A New Dynamic Visual Acuity Test to Assess Peripheral Vestibular Function

Objective: To evaluate a novel test for dynamic visual acuity (DVA) that uses an adaptive algorithm for changing the size of Landolt rings presented during active or passive head impulses, and to compare the results with search-coil head impulse testing. Design: Prospective study in healthy individuals and patients with peripheral vestibular deficits. Setting: Tertiary academic center. Participants: One hundred neuro-otologically healthy individuals (age range, 19-80 years) and 15 patients with bilateral (n=5) or unilateral (n =10) peripheral vestibular loss (age range, 27-72 years). Interventions: Testing of static visual acuity (SVA), DVA during active and passive horizontal head rotations (opto type presentation at head velocities >100 degrees/s and >150 degrees/s), and quantitative horizontal head impulse testing with scleral search coils. Main Outcome Measure: Difference between SVA and DVA, that is, visual acuity loss (VA loss), gain of the higha-cceleration vestibulo-ocular reflex. Results: Passive head impulses and higher velocities were more effective than active impulses and lower velocities. Using passive head impulses and velocities higher than 150 degrees/s, the DVA test discriminated significantly (P <.001) among patients with bilateral vestibulopathy, those with unilateral vestibulopathy, and normal individuals. The DVA test sensitivity was 100%, specificity was 94%, and accuracy was 95%, with search-coil head impulse testing used as a reference. In healthy individuals, VA loss increased significantly with age (P<.001; R-2=0.04). Conclusion: Dynamic visual acuity testing with Landolt rings that are adaptively changed in size enables detection of peripheral vestibular dysfunction in a fast and simple way.