Ocular Apraxia
Ocular Apraxia
Ocular apraxia (ocular motor apraxia) is a disorder of voluntary saccade initiation; reflexive saccades and spontaneous eye movements are preserved. Ocular apraxia may be overcome by using dynamic head thrusting, with or without blinking (to suppress vestibulo-ocular reflexes): the desired fixation point is achieved through reflex contraversive tonic eye movements to the midposition following the overshoot of the eyes caused by the head thrust.
The anatomical substrate of ocular apraxia is not certain. Ocular apraxia may occur as a congenital syndrome (in the horizontal plane only: Cogan’s syndrome), or may be acquired in ataxia telangiectasia (Louis-Bar syndrome), Niemann-Pick disease (mainly vertical plane affected), and Gaucher’s disease (horizontal plane only).
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