Do colour discrimination and contrast sensitivity help to distinguish Parkinson's disease, multiple system atrophy and progressive supranuclear palsy?

Objectives: To study, whether visual testing can contribute to the differential diagnosis of Parkinson syndromes. Background: Abnormalities of colour discrimination (CD) and visual contrast sensitivity (CS) in Parkinson's disease (PD) have been well documented by clinical, psychophysical and electrophysiological testing. Although these alterations are likely to be related to retinal dopaminergic dysfunction, the observation that CS is orientation-specific raises the possibility of additional visual cortex involvement. Subjects and Methods: CD and CS were investigated in 12 PD patients, 11 patients with multiple…