Visuospatial processing in patients with Alzheimer's disease and cerebral amyloid angiopathy

There is a well-established but poorly understood pathological and clinical overlap between cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD). Some studies have suggested a posterior predominance of CAA-related lesions, but it remains unclear how well this can be captured by specific measures of low- to high-level visual cortical processing.

We compared the characteristics of 30 patients with AD and/or CAA, grouped by impairment measures of low- to mid-level visual cortical processing, and explored associations with clinical characteristics, neurodegeneration biomarkers, CAA imaging features, and volumetric structural measures.

Twenty participants were classified as impaired on tasks of low- to mid-level visual cortical function. Impairment in these tasks was associated with performance on more complex visuoconstruction tasks, which in turn showed a correlation with structural integrity volume and cortical thickness in the occipital lobe. We found no association between impairment in low- to mid-level visual cortical functions or visuoconstruction tasks and specific measures of CAA or AD pathology.

Impairments in visuospatial functions, although reflecting structural damage in posterior brain regions, were not independently associated with markers of CAA or AD.