Transient loss of consciousness through the eyes of a witness.

OBJECTIVE: To assess the accuracy of eyewitness observations of transient loss of consciousness. METHODS: Two sequential cohorts of psychology students unexpectedly viewed videos of a generalized tonic-clonic seizure (n = 125) and of reflex syncope (n = 104) during a lecture on an unrelated subject. Directly afterward, the students filled in a multiple-choice questionnaire regarding muscle tone, twitches, head deviation, eye closure, gaze deviation, drooling, and facial color. The consensus of experienced neurologists served as a gold standard. Even though not all items could be ascertained from the videos, the full range of questions was included to simulate clinical practice. RESULTS: Of all responses to the observable items on the syncope video (flaccid limbs, twitches of one shoulder, head deviation), 44% were correct, 28% erroneous, and 29% had "I do not know" responses. The observable items on the epilepsy video (stiff limbs, twitches of all limbs, normal facial color, drooling, no head deviation) yielded 60% correct responses, 18% erroneous responses, and 22% "I do not know" responses. Regarding features that were not visible on the videos, 77% of the responses were accurate ("I do not know"), whereas 23% erroneously provided an observation. Of all items observable on both videos, muscle tone was the most accurately recalled item. CONCLUSIONS: An eyewitness account of a single episode of transient loss of consciousness (TLOC) should be interpreted with caution because salient features are frequently overlooked or inaccurately recalled. However, the accuracy of the eyewitness observations of TLOC differs per item; muscle tone was reported with high accuracy.