Palato-ocular synchrony during eyelid closure.

The effects of eyelid closure on oculomotor function was examined in 11 patients with palatal myoclonus. In eight patients, eyelid closure induced gross rhythmic vertical or almost oscillatory movements of the globes, which were synchronous with the rhythmic beat of the palatal myoclonus. The rhythmic vertical ocular movements induced by eyelid closure replaced calorically induced or spontaneous horizontal nystagmus present when the lids were open. Vertical ocular motions persisted during some stages of slow-wave sleep and reappeared during each stage of rapid eye movement. The physiologic basis of the palato-ocular synchrony may be similar to the eyelid closure, vertical eye movements, and palatal myoclonus that occurs in monkeys on stimulation of the central tegmental fasciculus.