Influence of peripheral vision upon vestibulo-ocular reflex suppression

The effect of peripheral vision upon the suppression of caloric induced nystagmus has been studied in normal subjects and patients with Parkinson's disease and cerebellar lesions. In normal subjects, caloric responses in the presence of optic fixation upon a target light viewed in darkness are further suppressed by a factor of two when background illumination is introduced. In both patient groups background illumination had significantly less effect. Additionally, optokinetic and pursuit test have revealed specific abnormalities consistent with the notion of a peripheral retinal feed-back mechanism deranged by disease. These in turn appear to have particular relevance to certain visuo-vestibular disturbances characteristic of patients in both groups.