Frontotemporal Dementia

There have been many case descriptions of PiD where the patients had prominent signs of Parkinson's such as slow movements and rigid muscles, known as extrapyramidal features. When Rebeiz and colleagues described selected degeneration of the brain structures they recognized the similarity of the pathology to PiD. This was subsequently confirmed by several investigators who contributed further clinical details and relabelled it corticobasal degeneration (CBD) or corticobasal ganglionic degeneration (CBGD). The asymmetrical extrapyramidal syndrome combined with an inability to perform complete movements (apraxia) and "alien hand," unresponsive to levodopa (the usual treatment for Parkinson's disease), was subsequently described mainly in movement disorder clinics. The interest focused on the extrapyramidal syndrome may have led to the belief that behavioral changes are rare and dementia occurs only in a minority of CBD cases. However, when well-documented case descriptions are specifically reviewed, behavioral, cognitive, and language disturbances suggestive of frontal and temporal lobe involvement seem to be frequent features during the course of the disease.