title: Assessment of abdominal muscle function in individuals with motor-complete spinal cord injury above T6 in response to transcranial magnetic stimulation.
abstract: OBJECTIVE
  To use transcranial magnetic stimulation and electromyography to assess the potential for preserved function in the abdominal muscles in individuals classified with motor-complete spinal cord injury above T6.
  
  
  METHODS
  Five individuals with spinal cord injury (C5-T3) and 5 able-bodied individuals.
  
  
  METHODS
  Transcranial magnetic stimulation was delivered over the abdominal region of primary motor cortex during resting and sub-maximal (or attempted) contractions. Surface electromyography was used to record motor-evoked potentials as well as maximal voluntary (or attempted) contractions in the abdominal muscles and the diaphragm.
  
  
  RESULTS
  Responses to transcranial magnetic stimulation in the abdominal muscles occurred in all spinal cord injury subjects. Latencies of muscle response onsets were similar in both groups; however, peak-to-peak amplitudes were smaller in the spinal cord injury group. During maximal voluntary (or attempted) contractions all spinal cord injury subjects were able to elicit electromyography activity above resting levels in more than one abdominal muscle across tasks.
  
  
  CONCLUSIONS
  Individuals with motor-complete spinal cord injury above T6 were able to activate abdominal muscles in response to transcranial magnetic stimulation and during maximal voluntary (or attempted) contractions. The activation was induced directly through corticospinal pathways, and not indirectly by stretch reflex activations of the diaphragm. Transcranial magnetic stimulation and electromyography measurements provide a useful method to assess motor preservation of abdominal muscles in persons with spinal cord injury.
authors.affiliation: Biomechanics and Motor Control Laboratory, The Swedish School of Sport and Health Sciences (GIH), Box 5626, SE-114 86 Stockholm, Sweden. anna.bjerkefors@gih.se.
authors.forename: Anna
authors.initials: A
authors.lastname: Bjerkefors
authors.forename: Jordan W
authors.initials: JW
authors.lastname: Squair
authors.forename: Romeo
authors.initials: R
authors.lastname: Chua
authors.forename: Tania
authors.initials: T
authors.lastname: Lam
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.forename: Mark G
authors.initials: MG
authors.lastname: Carpenter
mesh_terms: D000009:Abdominal Muscles / Q000503:physiopathology*; D000328:Adult; D002540:Cerebral Cortex; D003964:Diaphragm / Q000503:physiopathology; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D011712:Pyramidal Tracts / Q000502:physiology; D012026:Reflex, Stretch / Q000502:physiology; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013904:Thoracic Vertebrae; D050781:Transcranial Magnetic Stimulation