OBJECTIVES: This study aimed to assess vestibular function in 39 patients who underwent neurectomy for vestibular schwannoma. METHOD: Semicircular canal reactivity was measured by video head-impulse test using high-frequency passive head acceleration. Response gain was calculated as a ratio between the areas under the eye-velocity curve and the head-velocity curve. STATISTICAL ANALYSIS: Student t-test was used for to compare quantitative variables. ANOVA was used to test inter-group differences in categoric variables. RESULTS: In all cases, surgery-side gain on head impulse test was low, with increased gain asymmetry. A subgroup of 7 patients (18%) showed relatively high gain in vestibulo-ocular reflex on the surgery side. Caloric reaction was absent in all cases. These findings indicate that residual vestibular function can be conserved following vestibular schwannoma extirpation. CONCLUSION: Cases with moderate vestibulo-ocular reflex gain were a subgroup with partial conservation of vestibular nerve fibers. Whether this is a predictor of better functional prognosis remains to be elucidated. Higher gain correlated with less extensive surgery and sparing of the inferior vestibular nerve. Low gain correlated with complete vestibular neurectomy. This information may guide rehabilitation strategy following surgery.

Department of Epidemiology and Public Health Faculty of Medicine University of Ostrava Syllabova 19 Ostrava 703 00 Czech Republic

Department of Neurology 2 Faculty of Medicine Charles University Prague and Motol University Hospital 5 Úvalu 84 Prague 150 06 Czech Republic

Department of Otorhinolaryngology and Head and Neck Surgery 1 Faculty of Medicine Charles University and Motol University Hospital Postgraduate Medical School 5 Úvalu 84 Prague 150 06 Czech Republic

Faculty of Biomedical Engineering Kladno Czech Technical University Prague Sítná 3105 Kladno 271 01 Czech Republic

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