title: Topographic pattern of cortical thinning with consideration of motor laterality in Parkinson disease.
abstract: BACKGROUND
  The asymmetry of Parkinson's disease (PD) may contribute to the unilateral appearance of parkinsonism, as well as its cerebral morphological changes. However, previous studies have not considered that cerebral involvement would probably be asymmetric. Our study aimed to identify whether one-sided symptom dominance has an influence on cortical thinning patterns in early-stage, non-demented PD patients from cortical thickness analyses and cortical thinning patterns are associated with motor functions.
  
  
  METHODS
  We used cortical thickness analysis in 64 non-demented right-handed subjects: 21 PD patients with left-sided disease onset (LPD), 21 PD patients with right-sided disease onset (RPD) and 22 control subjects. We modeled local cortical thickness as a linear association with each motor symptom.
  
  
  RESULTS
  We identified three clusters exhibiting significant cortical thinning (p < 0.01 RFT corrected) in the LPD group compared with the control group: a cluster including the right primary sensory, motor cortex and paracentral lobule, as well as another two clusters in bilateral parahippocampal gyri. In the RPD group, there was only one cluster that exhibited significant cortical thinning compared with the control group, located in the left lingual gyrus. There were no significant correlations between cortical thinning clusters and motor severity, any of the motor subscales including tremor, rigidity, bradykinesia and axial impairment.
  
  
  CONCLUSIONS
  Our right-handed PD population revealed that significant thinning of motor-related cortical areas in contralateral hemisphere to symptomatic side in LPD, but not in RPD group. Our results support that neuroprotective effect of enhanced physical activity by handedness on contralateral motor cortex.
authors.affiliation: Department of Neurology, Soonchunhyang University Hospital, Soonchunhyang University School of Medicine, Republic of Korea.
authors.forename: Ji Sun
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Republic of Korea.
authors.forename: Jin-Ju
authors.initials: JJ
authors.lastname: Yang
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Republic of Korea.
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Republic of Korea.
authors.forename: Jinyoung
authors.initials: J
authors.lastname: Youn
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Republic of Korea.
authors.forename: Ju-Min
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Republic of Korea. Electronic address: jinwhan.cho@samsung.com.
authors.forename: Jin Whan
authors.initials: JW
authors.lastname: Cho
mesh_terms: D000368:Aged; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000473:pathology* / Q000503:physiopathology*; D012720:Severity of Illness Index
keywords: Asymmetry; Cortical thickness; Functional laterality; Parkinson's disease