All patients will have a lumbar puncture for ABeta 42 and Tau proteins for Alzheimer's Spectrum. This spinal fluid examination has been shown to be both sensitive and specific for Alzheimer's disease (ref 20). Cerebrospinal fluid (CSF) tau levels are also elevated in alpha synucleinopathy and frontotemporal lobar degeneration (ref 21). The lumbar puncture is performed once at entry.