The corticobasal degeneration syndrome overlaps progressive aphasia and frontotemporal dementia

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. Corticobasal degeneration has been mainly described as a movement disorder, but cognitive impairment is also increasingly noted. 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. 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. 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."