Comparative and longitudinal studies reveal clinical differences between subgroups of patients with frontotemporal dementia (FTD), including Progressive Non-fluent Aphasia (PNFA), Semantic Dementia (SD), patients with a disorder of social comportment and personality (SOC), and non-aphasic patients with executive dysfunction (EXEC). MRI studies of cortical atrophy and fMRI studies show correlated neural defects in FTD subgroups. The investigators will obtain converging evidence from multiple sources to test hypotheses about the neural basis for cognitive functions such as semantic memory, grammatical processing, and social functioning in these FTD subgroups, while improving clinical care for these patients. Recent studies have linked progressive supra nuclear palsy (PSP) and multiple systems atrophy (MSA) to FTD. The investigators will obtain comparable neuropsychological and biomarker data in order to compare these patient groups.
