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What is True about central nystagmus ? and explain in detail?
Ans. is 'd' i.e., All of the above Nystagmus Nystagmus is rhythmic oscillatory movement of eye. Nystagmus has following characteristics :? Rapid, Involuntary, Repetitive Nystagmus may be :? Side to side (horizontal nystagmus) Up and down (veicle nystagmus) Rotary Vestibular nystagmus has two components, i.e. a slow and a fast. The direction of nystagmus is indicated by the direction of fast component. Vestibular nystagmus may be :? Peripheral :- due to lesion of labyrinth or VIII nerve. Central :- due to lesion of vestibular nuclei, brainstem or cerebellum. i. Peripheral nystagmus Diminshes or suppresses with gaze fixation (optic fixation) Enhances in darkness or by use of Frenzel glasses Unidirectional fast component Direction is typically horzonto - rotary, not purely horizontal or rotary and not veical Direction is fixed towards undermost ear Present in one head position ii. Central nystagmus Not suppressed by optic fixation Fast component can be unidirectional or bidirectional Can be horizontal, veical or rotary Direction is changing Present in multiple head positions