Spatiotemporal contrast sensitivity differs in normal aging and Parkinson's disease.
 We measured contrast sensitivity for static and laterally drifting vertical gratings in 12 young adults, 7 normal elderly adults, and 8 patients with Parkinson's disease (PD).
 We compared static and motion contrast sensitivity for spatial frequencies of 0.25, 1, and 4 cycles per degree (cpd), and temporal frequencies of 1, 3, and 9 Hz.
 Results show that normal aging leads to a reduction of motion sensitivity for the spatial frequency of 0.25 cpd.
 Compared with elderly controls, PD patients do not present specific abnormalities in this domain.
 However, for spatial frequencies of 1 and 4 cpd and temporal frequencies of 1 and 3 Hz, motion sensitivity is worse than static sensitivity in PD patients and not in elderly controls.
 These findings suggest a specific deficit of motion perception in PD, and possible dopaminergic involvement in the control of visuospatial behavior.
