title: Multiple indices of diffusion identifies white matter damage in mild cognitive impairment and Alzheimer's disease.
abstract: The study of multiple indices of diffusion, including axial (DA), radial (DR) and mean diffusion (MD), as well as fractional anisotropy (FA), enables WM damage in Alzheimer's disease (AD) to be assessed in detail. Here, tract-based spatial statistics (TBSS) were performed on scans of 40 healthy elders, 19 non-amnestic MCI (MCIna) subjects, 14 amnestic MCI (MCIa) subjects and 9 AD patients. Significantly higher DA was found in MCIna subjects compared to healthy elders in the right posterior cingulum/precuneus. Significantly higher DA was also found in MCIa subjects compared to healthy elders in the left prefrontal cortex, particularly in the forceps minor and uncinate fasciculus. In the MCIa versus MCIna comparison, significantly higher DA was found in large areas of the left prefrontal cortex. For AD patients, the overlap of FA and DR changes and the overlap of FA and MD changes were seen in temporal, parietal and frontal lobes, as well as the corpus callosum and fornix. Analysis of differences between the AD versus MCIna, and AD versus MCIa contrasts, highlighted regions that are increasingly compromised in more severe disease stages. Microstructural damage independent of gross tissue loss was widespread in later disease stages. Our findings suggest a scheme where WM damage begins in the core memory network of the temporal lobe, cingulum and prefrontal regions, and spreads beyond these regions in later stages. DA and MD indices were most sensitive at detecting early changes in MCIa.
authors: Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt, Germany. larodwyer@gmail.com
authors: Laurence
authors: L
authors: O'Dwyer
authors: Franck
authors: F
authors: Lamberton
authors: Arun L W
authors: AL
authors: Bokde
authors: Michael
authors: M
authors: Ewers
authors: Yetunde O
authors: YO
authors: Faluyi
authors: Colby
authors: C
authors: Tanner
authors: Bernard
authors: B
authors: Mazoyer
authors: Des
authors: D
authors: O'Neill
authors: Máiréad
authors: M
authors: Bartley
authors: D Rónán
authors: DR
authors: Collins
authors: Tara
authors: T
authors: Coughlan
authors: David
authors: D
authors: Prvulovic
authors: Harald
authors: H
authors: Hampel
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged