Cerebrospinal fluid total tau as a marker of Alzheimer's disease intensity

Objectives: The aim of this longitudinal study was to test the hypothesis that CSF biomarkers in AD patients also may be forward-looking measures that are associated not only with the degree and profile of cognitive impairment but also with changes in cognition over time. Methods: Here, we assessed the association of CSF A beta 42, T-tau and P-tau with neuropsychological scores of disease severity, as well as the rate of disease progression, in 142 patients with Alzheimer's disease. All patients were part of a 3-year prospective longitudinal treatment study. Results: A more rapid progress in MM SE score reduction was seen in AD patients with T-tau levels higher than the upper quartile (800 ng/L) compared with Alzheimer's disease patients with lower T-tau levels (p = 0.008). We also found that individuals with T-tau > 800 ng/L performed worse in total scores and especially in memory and orientation when assessed with MMSE and A DAS cog than patients with T-tau <800 ng/L. Similar results were obtained for P-tau. No associations were seen between A beta 42 and cognitive scores or disease progression. Discussion: These findings support the hypothesis that increased levels of T-tau reflect the intensity of the disease and are associated with a more rapid disease progress. Copyright (C) 2009 John Wiley & Sons, Ltd.