title: Gray matter atrophy associated with mild cognitive impairment in Parkinson's disease.
abstract: OBJECTIVE
  The underlying pathology of brain leading to cognitive impairment in Parkinson's disease (PD) remains poorly understood. The aim of our study was to test the hypothesis that mild cognitive impairment (MCI) in PD may be related to atrophy of special gray matter regions.
  
  
  METHODS
  High-resolution T1-weighted magnetic resonance images of the brains and comprehensive cognitive function tests were acquired in 37 PD patients and 21 healthy controls (HC) from September 2013 to October 2014. Patients were divided into two groups: PD with MCI (PD-MCI, n=18) and PD with normal cognition (PDNC, n=19). Gray matter density differences were analyzed using voxel-based morphometry (VBM). VBM and cognitive results, UPDRS scores and Hoehn-Yahr stages were compared between PD-MCI, PDCN and HC group, and correlation analyses were performed between those brain areas and cognition scores, UPDRS scores and disease duration, which showed significant group differences.
  
  
  RESULTS
  The demographic data and motor severity among three groups were similar. However, comprehensive cognitive function results were more severe in PD-MCI than the other two groups. Compared to the HC group, the PDNC group showed reductions in gray matter density in frontal, temporal, parietal, bilateral insula lobes and many other regions of brain. Besides above changes, the PD-MCI group also revealed gray matter concentration decrease in left hippocampus and thalamus, and these changes still remained when compared with the PDNC group. The HC group did not show any more areas of atrophy in gray matter than others. Gray matter loss in PD represented significant correlations with global cognitive scores, motor severity or disease duration in some of these atrophic regions.
  
  
  CONCLUSIONS
  The initial stages of cognitive function decline in patients with PD is closely associated with gray matter atrophy in left hippocampus and thalamus. These two regions may serve as potential imaging biomarkers for PD-MCI.
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Fu-Xiang
authors.initials: FX
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China. Electronic address: kdz99988@sina.com.
authors.forename: De-Zhi
authors.initials: DZ
authors.lastname: Kang
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Fu-Yong
authors.initials: FY
authors.lastname: Chen
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.affiliation: Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, Zhejiang, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Liang-Hong
authors.initials: LH
authors.lastname: Yu
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Yuan-Xiang
authors.initials: YX
authors.lastname: Lin
authors.affiliation: Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Zhang-Ya
authors.initials: ZY
authors.lastname: Lin
mesh_terms: D000368:Aged; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000473:pathology*; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000473:pathology* / Q000523:psychology
keywords: Brain atrophy; Mild cognitive impairment; Parkinson’s disease; Voxel-based morphometry