title: The Neural Basis of Postural Instability Gait Disorder Subtype of Parkinson's Disease: A PET and fMRI Study.
abstract: OBJECTIVE
  The aim of this study is to further uncover the neural basis of postural instability gait disorder (PIGD) subtype of Parkinson's disease.
  
  
  METHODS
  With F-18 fluorodeoxyglucose PET (FDG-PET), brain glucose metabolism of patients with PIGD (n = 15) was compared with healthy controls (n = 17) and tremor-dominant (TD) patients (n = 15), and the correlation between metabolism and PIGD symptoms was also assessed. Within PIGD symptom-correlated hypometabolic areas, the relationship of functional connectivity (FC) with motor and cognitive symptoms was examined by using functional MRI.
  
  
  RESULTS
  Compared with controls, patients with PIGD displayed a distributed pattern of brain hypometabolism including striatal, frontal, and parietal areas. Relative to the pattern of TD patients, the pattern of patients with PIGD had additional metabolic decreases in caudate and inferior parietal lobule (IPL, Brodmann area [BA] 40). In PIGD group, the metabolic reductions in IPL (BA 40), middle frontal gyrus (MFG, BA 9) and fusiform gyrus (FG, BA 20) were associated with severe PIGD symptoms. Regions showing such correlation were chosen for further seed-based FC analysis. Decreased FC within the prefrontal-parietal network (between the MFG and IPL) was associated with severe PIGD symptoms.
  
  
  CONCLUSIONS
  The involvement of the caudate, FG, and prefrontal-parietal network may be associated with the prominent gait impairments of PIGD subtype. Our findings expand the pathophysiological knowledge of PIGD subtype and provide valuable information for potential neuromodulation therapies alleviating gait disorders.
authors: Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Li
authors: L
authors: Zhang
authors: Department of Nuclear Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Tian-Nv
authors: TN
authors: Li
authors: Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Yong-Sheng
authors: YS
authors: Yuan
authors: Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Si-Ming
authors: SM
authors: Jiang
authors: Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Qing
authors: Q
authors: Tong
authors: Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Min
authors: M
authors: Wang
authors: Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Jian-Wei
authors: JW
authors: Wang
authors: Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Hua-Jun
authors: HJ
authors: Chen
authors: Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Jian
authors: J
authors: Ding
authors: Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Qin-Rong
authors: QR
authors: Xu
authors: Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors: Ke-Zhong
authors: KZ
authors: Zhang
mesh_terms: D000368:Aged; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D020233:Gait Disorders, Neurologic / Q000000981:diagnostic imaging* / Q000209:etiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen; D010300:Parkinson Disease / Q000150:complications* / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D004856:Postural Balance / Q000502:physiology*; D012720:Severity of Illness Index; D014202:Tremor / Q000000981:diagnostic imaging / Q000209:etiology
chemical_list: D019788:Fluorodeoxyglucose F18; D010100:Oxygen
keywords: PET; Parkinson's disease; Postural instability gait disorder subtype; fMRI