A flurry of national news reports followed the publication last August of research that evaluated the association of β-amyloid and tau proteins in cerebrospinal fluid (CSF) with Alzheimer disease pathology in the brain, as well as their ability to predict which patients with mild cognitive impairment would progress to Alzheimer disease (De Meyer G et al. Arch Neurol. 2010;67:949-956). In the study, 90% of those with Alzheimer disease and 72% with mild cognitive impairment had these biomarkers, as did 36% of those classified as cognitively normal. Among autopsy-confirmed cases, 94% were correctly classified as having Alzheimer disease.