title: Alterations in central motor representation increase over time in individuals with rotator cuff tendinopathy.
abstract: OBJECTIVE
  To investigate whether rotator cuff tendinopathy leads to changes in central motor representation of a rotator cuff muscle, and to assess whether such changes are related to pain intensity, pain duration, and physical disability.
  
  
  METHODS
  Using transcranial magnetic stimulation, motor representation of infraspinatus muscle was assessed bilaterally in patients with unilateral rotator cuff tendinopathy.
  
  
  RESULTS
  Active motor threshold is significantly larger for the affected shoulder comparatively to the unaffected shoulder (n=39, p=0.01), indicating decreased corticospinal excitability on the affected side compared to unaffected side. Further, results suggest that this asymmetry in corticospinal excitability is associated with duration of pain (n=39; r=0.45; p=0.005), but not with pain intensity (n=39; r<0.03; p>0.43). In contrast with findings in other populations with musculoskeletal pain, no significant inter-hemispheric asymmetry was observed in map location (n=16; p-values ⩾ 0.91), or in the amplitude of motor responses obtained at various stimulation intensities (n=16; p=0.83).
  
  
  CONCLUSIONS
  Chronicity of pain, but not its intensity, appears to be a factor related to lower excitability of infraspinatus representation.
  
  
  CONCLUSIONS
  These results support the view that while cortical reorganization correlates with magnitude of pain in neuropathic pain syndromes, it could be more related to chronicity in the case of musculoskeletal disorders.
authors.affiliation: Centre for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Que G1M2S8, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Que G1R1P5, Canada; Department of Health Sciences, Université du Québec à Chicoutimi, Chicoutimi, Que G7H2B1, Canada.
authors.forename: Suzy
authors.initials: S
authors.lastname: Ngomo
authors.affiliation: Centre for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Que G1M2S8, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Que G1R1P5, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Mercier
authors.affiliation: Centre for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Que G1M2S8, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Que G1R1P5, Canada.
authors.forename: Laurent J
authors.initials: LJ
authors.lastname: Bouyer
authors.affiliation: Centre for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Que G1M2S8, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Savoie
authors.affiliation: Centre for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Que G1M2S8, Canada; Department of Rehabilitation, Faculty of Medicine, Université Laval, Quebec City, Que G1R1P5, Canada. Electronic address: jean-sebastien.roy@rea.ulaval.ca.
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Roy
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D010146:Pain / Q000175:diagnosis / Q000503:physiopathology; D010147:Pain Measurement / Q000379:methods / Q000639:trends*; D017006:Rotator Cuff / Q000503:physiopathology*; D052256:Tendinopathy / Q000175:diagnosis* / Q000503:physiopathology*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation / Q000379:methods / Q000639:trends*
keywords: Brain mapping; Chronic pain; Corticospinal tracts; Muscular diseases; Musculoskeletal pain; Shoulder