Modification Of Induced Ischemic Pain By Trans-Cutaneous Electrical Nerve-Stimulation

Endurance to ischaemic pain was assessed in healthy subjects receiving either continuous or trains of transcutaneous electrical nerve stimulation (TENS) at different intensity levels. Control subjects received no stimulation. Self-reports of pain thresholds and pain tolerance levels were obtained, and on-going pain was assessed by means of two linear pain scales. At the end of each trial, descriptions of intolerable pain were obtained using the McGill Pain Questionnaire. High intensity continuous stimulation raised pain tolerances and endurance of pain, but was associated with higher levels of reported pain when tolerance was reached. Low intensity trains of stimulation raised pain thresholds and tolerance levels but did not increase endurance to induced ischaemic pain. Our results suggest that the response to induced ischaemic pain can be selectively modified by peripheral electrical stimulation depending on its temporal and intensity characteristics.