title: Poor visual discrimination and visual hallucinations in Parkinson's disease.
abstract: This study examined the relationship between deficits in color and contrast discrimination and visual hallucinations (VH) in patients with Parkinson's disease (PD) and normal visual acuity. Thirty-five nondemented and nonpsychotic PD patients with normal visual acuity and without major ophthalmologic disease were interviewed twice and divided into two groups: hallucinators (n = 14) and non-hallucinating controls (n = 21). The groups were compared for color vision (assessed by Lanthony D-15 [LD] and Farnsworth-Munsell 100 hue [FM] tests), and for contrast sensitivity (tested by Vis tech tables [VT] and monocular and binocular Pelli-Robson test [PR]). There was no difference in age, duration or stage of PD, or dosage or duration of levodopa therapy between the two groups. Parkinson's disease patients showed impairment on all visual tests, with the hallucinators performing worse than the controls on all tests. This difference was significant for the LD (p < 0.007), the VT at 1.5 and 3 cycles per degree (p < 0.037 and 0.043, respectively) and the monocular PR tests (p < 0.049). The results led the authors to conclude that in patients with normal visual acuity, those with VH show added visual deficits of color and contrast discrimination. These ophthalmopathies may therefore be facilitating factors for visual hallucinations in PD and justify more focused research on the pathophysiology of visual hallucinations in Parkinson's disease.
authors.affiliation: Department of Neurology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA.
authors.forename: N J
authors.initials: NJ
authors.lastname: Diederich
authors.forename: C G
authors.initials: CG
authors.lastname: Goetz
authors.forename: R
authors.initials: R
authors.lastname: Raman
authors.forename: E J
authors.initials: EJ
authors.lastname: Pappert
authors.forename: S
authors.initials: S
authors.lastname: Leurgans
authors.forename: V
authors.initials: V
authors.lastname: Piery
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000009:adverse effects; D003118:Color Perception / Q000187:drug effects / Q000502:physiology*; D015350:Contrast Sensitivity / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006212:Hallucinations / Q000139:chemically induced / Q000503:physiopathology*; D006801:Humans; D007980:Levodopa / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology*; D011605:Psychoses, Substance-Induced / Q000209:etiology / Q000503:physiopathology*; D014786:Vision Disorders / Q000139:chemically induced / Q000503:physiopathology*; D014787:Vision Tests
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa