Using biomarkers to improve detection of Alzheimer's disease.

Disease-modifying approaches for Alzheimer's disease (AD) might be most effective when initiated very early in the course, before the pathologic burden and neuronal and synaptic degeneration make it unlikely that halting disease progression would have a significant impact on patient outcomes. Biomarkers of disease may provide important avenues of research to enhance the diagnosis of individuals with early AD and could assist in the identification of those individuals at risk for developing AD. However, for such biomarkers to become clinically useful, long-term follow-up studies are necessary to evaluate the relevance of cross-sectional biomarker changes to the longitudinal course of the disease. The objective of this article is to review recent progress in AD biomarkers for the early diagnosis, classification, progression and prediction of AD and their usefulness in new treatment trials.