Suppression of pain sensation caused by millimeter waves: A double-blinded, cross-over, prospective human volunteer study

We conducted a double-blinded, randomized, cross-over, prospective trial to evaluate the pain relief effect of millimeter waves (MW) under experimenta l conditions. The cold presser test was used as a model of tonic aching pai n. Twelve healthy male volunteers were exposed to an active medical MW gene rator and to a disabled sham generator with at least 24 h between exposures . Characteristics of continuous-wave electromagnetic output from the active generator were: wavelength 7.1 mm, incident power density 25 +/- 5 mW/cm(2 ), and duration of exposure 30 min. MW produced a significant (P < 0.05) su ppression of pain sensation, with an average 37.7% gain in pain tolerance a nd a 49.3% increase in pain sensitivity range (the latter being the differe nce between pain tolerance and pain threshold values). Of the 12 volunteers , 7 (58.3%) reacted to the active MW generator with an increased pain toler ance, and the individual reactions varied from 120% to 315% comparison with their own preexposure levels. MW therapy can potentially be used as a supp lementary or alternative treatment for pain relief. Implications: Pain mana gement is still a significant medical problem. In a double-blinded, experim ental setting, we confirmed that low-intensity millimeter wave therapy can reduce pain sensitivity in healthy human volunteers and can potentially be used as a supplementary or alternative treatment for pain relief.