Gaze stabilization and dynamic visual acuity in people with multiple sclerosis.

BACKGROUND: The functional capacity of the vestibulo-ocular reflex (VOR) is not well understood in people with multiple sclerosis (MS).

OBJECTIVE: To determine the psychometric properties of computerized Gaze Stabilization Test (GST) and Dynamic Visual Acuity Test (DVAT) in people with MS.

METHODS: This cross-sectional study determined discriminant validity of the GST and DVAT between 15 healthy controls and 30 participants with MS, and between participants with MS who had higher versus lower disability. This study also determined same-day and between-session test-retest reliability, and concurrent validity with patient-reported outcomes (PROs) of balance, dizziness, and fatigue.

RESULTS: GST (p < 0.001) and DVAT (p = 0.001) scores were lower in participants with MS compared to controls. GST (p = 0.035) but not DVAT (p = 0.313) scores were lower in those with higher compared to lower disability. Test-retest reliability intraclass correlation coefficients (ICC (2,1)) were fair-to-good for the GST (0.48 to 0.74) and DVAT (0.47 to 0.60). PROs correlated significantly with GST, but not DVAT scores.

CONCLUSIONS: This study provides initial evidence that the functional capacity of the VOR is impaired in people with MS as measured by the GST and DVAT. Further investigation is warranted to determine usefulness of both measures as outcomes for people with MS.