title: Spectral electromyographic assessment of back muscles in patients with low back pain undergoing rehabilitation.
abstract: METHODS
  A surface electromyographic procedure for evaluating back muscle impairment was studied in patients undergoing rehabilitation for low back pain.
  
  
  OBJECTIVE
  The results were analyzed to determine whether the electromyographic procedure was able to: 1) distinguish muscle impairment between patients with low back pain and normal subjects, and 2) monitor changes in muscle function after low back pain rehabilitation.
  
  
  METHODS
  Patients with chronic low back pain (n = 85) were tested to measure the median frequency of the electromyographic signals from six lumbar electrode sites during sustained trunk extensions. A subset (n = 28) of these patients was re-tested after low back pain rehabilitation. A discriminant function for classifying subjects into "low back pain" and "normal" groups was formulated using the electromyographic data from a subset of the patients with low back pain (n = 28) and a normative sample (n = 42). Results for this "learning" sample were compared with results using the same function on the remaining "holdout" sample of patients (n = 57) and an additional normative sample (n = 6). Differences in electromyographic parameters before and after rehabilitation also were analyzed.
  
  
  RESULTS
  The discriminant function classified subjects into low back pain and normal groups, with 86% and 89% correct classification for the "learning" and "holdout" samples, respectively. These classification results were independent of trunk extensor strength. Changes in median frequency after the rehabilitation program were consistent with improvements in back muscle fatigability.
  
  
  CONCLUSIONS
  These findings demonstrate how electromyographic spectral measurements may be used to identify and monitor back muscle impairment in patients undergoing rehabilitation for low back pain.
authors.affiliation: NeuroMuscular Research Center, Boston University, Massachusetts.
authors.forename: S H
authors.initials: SH
authors.lastname: Roy
authors.forename: C J
authors.initials: CJ
authors.lastname: De Luca
authors.forename: M
authors.initials: M
authors.lastname: Emley
authors.forename: R J
authors.initials: RJ
authors.lastname: Buijs
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004576:Electromyography; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000503:physiopathology*