title: Diffusion Tensor Imaging Predictors of Episodic Memory Decline in Healthy Elders at Genetic Risk for Alzheimer's Disease.
abstract: White matter (WM) integrity within the mesial temporal lobe (MTL) is important for episodic memory (EM) functioning. The current study investigated the ability of diffusion tensor imaging (DTI) in MTL WM tracts to predict 3-year changes in EM performance in healthy elders at disproportionately higher genetic risk for Alzheimer's disease (AD).
  
  
  
  Fifty-one cognitively intact elders (52% with family history (FH) of dementia and 33% possessing an Apolipoprotein E ε4 allelle) were administered the Rey Auditory Verbal Learning Test (RAVLT) at study entry and at 3-year follow-up. DTI scanning, conducted at study entry, examined fractional anisotropy and mean, radial and axial diffusion within three MTL WM tracts: uncinate fasciculus (UNC), cingulate-hippocampal (CHG), and fornix-stria terminalis (FxS). Correlations were performed between residualized change scores computed from RAVLT trials 1-5, immediate recall, and delayed recall scores and baseline DTI measures; MTL gray matter (GM) and WM volumes; demographics; and AD genetic and metabolic risk factors.
  
  
  
  Higher MTL mean and axial diffusivity at baseline significantly predicted 3-year changes in EM, whereas baseline MTL GM and WM volumes, FH, and metabolic risk factors did not. Both ε4 status and DTI correlated with change in immediate recall.
  
  
  
  Longitudinal EM changes in cognitively intact, healthy elders can be predicted by disruption of the MTL WM microstructure. These results are derived from a sample with a disproportionately higher genetic risk for AD, suggesting that the observed WM disruption in MTL pathways may be related to early neuropathological changes associated with the preclinical stage of AD. (JINS, 2016, 22, 1005-1015).
authors.affiliation: 1Department of Psychology,Rosalind Franklin University of Medicine and Science,North Chicago,Illinois.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Lancaster
authors.affiliation: 1Department of Psychology,Rosalind Franklin University of Medicine and Science,North Chicago,Illinois.
authors.forename: Michael
authors.initials: M
authors.lastname: Seidenberg
authors.affiliation: 2Department of Kinesiology,University of Maryland,College Park,Maryland.
authors.forename: J Carson
authors.initials: JC
authors.lastname: Smith
authors.affiliation: 3Department of Psychology,Marquette University,Milwaukee,Wisconsin.
authors.forename: Kristy A
authors.initials: KA
authors.lastname: Nielson
authors.affiliation: 5Department of Psychology,Wayne State University,Detroit,Wisconsin.
authors.forename: John L
authors.initials: JL
authors.lastname: Woodard
authors.affiliation: 4Department of Neurology,Medical College of Wisconsin,Milwaukee,Wisconsin.
authors.forename: Sally
authors.initials: S
authors.lastname: Durgerian
authors.affiliation: 6Neurological Institute,Cleveland Clinic,Cleveland,Ohio.
authors.forename: Stephen M
authors.identifier: 0000-0002-6463-7460
authors.initials: SM
authors.lastname: Rao
mesh_terms: D000359:Aftercare; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics / Q000473:pathology / Q000502:physiology; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D053327:Apolipoprotein E4 / Q000235:genetics*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D011379:Prognosis; D012306:Risk; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology*; D066127:White Matter / Q000000981:diagnostic imaging / Q000473:pathology*
chemical_list: D053327:Apolipoprotein E4
keywords: Alzheimer’s disease; Anatomical MRI; Apolipoprotein E; Diffusion tensor imaging; Episodic memory; Mesial temporal lobe