Optokinetic response and adaptation of the vestibulo-ocular reflex (VOR) in a patient with chronic cortical blindness.

Optokinetic response and adaptation of the VOR were investigated in a patient with chronic cortical blindness. Our results suggest that: 1) optokinetic response was present in a patient with cortical blindness. This optokinetic response may relate to the extrastriate pathways: 2) the occurrence of VOR adaptation was shown in a patient with cortical blindness, which may indicate preservation of the pathways of the visual-vestibular interaction in the brain stem and cerebellum. The result is in agreement with previous reports in experimental animals; 3) less adaptation of the VOR in this patient than in normal adults may relate to a chronic loss of visual feed back. To the best of our knowledge, this is the first report of adaptation of the VOR in a patient with cortical blindness.