Recovery of dynamic visual acuity in unilateral vestibular hypofunction

Objective: To determine the effect of vestibular exercises on the recovery of visual acuity during head movement in patients with unilateral vestibular hypofunction. Study Design: Prospective, randomized, double-blind study. Setting: Ambulatory referral center. Patients: Twenty-one patients with unilateral vestibular hypofunction, aged 20 to 86 years. Intervention: One group (13 patients) performed vestibular exercises designed to enhance the vestibuloocular reflex, and the other group (8 patients) performed placebo exercises. The placebo group was switched to vestibular exercises after 4 weeks. Outcome Measures: Measurements of dynamic visual acuity (DVA) during predictable (DVA-predictable) and unpredictable (DVA-unpredictable) head movements by means of a computerized test and measurement of intensity of oscillopsia by means of a visual analog scale. Results: As a group, patients who performed vestibular exercises showed a significant improvement in DVA-predictable (P<.001) and DVA-unpredictable (P<.001), while those performing placebo exercises did not (P=.07). On the basis of stepwise regression analysis., the leading factor contributing to improvement was vestibular exercises. This reached significance for DVA-predictable (P=.009) but not DVA-unpredictable (P=.11). Other factors examined included age, time from onset, initial DVA, oscillopsia, and duration of treatment. Changes in oscillopsia did not correlate with DVA-predictable or DVA-unpredictable. Conclusions: Use of vestibular exercises is the main factor involved in recovery of DVA-predictable and DVA-unpredictable in patients with unilateral vestibular hypofunction. Exercises may foster the use of centrally programmed eye movements that could substitute for the vestibulo-ocular reflex. The DVA-predictable would benefit more from this than would DVA-unpredictable.