title: Exploratory analysis of neuropsychological and neuroanatomical correlates of progressive mild cognitive impairment in Parkinson's disease.
abstract: BACKGROUND
  Parkinson's disease with mild cognitive impairment (PD-MCI) is a heterogeneous entity in terms of cognitive profiles and conversion to dementia. However, the risk factors for ongoing cognitive decline in patients with PD-MCI are not clearly defined.
  
  
  METHODS
  51 patients with PD-MCI were prospectively followed-up for a minimum of 2 years. Subjects were classified as MCI converters (n=15) or MCI non-converters (n=36) based on whether they were subsequently diagnosed with PD dementia. We explored cognitive profiles and neuroanatomical characteristics of PD-MCI converters using voxel based morphometry (VBM) of grey matter (GM) density and region of interest based volumetric analysis of the substantia innominata (SI).
  
  
  RESULTS
  PD-MCI converters showed more severe cognitive deficits in frontal executive functions, immediate verbal memory and visual recognition memory compared with PD-MCI non-converters. VBM analysis revealed that PD-MCI converters had significantly lower GM density in the left prefrontal areas, left insular cortex and bilateral caudate nucleus compared with that in PD-MCI non-converters. The mean normalised SI volume was significantly smaller in both PD-MCI converters (1.19±0.35, p<0.001) and PD-MCI non-converters (1.52±0.27, p<0.001) compared with that in controls (1.87±0.19). PD-MCI converters had a significantly smaller normalised SI volume than PD-MCI non-converters (p<0.001).
  
  
  CONCLUSIONS
  Our data show that atrophy in the frontostriatal areas and cholinergic structures, as well as frontal lobe associated cognitive performance, may act as predictors of dementia in PD-MCI patients, suggesting distinctive patterns of cognitive profiles and a neuroanatomical basis for progressive PD-MCI.
authors.affiliation: Department of Neurology and Brain Research Institute, Yonsei University College of Medicine, , Seoul, Korea.
authors.forename: Ji E
authors.initials: JE
authors.lastname: Lee
authors.forename: Kyoo H
authors.initials: KH
authors.lastname: Cho
authors.forename: Sook K
authors.initials: SK
authors.lastname: Song
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.forename: Young H
authors.initials: YH
authors.lastname: Sohn
authors.forename: Phil Hyu
authors.initials: PH
authors.lastname: Lee
mesh_terms: D000368:Aged; D001288:Attention / Q000502:physiology; D001921:Brain / Q000473:pathology; D060825:Cognitive Dysfunction / Q000209:etiology / Q000473:pathology* / Q000523:psychology*; D015331:Cohort Studies; D003704:Dementia / Q000209:etiology / Q000523:psychology; D018450:Disease Progression; D056344:Executive Function; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007807:Language Tests; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000473:pathology* / Q000523:psychology*; D011446:Prospective Studies; D011597:Psychomotor Performance / Q000502:physiology; D057190:Stroop Test
keywords: Cognition; Dementia; Neuroanatomy; Parkinson'S Disease