The corticobasal degeneration syndrome overlaps progressive aphasia and frontotemporal dementia

Objective: To provide evidence for the hypothesis that the corticobasal degeneration syndrome (CBDs) overlaps significantly with primary progressive aphasia and frontotemporal dementia, and that CBDs is part of the Pick complex. Background: Corticobasal degeneration has been mainly described as a movement disorder, but cognitive impairment is also increasingly noted. Methods: Thirty-five cases of clinically diagnosed CBDs were followed-up with clinical, neuropsychological, and neuroimaging investigations. Twenty-nine patients were seen prospectively in movement disorder and cognitive neurology clinics; five of these came to autopsy. Six other autopsied cases that fulfilled the clinical criteria of CBDs were added with retrospective review of records. Results: All 15 patients presenting with movement disorders developed behavioral, cognitive, or language deficits shortly after onset or after several years. Patients presenting with cognitive problems (n = 20), progressive aphasia (n = 13), or frontotemporal dementia (n = 7) developed the movement disorder subsequently. Eleven cases with autopsy had CBD or other forms of the Pick complex. Conclusions: There is a clinical overlap between CBD, frontotemporal dementia, and primary progressive aphasia. There is also a pathologic overlap between these clinical syndromes. The recognition of this overlap will facilitate the diagnosis and avoid consideration of CBD as 'heterogenous.