Postural vertigo and positional nystagmus.

Oscillation of the eyes of a patient when the head is placed in a certain position is objective evidence to support a complaint of postural vertigo-dizziness when the head is tilted forward or upward or turned to one side or the other. Since positional nystagmus may be difficult to evoke and may be elicited at one time and not at another, it is important to make repeated tests, lest a causative lesion be overlooked. Vertigo in such cases may be caused by pathologic change in the eighth peripheral nerve or in the central vestibular pathways. Sometimes no organic disease is observable even though positional nystagmus validates a complaint of vertigo. In such instances the patient should be assured that he does not have a progressive disease and be advised against activity in which dizziness would be hazardous.