD should be asked about the presence of paresthesias (sensations of numbness or tingling) and pain. Mild aching and cramplike sensations are common and are often poorly localized. It is important to examine for musculoskeletal aches and pains linked to lack of movement, faulty movements or posture, and ligamentous strain.

An examination of vision should include a determination of acuity, peripheral vision, tracking, accommodation, light and dark adaptation, and depth perception. Visual changes can be expected with aging such as loss of visual acuity, inability to focus on printed word (presbyopia), decreased adaptation to light, sensitivity to light and glare, and loss of color discrimination. Patients with PD may experience blurring of vision and difficulty reading not improved by corrective lenses, as well as problems with eye pursuit (cogwheeling). Specific deficits may be indicative of co-morbid pathologies that are common in the elderly, such as cataracts (clouding of central vision first, then peripheral), glaucoma (early loss of peripheral vision), senile macular degeneration or diabetic retinopathy (early loss of central vision), and cerebrovascular accident (homonymous hemianopsia). Medications may also produce impaired or fuzzy vision, for example, antidepressants and anticholinergics.

Musculoskeletal Function

Joint Flexibility and Posture

An examination of musculoskeletal ROM and flexibility is important. The therapist can document specific active range of motion (AROM) and passive range of motion (PROM) impairments using goniometric measurement. Patients with PD are likely to present with losses in hip and knee extension, dorsiflexion, shoulder flexion, elbow extension, dorsal spine and neck extension, and axial rotation. To a lesser extent, these impairments are also generalizable to the geriatric population.

It is particularly important to examine spinal ROM (ability to rotate, flex, and extend the spine) because patients with PD have been shown to exhibit impairments in this area.¹⁰⁴ All segments of the spine should be examined, including cervical, thoracic, and lumbar segments. Spinal inclinometers such as the Back Range of Motion II™ (BROM II) and Cervical Range of Motion™ (CROM) instruments have been shown to be valid and reliable in measuring spinal ROM and forward head posture (www.spineproducts.com).¹⁰⁵ The use of a head-mounted laser and wall measurements is a novel way to assess transverse plane spine ROM. Standing with feet stationary, the patient rotates as far as possible to one side. An objective measurement of full body (trunk) rotation is obtained by measuring the distance that the laser moves along the wall. This multisegmental measurement may be a better predictor of functional trunk mobility than isolated measurements of cervical and lumbar ROM. The mobility of the spine can also be examined using a series of functional movements, such as axial rotation (looking behind) in sitting and standing and walking. Hamstring length can be determined using a straight leg test.

An examination of resting posture and changes in posture that occur with movement is indicated. The therapist can use posture grids, plumb lines, still photography, or videotape to document changes. A flexible ruler contoured to the patient's spine in standing and then traced onto graph paper can be used to record static sagittal plane posture. This technique is affordable, with good intratester and intertester reliability, and was shown to have a high correlation to radiographic measurements of the lumbar and thoracic spine.^106,107,108 In standing, patients with PD typically assume a flexed, stooped posture (kyphosis with forward head) with the COM placed forward within the limits of stability (LOS) (Fig. 18.4). In supine, the flexed posture with forward head is still evident (shadow pillow posture) (Fig. 18.5).

Muscle Performance

An examination of strength and endurance is indicated. The therapist can measure strength using manual muscle testing (MMT). Handheld and isokinetic dynamometry can be used to quantify peak force (torque output). Patients with PD have been shown to exhibit impairments in the rate of force development and in maximum torque production capability. Isokinetic dynamometry can also be used to document muscle endurance and has been suggested for documenting tremor, using slow speeds of movement (25 mm/sec) and low torques.²⁶

Motor Function

Rigidity

Rigidity is usually equal in both agonist and antagonist muscle groups. As mentioned earlier, it can be sustained (lead pipe) or intermittent (cogwheel). Distribution of rigidity is often asymmetrical especially in the early stages of the disease and can vary during the course of the day, point in the medication cycle, and with stress. It is therefore important to determine which body segments are affected and the severity of involvement. The patient should be seated or supine in a relaxed position. The therapist moves each extremity through full PROM. For head and neck and spinal PROM the patient can be seated on a mat or at the edge of a chair, perch sitting, to allow for excursion of spinal motions (flexion, extension, rotation). A determination of severity of rigidity can be made based on the level of resistance to passive movement and availability of ROM. For example, a determination of severe rigidity is made if full PROM can only be achieved with difficulty. Tone changes in the neck and shoulders are suggestive of early disease, whereas tone changes in the trunk and extremities are typically present with moderate and extensive disease. Deficits in functional mobility and postural reactions should be suspected in the presence of significant trunk rigidity. The patient should also be examined for facial mobility (e.g., hypomimia or masked face) including ability to produce spontaneous expressions and part the lips; the ability to smile or use the muscles of facial expression should also be examined. An inspection of voluntary repetitive movements should be performed to determine active limitations imposed by rigidity.

Bradykinesia

Initially movements are slowed, then movements decrease in amplitude (hypokinesia); in later stages, movements become arrhythmic with frequent start hesitations and arrests (akinesia). A stopwatch can be used to quantify detectable slowing of movement (movement time) and start hesitancy or reaction time (elapsed time between the patient's desire to move and the actual movement response). The therapist should examine overall amplitude of movement and fluctuations in amplitude. For example, impaired coordination and asymmetry of arm swing during walking is a common finding in early PD. As the disease progresses, movements are characterized by marked slowness, poverty, and reduced amplitude. Timed tests for rapid alternating movements (RAM) can be used to determine the effects of bradykinesia. Examples of RAM include repeated opposition of the forefinger and thumb, alternating between pronation and supination, opening and closing of hands, and tapping (finger or foot tapping). Dexterity in complex motor tasks (e.g., writing, dressing, skilled object manipulation) can be expected to be impaired and should be examined. This is also true for motor tasks involving simultaneous use of both sides (e.g., bilateral RAM between pronation and supination). See Chapter 6, Examination of Coordination and Balance, for additional test examples.

More sophisticated methods have been used to study movement in patients with PD, largely in the research setting. EMG has been used to quantify the effects of rigidity and bradykinesia on motor performance. Long-latency EMG responses (50 to 120 msec) have been observed when muscles are subjected to sudden stretch. Abnormal patterns of motor unit recruitment have also been observed.¹⁰⁹

Tremor

The location, persistence, and severity (amplitude) of tremor should be recorded. The therapist should determine if tremor is present at rest (initial typical pattern) or present with action and interferes with function. This latter pattern may occur in severe, longstanding disease. UE functional skills such as drinking from a cup, feeding, dressing, and writing can be used to test for the effects of tremor during movement. With severe tremor, the patient will be unable to complete the functional task. Stress can increase tremor. The use of simultaneous cognitive tasks such as serial seven subtractions (i.e., counting backward from 100 by 7) can be used to test the impact of dual-task performance.¹¹⁰

Postural Control and Balance

A thorough examination of postural control and balance is indicated. The therapist should first observe the patient's resting posture in sitting and standing. The patient's perception of vertical may be impaired, as some patients with advanced disease will perceive themselves as fully upright when they are actually leaning forward.

Clinical measures of balance performance have been shown to be reliable and sensitive in the examination of functional performance and balance in patients with Parkinson's disease.^{111,112,113,114,115,116,117,118,119,120} These include the Berg Balance Scale (BBS),¹²¹ the Functional Reach Test (FRT),¹²² the Timed Up and Go test (TUG),¹²³ the Cognitive Timed Up and Go (CTUG),¹²⁴ and the Dynamic Gait Index (DGI).¹²⁵ These tests are discussed in Chapter 6, Examination of Coordination and Balance. The BBS correlates well with the UPDRS and has been found to be a good overall measure of function in this population.^111,112 Dibble and Lange¹¹³ demonstrated that each of these tests has the ability to discriminate among people with PD who had a history of falls from those without a history of falls and suggested cutoff scores to maximize sensitivity and minimize false negatives. False negatives can also be reduced when interpretation is based on the collective interpretation of multiple balance tests. A clinical decision making algorithm that involves the serial use of clinical balance tests has been proposed.¹¹⁴ Leddy et al¹¹⁵ examined the BBS, the Functional Gait Assessment (FGA),¹²⁶ and the Balance Evaluation Systems Test (BESTest)¹²⁷ and found that all three demonstrated high reliability scores and that the BESTest was most sensitive for identifying fallers. Steffen and Seney¹¹⁸ also found high reliability scores for the BBS, the 6-Minute Walk Test (6-MWT), and gait speed. Minimal detectable change (MDC) values were identified with MDC for the BBS = 5/56, the 6-MWT = 82 m, comfortable gait speed = 0.18 m/sec, and fast gait speed = 0.24 m/sec. In contrast, the Tinetti Gait Assessment (TGA) was not sensitive for detecting change in gait impairments in people with moderately disabling PD.¹²⁸ Strong stability of measurements on balance tests occurs during the "on" phase of the medication cycle while stability of measurements is not maintained during the "off" period.¹²⁹

Reduced postural control is evident during quiet standing (static control), with increased oscillations in both medial-lateral and anterior-posterior planes.¹³⁰ During dynamic posturographic tests, postural restabilization strategies are often inadequate to maintain balance. Available postural strategies and reactions should be carefully documented (e.g., use of ankle, hip, and stepping strategies). Healthy individuals typically respond initially using an ankle strategy with small shifts in their COM, followed by hip and stepping strategies with larger shifts in the COM. Persons with PD and the elderly population in general typically respond to destabilizing forces with postural strategies involving more the hip joints than ankle joints. Start hesitation, abnormal coactivation patterns (rigid body) with an inability to recover a stable posture, is common. An absence of postural strategies (i.e., patient would fall if not for overhead body support harness) is also seen in advanced disease. During complex postural situations involving sensory conflict (e.g., the Sensory Organization Test), persons with advanced PD typically demonstrate reduced postural performance, suggesting inadequate sensory organization.¹³¹ Balance control can also be expected to degrade under conditions of reduced cognitive monitoring. Patients with PD especially in the early stages of the disease may not demonstrate balance impairments in response to steady standing with normal BOS or self-initiated movements as along as their attention is fully directed to the task at hand. However, if competing attentional demands are instituted (i.e., dual-task interference such as talking while balancing), instability can be seen.¹³² Balance confidence is also related to functional mobility and falls in people with PD.¹³³

Gait

Parameters and characteristics of gait that should be examined during unobstructed walking on level surfaces include start time or gait initiation, speed of walking, stride length, cadence, stability, variability, and safety. The 10-Meter Walk Test can be used to determine speed, average stride, and cadence or more sophisticated kinetic analysis can be obtained from embedded force plates, body markers, and computerized equipment (motion analysis systems typically seen in the laboratory setting). Persons with PD frequently demonstrate decreased step length and trunk rotation, difficulty initiating gait, and difficulty attaining increased walking speed. When instructed to walk as fast as possible, the movements produced are smaller and more variable when compared to healthy elders.^134,135

Gait should be examined for kinematic or qualitative changes, including reductions in hip, knee, and ankle motions that result in a short-stepped, shuffling (festinating) gait pattern with reduced trunk rotation and arm swing. Postural abnormalities that contribute to the development of a festinating gait pattern should be documented (i.e., flexed, stooped posture). Gait should be examined in all movement directions: forward, backward, and side-ward. A complex gait pattern such as cross-stepping or braiding can be used to examine deficits in motor planning. Patients with advanced PD typically experience difficulty with adaptability and cannot easily vary walking or walk in complex confined areas such as narrow doorways or open environments. Walking should be examined in varied environments (e.g., community environment) or negotiating an obstacle course. Increased difficulty in walking is also experienced in response to varying attentional demands and dual-task interference. Changes in gait speed, stride length, and cadence can be observed while simultaneously performing a secondary cognitive task (e.g., Walkie-Talkie Test) or walking while simultaneously performing a secondary motor task (e.g., carrying objects on a tray). The degree of change was not significantly different with regard to type of dual task interference.¹³² Clinical measures of locomotor performance shown to be reliable and sensitive for people with PD include the DGI, the FGA, and the TUG (all previously discussed). Huang et al¹³⁶ identified the minimal detectable change values for both the TUG and the DGI.

Freezing of Gait

Freezing of gait, an episodic inability to generate effective stepping in the absence of any known cause, has a dramatic effect on quality of life and risk of falls for patients with PD.^137,138 Assessment is often difficult due to the unpredictable nature of the episodes. The therapist needs to document triggers or provoking factors. Common triggers for FOG include initiating gait, walking through narrow passages (e.g., doorway) or turning in tight spaces, a change in the environment or attentional demands, and walking under time pressure, anxiety, or stress. In the early stages of the disease, episodes are levodopa sensitive and more common in the "off" time. In advanced stages, FOG can occur during the "on" time.¹³⁹ The New Freezing of Gait Questionnaire (NFOG-Q) is a reliable three-part questionnaire and short video to detect and rate FOG severity and impact.¹⁴⁰

Fall Risk

A determination of fall history and fall injuries is an important component of the examination of balance and gait function. There is a strong association between duration and severity of PD with increased risk of falls. Of particular significance is balance and walking impairments including FOG, anterior displacement of COM, decreased postural righting reactions, and the presence of dyskinesias. Other linked factors include postural hypotension, dementia, depression, and prior history of falls.^{112,113,114,115} A fall risk diary can be used to assist the patient and family/caregivers in accurately recording a fall event and the context of daily life in which the fall occurred. For example, activity at the time of the fall, relation to timing of medication and food intake, type of footwear, degree of fatigue and injury, and other risk factors all should be documented. The need for assisted gait and frequency of contact guarding from family members or caregivers during walking should also be documented.

Fatigue

Fatigue is a common impairment associated with PD. As the disease process progresses so does the prevalence of fatigue and its impact on quality of life.^141,142 The Movement Disorders Society (www.movementdisorders.org) created a task force to evaluate and make recommendations on available fatigue rating scales.¹⁴³ Following the systematic review, the task force recommended the Multidimensional Fatigue Inventory (MFI) and the Fatigue Severity Scale (FSS) for assessment of fatigue in patients with PD. The MFI is a 20-item self-report scale that measures general fatigue, physical fatigue, mental fatigue, reduced motivation, and reduced activity.¹⁴⁴ The FSS is a self-administered 9-item rating scale that emphasizes the functional impact of fatigue.¹⁴⁵

Dyskinesias

Drug-induced dyskinesias have a profound effect on physical and social functioning. Risk factors include high total dosage of dopaminergic drugs, young age at onset of PD, and extended duration of the disease process.^146,147 The Rush Dyskinesia Scale assesses functional disability by grading the subject walking, drinking from a cup, and putting on and buttoning a coat. The scale is recommended by the Movement Disorders Society (MDS) Task Force on scales to assess dyskinesia in PD and has been used extensively in clinical trials and patient care, and has undergone extensive clinimetric testing.¹⁴⁸

The therapist can explore the impact of motor fluctuations using questions that address changes in performance during the day. Sample questions might include the following:

• Do you experience increasing difficulties with your functional activities during certain times of the day?

• What time of day do you experience the greatest difficulty?

• How long after you take your medications do you start to move better?

• Do you experience increasing difficulties as your medications wear off?

Swallowing and Speech

An examination of swallowing function, feeding, and speech is important. Referral to a speech-language pathologist may be indicated if the patient demonstrates significant limitations in any of these areas.

Autonomic Function

The therapist should examine for problems with autonomic dysfunction. Excessive drooling (salivation) or sweating, greasy skin, and abnormalities in thermoregulation should be noted. Excessive sweating and flushing during the "on" state is linked to the presence of dyskinesias.

Cardiorespiratory Function

Endurance may be reduced as a result of impaired cardiorespiratory function and long-standing inactivity, both common problems in PD. An examination of respiratory function should include inspection of rib cage compliance, chest wall mobility, and thoracic expansion. Visual inspection of breathing patterns and an examination of the influence of posture and activity on breathing should be performed. Objective measurements include respiratory rate (RR) and circumferential measurements of the chest. Specific ventilation parameters may be determined in patients with significant respiratory compromise. These can include FVC, FEV₁, maximal expiratory flow (MEF), maximal inspiratory flow (MIF), total lung capacity (TLC), residual volume (RV), and RAW.

Individuals with mild PD (Hoehn-Yahr Classification Stages I and II) can demonstrate aerobic exercise capacities similar to healthy adults. Individuals with more advanced disease (Hoehn-Yahr Classification Stages III and IV) demonstrate greater variability and lower aerobic capacities compared to healthy adults. It is important to remember that many older adults are at high risk for latent cardiovascular disease. Exercise testing can be used to determine the patient's level of fitness before commencing an exercise program. Patients who have balance deficits or freezing episodes should not be tested on a treadmill without the use of a safety harness. Cycle ergometry (arm or leg) may be an acceptable alternative. A 6- or 12-Minute Walk Test can be used to determine endurance capacity and walking velocity. The therapist should document vital signs (HR, RR, BP), exertional symptoms (dyspnea, dizziness or confusion, excessive fatigue, pallor, and so forth), time, distance, and number of rest stops.⁵⁴ For patients with advanced PD (Hoehn-Yahr Classification Stages III and IV), Light et al¹⁴⁹ used a 2-Minute Walk Test to evaluate walking endurance and found it to be a sensitive and feasible test. Perceived exertion can be documented using Borg's Rating of Perceived Exertion Scale (RPE Scale).¹⁵⁰

Orthostatic Hypotension

Orthostatic hypotension (OH) with positional change should be examined. Subjective signs and symptoms of OH on sitting up and standing up are documented (e.g., dizziness, light-headedness, pallor, diaphoresis, or syncope). A drop in systolic blood pressure (SBP) of 20 mm Hg, or a drop of 10 mm Hg in diastolic blood pressure (DBP), and a 10% to 20% increase in pulse rate is diagnostic of the condition. The examination begins with the patient resting in supine for 2 to 3 minutes. Resting BP and HR are taken. The patient is then asked to move from supine-to-sitting. After at least 1 minute, BP and HR are taken. If the patient is stable after at least 3 minutes (no symptoms), testing can be performed in the standing position. The patient is asked to move from sitting-to-standing with BP and HR again taken after at least 1 minute and repeated between 3 and 5 minutes. BP that continues to drop after at least 1 minute of standing is problematic and is evident in advanced PD.¹⁵¹

Integumentary Integrity

Sympathetic skin responses may be abnormal. For example, the skin may become oily (e.g., on face). Seborrhea or seborrheic dermatitis occurs frequently in patients with PD. The therapist should examine the patient closely for areas of bruising and skin breakdown. Patients who are severely disabled (Hoehn-Yahr Classification Stage V) are restricted to bed, wheelchair, or both. Incontinence may occur during late-stage disease. The effect of these problems on skin integrity should be carefully documented. Use and effectiveness of pressure-relieving strategies and devices should also be documented.

Functional Status

An examination of functional status is indicated, including performance of functional mobility skills, basic activities of daily living (BADL), and instrumental activities of daily living (IADL). For patients undergoing inpatient rehabilitation, the Functional Independence Measure (FIM) is commonly administered¹⁵² (see Chapter 8, Examination of Function). Need for and appropriate use of protective and supportive devices is an important component of the functional status examination. Close collaboration with the occupational therapist is essential.

During functional performance tests, each skill should be analyzed to determine the impact of direct and indirect impairments on performance. For example, sit-to-stand transfers typically present a significant challenge for patients with moderate to severe PD as evidenced by increased time and increased falls. These changes have been attributed to hypokinesia, decreased rates of force production, and changes in distal muscle timing.^153,154 The Five Times Sit-to-Stand Test (FTSTS) is a timed test that has been used to determine performance in patients with PD at different disease stages and to discriminate between fallers and nonfallers with PD. In one study the average time for FTSTS performance for community-dwelling individuals with PD was 20 seconds with a cutoff time of 16 seconds discriminating between fallers and nonfallers.¹⁵⁵ Timed performance can also be used for other functional tasks such as rolling over in bed or moving from supine-to-sitting that are likely to prove difficult. These activities have a large rotational component of the trunk, typically lacking in many patients with PD.

Functional testing should be balanced with adequate rest to ensure that fatigue does not degrade performance with resultant fluctuations. Repeat testing should be undertaken at the same time of day and importantly at the same time in the medication cycle. Filming task activities can provide an objective record of functional performance. This is particularly useful to document motor fluctuations and dyskinesias. An examination of functional performance in the home (or work) environment is also indicated. The patient's physical environment is examined for barriers, access, and safety.

Profile of Function and Impairment Level Experience with Parkinson's Disease

The Profile of Function and Impairment Level Experience with Parkinson's Disease (Profile PD) was developed to assist the physical therapist's examination and evaluation of individuals with PD in the early and middle stages of disease. It uses a 0 to 4 scale with 0 = no problem and 4 = severe or marked difficulty with descriptive anchors for each score. Approximately 50% of the test relates to deficits in body systems and cognitive/emotional factors. These include questions on tremor (with activity and at rest), rigidity, posture, postural stability, dyskinesia, dystonia, clinical fluctuations, falling, FOG, bradykinesia, speech, depression, memory, and involvement (routine daily/leisure/social activities). The remaining 50% of items focus on functional activities that are typically difficult for individuals with PD (e.g., dressing, hygiene, mealtime activities, transfers, bed mobility, chair rise, gait, fine and gross motor performance). Initial testing revealed it to be a reliable and valid scale with an inter-rater reliability of 0.97 and construct validity with the UPDRS of 0.86. It has an estimated administration time of 15 minutes.¹⁵⁶

Global Health Measures

Global health measures can be used to determine individual outcomes across a broad spectrum of populations. Instruments typically include items that examine ability to perform routine daily activities and quality of life (e.g., physical and social function, general health and vitality, emotional well-being, bodily pain, and so forth). General health measures have been used to study large populations and are most useful in determining long-term health outcomes. They lack the sensitivity needed to document short-term outcomes of treatment. Commonly used measures of general health status include the Rand 36-Item Health Survey SF-36¹⁵⁷ and the Sickness Impact Profile.¹⁵⁸

Disease-Specific Measures

Disease-specific measures are designed to determine attributes unique to a specific disease entity. Items are included that provide information about the disease process and outcomes, and ideally document clinically meaningful change over time. Thus, these instruments have greater responsiveness or sensitivity to change than general health measures. The Parkinson's Disease Questionnaire (PDQ-39) is a 39-item questionnaire developed from in-depth interviews with patients with PD.¹⁵⁹ It focuses on the subjective report of the impact of PD on daily life and addresses eight health-related quality-of-life dimensions (mobility, ADL, emotional well-being, stigma, social support, cognition, communication, and bodily discomfort). The PDQ-39 produces a profile of scores on the eight individual dimensions. A summary score using the Parkinson's Disease Summary Index (PDSI) can also be determined, with scores that range from 0 (perfect health) to 100 (worst health). It provides a useful indication of the global impact of PD on health status. Internal and test–retest reliability were found to be moderate to high with reported ranges from 0.68 to 0.96. Construct validity was examined by comparing the PDSI with other measures of health. Significant and high correlations were found between the PDQ-39 and the SF-36 and the Hoehn and Yahr staging score.¹⁶⁰

A determination of goals and outcomes is based on careful examination and evaluation of the patient's individual abilities, impairments, activity limitations, and disability. Box 18.4 provides examples of general goals and outcomes for patients with progressive disorders of the CNS and is adapted from the Guide to Physical Therapist Practice.⁹⁷

A combined approach of physical therapy and pharmacological intervention plays a key role in the management of the patient with PD. Despite best efforts, progressive disability develops and affects the patient's quality of life. A variety of interventions to maximize functional ability and minimize secondary complications are used to achieve goals and outcomes, including direct interventions, supervision of assistive personnel, patient/family/caregiver instruction, environmental modification, and supportive counseling. Early intervention is critical in preventing the devastating musculoskeletal impairments these patients are so prone to develop. Interventions also focus on improvement of motor function, exercise capacity, functional performance, and activity participation. Education and support of patients, family members, and caregivers at each stage of the disease is critical to attaining optimal outcomes. The research team for the Cochrane Database of Systematic Reviews found that there was insufficient evidence to support or refute the efficacy of any given form of physical therapy over another in PD. The researchers stressed the need for improved research in this area, including large well-designed placebo-controlled randomized controlled trials (RCTs) to demonstrate the efficacy and effectiveness of "best practice" physical therapy in PD.^161,162

Motor Learning Strategies

Patients with PD typically demonstrate motor learning deficits, including slower learning rates reduced efficiency, and increased context-specificity of learning. Learning complex movement sequences and movements dependent on internally generated cues are more difficult than those dependent on external cues. In the early and middle stages of the disease, patients can improve their performance through practice and by using additional sensory information. The amount and persistence of learning are variable and can be expected to be lower than in healthy age-matched people. In more advanced stages and in the presence of pronounced cognitive deficits, training will likely be less successful.^163,164,165 The therapist needs to structure treatment sessions to optimize motor learning.

Critical elements of practice include a large number of repetitions to develop procedural skills. The therapist should instruct the patient to deliberately focus his or her full attention on the desired movement. The environment should also be modified to reduce clutter and competing attentional demands that may trigger freezing episodes. The task should be modified to minimize competing cognitive demands (e.g., dual tasking). Long and complex movement sequences should be avoided or broken down into component parts. Initially, random practice order (i.e., practice in which the patient switches back and forth between tasks) should be avoided in favor of a blocked practice order, thereby reducing the effects of contextual interference. Use of structured instructional sets has been shown to improve movement speed and consistency.¹⁶⁶ For example, walking patterns can be improved with focused instructions of "swing your arms," "walk fast," or "take large steps." For the patient with advanced disease and cognitive deficits, repetitive drill-like practice should be used together with an increased focus on caregiver training to ensure safety.

External cues have been shown to be effective in triggering sequential movements and improving movement characteristics in individuals with mild to moderate PD.¹⁶⁷ Box 18.5 Evidence Summary presents a review of selected research in this area. Visual cues include stationary floor markings (e.g., brightly colored lines on the floor placed perpendicular to the gait path and spaced about one step length apart) and dynamic transportable cues (e.g., laser light signals). A laser light that projects a line onto the floor in front of the patient can be mounted on an assistive device (cane or walker) or on a subject's chest harness. ¹⁶⁸ Visual cues have been shown to improve stride length and velocity while cadence was relatively unchanged. Freezing episodes are also reduced.¹⁶⁹ Rhythmic auditory stimulation (RAS) includes use of a metronome beat or a steady beat from a musical listening device. RAS has been shown to improve gait speed, cadence, and stride length.^170,171,172 The beat is typically set 25% faster than the patient's preferred pace. Auditory cues such as "Big step" have also been shown to improve gait. Examples include "1, 2, 3 stand, ready set go, big first step." Cues should be consistent, not rushed and have a rhythmical quality to them. Auditory cues appear to have a greater influence on the temporal components of movement (e.g., gait cadence, stride synchronization) rather than on spatial components. Multisensory cueing (use of both visual and auditory cueing) has been used for patients with PD. When sensory enhanced therapy using multisensory cueing was compared with conventional therapy, significant improvements were found in the sensory training group.^{173,174,175,176,177,178,179,180,181,182}

External cues appear to facilitate movement by utilizing different brain areas. For example, the premotor cortex is active in the generation of movement in response to visual or auditory stimuli. Normally the supplementary motor area (SMA) with inputs from the BG is involved in the initiation of self-generated movements and the performance of well-learned, repetitive movement sequences. External cues heighten patient attention through a common mode of action, that is, to bypass the diminished internal cueing of the BG. Thus, focus is shifted to less automatic movement using alternative, more conscious motor control pathways. This is supported by the finding that when patients were requested to carry out a secondary task while walking (dual-tasking), the beneficial effects of visual and attentional cues was reduced.¹⁸³

Selection of the type of cue and successful use will depend on the individual patient with predicted long-term benefit of a particular type of cue linked to its initial success. External cues are clearly not effective for all patients with PD. For patients with advanced disease and severe reductions in stride length, cueing is not effective. When cueing is withheld, performance can be expected to deteriorate. Focused attention with cueing requires constant vigilance and is cognitively demanding. Thus, cueing is not suitable for patients with dementia.

Cueing may also not be effective when medication instability and disease fluctuations are present. However, for many patients, use of external cues is a valid treatment strategy and one in which improved performance can be anticipated.

Exercise Training

Amplitude-based behavioral intervention is a concept that can be applied in different contexts in the treatment of PD.¹⁸⁴ The "Training Big" program, also known as the Lee Silverman Voice Treatment (LSVT) Big program, is based on the concept that repetitive high-amplitude movements yield greater improvements in motor performance and possibly have a neuroprotective effect.¹⁸⁵ Patients are guided by a physical therapist to exercise at a high intensity (8/10 Borg's RPE Scale) for 1 hour 4 times a week for 4 weeks with large amplitude, multiple repetitions, and whole body movements that increase in complexity (Fig. 18.6). Examples of the exercises and patient directions include the following:

• "Reach left arm across the body to opposite side, keep hand open, palm up, right leg fully extended, toe pushing into the floor. Repeat on other leg and alternate."

• "Step out and land 'Big,' pushing the left foot into the floor while reaching with bilateral 'Big arms,' open hands, palms up (Fig. 18.7). Return the foot back to the start, end 'Big.' Repeat on other leg and alternate."¹⁸⁶

These vigorous large movements of the trunk and extremities are counter to the paucity of movement normally associated with PD. After a 4-week program of LSVT "Big" training the subjects had significant improvements in UPDRS motor scores, TUG, and timed 10-m walking.¹⁸⁷

Relaxation Exercises

Gentle rocking can be used to produce generalized relaxation of excessive muscle tension owing to rigidity. Professor Charcot, who noted dramatic improvement in patients with PD following rides in bumpy, horse-drawn carriages, first described this effect almost 100 years ago in Paris. Following this observation he constructed a vibrating chair to use with his patients.¹⁸⁸ Although the exact mechanism underlying rigidity has not been identified, the beneficial effects of slow rocking on excess tone have been demonstrated.¹⁸⁹ Following Charcot's lead, a rocking chair can be used to temporarily relax the patient and enhance sit-to-stand transfers. During therapy, slow, rhythmic, rotational movements of the extremities and trunk can precede interventions such as ROM and stretching, and functional training. For example, hook-lying, lower trunk rotation, or side-lying rolling can be used to promote relaxation. The proprioceptive neuromuscular facilitation (PNF) technique of rhythmic initiation (RI), in which movement progresses from passive to active-assistive to lightly resisted or active movement, was specifically designed to help overcome the effects of rigidity in PD.^190,191

Another strategy to promote relaxation is emphasis on diaphragmatic breathing during exercise. For example, bilateral symmetrical PNF D2 flexion patterns are important patterns that can be used to expand the restricted chest and promote shoulder ROM (Fig. 18.8). The patient's attention can be focused on deep inspiration during D2F ("breathe in deeply") while during D2E patterns attention is focused on expiration ("breathe out deeply").¹⁹¹ Patients may also benefit from cognitive imaging or meditation techniques (e.g., the relaxation response of Benson¹⁹²). Relaxation audiotapes can be used at home as part of the home exercise program (HEP). Stress management techniques are an important adjunct to relaxation training. A daily schedule needs to be planned to accommodate the restrictions of the disease and the functional needs of the patient. Lifestyle modifications and time management strategies reduce anxiety associated with movement difficulties and prolonged times required to complete basic functional tasks.

Flexibility Exercise

The purpose of flexibility exercise (stretching) is to improve ROM and physical function. A combination of static (PROM), dynamic (AROM), and facilitated PNF exercises is used to achieve maximum ROM. Flexibility exercises should be performed a minimum 2 to 3 days per week and ideally 5 to 7 days per week. A minimum of 4 repetitions per stretch held for 15 to 60 seconds is recommended.⁵⁴ Special consideration should be given to stretching common areas of limitation (Table 18.4). Stretching can be combined with joint mobilization techniques to reduce tightness of the joint capsule or of ligaments around a joint (Fig. 18.9). By using selected grades of accessory movement, both improved ROM and decreased pain can be achieved. The stretching will be more effective if the muscles have been warmed with active exercise or with an external heating modality. Stretching exercises are an important component of the HEP. The patient and caregiver should be instructed in the appropriate stretching exercises.

A yoga sequence can be used effectively to focus attention on developmental postures, core stability, and stretching of structures that are traditionally restricted with PD, as well as to promote relaxation (Appendix 18.B).

Patients with PD have a minimum of energy to expend and multiple clinical problems. They may benefit from ROM exercises in physiological patterns of motion. For example, PNF patterns combine several motions at once while emphasizing rotation, a movement component typically lost early in PD. In the UEs, bilateral symmetrical D2 flexion patterns are ideal in promoting upper trunk extension and in counteracting kyphosis. Unilateral bridging with trunk rotation, bilateral bridging, and high-kneeling with anterior pelvis translation can all be used to stretch tight hip flexors and strengthen spinal and hip extensors. In the LEs, hip and knee extension should be emphasized, ideally in a D1 extension pattern (hip extension, abduction, internal rotation) to counteract the typical flexed, adducted position of the LEs. Muscle contractures typically respond well to PNF facilitated stretching techniques such as the hold–relax (HR) or contract–relax (CR) techniques.^191,192 Of the two, CR is the preferred technique because it combines autogenic inhibition from isometric contraction of the tight agonist muscle and active rotations of the limb. A 6-second contraction followed by a 10- to 30-second assisted stretch is recommended for these PNF techniques.⁵⁴

Patients with PD benefit from additional attention and cueing strategies during active stretching exercises. Patients are instructed to "Think BIG, and move through the whole range" and maintain full focus and attention during each repetition. Additional tactile or visual cueing can assist in maximizing range during active motions. For example, during active trunk rotation and reaching movements in sitting, the patient can be cued to touch an object or target. Ballistic stretches (high-intensity bouncing stretches) should be avoided because they are linked to increased injury. Muscle tears or ruptures of weakened tissues are especially prevalent in elderly, sedentary individuals. Vigorous stretching can stimulate pain receptors and cause rebound muscle contraction. Patients with PD who are elderly and have long-standing disease must be considered at risk for osteoporosis and therefore must be stretched accordingly. The therapist should also use caution when stretching edematous tissue, a common LE problem associated with prolonged immobility, because risk of injury is also increased in this situation.

Positioning can also be used to stretch tight muscles and soft tissues. Patients in late-stage PD are likely to demonstrate severe flexion contractures of the trunk and limbs. Early on, the patient may benefit from daily positioning in prone-lying. As the disease progresses and significant postural deformity and cardiorespiratory impairments develop, the patient may not tolerate this position. The patient with a developing lateral curvature can be positioned in side-lying with a small pillow under the lateral trunk. Positional stretching is prolonged, with times typically ranging from 20 to 30 minutes. Additional mechanical stretching can be achieved through the use of a tilt table, for example, the patient is positioned with fixed leg straps to reduce hip and knee flexion contractures and toe wedges to reduce plantarflexion contractures.

Resistance Training

Resistance training is indicated for patients with PD who demonstrate primary muscle weakness with impaired motor unit recruitment and rate of force development and disuse weakness associated with prolonged inactivity. Specific areas of weakness are targeted, such as the antigravity extensor muscles. Weakness of these muscles is associated with poor posture (e.g., a flexed, stooped posture) and functional deficits (e.g., inability to get out of a chair, limitations in gait function).^193,194,195 Weakness also contributes to postural instability, falls, and fall injury, as well as increased sense of effort.¹⁹⁶ The benefits of strength training in the frail elderly have been well documented by the Frailty and Injuries: Cooperative Studies of Intervention Techniques (FICSIT) trials.¹⁹⁷ Collectively these studies have shown that the frail elderly improve on measures of strength, functional mobility, balance, gait, fall risk, and quality of life following interventions that include strength training.^198,199 Strength training has also been shown to improve muscle force, bradykinesia, and quality of life in patients with PD.²⁰⁰ Hirsch et al²⁰¹ compared two different exercise training programs for patients with PD. They found significantly greater improvements in balance and strength using a combined program of balance training and high-intensity resistance training for knee extensors and flexors and ankle plantarflexors as compared to balance training alone.

Resistance training is based on the progressive overload principle. The amount of resistance is increased during training. Load can be applied using resistance machines, free weights, elastic resistance bands, or manually. With older adults the recommendation is to begin at a lower intensity (e.g., using an RPE Scale of somewhat hard, 5 to 6 on a 10-point scale), ensuring that a set of 10 to 12 repetitions per set can be completed.²⁰² Progression is as tolerated. Each repetition should be held for 10 seconds. Strength training can be performed 2 days per week on nonconsecutive days. Exercise machines may be safer than free weights for patients with more advanced disease because the movements are more controlled, especially for the patient who demonstrates dyskinesias at peak dose or cognitive changes.⁵⁴ Because patients with PD already demonstrate too much stiffness and coactivation, isometric training is generally contraindicated. Functional training activities (see next section) can also be effective interventions to improve strength.

Corcos et al²⁴ found a significant interaction between medication and strength. Withdrawal of L-dopa during an "off" state period caused a decrease in strength and rate of force development. Exercise training should therefore optimally be timed for "on" periods when the patient is at his or her best (i.e., 45 minutes to 1 hour after medication has been taken). Exercising during an "off" period may not be possible or pose great difficulty for the patient. The patient should consistently exercise at the same time during a medication cycle.

Functional Training

An exercise program should be based on focused practice of functional skills. The overall emphasis is on improving functional mobility with specific emphasis on improving mobility of axial structures, the head, trunk, hips, and shoulders. Progression to more difficult motor activities should be gradual. The more severely involved patient may benefit initially from assisted movements progressing to active movements (e.g., the PNF technique of RI) to improve initial motor performance.²⁰³

Bed mobility skills (i.e., rolling, bridging, supine-to-sit transitions) are essential skills that are often very difficult owing to truncal rigidity and bradykinesia. Side-lying rolling activities that emphasize segmental rotation patterns (i.e., isolated upper and lower trunk rotations) should be practiced rather than a log-rolling pattern. Patients with very stiff trunks may benefit from compensatory rolling strategies using the UE or LE to reach over and initiate the movement (e.g., D1F patterns of the UE or LE). Rolling should be practiced on different surfaces progressing from firm to soft and finally simulating the patient's bed surface at home. Bridging is an important activity that improves scooting in bed as well as sit-to-stand transfers (Fig. 18.10).

Sitting can be enhanced through exercises designed to improve pelvic mobility as the patient with PD typically sits with a stiff and posteriorly tilted pelvis (i.e., sacral sitting position) along with a flexed upper trunk. Anterior and posterior tilts, side-to-side tilts, and pelvic clock exercises can be practiced while sitting on a therapy ball, which enhances ease of movement (Fig. 18.11). These activities can then be progressed to sitting on a stationary surface such as a mat table using an inflatable disc to finally no apparatus. Sitting activities should include weight shifting emphasizing upper trunk rotations and reaching. PNF extremity patterns in sitting can be used to enhance trunk mobility. For example, bilateral symmetrical UE D2F and D2E patterns are ideal to promote upper trunk extension. Or a lift/reverse lift pattern can be used to promote upper trunk extension with rotation.

Sit-to-stand (STS) is a difficult activity for many patients with PD, especially with moderate or advanced disease or when in the "off" state. Issues in poor dynamic stability and inadequate limb support contribute to falls. Patients demonstrate poor timing in controlling their COM forward velocity, which tends to be slower. Insufficient upward momentum (LE extension torques) in standing up is also problematic.¹⁹⁴ Other factors include level of agonist-antagonist coactivation and rigidity. STS training begins with the patient scooting to the edge of the mat and placing both feet under the knees and apart. Forward trunk flexion can be enhanced through initial rocking, which encourages relaxation. Cueing strategies (e.g., counting, placing one hand between the patient's shoulder blades) can be used to assist the forward lean. Sitting on an inflated disc can also assist in the forward weight shift and seat-off. Standing-up is enhanced by improved LE muscle strength. Strengthening of the hip and knee extensors can be achieved using modified wall squats. Practice standing up from a firm raised seat decreases the total excursion and work of extensor muscles and promotes ease of rise. Once control is achieved, progression is then to lower, standard height seats. Standing directly in front of the patient should be avoided, because this may block initial standing attempts. Instead, the therapist or caregiver should stand to the patient's side. If safety issues are apparent, a safety gait belt should be used. The more involved patient can practice STS from a chair with both hands on armrests.¹⁹³

Standing activities can model the progression used in sitting. The patient needs to first gain the fully upright position with symmetrical weight-bearing over the BOS. Tactile cueing or light resistance can be used on the anterior pelvis to encourage movement of the hips forward into full extension. Once standing, weight shifts and rotational movements of the trunk should be practiced (e.g., reciprocal arm swings or reaching movements). Step-ups using a low platform step (forward, lateral) should be practiced. Backward stepping can be used to strengthen hip and spinal extensors and promote upright posturing. To increase the challenge during stepping, elastic resistive bands can be used (Fig. 18.12). The patient can also practice standing with UEs extended and hands weight-bearing on a wall to promote upper trunk extension.

Patients with PD typically experience a high number of falls and should be taught how to get up after a fall. To that end, skills in quadruped creeping should be practiced so the patient is able to move to a nearby stable chair or couch at home. The patient should also practice transitions moving from quadruped to kneeling to half-kneeling and finally to standing using UE support.

Mobilizing facial muscles is another important component of the exercise program because the patient will have limited social interaction and poor feeding skills in the presence of marked facial rigidity and bradykinesia. These factors can greatly influence the patient's overall psychological state, motivation, and social participation. Massage, stretch, manual contacts, and verbal cueing can be used to enhance facial movements. The patient can be instructed to practice lip pursing, movements of the tongue, swallowing, and facial movements such as smiling, frowning, and so forth. A mirror can be used to provide visual feedback. In cases where eating is impaired by immobility, the movements of opening and closing the mouth and chewing should be combined with neck stabilization in a neutral position. Verbal skills should be practiced in association with breath control.

Balance Training

It is important to recall that learning is task and context specific. Thus, a balance training program should include a variety of activities that alter task demands and expose the patient to varying environmental conditions. Whenever possible the therapist should try to duplicate the conditions the patient will encounter in everyday life. The level of challenge is important. A therapist should know the limitations of the patient and the specific demands of the task and environment in order to select and progress tasks accordingly and ensure patient safety. See Chapter 10, Strategies to Improve Motor Function, for a more complete discussion of balance training.

An important focus of balance training for the patient with PD is COM and LOS control training. Patients should be instructed in how COM influences balance and how to improve posture in sitting, in standing, and during dynamic movement tasks. Patients should also explore their LOS and practice working toward expanding them in both sitting and standing. In standing, patients with PD typically demonstrate restricted LOS with forward displacement of center of foot pressure. Patients should be instructed in how to improve postural alignment and in ways to avoid postural disturbances and falls. The therapist can assist with postural and safety awareness by using appropriate verbal, tactile, or proprioceptive cues to facilitate the desired responses. For example, the patient is instructed to "sit tall" or "stand tall" and a mirror is used to provide feedback concerning upright posture. A standing platform training device (i.e., posturography system) can be valuable in providing COM position and LOS biofeedback. The patient is instructed in weight shifting that expands the LOS. The Nintendo Wii Balance Board is a widely available and economical force platform and biofeedback system. When compared to a laboratory-grade force platform the Nintendo Wii Balance Board was valid in quantifying center of pressure, an important component of standing balance.²⁰⁴ Subjects with poor positional awareness who trained on the Wii Balance Board with real-time visual biofeedback demonstrated significant improvements in weight-bearing symmetry.²⁰⁵ Elderly subjects who trained with this device over a 4-week period improved on average 9.14 points on the BBS.²⁰⁶

Balance training should emphasize practice of dynamic stability tasks (e.g., weight shifts, alternating unilateral weight-bearing, reaching, axial rotation of the head and trunk, axial rotation combined with reaching, and so forth). Seated activities can include sitting on a compliant surface (inflatable disc) or a therapy ball. Challenges to balance can also be introduced in quadruped (Fig. 18.13), kneeling (Fig. 18.14), half-kneeling (Fig. 18.15), and standing on a disc (Figs. 18.16 and 18.17). Altering arm positions (e.g., arms out to side, arms folded across chest, reaching); altering foot/leg positions (e.g., feet apart, feet together); or adding voluntary movements (e.g., overhead arm clapping, head and trunk rotations, single leg raises, stepping or marching in place) can all be used to increase difficulty of the activity. Training should focus on achieving faster initiation and execution movement times supported by the use of appropriate cueing strategies.¹⁶⁶ Externally induced perturbations in the form of gentle manual displacements of the patient's COM are generally contraindicated for many patients with PD because they can produce an increase in postural stiffness and fixation. Strategies for varying environmental demands include altering the support surface (e.g., standing on foam), visual inputs (e.g., reduced lighting, eyes closed), or challenging the patient with a variable open environment (e.g., busy clinic setting).

Adequate strength and ROM are important components needed to withstand the challenges of balance. The patient can be instructed in standing exercises to enhance balance, including heel-rises and toe-offs, partial wall squats and chair rises, single-limb stance with sidekicks or back-kicks, and marching in place. Collectively these exercises are sometimes referred to as the "kitchen sink exercises" and are important components of the HEP for patients with balance deficiencies. The patient may require light touch-down support of the hands to start in order to stabilize; progression should be to no support as soon as possible.

Whole body vibration (WBV) is gaining popularity as a treatment for patients with neurological diseases. It is theorized that the seesaw-like displacement of the platform mimics human gait²⁰⁷ and that postural responses are induced by vibration of the foot soles.^208,209 It is also believed that WBV increases efficiency of agonist/antagonist pairs.^210,211 Systematic literature reviews reveal insufficient high-quality studies and only minor evidence from the current literature that WBV improves strength, proprioception, gait, and balance.^212,213 For people with PD, WBV seated in a physioacoustic chair resulted in improved gait, UPDRS scores, and upper limb control and significant reductions in tremor and rigidity.²¹⁴ Another study examined the effect of treatment standing on a random multidirectional vibrating platform. After WBV, subjects presented with significantly improved scores on the UPDRS with reductions in tremor and rigidity.²¹⁵ Additional quality research examining the efficacy of WBV in the treatment of people with PD is needed.

Locomotor Training

Locomotor training goals focus on reducing primary gait impairments, which typically include slowed speed, decreased stride length, lack of a heel-toe sequence with forward progression characterized by a shuffling (festinating) gait pattern, diminished contralateral trunk movement and arm swing, and an overall attitude of flexion while walking. Goals also focus on increasing the patient's ability to safely perform functional mobility activities and prevent falls.²¹⁶ Effective strategies for improving upright alignment and safety include having the patient walk with vertical poles (pole walking) (Fig. 18.18). Strategies to enhance posture, step length, velocity, and arm swing include the use of verbal instructional sets (e.g., "Walk tall," "Walk fast," "Take large steps," "Swing both arms"). Behrman et al²¹⁷ found that commands for large step and arm swing were more effective instructional strategies than the command to walk fast. As previously discussed, visual and auditory cues are also effective in improving gait speed and step length. Transverse visual–spatial cues (across the gait path) were more beneficial than parallel visual cues (alongside the gait path) in improving gait velocity, stride length, and percentage of leg stance time.²¹⁸ Strategies to improve foot placement can include use of floor markers or footprints on the floor. Strategies to improve step height include practice marching in place progressing to walking using an exaggerated high stepping pattern. Brisk marching music can be used to enhance pace. Sidestepping and crossed-step walking can be practiced (Fig. 18.19). The PNF activity of braiding, which combines side-stepping with alternate crossed-stepping, is an ideal training activity for the patient with early PD because it emphasizes lower trunk rotation with stepping and side-stepping movements. It can be practiced with the patient holding on lightly to a dowel held jointly with therapist or as a free walking pattern. Advanced stepping and balancing can be achieved by having the patient practice juggling scarves (Fig. 18.20). Reciprocal arm swing during gait can be enhanced by having the patient and therapist hold onto a set of two dowels (one in each hand). The therapist walks behind the patient and uses his or her arm swing to assist the patient's.

Patients with PD who practiced locomotor training on a motorized treadmill with an overhead harness demonstrated improvements in postural stability, gait (e.g., walking speed, step and stride length), motor function, and quality of life.^{219,220,221,222,223,224,225,226,227} Both body weight support (e.g., up to 20%)²²⁰ and no body support have been used.²¹⁹ In a long-term study, Miyai et al²²¹ found that gains in walking speed and number of steps following this type of training were maintained at 4 months. The researchers stated that attentional strategies were not used and speculate that the enhancement of gait might be due to activation of central pattern generators as is thought the case in stroke and spinal cord injury (SCI) studies. The treadmill may be acting as an external cue to enhance gait rhythmicity and reduce gait variability.²²⁴ The benefits of treadmill training, as with exercise training in general, are dose dependent. More pronounced improvements are noted with high-intensity practice and incremental increases in treadmill speed.^225,226 High-intensity treadmill training has been shown to normalize corticomotor excitability in early PD.²²⁶ The motorized treadmill has also been used for step training in people with PD. While supported in a safety harness, patients practiced stepping in all four directions in response to suddenly turning the treadmill on and off.²²⁸

Locomotor training should also include task-specific training designed to promote full participation in social roles pertaining to family life, leisure, and community participation. This includes varying the walking task (e.g., walking on a tile floor, on carpet, outdoors on sidewalks and grassy terrain). Additional challenges include walking in the community (e.g., variable open environments), stair climbing, up and down curbs, and ramp walking. Patients with PD often demonstrate difficulties in obstacle stepping due to minimized foot clearance. Foot clearance can be improved with repeated practice of stepping over horizontal floor markers or laser light signals.

Patients in the advanced stage of the disease will be limited in terms of walking and variations that can be utilized. The overall goal at this stage is to promote regular walking while maintaining safety and preventing falls. Compensatory training strategies are indicated. Caregiver instruction regarding assisted walking and safety is imperative. Freezing episodes are common and are often resistant to drug therapy. The therapist and patient should identify and practice strategies for unfreezing gait.²²⁹ For example, cueing or "trick" movements such as dropping a tissue that the patient must step over can be successful in reducing freezing. Some patients, especially those in the postural instability gait disturbed group, can benefit from walking with a therapy dog. The dog provides an assist in balance and momentum, and a source of external cueing of stepping movements (Fig. 18.21).

Spinal Orthotics

Spinal bracing may be an appropriate adjunct to therapy for patients with postural deformities common to PD (e.g., increased thoracic kyphosis, decreased costal expansion, and forward head posture). The Spinomed thoracolumbar orthosis is unique in that it not only corrects faulty posture but also has been shown to increase trunk stability, increase respiratory vital capacity, and improve a patient's self-report of well-being.^230,231 When the brace was worn for 6 months the subjects had a 73% increase in back extensor strength and a 58% increase in abdominal flexor strength. These strength gains are attributed to increased muscular activity in response to the proprioceptive biofeedback of the brace.²³² A study investigating gait stability and physical functioning in women with postmenopausal osteoporosis demonstrated decreased double limb stance time associated with a beneficial impact on gait stability.²³³ Further research is warranted to determine if this type of orthotic intervention holds potential for patients with PD.

Pulmonary Rehabilitation

The four main classifications of respiratory disorders in patients with PD are medication complications, upper airway obstructions, restrictive disorders, and aspiration pneumonia.²³⁴ Since respiratory dysfunction in the neurological movement disorders population is linked to a high rate of disability and mortality, it is critical that the prevention and treatment of these dysfunctions take priority. Components include diaphragmatic breathing exercises, air-shifting techniques, and exercises that recruit neck, shoulder, and trunk muscles. Manual techniques such as vibration and shaking can be used to ensure complete exhalation, distal alveoli opening, and to assist with secretion clearance. The patient should be instructed in deep-breathing exercises to improve chest wall mobility and vital capacity. Air shifts are promoted to lesser-ventilated areas of the lung. For example, basal expansion can be promoted using side-lying recumbent positioning, manual stretch, and resistance to those segments. Upper body resistance training exercises are indicated. These can include raising and lowering a dowel with light weights added to increase resistance (e.g., 1 lb [453.5 g]). Weights are increased as function improves. As previously mentioned, chest wall mobility can be improved by using PNF UE bilateral symmetrical D2 flexion and extension patterns. Light weights (wrist cuffs) can also be added to these exercises. Patients are encouraged to coordinate breathing with UE movement. Exercises are performed in unsupported sitting to promote trunk stabilization. A focus on improving trunk extension is especially important in improving breathing patterns in patients with postural kyphosis. Pulmonary rehabilitation programs have been shown to be safe and effective for patients with PD in improving pulmonary function (i.e., oxygen consumption [VO₂], minute ventilation [VE], respiratory rate, inspiratory muscle strength)^235,236 and perception of dyspnea.²³⁷

Speech Therapy

The quality of speech in patients with PD is often a breathy monotone, soft voice that is perceived by the patient to be of normal loudness. Hypophonia is caused by a bradykinetic bellows mechanism (chest wall and diaphragm) and patients' inaccurate perception of their own speech effort. Speech deficits are seen in 80% of patients with PD and have a dramatic effect on function with 30% reporting it as the most disabling part of the disease.²³⁹ As mentioned earlier, the Lee Silverman Voice Treatment (LSVT) was designed specifically for patients with PD.²³⁹ It focuses on intensive high-effort exercise with a single functionally relevant target (loudness) and a recalibration of self-perception of vocal loudness. This technique effectively increases vocal loudness and improves facial expressions in patients with PD.^240,241,242

Aerobic Exercise

An individualized exercise prescription is developed based on the ACSM guidelines for frequency, intensity, duration, and progression.⁵⁴ Intensities will be less than normal training intensities or submaximal (i.e., 60% to 80% of maximum HR), based on the patient's level of disease, fitness, and lifestyle. When lower intensities are used, longer-duration or more frequent exercise sessions are necessary to improve fitness. Careful monitoring is indicated, because autonomic dysfunction is common. Long-term L-dopa use can produce arrhythmias and OH along with dyskinesias. The therapist should monitor vital signs (HR, RR, BP), RPE, fatigue levels, and symptoms of exertional intolerance (e.g., significant dyspnea, hypotensive response, and so forth).

Training modes can include leg and arm ergometry and walking. Selection will depend on the specific abilities of the patient; for example, postural instability and increased risk of falls may rule out use of a treadmill without an overhead harness. Recumbent or seated LE ergometry is a suitable alternative. For most patients a program of regular walking is recommended. The duration, speed, and terrain covered can be modified, based on individual ability. Accessibility to a supervised walking program using an indoor walking track is important for some to ensure safety. A shopping mall can provide an acceptable environment for community walkers in case of inclement or extremes of weather. A supervised aerobic pool program can also provide an acceptable mode of exercise for some patients. The warmth of the water may be relaxing and the buoyancy may enhance stepping movements. The minimum recommended aerobic exercise frequency is 3 sessions per week. Daily walking with short multiple bouts (20 to 30 minutes) spaced throughout the day is recommended for individuals with lower functional capacity. Intermittent exercise with adequate rest intervals is indicated for those patients who are elderly and deconditioned, and who present with restrictive pulmonary dysfunction. Aerobic training programs have been shown to be safe and effective for patients with PD in improving aerobic capacity.^243,244

Group and Home Exercises

Community-based group exercise classes can be valuable for patients with PD. Patients benefit from the positive support, camaraderie, and communication the group situation offers.^245,246 Careful evaluation of each patient before admission into a group is essential. Patients should be able to perform the therapeutic core of the class. Selecting patients with similar levels of disability is often advisable because the sense of competition can frequently be a key factor in motivating groups. The ratio of staff to patients should be kept small (ideally 1:8 or 1:10), and extra staff should be added if patients are unable to work on their own. A variety of activities can be used to stimulate and motivate patients. The patients can begin in the seated position and progress to standing, using light, touch-down support of the back of the chair. Stretching exercises or calisthenics involving large muscle groups and multijoint compound movements can be used as an initial warm-up activity. Progression is to combination movements (UEs and LEs with axial trunk rotation). Well-structured, low-impact aerobics are an appropriate focus for a group class. For example, patients can march in place, first in sitting, then in standing. The group can then practice walking with an emphasis on taking large, high steps. Music is used to provide necessary stimulation to movement and movement pacing. Exercise stations (e.g., stationary bicycle, mats, pulleys, and so forth) can also be used. Exercises done by the whole group together should focus on important exercise goals (e.g., improving ROM, mobility, and so forth). Recreational activities can follow the aerobic portion, such as line dancing, ball activities, beanbag toss, and so forth. The activities selected should be interesting and varied. A relaxation segment should be incorporated into each class. Yoga and Tai Chi group classes effectively address multiple components of PD by improving posture, flexibility, core stability, functional mobility, balance, relaxation, and socialization.^{247,248,249,250,251} King and Horak²⁵² recommend incorporating Tai Chi with other agility exercises (e.g., kayaking, boxing, lunges, agility training, and Pilates exercises) to delay loss of mobility in people with PD.²⁵²

The home-based exercises include exercises designed to improve relaxation, flexibility, strength, and cardiopulmonary function (all previously discussed). A key element is stressing the importance of regular daily exercise and avoidance of prolonged periods of inactivity. The HEP should be realistic and of moderate duration and intensity. The patient should be cautioned against overdoing activity, which could result in excessive fatigue. Early morning warm-up calisthenics are often helpful in reducing the increased stiffness patients may experience on arising. Stretching and strengthening exercises are performed in supine, sitting, and standing positions. Home ROM exercises can often be assisted by use of adaptive equipment. For example, to reduce the effects of forward head and kyphotic posture, the patient can be instructed to hang by the hands using an overhead bar. Standing, corner wall stretches can also be used to provide a maintained stretch on the upper trunk flexors. Use of a wand or cane can be effective in promoting overhead motions. In standing, a countertop or back of a sturdy chair can be used to assist in stabilization during standing calisthenics and balance activities. Home-based exercise programs have been found to be effective in improving postural control and mobility in people with PD.^253,254

Attention should be directed toward needs for adaptive and supportive devices that can improve function. To promote bed mobility, the patient can be helped to assume a sitting position by elevating the head of an electronic hospital bed or with commercially available blocks approximately 4 in (10 cm) high (furniture legs fit into a recess in the block). A simpler solution might include attaching a knotted rope or canvas "ladder" to the end of the bed to pull on. The bed should be stable and the mattress firm to facilitate mobility. Satin sheets and pajamas have sometimes been helpful to enhance bed mobility. Patients should be instructed to select firm chairs with armrests and avoid soft, low seats such as a low sofa. The chair can be raised (i.e., 4 in [10 cm] and secured with blocks, or tilted forward by elevating only the back legs about 2 in [5 cm]). Some patients benefit from the use of a rocking chair to facilitate independent sit-to-stand transfers. Chairs that have spring-loaded seats that push the patient into standing are heavily marketed to the geriatric population but should be used with caution. The patient is propelled into standing but may have difficulty stopping the movement and/or getting his or her balance within an appropriate time frame when first reaching the standing position. A raised toilet seat and toilet rails are also essential devices to facilitate ease of sit-to-stand transitions in the bathroom.

Loose-fitting clothing and sneakers with hook and loop closures can be used to facilitate dressing. If the patient demonstrates a shuffling gait, shoes should have leather or hard composition soles, because shoes with crepe or rubber soles will not slide easily and can result in falls. A festinating gait can sometimes be alleviated by the addition of modified heel or shoe wedges. A flat heel or toe wedge may slow down a propulsive gait. The use of assistive devices can be problematic owing to movement difficulties. A cane can be helpful for patients with mild to moderate disease to assist in balance or cue stepping (inverted walking stick). It is important that the height of the device not promote increased flexion of the trunk. Vertical poles (previously mentioned) can also be helpful to improve upright posture, trunk rotation, and arm swing during walking. Patients with more pronounced movement difficulties and poor balance are not likely to benefit from assistive devices. Walkers with wheels are particularly hazardous and are likely to increase a festinating gait; hand brakes are an essential requirement.

Most patients use adaptive devices to assist in ADL. Reachers can be used to provide assistance in dressing as well as for other activities. Eating can be facilitated in a number of ways. The patient should be seated properly, close to the table, with good posture. Specially adapted utensils, plate guards, and enlarged handles can aid the patient's efforts. Because eating time will be prolonged, heated plates or pads may help keep food warm and palatable. Drooling and/or spills should be anticipated and clothing protected. Extra time should be planned, and the patient should not feel rushed.

The progressive nature of PD necessitates frequent personal and social adjustments, and affects all aspects of life for both the patient and family. Disruptions in daily functions, roles, and activities are experienced. Some of the changes associated with PD are socially isolating (masked face, progressive immobility, and unintelligible speech) whereas other changes (increased salivation, perspiration, decreased sexual function) are distressing and can be socially embarrassing. The patient may feel increasingly isolated and family relationships may suffer. The principal goal for team members is to assist the patient and family in their understanding of the disease and in developing insights and adjustments that lead to more effective self-management. Some individuals are able to successfully deal with the changes associated with the disease; others are not. Coping skills can be facilitated. First and foremost, education is the key to assisting patients and family members assume responsibility. Feelings of hopelessness and dependency are reduced as the patient develops a sense of control over his or her own life. Self-management skills that should be promoted include advanced planning of activities, effective time management strategies, and stress management techniques. It is equally important to ensure that patients do not become isolated and that appropriate services are available. Team members must be vigilant regarding their assumptions and expectations. A condescending or pessimistic and limiting attitude can become a self-fulfilling prophecy. Patients and family members need reassurances and encouragement. An overall emphasis on what patients can do rather than what they cannot do helps to empower patients. Therapists need to provide a message of hope tempered with realism.

The interdisciplinary team provides information about a variety of topics related to living with PD. These are presented in Box 18.6. Interventions can take the form of direct one-on-one instruction, group sessions, printed materials, and video or computer presentations. The therapist's overall approach needs to be positive and supportive.

Community support groups are available for patients and their families. They disseminate information and offer a chance to discuss common issues, problems, and management tips. They also can provide a stabilizing influence, assisting patients and families to focus on healthy behaviors, coping skills, and effective self-management. For some patients in the early stages of the disease, participation in a support group may increase levels of anxiety as they observe more disabled patients. Groups particularly targeted to patients with early-stage disease and similar ages may be more helpful.

Educational pamphlets, newsletters, and location of support groups can be obtained through national PD associations.

National Parkinson Foundation (NPF)

1501 Northwest 9th Street (Bob Hope Road)

Miami, FL 33136-1407

Website: www.parkinson.org

Phone: 800-327-4545

E-mail: mailbox@parkinson.org

Parkinson's Disease Foundation (PDF)

1359 Broadway, Suite 1509

New York, NY 10018

Website: www.pdf.org

Phone: 800-457-6676

E-mail: info@pdf.org

Web-based resources for clinicians and patients/families living with PD are presented in Appendix 18.C. A listing of sample educational and video materials can be found in Supplemental Readings and Materials.

PD is a chronic, progressive disorder of the BG characterized by the cardinal features of rigidity, bradykinesia, tremor, and postural instability. Additional impairments include the development of abnormal fixed postures, poverty of movement, fatigue, masked face, contractures, a festinating gait pattern, swallowing and communication difficulties, visual and sensorimotor disturbances, cognitive and behavioral dysfunction, autonomic dysfunction, and cardiopulmonary changes. Pharmacological interventions have become the mainstay of treatment and provide protective and symptomatic treatment. Effective rehabilitation focuses on the patient's stage of disease and symptoms, activity limitations, and residual abilities and assets. Interventions are restorative; that is, rehabilitation is focused on the improvement of strength, ROM, functional skills, endurance, and so forth. Individuals with PD also benefit from functional maintenance programs designed to manage the effects of progressive disease. Strategies are developed to prevent or reduce indirect impairments and promote regular exercise, good health, and self-management skills. A comprehensive team approach including active involvement of patient and family provides optimal benefits. Team members need to be active during all stages of the disease, assisting the patient and family in maintenance of function and providing psychosocial support as needed.

Questions for Review

1. What are the major CNS structures involved in Parkinson's disease and what are the pathophysiological changes associated with the disease?

2. Differentiate between cogwheel rigidity and lead pipe rigidity.

3. What impairments in postural stability are typically seen in patients with PD?

4. What are the nonmotor impairments in cognition associated with PD?

5. What are the major adverse effects associated with long-term use of levodopa/carbidopa?

6. How might the goals/outcomes and interventions vary by stage of disease?

7. Orthostatic hypotension is a common problem in patients with PD. How should it be examined?

8. Identify appropriate motor learning strategies for the patient with PD in terms of practice and feedback.

9. Describe the gait impairments common in patients with PD. What interventions can be used to improve locomotor function?

10. What guidelines for aerobic training are appropriate for the patient with early- to middle-stage PD?

The patient is a 60-year-old woman with a 7-year history of PD. Lately she has experienced increasing severity of symptoms and is referred for outpatient physical therapy and a home exercise program (HEP).

HISTORY

The patient first presented with tremor of her left hand that progressed to include stiffness and awkwardness of her left UE and LE. Her family physician referred her to a neurologist who found moderate tremor and rigidity on the left side. He prescribed Artane, which was helpful for a while. Eventually the tremor became worse, especially under conditions of stress when she was unable to use her left UE at all. She was then started on Sinemet and referred for an initial episode of physical therapy as an outpatient. Once Sinemet began to work and her symptoms dramatically lessened, she stopped physical therapy and her HEP. Over the next few years as her symptoms increased, her dose of Sinemet was increased.

CURRENT STATUS

The patient is currently taking Sinemet and bromocriptine. She reports bouts of dyskinesia about 45 minutes into taking her Sinemet that involve involuntary writhing movements of her LUE. Her chief complaints are:

• Difficulty walking, especially when she has to go through a narrow doorway, or walk in a crowded place.

• Episodes of gait blocks (freezing of gait); if she tries to do something while walking, such as take a tissue out of her pocket, she stops abruptly in her tracks. The harder she tries to move, the worse it gets. Episodes of freezing have lasted up to 20 minutes.

• Postural instability: over the past few years she has experienced increasing bouts of uncontrolled or unsteady balance. This is particularly disturbing to her because if it occurs while she is walking, it causes her to fall. She has fallen seven times in the past month, with no residual fall injury. Because of her increased fear of falling, she has stopped going out by herself.

• Experiences increased difficulty rolling over in bed, getting out of bed, and standing up from a chair independently. Her husband now has to provide assistance 90% of the time to accomplish these activities.

• Reports having trouble sleeping at night. She has stopped drinking coffee but this has not helped. She wakes four to five times a night, and requires assistance from her husband to go to the bathroom at night. She also has hallucinated at night, claiming to see bugs on the wall. During these periods she becomes extremely frightened.

• Complains her medication seems to be helping less and less. If she plans to go out, she takes an extra Sinemet. She revisited her neurologist in hopes that he would increase her dosage. Instead he told her the symptoms were most likely the result of excess medication. He instructed her not to take the extra Sinemet and adjusted her dosage.

EXAMINATION FINDINGS

Cognition

Alert, oriented × 3; she is displaying mild impairments in short-term memory.

Psychosocial

She is showing signs of depression; she is less interested in going out and socializing; she reports "it is just too much effort."

Speech

Mild dysarthria, hypophonia.

Sensation

Slightly decreased proprioception bilaterally in both ankles; otherwise intact.

Tone

Rigidity (cogwheel type) moderate in all extremities L > R.

Marked rigidity throughout neck and trunk.

Masklike face.

Range of Motion

Decreased due to moderate rigidity; with limitations in:

• Bilateral elbow extension (10° to 140°)

• Bilateral hip extension (0° to 10°)

• Bilateral knee extension (10° to 120°)

• Bilateral ankle dorsiflexion (0° to 15° RLE; 0° to 10° LLE).

Strength

Generally fair (3/5) to good minus (4–/5).

Poor (2/5) dorsiflexor muscle grades in both ankles.

Motor Function

Moderate to severe resting tremors, L hand > R hand.

Bradykinesia: marked slowness, poverty of movement.

Hesitation on initiation of movement; frequent arrests of ongoing movement.

Dyskinesias: LUE

Posture

Forward head position; flexed; kyphotic spine.

Stands with flexion of elbows, hips, and knees.

Balance

Decreased limits of stability.

Patient's forward alignment position increases her tendency to fall forward.

Sitting static control: good (able to maintain balance without handhold).

Sitting dynamic control: fair (accepts minimal challenge; able to lift both arms).

Standing static control: good (able to maintain balance without handhold).

Standing dynamic control: poor (unable to accept minimal challenge without handhold).

She has slowed reactions to loss of balance with decreased rotational movements of head/trunk and ineffective use of stepping strategies.

Timed Up and Go score is 36 seconds.

Patient is fearful of falling.

Functional Mobility

Generally decreased.

Requires moderate assist: rolling in bed, supine-to-sit and sit-to-stand transfers.

Unable to bridge secondary to hip flexion contractures.

Patient has good safety awareness.

Locomotion

Ambulates independently with a shuffling gait pattern with decreased step length and arm, trunk, hip, and knee motions; tendency for propulsive gait.

Afraid to walk outside alone for fear of falling.

Frequent freezing of gait.

Self-Care

Requires minimal assistance to supervision for feeding.

Requires minimal to moderate assist for dressing/bathing.

Cardiopulmonary Function/Endurance

Shallow (upper respiratory) breathing pattern.

Generally decreased functional capacity (estimated functional work capacity [FWC] is 6 metabolic equivalents [METs]).

Patient fatigues easily and requires frequent rest periods.

Mild edema both ankles.

Skin

Intact, no areas of breakdown.

Experiences bouts of increased perspiration.

1. Identify/categorize this patient's problems in terms of:

   1. Direct impairments

   2. Indirect impairments

   3. Activity limitations

   4. Participation restrictions/disability

2. Identify two outcomes (the remediation of activity limitations and disability) and two goals (remediation of impairments) for this patient.

3. Determine four interventions that could be used at the start of therapy to achieve the outcomes and goals provided for question 2. Provide a brief rationale for each.

4. What motor learning strategies will assist in improving her motor function?

Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Score Sheet, 2008 version. Used with permission of the MDS.