title: Different patterns of white matter degeneration using multiple diffusion indices and volumetric data in mild cognitive impairment and Alzheimer patients.
abstract: Alzheimeŕs disease (AD) represents the most prevalent neurodegenerative disorder that causes cognitive decline in old age. In its early stages, AD is associated with microstructural abnormalities in white matter (WM). In the current study, multiple indices of diffusion tensor imaging (DTI) and brain volumetric measurements were employed to comprehensively investigate the landscape of AD pathology. The sample comprised 58 individuals including cognitively normal subjects (controls), amnestic mild cognitive impairment (MCI) and AD patients. Relative to controls, both MCI and AD subjects showed widespread changes of anisotropic fraction (FA) in the corpus callosum, cingulate and uncinate fasciculus. Mean diffusivity and radial changes were also observed in AD patients in comparison with controls. After controlling for the gray matter atrophy the number of regions of significantly lower FA in AD patients relative to controls was decreased; nonetheless, unique areas of microstructural damage remained, e.g., the corpus callosum and uncinate fasciculus. Despite sample size limitations, the current results suggest that a combination of secondary and primary degeneration occurrs in MCI and AD, although the secondary degeneration appears to have a more critical role during the stages of disease involving dementia.
authors.affiliation: Alzheimer's Disease Center-Institute of Psychiatry, Universidade Federal do Rio de Janeiro, Brazil. gsalves123@hotmail.com
authors.forename: Gilberto Sousa
authors.initials: GS
authors.lastname: Alves
authors.forename: Laurence
authors.initials: L
authors.lastname: O'Dwyer
authors.forename: Alina
authors.initials: A
authors.lastname: Jurcoane
authors.forename: Viola
authors.initials: V
authors.lastname: Oertel-Knöchel
authors.forename: Christian
authors.initials: C
authors.lastname: Knöchel
authors.forename: David
authors.initials: D
authors.lastname: Prvulovic
authors.forename: Felipe
authors.initials: F
authors.lastname: Sudo
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Alves
authors.forename: Letice
authors.initials: L
authors.lastname: Valente
authors.forename: Denise
authors.initials: D
authors.lastname: Moreira
authors.forename: Fabian
authors.initials: F
authors.lastname: Fußer
authors.forename: Fabian
authors.initials: F
authors.lastname: Fuβer
authors.forename: Tarik
authors.initials: T
authors.lastname: Karakaya
authors.forename: Johannes
authors.initials: J
authors.lastname: Pantel
authors.forename: Eliasz
authors.initials: E
authors.lastname: Engelhardt
authors.forename: Jerson
authors.initials: J
authors.lastname: Laks
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D016880:Anisotropy; D001931:Brain Mapping; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000473:pathology*; D003337:Corpus Callosum / Q000473:pathology* / Q000503:physiopathology; D004058:Diffusion; D056324:Diffusion Tensor Imaging; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology / Q000503:physiopathology; D006624:Hippocampus / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D009929:Organ Size; D014855:Wallerian Degeneration / Q000473:pathology