SYNCOPE - A VIDEOMETRIC ANALYSIS OF 56 EPISODES OF TRANSIENT CEREBRALHYPOXIA

To investigate the clinical features of transient cerebral hypoxia, sy ncope was induced in 56 of 59 healthy volunteers through a sequence of hyperventilation, orthostasis, and Valsalva maneuver. All events were monitored on video by two cameras. Complete syncope with falling and loss of consciousness was observed in 42 subjects, lasting 12.1 +/- 4. 4 seconds. Myoclonic activity occurred in 38 of these 42 episodes (90% ). The predominant movement pattern consisted of multifocal arrhythmic jerks both in proximal and distal muscles. Superposition of generaliz ed myoclonus was common. Additional movements such as head turns, oral automatisms, and righting movements occurred in 79%. Eyes remained op en throughout syncope in most subjects and initial upward deviation wa s common. Sixty percent reported visual and auditory hallucinations. T hirteen subjects had incomplete syncope with falls but partially prese rved consciousness. These episodes were shorter and usually not accomp anied by myoclonus and hallucinations. Transient amnesia and unrespons iveness without falling occurred in 1 subject.