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Oculomotor apraxia (OMA), also known as Cogan ocular motor apraxia or saccadic initiation failure (SIF) is the absence or defect of controlled, voluntary, and purposeful eye movement.〔Tada, M, Yokoseki, A, Sato, T, Makifuchi, T, Onodera, O. Early-onset ataxia with ocular motor apraxia and hypoalbuminemia/ataxia with oculomotor apraxia 1. Advances in Experimental Medicine and Biology 685 (2010): 21-33.〕 It was first described in 1952 by the American ophthalmologist David Glendenning Cogan.〔Le Ber, I, Brice, A, Dürr, A. New autosomal recessive cerebellar ataxias with oculomotor apraxia. Current Neurology and Neuroscience Reports 5.5 (2005): 411-7.〕 People with this condition have difficulty moving their eyes horizontally and moving them quickly. The main difficulty is in saccade initiation, but there is also impaired cancellation of the vestibulo-ocular reflex. Patients have to turn their head in order to compensate for the lack of eye movement initiation in order to follow an object or see objects in their peripheral vision, but they often exceed their target. There is controversy regarding whether OMA should be considered an apraxia, since apraxia is the inability to perform a learned or skilled motor action to command, and saccade initiation is neither a learned nor a skilled action.〔Galvaez-Jimenez N, Tuite P, Bhatia K, editors. Uncommon Causes of Movement Disorders. New York: Cambridge University Press; 2011:38-40.〕 == Symptoms == * Absence of fast phase nystagmus on horizontal optokinetic testing * Problems in nerve function involved in eye movement control, called neuropathy * Inability to visually follow objects * Head thrusts to compensate for the inability to accomplish voluntary horizontal gaze .〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「oculomotor apraxia」の詳細全文を読む スポンサード リンク
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