Upon completion of this chapter, the learner should be able to:
Summarize the neuroanatomical regions, structures, and pathways related to sensory abilities and impairments caused by neuromuscular pathology/injury.
List and describe the variety of sensory modalities that can be tested.
Infer the impact of specific sensory deficits on functional abilities.
Synthesize patient factors to select the most appropriate sensory tests and measures for application to a given patient.
Implement each test described and document results in a patient medical record.
Sensation has been defined as “a feeling; the translation into consciousness of the effects of a stimulus exciting any of the organs of sense” (Stedman, 1982). The term sensation implies that the feeling or impression is conveyed to and processed by the central nervous system. Most sensation is processed at an awareness level and is therefore termed conscious sensation. However, some important sensory systems will be discussed (e.g., spinocerebellar “unconscious” proprioception) that are processed primarily at a subconscious or unconscious level although, with intent, one can transfer that sensory information to a conscious level. Sensation reflects information from the internal or external environment. Humans are aware of certain sensations and can purposely bring others to a level of awareness. The modalities of sensation are the specific types of sensation including pain, pressure, and joint position sense. A related term, sensibility, is the aspect therapists test as part of the neurological examination and has been described as “the capability of perceiving sensible stimuli” (Stedman, 1982). Cortical sensibility processed by the cerebral cortex is the recognition of sensory information and related discrimination of sensory impression (Waylett-Rendall, 1988). In our sensory evaluation for some modalities we must determine the threshold stimulus, also called the limen, which is the minimal stimulus level that will produce a sensation (Jimenez, 1993). This must be determined for some of the modalities of sensation. These terms are descriptive of the stimuli we experience, the ability to feel the stimuli, or the degree to which we detect the stimuli, and they represent the content of the sensory examination.
Sensation includes all incoming information brought into the nervous system, whether processed consciously or subconsciously. In neuroscience, the term afferent impulses is used for sensory or incoming signals, while efferent impulses are those that transmit information away from the nervous system to an effector organ (muscle or gland). Sensory signals always originate from sensory receptors designed to monitor either conditions from the external environment such as pressure or temperature or internal conditions such as joint position or visceral sensation.
Examination of sensation and sensory awareness is an essential, but sometimes incomplete, portion of the neurological examination. This part of the evaluation is useful as part of the basis for clinical decision-making and to quantify sensory aspects of recovery (Cooke, 1991). Although motor integrity is a primary examination focus for rehabilitation professionals ...