title: Disrupted white matter integrity is associated with cognitive deficits in patients with amnestic mild cognitive impairment: An atlas-based study.
abstract: OBJECTIVE
  This study investigated white matter integrity in patients with amnestic mild cognitive impairment by diffusion tensor imaging.
  
  
  METHODS
  A total of 83 patients with amnestic mild cognitive impairment and 85 elderly healthy controls underwent neuropsychological testing and a diffusion tensor imaging scan. Whole-brain white matter data were parcellated into 50 regions based on the anatomical ICBM-DTI-81 atlas, and regional diffusion metrics consisting of fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity were calculated for each region. Diffusion tensor imaging indices were compared between groups, and it was determined that between-group differences were significantly correlated with neurocognitive performance.
  
  
  RESULTS
  Relative to the healthy controls group, the amnestic mild cognitive impairment group exhibited poorer cognitive performance in all neuropsychological tests except the complex figure test (p = 0.083) and showed decreased mean fractional anisotropy in the fornix, increased mean diffusivity in the fornix and bilateral uncinate fasciculus, elevated axial diffusivity in the fornix and genu of corpus callosum, and elevated radial diffusivity in the fornix and bilateral uncinate fasciculus (p < 0.05). Behaviorally, integrity of the bilateral uncinate fasciculus was correlated positively with episodic memory function, while left uncinate fasciculus integrity was positively associated with language function in the amnestic mild cognitive impairment group (p < 0.05).
  
  
  CONCLUSIONS
  White matter abnormalities in neural pathways associated with memory were correlated with neurocognitive deficiencies in amnestic mild cognitive impairment. Given that amnestic mild cognitive impairment is putatively a prodromal syndrome for Alzheimer's disease, this study furthers our understanding of the white matter changes associated with Alzheimer's disease pathogenesis in the predementia stage.
authors.affiliation: Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China.
authors.forename: Duan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China.
authors.forename: Zan
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Shu
authors.affiliation: Department of Neurology, The Second People's Hospital Of Chengdu, Chengdu, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Zhang
keywords: Amnestic mild cognitive impairment; atlas-based analysis; cognitive function; diffusion tensor imaging