Corticobasal degeneration and progressive aphasia.

OBJECTIVE: To describe language impairment in the corticobasal degeneration syndrome (CBDS) presenting as either a cognitive or motor disorder, to compare the evolution of aphasia in CBDS with primary progressive aphasia (PPA), and to examine whether the side of maximal cerebral atrophy or akinesia reflects the severity of aphasia.

METHODS: We divided 40 patients with CBDS according to motor or cognitive onsets and conducted detailed language assessments with the Western Aphasia Battery (WAB). We analyzed scores according to the side of atrophy and motor rigidity. Longitudinal performance over three annual assessments was compared against matched patients with PPA and Alzheimer disease.

RESULTS: Language at baseline was more impaired in cognitive than motor-onset CBDS but there was no correlation between the side of atrophy or motor impairment and the WAB. Serial assessment (n = 19) showed a similar evolution of aphasia in cognitive-onset CBDS and PPA and delayed aphasia in motor-onset CBDS.

CONCLUSION: Aphasia is common in the corticobasal degeneration syndrome but there is little correlation with the laterality of clinical deficits. Cognitive-onset corticobasal degeneration syndrome and primary progressive aphasia are similar such that their aphasia appears identical.