Subjective cognitive concerns, amyloid-β, and neurodegeneration in clinically normal elderly

Objective: To determine whether neuroimaging biomarkers of amyloid-beta (A beta) and neurodegeneration (ND) are associated with greater self-reported subjective cognitive concerns (SCC) in clinically normal older individuals. Methods: A total of 257 participants underwent Pittsburgh compound B PET, PET with fluorodeoxyglucose F-18, and structural MRI, as well as a battery of neuropsychological measures including several questionnaires regarding SCC. Individuals were classified into 4 biomarker groups: biomarker negative (A beta-/ND-), amyloidosis alone (A beta+/ND-), amyloidosis plus ND (A beta+/ND+), and ND alone (A beta-/ND+). Results: Both A beta and ND were independently associated with greater SCC controlling for objective memory performance. By contrast, neither A beta nor ND was associated with objective memory performance controlling for SCC. Further examination revealed greater SCC in individuals with A beta or ND positivity compared to biomarker-negative individuals. In addition, greater SCC predicted A beta positivity when controlling for ND status. Conclusions: When individuals were grouped by biomarker status, those who were positive on A beta or ND had the highest report of SCC compared to biomarker-negative individuals. Findings were consistent when SCC was used to predict A beta positivity. Taken together, results suggest that both A beta and ND are associated with SCC, independent of objective memory performance. Enrichment of individuals with SCC may increase likelihood of A beta and ND markers in potential participants for secondary prevention trials.