title: Modulation of laser-evoked potentials and pain perception by transcutaneous electrical nerve stimulation (TENS): a placebo-controlled study in healthy volunteers.
abstract: OBJECTIVE
  To investigate the effects of transcutaneous electrical nerve stimulation (TENS) on brain nociceptive responses (laser-evoked potentials, LEPs) and pain perception.
  
  
  METHODS
  Twenty healthy subjects were included. Nociceptive CO(2)-laser pulses were sequentially delivered to the dorsum of both feet. The amplitude of LEPs and nociceptive thresholds were collected in three consecutive conditions: T1: "sham" TENS (2 Hz/low-intensity) positioned heterotopically, over the left thigh; T2: "active" TENS (120 Hz/low-intensity) applied homotopically, over the left common peroneal nerve; and T3: "sham" TENS (replication of condition T1).
  
  
  RESULTS
  Compared with "sham" TENS, "active" TENS significantly decreased the LEPs amplitude. This effect was observed exclusively when "active" TENS was applied ipsilaterally to the painful stimulus. Nociceptive thresholds increased with sessions in both limbs, but the increase observed during the "active" condition of TENS (T2) exceeded significantly that observed during the condition T3 only on the foot ipsilateral to TENS.
  
  
  CONCLUSIONS
  Compared with a credible placebo TENS, high-frequency TENS induced a significant attenuation of both the acute pain and LEPs induced by noxious stimuli applied on the same dermatome.
  
  
  CONCLUSIONS
  This modulation of subjective and objective concomitants of pain processing reflects a real neurophysiological TENS-related effect on nociceptive transmission.
authors: Service de Neurochirurgie, Hôpital Nord, Centre Hospitalier Régional Universitaire de Saint-Etienne, France. francoisvassal@wanadoo.fr
authors: François
authors: F
authors: Vassal
authors: C
authors: C
authors: Créac'h
authors: Ph
authors: P
authors: Convers
authors: B
authors: B
authors: Laurent
authors: L
authors: L
authors: Garcia-Larrea
authors: R
authors: R
authors: Peyron
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D053685:Laser Therapy / Q000379:methods; D008297:Male; D059225:Nociception / Q000502:physiology*; D059408:Pain Management / Q000379:methods*; D010147:Pain Measurement; D012016:Reference Values; D004561:Transcutaneous Electric Nerve Stimulation; D055815:Young Adult
keywords: Laser-evoked potentials; Neuromodulation; Pain; Transcutaneous electrical nerve stimulation