Amplitude and speed change of the optokinetic response in patients with and without neglect

The present study quantitatively investigated the slow and quick phases of optokinetic nystagmus (OKN) in four groups of patients: right unilateral brain-damaged patients with neglect, left and right patients without neglect or hemianopia and patients with left or right retrogeniculate lesions and lateral homonymous hemianopia. Our results indicate that only neglect patients show a perturbation of both components of OKN. A comparison among MRI images of different patients shows that a region involving area 37 and adjacent areas 39 and 19, was impaired in all patients with neglect, but not in any other patient with either right or left lesions.