No increase in cerebrospinal fluid tau protein levels in patients with vascular dementia

Tau protein levels in cerebrospinal fluid (CSF-tau) were determined in 29 p atients with old cerebrovascular disease (CVD, 21 demented and eight non-de mented), 69 patients with Alzheimer's disease (AD) and 17 age-matched norma l controls. The CSF tau level in the vascular dementia (VD) group (24.0 +/- 17.0 pg/ml) was significantly lower (P < 0.0001) than that in the AD group (90.0 +/- 45.3 pg/ml), but not significantly different from that in the no n-demented patients with CVD (18.1 +/- 10.2 pg/ml) or controls (20.3 +/- 13 .0 pg/ml). Among the VD patients, 1/21 exceeded a cut-off value (mean +/- 2 SD of controls), whereas 8/69 of the AD patients had CSF-tau levels below this value. These findings suggest that VD constitutes a group of dementias that can be separated from AD by normal CSF-tau levels. CSF-tau determinat ions in combination with other clinical findings may provide another diagno stic aid in the differential diagnosis between VD and AD. (C) 1998 Elsevier Science ireland Ltd. All rights reserved.