Different profiles of Alzheimer's disease cerebrospinal fluid biomarkers in controls and subjects with subjective memory complaints.

Cerebrospinal fluid (CSF) biomarkers, such as Aβ(42), total-tau and phosphorylated-tau(181) reflect neuropathological changes of Alzheimer's disease (AD). We studied these biomarkers in 24 controls and 19 subjects with subjective memory complaints, and we distinguished different CSF profiles: normal (group 1, 55.8%), only pathologic Aβ(42) (group 2, 27.9%), pathologic Aβ(42) plus pathologic total-tau and/or phosphorylated-tau(181) (group 3, 7%), and only pathologic total-tau and phosphorylated-tau(181) (group 4, 9.3%). Group 2 could represent an earlier phase of preclinical AD than group 3, and group 4 an unknown etiology.