title: Freezing of gait in Parkinson's disease is associated with altered functional brain connectivity.
abstract: BACKGROUND
  Patients with Parkinson's disease (PD) may develop several gait disturbances during the course of illness and Freezing of gait (FOG) is one of them. Several neuroimaging studies have been conducted to identify the neural correlates of FOG but results have not been uniform. Resting state functional MRI (rs-fMRI) is relatively less explored in PD patients with FOG. This study aims to compare the whole brain resting state connectivity of PD patients with and without FOG using rs-fMRI.
  
  
  METHODS
  rs-fMRI was obtained for 28 PD patients (15 with and 13 patients without FOG) who were matched for various demographic and clinical characteristics. Seed to voxel analysis was performed at whole brain level and compared between the two groups.
  
  
  RESULTS
  When compared to patients without FOG, the patients with FOG had reduced functional connectivity across multiple seeds. Major finding was reduced inter-hemispheric connectivity of left parietal opercular cortex with multiple regions of the brain primarily involving the primary somatosensory and auditory areas, which also negatively correlated with the FOGQ scores.
  
  
  CONCLUSIONS
  Our findings suggest that alterations in the resting state functional connectivity of the opercular parietal cortex may be one of the substrates of FOG. Reduced interhemispheric connectivity probably is the reason for impairment of control and coordination in bilateral leg movements while walking.
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India; Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Lenka
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Rajini M
authors.initials: RM
authors.lastname: Naduthota
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Menka
authors.initials: M
authors.lastname: Jha
authors.affiliation: Department of Neuroimaging & Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Rajanikant
authors.initials: R
authors.lastname: Panda
authors.affiliation: Department of Neuroimaging & Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Arvind
authors.initials: A
authors.lastname: Prajapati
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India; Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Ketan
authors.initials: K
authors.lastname: Jhunjhunwala
authors.affiliation: Department of Neuroimaging & Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Jitender
authors.initials: J
authors.lastname: Saini
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India.
authors.forename: Ravi
authors.initials: R
authors.lastname: Yadav
authors.affiliation: Department of Neuroimaging & Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India. Electronic address: drrosedawn@yahoo.com.
authors.forename: Rose Dawn
authors.initials: RD
authors.lastname: Bharath
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, Karnataka, India. Electronic address: pal.pramod@rediffmail.com.
authors.forename: Pramod Kumar
authors.initials: PK
authors.lastname: Pal
mesh_terms: D000328:Adult; D000368:Aged; D000977:Antiparasitic Agents / Q000627:therapeutic use; D001921:Brain / Q000000981:diagnostic imaging*; D004185:Disability Evaluation; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007980:Levodopa / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging*; D010100:Oxygen / Q000097:blood; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy; D012720:Severity of Illness Index
chemical_list: D000977:Antiparasitic Agents; D007980:Levodopa; D010100:Oxygen
keywords: Freezing of gait; Functional brain connectivity; Parkinson's disease; Resting state functional MRI; rs-fMRI