Long-term vestibule-ocular reflex changes in patients with vestibular ablation

Long-term changes in the parameters of the vestibulo-ocular reflex (VOR) we re evaluated using recently developed multilevel statistical modelling tech niques in a group of patients who had undergone ablative inner ear procedur es. Data From 84 patients were available for study. The most dramatic recov ery in the VOR occurred during the first 60 postoperative days, however, sl ow changes continued, levelling off at about 120 days. While frequency was a highly significant predictor of outcomes in all parameters, age showed si gnificant predictive value only to phase measures (p = 0.006) acid gender h ad no effect. Sum gain at the lowest Frequency tested remained below the 5t h percentile and at the higher frequencies remained below the 50th percenti le for normal subjects. Phase decreased exponentially, but remained above t he 95th percentile for normal subjects, except at the highest frequency whe re it remained above the 50th percentile. DC bias decreased exponentially, dropping to the 50th percentile by day 146. Asymmetry stayed between the 50 th and 95th percentile, except at the highest frequency, where it was at th e 50th percentile by day 125.