Peripheral vestibular dysfunction, which involves the vestibular end organs and/or the vestibular nerve, can produce a variety of signs and symptoms. A thorough evaluation by a physician is needed to identify the specific pathology behind the patient's complaints of vertigo or disequilibrium. Patient history is the main key for diagnosis, supported by a careful otoneurologic examination. Determining whether vestibular rehabilitation is appropriate and, if it is, which approach should be used is based in part on the patient's diagnosis. This chapter describes the clinical presentation of the more common peripheral vestibular disorders. The results of diagnostic tests, and the medical, surgical, and rehabilitative management of each of these disorders is presented as an overview only, because this material is covered in detail in other chapters.
Benign Paroxysmal Positional Vertigo
Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo. Typically, a patient with BPPV complains of brief episodes of vertigo precipitated by rapid changes of head posture. Sometimes symptoms are brought about by assuming very specific head positions. Most commonly these head positions involve rapid extension of the neck, often with the head turned to one side (as when looking up to a high shelf or backing a car out of a garage) or lateral head tilts toward the affected ear. The symptoms often appear when a patient rolls from side to side in bed. Patients can usually identify the offending head position, which they often studiously avoid. Many patients also complain of mild postural instability between attacks. The vertigo lasts only 30 seconds to 2 minutes (usually less than 1 minute) and disappears even if the precipitating position is maintained. Hearing loss, aural fullness, and tinnitus are not seen in this condition, which most commonly occurs spontaneously in the elderly population but can be seen in any age group after even mild head trauma. Women are more commonly affected than men (2:1) and the right labyrinth is slightly more often involved than the left (1.4:1). Bilateral involvement can be found in 7.5%; 90% of these are traumatic cases.1 Spontaneous remissions are common, but recurrences can occur, and the condition may trouble the patient intermittently for years with a high recurrence rate of up to 50% within 10 years.2
Evaluation should include a careful otoneurologic examination, the most important part being the history. In the case of the most common posterior canal BPPV, a key diagnostic maneuver is the Dix-Hallpike positioning test3 while the examiner observes the patient's eyes with a pair of Frenzel lenses or in combination with videooculography monitoring. Electronystagmography (ENG) can also be used, but because the typical response in posterior BPPV is a combined vertical-torsional nystagmus, recordings might be hard to interpret, because this technique cannot measure torsional eye movements and in the vertical dimension recordings might be hampered by artifacts.
A typical response is induced by rapid ...