title: Motor evoked potentials of trunk muscles in traumatic brain injury patients.
abstract: OBJECTIVE
  To evaluate the motor innervation of trunk muscles in traumatic brain injury patients.
  
  
  METHODS
  Twenty patients (12 men and 8 women) with traumatic brain injury were enrolled in this study. Their mean age was 41 years. Motor evoked potentials (MEPs) were performed on the motor cortex. Electromyographic activities were recorded from the bilateral rectus abdominis muscles, the external oblique abdominal muscles, and the 4th and 9th thoracic erector spinae muscles. The onset latency and amplitude of contralateral and ipsilateral MEPs were measured. All patients were assessed by the Korean version of the Berg Balance Scale (K-BBS) to investigate the relationship between the frequency of MEPs in trunk muscles and gait ability.
  
  
  RESULTS
  The mean frequency of ipsilateral MEPs was 23.8% with more damaged hemisphere stimulation, while the contralateral MEPs showed a mean frequency of 47.5% with more damaged hemisphere stimulation in traumatic brain injury patients. The latencies and amplitudes of MEPs obtained from the more damaged hemisphere were not significantly different from those of the less damaged hemisphere. There was no correlation between the manifestation of MEPs in trunk muscles and gait ability.
  
  
  CONCLUSIONS
  The ipsilateral and contralateral corticospinal pathways to trunk muscles are less likely to be activated in traumatic brain injury patients because of direct injury of the descending corticospinal motor tract or decreased excitability of the corticospinal tract from prefrontal contusion.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Institute for Medical Sciences, Chonbuk National University Medical School, Research Institute of Clinical Medicine, Chonbuk National University Hospital, Jeonju 561-180, Korea.
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Seo
authors.forename: Sung-Hee
authors.initials: SH
authors.lastname: Park
authors.forename: Myoung-Hwan
authors.initials: MH
authors.lastname: Ko
authors.forename: Jeong-Hwan
authors.initials: JH
authors.lastname: Seo