title: White matter predictors of cognitive functioning in older adults.
abstract: Few studies have applied multiple imaging modalities to examine cognitive correlates of white matter. We examined the utility of T2-weighted magnetic resonance imaging (MRI) -derived white matter hyperintensities (WMH) and diffusion tensor imaging-derived fractional anisotropy (FA) to predict cognitive functioning among older adults. Quantitative MRI and neuropsychological evaluations were performed in 112 older participants from an ongoing study of the genetics of Alzheimer's disease (AD) in African Americans. Regional WMH volumes and FA were measured in multiple regions of interest. We examined the association of regional WMH and an FA summary score with cognitive test performance. Differences in WMH and FA were compared across diagnostic groups (i.e., normal controls, mild cognitive impairment, and probable AD). Increased WMH volume in frontal lobes was associated with poorer delayed memory performance. FA did not emerge as a significant predictor of cognition. White matter hyperintensity volume in the frontal and parietal lobes was increased in MCI participants and more so in AD patients relative to controls. These results highlight the importance of regionally distributed small vessel cerebrovascular disease in memory performance and AD among African American older adults. White matter microstructural changes, quantified with diffusion tensor imaging, appear to play a lesser role in our sample.
authors.affiliation: Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
authors.forename: Irene B
authors.initials: IB
authors.lastname: Meier
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Manly
authors.forename: Frank A
authors.initials: FA
authors.lastname: Provenzano
authors.forename: Karmen S
authors.initials: KS
authors.lastname: Louie
authors.forename: Ben T
authors.initials: BT
authors.lastname: Wasserman
authors.forename: Erica Y
authors.initials: EY
authors.lastname: Griffith
authors.forename: Josina T
authors.initials: JT
authors.lastname: Hector
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Allocco
authors.forename: Adam M
authors.initials: AM
authors.lastname: Brickman
mesh_terms: D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications* / Q000473:pathology*; D000704:Analysis of Variance; D016880:Anisotropy; D060825:Cognitive Dysfunction / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009483:Neuropsychological Tests; D018709:Statistics, Nonparametric