The diagnostic value of cerebrospinal fluid tau protein in dementing and nondementing neuropsychiatric disorders

Cerebrospinal. fluid (CSF) total tau protein (tau(T)) is increased in Alzheimer's disease (AD) and may be of some help in the diagnostic work-up of demented patients. The aim of the present study was to investigate the diagnostic aid and the additional help (over that of clinical criteria) of tau(T) in different clinical situations. Double-sandwich enzyme-linked immunosorbent assay was used to quantify tau(T) in 61 healthy controls and 241 patients with various neuropsychiatric diseases. Our results suggest that CSF tau(T) offers significant additional information over that of clinical criteria of AD, for the discrimination of AD from normal aging, depression, synucleinopathy, and possibly vascular dementia. However, for the differential diagnosis from frontotemporal dementia, corticobasal ganglionic degeneration, and secondary dementia, the diagnostic value is inadequate.