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.