title: Periodic alternating nystagmus.
abstract: A typical case of periodic alternating nystagmus is described. Periodic alternating nystagmus is a form of horizontal or horizontal-rotary jerk nystagmus of which the most characteristic feature is an alternation in direction at regular intervals. The condition appears to be not as rare as has been believed previously and may indicate a lesion in the upper part of the medulla.
mesh_terms: D000328:Adult; D006801:Humans; D008297:Male; D009759:Nystagmus, Pathologic; D010507:Periodicity