Objective: To analyze the relationship between color vision deficits in Parkinson’s disease (PD) and the integrity of the visual system, cognition and other relevant networks of the brain.

Background: Color vision deficits in PD have been traditionally attributed to PD-related abnormalities of the retina or primary visual cortex. Most studies supporting this idea used psychophysical tests such as Roth-28 color test, which are highly influenced by cognitive and psychomotor abilities, typically affected in PD. Despite this, the neural mechanisms that could explain color vision deficits in PD have not yet been fully evaluated.

Method: We studied cross-sectionally 38 PD and 22 healthy controls (HC). Participants were evaluated with best-corrected high- and low-contrast visual acuity, contrast sensitivity, Roth-28 test, neuropsychological tests of visual cognition, macular layer thickness from optical coherence tomography (OCT), cortical thickness and resting-state functional connectivity (FC) from 3T brain MRI. Using the mean + 2 standard deviations of total error score (TES) of Roth-28 in controls as reference, patients were classified as PD with altered color vision (PD-ACV) (n=11) and PD with normal color vision (PD-NCV) (n=27). Statistical comparisons were performed between groups with MANCOVA and group-wise correlations were computed between color vision metrics and clinical and imaging measurements.

Results: Compared to controls and PD-NVC, PD-ACV showed significant impairment in contrast sensitivity, visual attention and processing speed, executive functions, visual memory, and visuospatial and visuoconstructive abilities. Moreover, PD-ACV patients showed significantly reduced thickness in the occipital cortex and altered within-network FC in the visual network (VIS) and between-network FC between VIS and dorsal attention, fronto-parietal and ventral attention networks compared to PD-NCV and HC. Furthermore, the impairment in neuropsychological tests and in within-network FC in VIS observed in PD-ACV significantly correlated with the Roth-28 TES value.

Conclusion: This study suggests that color vision deficits in PD are not explained exclusively by damage to the primary visual pathway, but rather are influenced by alterations in visual cognition, occipital cortex atrophy, and alterations in Cerebral FC between visual networks, attentional and fronto-parietal networks.

« Back to 2022 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/color-vision-deficits-in-parkinsons-disease-are-linked-to-brain-abnormalities-in-attentional-fronto-pariental-and-visual-networks/