title: Dual-task-related neural connectivity changes in patients with Parkinson' disease.
abstract: OBJECTIVE
  Dual-task (DT) gait impairment in people with Parkinson's disease (PD) and specifically in those with freezing of gait (FOG), reflects attentional dependency of movement. This study aimed to elucidate resting-state brain connectivity alterations related to DT gait abnormalities in PD with and without FOG.
  
  
  METHODS
  PD patients (n=73) and healthy age-matched controls (n=20) underwent DT gait analysis and resting-state functional Magnetic Resonance Imaging (rs-MRI) while 'off' medication. Patients were classified as freezer (n=13) or non-freezer (n=60). Functional connectivity (FC) alterations between PD and controls and between patient subgroups were assessed in regions of interest (ROIs) within the fronto-parietal and motor network.
  
  
  RESULTS
  PD had longer stance times, shorter swing times and more step length asymmetry during DT gait and needed more time and steps during DT turning compared to controls. Additionally, freezers showed similar impairments and longer double support times compared to non-freezers during DT gait. PD demonstrated hyper-connectivity between the inferior parietal lobule and premotor cortex (PMC) and between the cerebellum and the PMC and M1. FOG-specific hypo-connectivity within the striatum and between the caudate and superior temporal lobe and hyper-connectivity between the dorsal putamen and precuneus was correlated with worse DT performance.
  
  
  CONCLUSIONS
  PD showed FC alterations in DT-related networks, which were not correlated to DT performance. However, FOG-specific FC alterations in DT-related regions involving the precuneus and striatum were correlated to worse DT performance, suggesting that the balance between cognitive and motor networks is altered.
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Leuven, Belgium. Electronic address: griet.vervoort@faber.kuleuven.be.
authors.forename: G
authors.initials: G
authors.lastname: Vervoort
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Leuven, Belgium. Electronic address: elke.heremans@faber.kuleuven.be.
authors.forename: E
authors.initials: E
authors.lastname: Heremans
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Leuven, Belgium. Electronic address: aniek.bengevoord@faber.kuleuven.be.
authors.forename: A
authors.initials: A
authors.lastname: Bengevoord
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Leuven, Belgium. Electronic address: carolien.strouwen@faber.kuleuven.be.
authors.forename: C
authors.initials: C
authors.lastname: Strouwen
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Leuven, Belgium. Electronic address: evelien.nackaerts@faber.kuleuven.be.
authors.forename: E
authors.initials: E
authors.lastname: Nackaerts
authors.affiliation: University Hospitals Leuven, Department of Neurology, Leuven, Belgium. Electronic address: wim.vandenberghe@uzleuven.be.
authors.forename: W
authors.initials: W
authors.lastname: Vandenberghe
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Leuven, Belgium. Electronic address: alice.nieuwboer@faber.kuleuven.be.
authors.forename: A
authors.initials: A
authors.lastname: Nieuwboer
mesh_terms: D000368:Aged; D001921:Brain / Q000098:blood supply / Q000473:pathology*; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D007839:Functional Laterality; D020233:Gait Disorders, Neurologic / Q000209:etiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009434:Neural Pathways / Q000098:blood supply / Q000473:pathology*; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010300:Parkinson Disease / Q000150:complications* / Q000473:pathology*; D013223:Statistics as Topic
chemical_list: D010100:Oxygen
keywords: Parkinson’s disease; dual-tasking; freezing of gait; resting-state fMRI