THE EYE-MOVEMENTS OF SYNCOPE

We videotaped the eye movements of syncope in 25 healthy volunteers wh o induced fainting by hyperventilation and Valsalva maneuver on a tilt table. In an additional three subjects, syncope was similarly induced during horizontal sinusoidal oscillation on a rotating chair while ey e movements were recorded by electro-oculogram. Fourteen of 25 subject s experienced syncope on the tilt table. Six had downbeat nystagmus (D BN) at the onset that evolved into upward eye deviation, whereas seven showed isolated tonic upward deviation. In one subject the eyes remai ned in primary position. The gain of the vestibule-ocular reflex (VOR) increased by 65% on average during syncope with concurrent vestibular stimulation. DBN, upward eye deviation, and increased VOR gain may al l be caused by vestibular disinhibition caused by cerebellar hypoperfu sion.