title: Effect of stimulus orientation on contrast sensitivity in Parkinson's disease.
abstract: We studied the effect of stimulus orientation on contrast sensitivity function in 21 patients with Parkinson's disease and in 10 normal subjects. This was done by measuring contrast sensitivity over a range of spatial frequencies for vertical and horizontal sine wave grating stimuli. There was a great test-retest consistency in normal subjects and patients. Fifteen of the 21 patients showed contrast sensitivity deficit in at least one eye. Orientation-specific loss was demonstrated in 17 of the 25 "affected" eyes. The most frequent type of orientation-specific loss was a notch defect, which preferentially affected the middle spatial frequencies. We attribute orientation-specific and spatial frequency-selective loss in Parkinson's disease to a functional disruption of neurons on the visual cortex.
authors.affiliation: Department of Neurology, Sint Franciscus Gasthuis, Rotterdam, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: Bulens
authors.forename: J D
authors.initials: JD
authors.lastname: Meerwaldt
authors.forename: G J
authors.initials: GJ
authors.lastname: Van der Wildt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D012016:Reference Values; D014787:Vision Tests; D014785:Vision, Ocular / Q000502:physiology*