title: The contributions of MRI-based measures of gray matter, white matter hyperintensity, and white matter integrity to late-life cognition.
abstract: OBJECTIVE
  GM volume, WMH volume, and FA are each associated with cognition; however, few studies have detected whether these 3 different types of MR imaging measurements exert independent or additive effects on cognitive performance. To detect their extent of contribution to cognitive performance, we explored the independent and additive contributions of GM atrophy, white matter injury, and white matter integrity to cognition in elderly patients.
  
  
  METHODS
  Two hundred and 9 elderly patients participated in the study: 97 were CN adults, 65 had MCI, and 47 had dementia. We measured GM on T1-weighted MR imaging, WMH on FLAIR, and FA on DTI, along with psychometrically matched measures of 4 domains of cognitive performance, including semantic memory, episodic memory, executive function, and spatial abilities.
  
  
  RESULTS
  As expected, patients with dementia performed significantly more poorly in all 4 cognitive domains, whereas patients with MCI performed generally less poorly than dementia patients, though considerable overlap in performance was present across groups. GM, FA, and WMH each differed significantly between diagnostic groups and were associated with cognitive measures. In multivariate models that included all 3 MR imaging measures (GM, WMH, and FA), GM volume was the strongest determinant of cognitive performance.
  
  
  CONCLUSIONS
  These results strongly suggest that MR imaging measures of GM are more closely associated with cognitive function than WM measures across a broad range of cognitive and functional impairment.
authors.affiliation: Imaging of Dementia & Aging (IDeA) Laboratory, Department of Neurology, University of California, Davis, 1544 Newton Ct, Davis, CA 95618, USA. jing.he@ucdmc.ucdavis.edu
authors.forename: J
authors.initials: J
authors.lastname: He
authors.forename: V S S
authors.initials: VS
authors.lastname: Wong
authors.forename: E
authors.initials: E
authors.lastname: Fletcher
authors.forename: P
authors.initials: P
authors.lastname: Maillard
authors.forename: D Y
authors.initials: DY
authors.lastname: Lee
authors.forename: A-M
authors.initials: AM
authors.lastname: Iosif
authors.forename: B
authors.initials: B
authors.lastname: Singh
authors.forename: O
authors.initials: O
authors.lastname: Martinez
authors.forename: A E
authors.initials: AE
authors.lastname: Roach
authors.forename: S N
authors.initials: SN
authors.lastname: Lockhart
authors.forename: L
authors.initials: L
authors.lastname: Beckett
authors.forename: D
authors.initials: D
authors.lastname: Mungas
authors.forename: S T
authors.initials: ST
authors.lastname: Farias
authors.forename: O
authors.initials: O
authors.lastname: Carmichael
authors.forename: C
authors.initials: C
authors.lastname: DeCarli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology / Q000502:physiology*; D001921:Brain / Q000166:cytology / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D003704:Dementia / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000502:physiology*; D009474:Neurons / Q000166:cytology* / Q000502:physiology