Cerebrospinal fluid markers detect Alzheimer's disease in nonamnestic dementia

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

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.

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.

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.