title: A comparative analysis of cognitive profiles and white-matter alterations using voxel-based diffusion tensor imaging between patients with Parkinson's disease dementia and dementia with Lewy bodies.
abstract: BACKGROUND
  Despite clinical and neuropsychological similarities between Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB), recent studies have demonstrated that structural and pathological changes are more severe in DLB than in PDD.
  
  
  METHODS
  19 patients with probable PDD and 18 patients with probable DLB who had a similar overall severity of dementia and demographic characteristics were examined by a standardised neuropsychological test and voxel-based analysis of fractional anisotropy (FA) using diffusion tensor imaging (DTI).
  
  
  RESULTS
  The patients with DLB performed significantly worse in visual recognition memory, semantic fluency and ideomotor praxis than those with PDD (p<0.05). Compared with controls, the FA value in patients with PDD was significantly lower in bilateral frontal, left temporal and left parietal white matter. In patients with DLB, the pattern of FA reduction was similar to that of patients with PDD; however, white-matter abnormalities were more severe and extended into bilateral insular, bilateral posterior cingular and bilateral visual association regions. In a direct comparison between PDD and DLB, the FA value in patients with DLB was significantly decreased in bilateral posterior temporal, posterior cingular and bilateral visual association fibres extending into occipital areas.
  
  
  CONCLUSIONS
  Despite global similarities in cognitive performance and white-matter pathology between DLB and PDD patients, those with DLB had more severely impaired frontal and temporal area-associated cognitive subsets, and more severe white-matter pathology in temporal and visual association fibres. These data suggest that differences in the underlying nature of PDD and DLB may exist with global similarities in their cognitive performance and white-matter pathology.
authors.affiliation: Department of Neurology and Brain Research Institute, Yonsei University Medical College, Seodaemun-gu, Seoul, 120-752, South Korea.
authors.forename: Ji E
authors.initials: JE
authors.lastname: Lee
authors.forename: Hae-Jeong
authors.initials: HJ
authors.lastname: Park
authors.forename: BoSuk
authors.initials: B
authors.lastname: Park
authors.forename: Sook K
authors.initials: SK
authors.lastname: Song
authors.forename: Young H
authors.initials: YH
authors.lastname: Sohn
authors.forename: Jong Doo
authors.initials: JD
authors.lastname: Lee
authors.forename: Phil Hyu
authors.initials: PH
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002540:Cerebral Cortex / Q000473:pathology*; D003704:Dementia / Q000175:diagnosis*; D003937:Diagnosis, Differential; D056324:Diffusion Tensor Imaging; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology*; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000175:diagnosis*