RT Journal Article
SR Electronic
T1 Left frontal cortex connectivity underlies cognitive reserve in prodromal Alzheimer disease
JF Neurology
JO Neurology
FD Lippincott Williams & Wilkins
SP 1054
OP 1061
DO 10.1212/WNL.0000000000003711
VO 88
IS 11
A1 Franzmeier, Nicolai
A1 Duering, Marco
A1 Weiner, Michael
A1 Dichgans, Martin
A1 Ewers, Michael
A1 ,
YR 2017
UL http://n.neurology.org/content/88/11/1054.abstract
AB Objective: To test whether higher global functional connectivity of the left frontal cortex (LFC) in Alzheimer disease (AD) is associated with more years of education (a proxy of cognitive reserve [CR]) and mitigates the association between AD-related fluorodeoxyglucose (FDG)-PET hypometabolism and episodic memory.Methods: Forty-four amyloid-PET–positive patients with amnestic mild cognitive impairment (MCI-Aβ+) and 24 amyloid-PET–negative healthy controls (HC) were included. Voxel-based linear regression analyses were used to test the association between years of education and FDG-PET in MCI-Aβ+, controlled for episodic memory performance. Global LFC (gLFC) connectivity was computed through seed-based resting-state fMRI correlations between the LFC (seed) and each voxel in the gray matter. In linear regression analyses, education as a predictor of gLFC connectivity and the interaction of gLFC connectivity × FDG-PET hypometabolism on episodic memory were tested.Results: FDG-PET metabolism in the precuneus was reduced in MCI-Aβ+ compared to HC (p = 0.028), with stronger reductions observed in MCI-Aβ+ with more years of education (p = 0.006). In MCI-Aβ+, higher gLFC connectivity was associated with more years of education (p = 0.021). At higher levels of gLFC connectivity, the association between precuneus FDG-PET hypometabolism and lower memory performance was attenuated (p = 0.027).Conclusions: Higher gLFC connectivity is a functional substrate of CR that helps to maintain episodic memory relatively well in the face of emerging FDG-PET hypometabolism in early-stage AD.Aβ=β-amyloid; AD=Alzheimer disease; ADNI=Alzheimer's Disease Neuroimaging Initiative; BNT=Boston Naming Test; CR=cognitive reserve; EPI=echo-planar imaging; FDG=fluorodeoxyglucose; gLFC=global left frontal cortex; GM=gray matter; HC=healthy controls; LFC=left frontal cortex; MCI=mild cognitive impairment; MEM=episodic memory composite score; OP=occipital pole; ROI=region of interest; SUVR=standardized uptake value ratio; TMT-B=Trail-Making Test B