title: Changes in mild cognitive impairment and its subtypes as seen on diffusion tensor imaging.
abstract: BACKGROUND
  Previous studies using diffusion tensor imaging (DTI) have observed microstructural abnormalities in white matter regions in both Alzheimer's disease and mild cognitive impairment (MCI). The aim of this work was to examine the abnormalities in white matter and subcortical regions of MCI and its subtypes in a large, community-dwelling older aged cohort.
  
  
  METHODS
  A community-based sample of 396 individuals without dementia underwent medical assessment, neuropsychiatric testing, and neuroimaging. Of these, 158 subjects were classified as MCI and 238 as cognitively normal (controls) based on international MCI consensus criteria. Regional fractional anisotropy (FA) and mean diffusivity (MD) measures were calculated from the DTI and compared between groups. The false discovery rate correction was applied for multiple testing.
  
  
  RESULTS
  Subjects with MCI did not have significant differences in FA compared with controls after correction for multiple testing, but had increased MD in the right putamen, right anterior limb of the internal capsule, genu and splenium of the corpus callosum, right posterior cingulate gyrus, left superior frontal gyrus, and right and left corona radiata. When compared with controls, changes in left anterior cingulate, left superior frontal gyrus, and right corona radiata were associated with amnestic MCI (aMCI), whereas changes in the right putamen, right anterior limb of the internal capsule, and the right corona radiata were associated with non-amnestic MCI (naMCI). On logistic regression, the FA values in the left superior gyrus and MD values in the anterior cingulate distinguished aMCI from naMCI.
  
  
  CONCLUSIONS
  MCI is associated with changes in white matter and subcortical regions as seen on DTI. Changes in some anterior brain regions distinguish aMCI from naMCI.
authors.affiliation: Brain and Ageing Research Program, School of Psychiatry, University of New South Wales, Sydney, Australia.
authors.forename: Senthil
authors.initials: S
authors.lastname: Thillainadesan
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
authors.forename: Lin
authors.initials: L
authors.lastname: Zhuang
authors.forename: John
authors.initials: J
authors.lastname: Crawford
authors.forename: Nicole
authors.initials: N
authors.lastname: Kochan
authors.forename: Simone
authors.initials: S
authors.lastname: Reppermund
authors.forename: Melissa
authors.initials: M
authors.lastname: Slavin
authors.forename: Julian
authors.initials: J
authors.lastname: Trollor
authors.forename: Henry
authors.initials: H
authors.lastname: Brodaty
authors.forename: Perminder
authors.initials: P
authors.lastname: Sachdev
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology; D060825:Cognitive Dysfunction / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D003337:Corpus Callosum / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D005625:Frontal Lobe / Q000473:pathology; D006179:Gyrus Cinguli / Q000473:pathology; D006801:Humans; D016015:Logistic Models; D008297:Male; D059906:Neuroimaging; D009483:Neuropsychological Tests