True about central nystagmus:: (A) Duration > 1 min, (B) Direction fixed, (C) Latency present, (D) Suppressed by visual fixation
Answer is A. Impoant differentiating features between peripheral and central nystagmus include the following: Characteristic of spontaneous nystagmus Peripheral vestibular Central vestibular Direction Direction-fixed i.e. unidirectional nystagmus. Direction changing i.e. bidirectional. On visual/optic fixation The nystagmus disappears with visual fixation. The nystagmus, does not disappear with visual fixation Latency 2 - 20 seconds No latency Duration Less than 1 minute More than 1 minute Fatigability Fatigable Non-fatigable