A comparison of the analgesic efficacy of medium-frequency alternating current and TENS.
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.
Ward
Alex R
AR
Musculoskeletal Research Centre, Faculty of Health Sciences, La Trobe University, Victoria 3086, Australia. A.Ward@latrobe.edu.au
Lucas-Toumbourou
Stacey
S
McCarthy
Brigid
B
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