title: A comparison of the analgesic efficacy of medium-frequency alternating current and TENS.
abstract: OBJECTIVE
  To compare the analgesic efficacy of burst-modulated medium-frequency alternating current (BMAC) and transcutaneous electrical nerve stimulation (TENS) using an experimental cold pain model.
  
  
  METHODS
  Within-group crossover study.
  
  
  METHODS
  A university research laboratory.
  
  
  METHODS
  Twenty healthy subjects.
  
  
  METHODS
  BMAC (4-kHz AC applied in 4-millisecond bursts at 50Hz) and TENS (125-microsecond phase duration applied at a frequency of 50Hz) administered to each participant on separate occasions.
  
  
  METHODS
  Time to cold pain threshold.
  
  
  RESULTS
  The mean time to cold pain threshold with the BMAC intervention was no different than with TENS. Statistical analysis showed that both interventions elevated the cold pain threshold significantly [BMAC: increase=15.2seconds, 97.5% confidence interval (CI) 3.1 to 27.2, P=0.01; TENS: increase=15.4seconds, 97.5%CI 2.5 to 28.4, P=0.02], and the difference between interventions was not simply insignificant but the intervention effects were 'significantly the same' (mean difference=0.3seconds, 95%CI -15.3 to 15.9, P=0.97).
  
  
  CONCLUSIONS
  BMAC is as effective as TENS in increasing cold pain thresholds in healthy subjects. Since BMAC has been shown to be more comfortable than TENS in previous studies and is likely to be better accepted and tolerated by patients, clinical investigation is warranted.
authors.affiliation: Musculoskeletal Research Centre, Faculty of Health Sciences, La Trobe University, Victoria 3086, Australia. A.Ward@latrobe.edu.au
authors.forename: Alex R
authors.initials: AR
authors.lastname: Ward
authors.forename: Stacey
authors.initials: S
authors.lastname: Lucas-Toumbourou
authors.forename: Brigid
authors.initials: B
authors.lastname: McCarthy
mesh_terms: D000698:Analgesia / Q000379:methods*; D000704:Analysis of Variance; D003080:Cold Temperature; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D055815:Young Adult