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Background/Objectives To examine vestibulo-ocular reflex (VOR) characteristics in patients with definite amyotrophic lateral sclerosis (ALS) using 3-dimetional video-head impulse testing (v-HIT) and to determine the relationship between VOR function and functional impairment.Methods VOR-gain, refixation saccade prevalence and the first-saccade amplitude, onset-latency and peak-velocity were examined in 18 ALS patients (10 bulbar-onset) and compared against age-matched controls.Results The mean patient age was 63.4±7.2 years, disease duration was 15.7±13 months, and ALS-functional rating scale (ALS-FRS) score was 36.3±8.0. 8/18 (44.4%) patients reported gait imbalance resulting in recurrent falls in 4/18 (22.2%).Horizontal, anterior and posterior canal (HC, AC, PC) v-HIT gains for ALS were 1.1±0.1, 0.87±0.2, 0.78±0.1 and for controls were 0.98±0.1, 0.91±0.1, and 0.82±0.1. During HC v-HIT, eye-velocity traces reached their peak velocity ahead of head-velocity resulting in mildly elevated VOR-gain in bulbar-onset ALS patients (n=8). No patient had reduced HC VOR-gain. AC VOR-gain was reduced (mean-2SD) in 5/18 (27.7%) and PC in 6/18 (33.3%) of patients.Refixation saccade prevalence for HC, AC, PC were 67±32%, 22±18%, 74±34% in ALS, and 62±31%, 17±12% and 58±42% in controls. The first-saccade peak-velocity was higher in HC plane in ALS group compared to controls (p < 0.05). Patients with reduced PC VOR-gain had a lower ALS-FRS score than patients with normal VOR-gain (30.7±7.8 vs 38.5±6.7, p<0.05).Conclusions Reduction in the PC VOR-gain was not uncommon in ALS patients. Hyperactive HC VOR in bulbar-onset ALS, as evidenced by increased gains may serve as a marker of bulbar involvement in ALS and merits further investigations.