Objective: To characterise visual processing impairments as an early feature of dementia in Lewy Body disease (LBD).
Background: Occipital and posterior parieto-temporal hypometabolism is a hallmark of dementia in LBD. These regions are known to process vision. Visual impairments are an acknowledged, albeit under-researched feature of LBD. We predict that visual impairments are an early feature of an impending dementia in LBD.
Method: To accurately identify visual impairments, we developed novel measures of dorsal and ventral visual function. The tests have inbuilt graded difficulty to parallel the insidious nature of dementia and allows for the tracking of cognitive change over disease course. A standard neuropsychological battery and the novel tests were administered to n=53 LBD participants ranging from cognitively asymptomatic through to Parkinson’s Disease Dementia and Dementia with Lewy Bodies. For comparison, n=29 Alzheimer’s Disease (AD) patients were also included. As hallucination status is a predictor of dementia in LBDs, performance on novel visual measures were compared between LBD groups with and without a history of hallucinations. Performance between novel and traditional visual measures were compared. Performance on common, visually-weighted executive function and attention measures were also compared to novel visual test performance.
Results: Impairments on novel visual tests were identified in all included patient groups. The LBD group showed both ventral and dorsal impairments with normal global cognitive abilities. Impairments on both dorsal and ventral measures occurred earlier in LBD compared to AD; this difference was greater for ventral impairments. LBD patients with a history of visual hallucinations demonstrated greater visual impairments compared to LBD patients without hallucinations. On common, visually-weighted executive function and attention measures, performance on novel visual tests explained a significant proportion of variance in performance.
Conclusion: Visual impairments are an early, hallmark predictor of a developing dementia in LBD. Visual impairments are qualitatively different between LBD and AD: both dorsal and ventral impairments are equally impaired in LBD, whereas in AD, impairments preferentially affect the dorsal stream.
To cite this abstract in AMA style:
E. Mccann, F. Coleman, A. Fazlollahi, S. Lee, J. O'Sullivan, P. Nestor. Visual processing impairments are predictive of dementia in Lewy Body disease [abstract]. Mov Disord. 2025; 40 (suppl 1). https://www.mdsabstracts.org/abstract/visual-processing-impairments-are-predictive-of-dementia-in-lewy-body-disease/. Accessed October 5, 2025.« Back to 2025 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/visual-processing-impairments-are-predictive-of-dementia-in-lewy-body-disease/