Cerebrospinal fluid markers detect Alzheimer's disease in nonamnestic dementia.

INTRODUCTION: The accuracy of cerebrospinal fluid (CSF) biomarkers for detecting Alzheimer's disease (AD) pathology has not been fully validated in autopsied nonamnestic dementias.

METHODS: We retrospectively evaluated CSF amyloid β 1-42, phosphorylated-tau, and amyloid-tau index as predictors of Alzheimer pathology in patients with primary progressive aphasia, frontotemporal dementia, and progressive supranuclear palsy.

RESULTS: Nineteen nonamnestic autopsied cases with relevant CSF values were included. At autopsy, nine had AD and 10 had non-AD pathologies. All six patients whose combined CSF phosphorylated-tau and amyloid β levels were "consistent with AD" had postmortem Alzheimer pathology. The two patients whose biomarker values were "not consistent with AD" had non-AD pathologies. The CSF values of the remaining eight non-AD cases were in conflicting or borderline ranges.

DISCUSSION: CSF biomarkers reliably identified Alzheimer pathology in nonamnestic dementias and may be useful as a screening measure for inclusion of nonamnestic cases into Alzheimer's trials.