Vestibulo-ocular reflex and gaze functions in a patient with congenital inner ear anomalies

We report on the vestibulo-ocular reflex (VOR) and gaze functions during horizontal rotations as well as upright locomotions in a fisherman with congenital inner ear anomalies. The finding of a marked gaze disturbance due to low VOR gain during passive rotations resembled that found in early acquired lesions. There was an improvement during active rotations, suggesting an intensified cervico-ocular reflex. Although head oscillations in the horizontal plane were abnormally large during stepping and running, they were compensated for visually even at high frequencies. The absence of complaints of oscillopsia as well as his ability to achieve proper balance seemed to be accomplished by his optokinetic ability, regularly transformed head oscillations and modified perceptive mechanisms at higher cortical levels.