[o2–10–03]: Severity of Subjective Cognitive Decline Aligns With Regional Amyloid Severity: Findings From the Harvard Aging Brain Study
Year: 2017
Type: article
Study design: Observational Study
Abstract: Post-mortem and neuroimaging studies suggest that striatal Aβ is a useful predictor of Alzheimer's disease clinicopathology, and later Braak neurofibrillary tangle stages. Striatal Aβ deposition appears after neocortical Aβ deposition, with evidence of both predicting the steepest cognitive decline in clinically-normal older adults (Hanseeuw, submitted 2017). Subjective cognitive decline (SCD) is associated with neocortical Aβ, but studies have not examined neocortical Aβ and striatal Aβ simultaneously. We examined the hypothesis that neocortical Aβ, followed by neocortical and striatal Aβ, would incrementally influence SCD severity. 286 older participants (74yrs, SD=6.4, CDR 0=281/CDR 0.5=5) from the Harvard Aging Brain Study underwent PiB-PET imaging and neuropsychological assessment. Striatal Aβ was an average of caudate and putamen ROIs, with a cut-off>1.64 distribution value ratio as derived using Gaussian mixture modeling. Neocortical Aβ was a composite measure of frontal, lateral and retrosplenial tracer (FLR) uptake. An Aβ group was created to emulate three stages of increasing amyloidosis severity; Aβ FLR- (n=207); Aβ FLR+/striatal Aβ- (n=42); Aβ FLR+/striatal Aβ+ (n=37). The Aβ FLR- group was not stratified by striatal Aβ, as only two participants exhibited high striatal Aβ burden with low Aβ FLR. An SCD composite was created using z- transformed subscales from three measures; the Memory Functioning Questionnaire (MFQ), the Everyday Cognition (ECog) battery and a seven-item concern measure. Greater SCD was correlated with greater continuous striatal Aβ, r(284)=0.22, p=.0002 (A), and also greater Aβ FLR, r(284)=.23, p=.0001. SCD severity differed across the Aβ groups, Kruskal-Wallis χ(2)=14.6, p=.0006 (B), with the most severe SCD endorsed in the Aβ FLR+/striatal Aβ+ group in comparison with Aβ FLR-, p=.0004 and Aβ FLR+/striatal Aβ-, p=.02. Multinomial logistic regression suggested that a one unit increase in SCD doubled the risk of being in the Aβ FLR+/striatal Aβ+ group in comparison with Aβ FLR- (p=.0005).
Source: Alzheimer s & Dementia
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2766534472