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 vestibulo-ocular 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.