Anti-Compensatory Saccades Changes After Visuo-Vestibular Physical Therapy in People With Acute Unilateral...

Acute unilateral vestibulopathy (AUVP) impairs the vestibulo-ocular reflex (VOR), leading to gaze instability and significant functional disability. Anti-compensatory saccades (AcS) assessed using the Suppression Head Impulse Paradigm (SHIMP) reflect vestibulo-saccadic interaction and may represent a marker of central compensation. The aim of the study was to analyze changes in AcS following structured visuo-vestibular physical therapy (VVPT).

Ninety-two patients with AUVP (mean age 59 years, 57 women and 35 men) completed an 8-week VVPT program (one session per week). Assessments at baseline (T0) and post-intervention (T1) included the video Head Impulse test (vHIT- HIMP and SHIMP) and the Dizziness Handicap Inventory (DHI). The primary outcome was the change in AcS amplitude. Secondary outcomes included changes in VOR gain and DHI score. Paired comparisons were performed using the Wilcoxon signed rank-test.

AcS amplitude increased significantly after VVPT (median 189.5°-239.0°; p < 0.001). VOR gain showed a modest but significant increase (0.37-0.40; p < 0.001), remaining within dysfunctional ranges. DHI scores decreased markedly (51-26; p < 0.001). No significant association was found between baseline VOR gain and AcS variation (R² = 0.001; p = 0.723), suggesting that baseline residual vestibular function did not explain the magnitude of the observed AcS change.

A significant increase in AcS amplitude was observed after an 8-week VVPT program in people with AUVP, despite only limited improvement in VOR gain. These findings suggest that AcS may provide clinically relevant information on vestibulo-saccadic adaptation during recovery after unilateral vestibular loss and may complement traditional VOR gain and patient-reported outcome measures. However, given the study design, the observed changes should be interpreted with caution.