Reduction or loss of vestibular function bilaterally results in difficulty maintaining balance, especially when walking in the dark or on uneven surfaces, and in a decrease in the patient's ability to see clearly during head movements. In addition, patients with bilateral vestibular hypofunction or loss (BVH or BVL) also complain of intense feelings of being off-balance and of strange but disturbing sensations in their heads with head movement. Because of these problems, patients with BVH may restrict their activities and can become socially isolated.
Vestibular rehabilitation can improve postural stability, decrease the sense of disequilibrium, and improve visual acuity during head movements enabling people with BVH to resume a more normal life.1–5 Unfortunately, most patients have residual functional problems and subjective complaints.5 The exercises used for patients with BVL are aimed at fostering the substitution of alternative strategies to compensate for the lost vestibular function and at improving any remaining vestibular function. This chapter presents the assessment and physical therapy treatment of these patients. Case studies are used to illustrate different points.
Bilateral vestibular hypofunction and loss can occur secondary to a number of different problems including ototoxicity, meningitis, sequential vestibular neuritis, progressive disorders, autoimmune disorders, chronic inflammatory peripheral polyneuropathy, congenital loss, and neurofibromatosis. In most cases, however, BVH is considered to be “idiopathic,” because the underlying cause cannot be identified (see Chapter 4). The incidence of the various forms of BVH is also not clear, because it varies depending on the type of clinical practice examined (Table 23-1).
Table 23-1REPORTED FREQUENCY OF TYPES OF BVH |Favorite Table|Download (.pdf) Table 23-1 REPORTED FREQUENCY OF TYPES OF BVH
|Study ||Herdman et al5 (n=69) ||Zingler et al 20076 (n=255) ||Rinne et al 19987 (n=53) ||Brown et al 20018 (n=13) ||Gillespie and Minor 19992 (n=35) |
|Mean age (years) ||63.2 ± 14.4 ||62 ± 16 ||— ||61.1 ± 18.2 ||56 |
|Gender: % male ||66.7% ||62.0% ||— ||46% ||51% |
|Etiology unknown ||38.4% ||51% ||21% ||38.5% ||5.7% |
|Ototoxic ||20.2% ||13% ||17% ||61.5% ||57.1% |
|Progressive ||20.2% || || || || |
|Sequential ||23.9% ||36% || || ||14.3% |
|Autoimmune || ||7% ||9% || ||5.7% |
|Ménière's/other otological || ||5% ||13% || ||5.7% |
|Tumor || || ||5.7% || || |
|Plus cerebellar ||excluded || ||13% || || |
|Meningitis/other neurological ||26% ||11.4% || || || |
Balance and Risk for Falling
Patients with bilateral vestibular loss are primarily concerned with their balance and gait problems. During the acute stage, they may feel off balance even when lying or sitting down. More typically, however, their balance problems become obvious only when they are standing or walking. Thus, patients who are bedridden, such as those who develop BVH after receiving a vestibulotoxic medication such as gentamicin, often do not know they have a balance problem until they get out of bed. Typically, these patients have been treated with the ototoxic ...