Journal ArticleDOI
Orientation-selective visual loss in patients with parkinson's disease
David Regan,C. Maxner +1 more
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TLDR
It is concluded that orientation selectivity implicates visual cortical cells in Parkinson's disease and that a preferential loss of contrast sensitivity to horizontal gratings might be due to a functional abnormality in the striate cortex that relatively spares the extrastriate cortex.Abstract:
Visual contrast sensitivity was measured using 2 cycle/deg sinewave gratings of different orientations in 10 patients with Parkinson's disease and in 15 age-matched controls. Loss of visual contrast sensitivity was found in 6 patients, all of whom had normal visual acuity. Visual loss depended on grating orientation; in all cases the maximum sensitivity loss was for the horizontal. Sensitivity loss was most marked at a temporal frequency of 4 to 8 Hz. Visual fields gave no hint of the orientation selectivity. We conclude that orientation selectivity implicates visual cortical cells in Parkinson's disease. We tentatively suggest that a preferential loss of contrast sensitivity to horizontal gratings might be due to a functional abnormality in the striate cortex that relatively spares the extrastriate cortex. The dependence of visual loss on temporal frequency combined with the sparing of visual acuity might possibly be understood if Parkinson's disease preferentially affects the visual pathway leading from the retina to cortex via the magnocellular layer of the lateral geniculate nucleus. There is an intriguing similarity between the pattern of visual loss in Parkinson's disease and in multiple sclerosis.read more
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Journal ArticleDOI
The retina in Parkinson's disease
TL;DR: This review will draw together work from animal and human studies in an attempt to provide an insight into how Parkinson's disease affects the retina and how these changes might contribute to the visual symptoms experienced by patients.
Journal ArticleDOI
Visual dysfunction in Parkinson's disease.
Rimona S. Weil,Rimona S. Weil,Anette Schrag,Jason D. Warren,Sebastian J. Crutch,Andrew J. Lees,Huw R. Morris,Huw R. Morris +7 more
TL;DR: The role of visual dysfunction as a marker of dementia in Parkinson’s disease is discussed and links between visual changes and other features of Parkinson's disease are examined.
Journal ArticleDOI
Visual deficits related to dopamine deficiency in experimental animals and parkinson's disease patients
TL;DR: In patients affected by Parkinson's disease, and in the monkey model of this disease, visual defects shown using psychophysical and electrophysiological measures of spatial and temporal contrast sensitivity imply an essential role for dopamine in primate vision.
Journal ArticleDOI
Repeated visual hallucinations in Parkinson's disease as disturbed external/internal perceptions: Focused review and a new integrative model
TL;DR: This work suggests that VH should be considered as a dysregulation of the gating and filtering of external perception and internal image production and suggests new, testable hypotheses regarding their pathophysiology and therapy.
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