Effectiveness of head-mounted vibrotactile stimulation in subjects with bilateral vestibular loss: a phase 1 clinical trial.

OBJECTIVE: Evaluate the effectiveness of a head-mounted vibrotactile prosthesis for balance improvement in subjects with severe bilateral vestibular loss (BVL). STUDY DESIGN: Crossover study. SETTING: Academic tertiary care vestibular function test center. PATIENTS: Five subjects with severe BVL as defined by video-oculography, rotational chair, and computerized dynamic posturography criteria. INTERVENTION: Vibrotactile head tilt feedback MAIN OUTCOME MEASURES: Change in Sensory Organization Test (SOT) Conditions 5 and 6 performance (fall-no fall, time to fall, strategy analysis) and dynamic subjective visual vertical (DSVV) response. RESULTS: 1) Significant improvement in binary fall-no fall ratio on SOT 5 and SOT 6 combined (chi2 = 9.603, df = 1, p = 0.001); 2) Significant increase in time to fall measurements on SOT 5 (p < 0.001) and SOT 6 (p < 0.01; 1-tailed t test); 3) Nonsignificant improvement in strategy scores on SOT 5 (p = 0.156) and SOT 6 (p = 0.259; 1-tailed t test); and 4) No significant effect during eccentric DSVV testing (analysis of variance). CONCLUSION: Head-mounted vibrotactile stimulation produced significant improvement in postural stability in subjects with BVL undergoing SOT 5 and 6 testing with no effect on subjective visual vertical during DSVV testing.