This study examined whether physical therapy with vestibular rehabilitation exercises would benefit patients with agoraphobia and vestibular dysfunction. Nine patients went through a 2-week no-treatment baseline phase, a 4-week behavioral treatment phase focusing on self-directed exposure, and an 8–12-week vestibular rehabilitation phase (weekly sessions). On the main outcome measure, clinical global impressions (CGI) ratings of severity, behavioral treatment was accompanied by a reduction in severity (effect size d=0.8; P<.10). On the supplementary measures, the Hamilton Anxiety Scale (Hamilton-A) and the Chambless Mobility Inventory (MI), no significant improvements were noted. After vestibular rehabilitation therapy, further improvement occurred in CGI severity (d=0.65; two-tailed P<.10), and significant improvements occurred in the supplementary measures. The physical therapist identified motion-induced dizziness and disturbances in balance in most patients. These improved with rehabilitation. Although the results can be attributed to other explanations, they are not inconsistent with the hypothesis that vestibular dysfunction maintains agoraphobic symptoms in some patients.
Several investigations have found a correlation between vestibular dysfunction and certain constellations of anxiety symptoms, particularly those that characterize panic disorder with agoraphobia or height phobia. Such correlations are apparent both in studies on balance-disordered patients and in studies on anxiety-disordered patients Clark et al., 1994, Eagger et al., 1992, Jacob et al., 1996, Stein et al., 1994 and Yardley et al., 1995. We have speculated that the presence of vestibular dysfunction may result in a compensatory increase in the sensitivity to visual or proprioceptive balance cues, thus, facilitating the development of fear of heights or agoraphobia (Furman & Jacob, 2001). However, being cross-sectional in nature, the extant studies actually provide no evidence for whether or not the anxiety/vestibular link reflects a causal relationship, and if so, in what direction. Logically related to the question of cause and effect, the implication of the anxiety/balance link for treatment also remains largely unexplored.
An assessment of the causal nature of a relationship requires a longitudinal rather than cross-sectional approach. If we wish to examine whether vestibular dysfunction causes certain types of anxiety symptoms, two longitudinal approaches would be available. We can follow individuals prospectively and examine the development of anxiety symptoms after the onset of a vestibular disorder. Alternatively, we can follow individuals with anxiety symptoms presumably maintained by vestibular dysfunction and examine if treatment directed at the vestibular dysfunction affects the symptoms of anxiety. The latter is the approach pursued in this pilot study.
The approach just outlined requires that the treatment implemented for the vestibular problem does not have a direct effect on anxiety symptoms. For this reason, drug treatment is not an option, because the classes of drugs most commonly used to suppress vestibular symptoms, benzodiazepines and antihistamines, are known as antianxiety agents as well. The option pursued in the study, therefore, is vestibular rehabilitation therapy. Even this option is not ideal, because, as shown by Beidel and Horak (2001), there is considerable overlap between the procedures used in the behavioral treatment of anxiety and in vestibular rehabilitation therapy. For example, during vestibular rehabilitation, patients often receive instructions regarding exposure to difficult environments or are prescribed relaxation exercises.
We approached the problem of the overlap between anxiety management and vestibular rehabilitation therapy using a preemptive strategy. Patients received a 1-month course in self-directed behavioral exposure instructions before beginning vestibular rehabilitation. The clinical issue that can be pursued with this approach is to provide preliminary data for the question of whether or not agoraphobic patients with residual symptoms after exposure instructions can be helped with vestibular rehabilitation therapy.
