SHORT REPORT Time resolution for visual information processing in Parkinson’s disease

It has been suggested that a deficit in tim-ing could be the cause of the sensory disturbances reported for Parkinson’s dis-ease. To test this hypothesis the temporal discrimination thresholds in four visual tasks were used to study 45 healthy young people, 14 healthy elderly people, and 17 patients with Parkinson’s disease. In these tasks, subjects watched a computer con-trolled light emitting diode display and pushed a button when the visual event previously specified by the researcher was perceived. The time between successive images required to discriminate a visual detail was accurately quantified. In two of the four tasks, the time for visual process-ing of image sequences was longer in the elderly group than in the young group. No significant diVerences were found between patients with Parkinson’s disease and their age matched controls for any of the four tasks. Present data show normal temporal discrimination and no slowing in the initial steps of visual processing in Parkinson’s disease