Both actual and imagined locomotion suppress spontaneous vestibular nystagmus.

Acute unilateral vestibulopathy is characterized by a combination of signs and symptoms including spontaneous nystagmus, postural imbalance and gait disturbance. A functional link between these vestibulo-ocular and vestibulo-spinal motor responses has been demonstrated. These responses use common vestibular input and partially overlapping neuronal networks, but it is not known if and to what extent they are linked or operate separately. We found that slow phase velocity of spontaneous vestibular nystagmus in patients with acute vestibulopathy was suppressed by 26% during actual walking (ANOVA p< 0.02, = 6). It was also suppressed by imagined locomotion: by 26% during the imagination of walking and by 42% during the imagination of running ( p< 0.003, = 10). The suppression of vestibular nystagmus might be beneficial for patients, for it alleviates the disturbing impression of movement of the visual scene (oscillopsia) caused by involuntary eye movements.