Clinical and pathological features of cognitive-predominant corticobasal degeneration

OBJECTIVE: To describe clinical and pathological characteristics of CBD with cognitive predominant problem during the disease course.

METHODS: In a series of autopsy-confirmed cases of CBD, we identified patients with cognitive rather than motor predominant features (CBD-Cog), including five patients thought to have Alzheimer disease (AD) (CBD-AD) and ten patients thought to have behavioral variant frontotemporal dementia (FTD) (CBD-FTD). We compare clinical and pathological features of CBD-Cog with those from a series of 31 patients with corticobasal syndrome (CBD-CBS). For pathological comparisons between CBD-Cog and CBD-CBS, we use semiquantitative scoring of neuronal and glial lesion types in multiple brain regions and quantitative assessments of tau burden from image analysis.

RESULTS: Five of 15 CBD-Cog patients never had significant motor problems during their disease course. The most common cognitive abnormalities in CBD-Cog were executive and visuospatial dysfunction. The frequency of language problems did not differ between CBD-Cog and CBD-CBS. Argyrophilic grain disease, which is a medial temporal tauopathy associated with mild cognitive impairment, was more frequent in CBD-Cog. Apathy was also more frequent in CBD-Cog. Tau pathology in CBD-Cog was greater in the temporal and less in peri-Rolandic cortices than in CBD-CBS.

CONCLUSION: A subset of patients with CBD has a cognitive predominant syndrome than can be mistaken for AD or FTD. Our findings suggest that distribution of tau cortical pathology (greater in temporal and less in peri-Rolandic cortices) may be the basis of this uncommon clinical variant of CBD.