Psychophysical study on pain relief using transcutaneous electrical nerve stimulation

The satisfactory management of chronic pain remains a major problem for the clinician. Transcutaneous electrical nerve stimulation (TENS) is used extensively in the clinic for the relied of pain and it has become an accepted form of treatment in the management of patients with acute and chronic pain. In spite of the usefulness of TENS in the clinical practice, there is a paucity of scientifically valid data on TENS and mechanisms underlying neural responsiveness to this treatment modality The development of TENS was considered to be emerged from the gate control theory of pain (Melzack and Wall, 1965) to account for pain modulation with TENS. Numerous clinicians have, in fact, subscribed to this theory (Wall & Street, 1967; Mannhimer & Lampe, 1984; Woolf, 1984-. However, the theory works on a segmental basis, and if TENS activates large diameter afferent nerve fibres then it must be exposed to the criticisms against gate control theory. Thus, alternative mechanism, release of endogenous morphine like substances and physiological effect, but the mechanism explaining the analgesic effect of TENS is still unclear. In the present study, we hypothesized that: 1 TENS may increase skin temperature by decreasing the sympathetic tone which in addition to the other effects can explain the analgesic effect of TENS. 2 TENS may alleviate clinical inflammatory pain by inhibiting the function status of the nocifensor system. These hypothesis were tested by studying: 1 A new of psychophysical method for measuring pain perception and its modulation in experimental and clinical investigations. 2 The effect of TENS on pain threshold, nociceptive flexion reflex (RIII) and Skin temperature 3 The effect of TENS on neurogenic vasodilatation elicited by painful electrical stimulation on the volar surface of the fore-arm measured by laser Doppler flowmetry. Skin temperature was measured beside the tested areaThèse de DES en sciences biomédicales -- UCL, 199