| Abstract: | Since the localizing value of optokinetic nystagmus (OKN) in cerebral hemispheric lesions has been questioned by some investigators, 96 patients with hemispheric lesions of various origin demonstrated on CT scan were studied by EOG (optokinetic stimulation at 30, 60 and 120 deg/ sec), EEG, perimetry and neurologic examination.A severe OKN diminution was found in 17 cases, a moderate diminution in ninecasesand a slight diminution only in seven cases (contralateral deficit in OKN). M onocular stimulation revealed further OKN deficits in two additional cases. Both severe and moderate OKN diminution could be located significantly in the deep white matter of the dorsoparietal and dorsotemporal lobe (CT 2A, 2B, 3A). In contrast to this specific OKN deficit a slight unilateral diminution determined only the involved hemisphere in general but did not correlate with any anatomic area within one hemisphere. |
