Poor Higher Order Vision Predicts Dementia in Patients With Parkinson Disease

Higher order visual dysfunction in patients with Parkinson disease was a more robust predictor of dementia and poor outcomes than retinal thickness, according to study results published online ahead of print in the Journal of Neurology, Neurosurgery & Psychiatry.

“Our findings provide evidence that higher order visual changes in Parkinson disease show greater predictive value over retinal thickness for incipient dementia and provide insights into the sequence of degenerative changes in Parkinson disease, with cortical neurodegeneration potentially an earlier event than retinal degeneration,” wrote corresponding author Rimona Sharon Weil, of the University College London Department of Molecular Neuroscience in the United Kingdom, and coauthors.

The longitudinal cohort study included 100 people with Parkinson disease. Researchers prospectively examined participants’ higher order vision and retinal thickness, and conducted cognitive assessments at baseline, 18 months, and 36 months.

Patients with Parkinson disease who had poor higher order vision at baseline had lower cognitive scores and, over time, greater decreases in cognition, according to the study.

Worse higher order visual performance also predicted a higher likelihood of dementia, frailty, and death over 3 years, researchers reported. However, retinal thickness of the ganglion cell–inner plexiform layer at baseline did not predict cognition or poor outcomes over the study period.

“This study confirms that higher order visual tests could be useful to stratify patients to enrich clinical trials and as predictive measures in the clinic, but that structural retinal measures are less likely to be effective in this way,” researchers advised.

Reference: 
Hannaway N, Zarkali A, Leyland LA, et al. Visual dysfunction is a better predictor than retinal thickness for dementia in Parkinson’s disease. J Neurol Neurosurg Psychiatry. Published online April 20, 2023. doi:10.1136/jnnp-2023-331083