Increasing CSF phospho-tau levels during cognitive decline and progression to dementia

Background: Little is known about longitudinal changes of cerebrospinal fluid (CSF) biomarders during cognitive dicline in neurodegenerative disease progression. Objective: To investigate longitudinal changes in CSF biomarkers - total-tau (T-tau), phospho-tau (P-tau) and beta-amyloid (A beta 42) - during cognitive decline. Methods: Forty, memory clinic patients (47.5% females), aged 61.3 +/- 7.6 (S.D.) years, non-demented at baseline, underwent lumbar puncture and neuropsychological testin, Lit two occasions. Baseline mean MMSE-score was 28.3 +/- 1.8. Patient,-, were divided into three groups, based on baseline memory functioning severely impaired (SIM), moderately impaired (MIM) and no impairment (NIM). Results: There was a significant increase in P-tau in the SIM-group during follow-up. while P-tau in MIM and NIM did not change. Eighty-three percent of the SIM-patients converted to dementia (80% AD), while most MIM- and NIM-patients remained non-demented. T-tau- and A beta 42-levels did not change in any of the memory groups during follow-up. Conclusion: Increasing P-tau levels during cognitive decline and conversion to dementia Suggest that P-tau may be useful as a longitudinal marker of the neurodegenerative process. (C) 2007 Elsevier Inc. All rights reserved.