The application of cerebrospinal fluid biomarkers in early diagnosis of Alzheimer disease.

This article gives an updated account of the clinical application of cerebrospinal fluid (CSF) biomarkers for Alzheimer disease (AD). The clinically most relevant biomarkers, total tau, phospho-tau and Aβ42 are discussed, and how they may be used, together with other diagnostic investigations, to make a predementia diagnosis of AD. Recent findings in sporadic and genetic preclinical AD are also discussed and, more specifically, what the biomarkers have taught us on the sequence of events in the pathogenic process underlying AD.