title: Resting-state connectivity of pre-motor cortex reflects disability in multiple sclerosis.
abstract: OBJECTIVE
  To characterize the relationship between motor resting-state connectivity of the dorsal pre-motor cortex (PMd) and clinical disability in patients with multiple sclerosis (MS).
  
  
  METHODS
  A total of 27 patients with relapsing-remitting MS (RR-MS) and 15 patients with secondary progressive MS (SP-MS) underwent functional resting-state magnetic resonance imaging. Clinical disability was assessed using the Expanded Disability Status Scale (EDSS). Independent component analysis was used to characterize motor resting-state connectivity. Multiple regression analysis was performed in SPM8 between the individual expression of motor resting-state connectivity in PMd and EDSS scores including age as covariate. Separate post hoc analyses were performed for patients with RR-MS and SP-MS.
  
  
  RESULTS
  The EDSS scores ranged from 0 to 7 with a median score of 4.3. Motor resting-state connectivity of left PMd showed a positive linear relation with clinical disability in patients with MS. This effect was stronger when considering the group of patients with RR-MS alone, whereas patients with SP-MS showed no increase in coupling strength between left PMd and the motor resting-state network with increasing clinical disability. No significant relation between motor resting-state connectivity of the right PMd and clinical disability was detected in MS.
  
  
  CONCLUSIONS
  The increase in functional coupling between left PMd and the motor resting-state network with increasing clinical disability can be interpreted as adaptive reorganization of the motor system to maintain motor function, which appears to be limited to the relapsing-remitting stage of the disease.
authors: Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark.
authors: A-M
authors: AM
authors: Dogonowski
authors: H R
authors: HR
authors: Siebner
authors: P
authors: P
authors: Soelberg Sørensen
authors: O B
authors: OB
authors: Paulson
authors: T B
authors: TB
authors: Dyrby
authors: M
authors: M
authors: Blinkenberg
authors: K H
authors: KH
authors: Madsen
mesh_terms: D000328:Adult; D004185:Disability Evaluation; D006233:Persons with Disabilities; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply* / Q000503:physiopathology*; D009103:Multiple Sclerosis / Q000473:pathology* / Q000503:physiopathology*; D009434:Neural Pathways / Q000098:blood supply / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D025341:Principal Component Analysis; D012146:Rest / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: dorsal pre-motor cortex; functional imaging; magnetic resonance imaging; motor network; multiple sclerosis; resting-state connectivity