Transcutaneous electrical nerve stimulation (TENS) therapy involves the use of low-voltage electric currents to treat pain. Electrodes or mediums for electricity to travel to the body, placed on the body at the site of pain, deliver electricity that travels through the nerve fibers. Pain treatment with TENS has been described for cancer pain (Hurlow et al, 2012), labor pain (Dowswell et al, 2019), back pain (FAcci et al, 2011), and even TMD (Chellappa, 2020). The electric currents block the pain receptors from being sent from the nerves to the brain. A patient will receive a small, battery-operated TENS machine to use at home. In most cases, a doctor, physical therapist, or acupuncturist adjusts the machine to the correct settings.
*Note: In older publications, the gate control theory of pain is typically used to explain the actions of high-frequency TENS, whereas, low-frequency TENS is typically explained by release of endogenous opioids. (Sluka 1999)
Pain inhibition by additional somatosensory input is the rationale for the widespread use of Transcutaneous Electrical Nerve Stimulation (TENS) to relieve pain. Two main types of TENS produce analgesia in animal models: high-frequency (∼50-100 Hz) and low-intensity 'conventional' TENS, and low-frequency (∼2-4 Hz) and high-intensity 'acupuncture-like' TENS. (Peng et al, 2019)
Hurlow A, Bennett MI, Robb KA, Johnson MI, Simpson KH, Oxberry SG. Transcutaneous electric nerve stimulation (TENS) for cancer pain in adults. Cochrane Database Syst Rev. 2012 Mar 14;2012(3):CD006276. doi: 10.1002/14651858.CD006276.pub3. PMID: 22419313; PMCID: PMC6669272.
Dowswell T, Bedwell C, Lavender T, Neilson JP. Transcutaneous electrical nerve stimulation (TENS) for pain relief in labour. Cochrane Database Syst Rev. 2009 Apr 15;(2):CD007214. doi: 10.1002/14651858.CD007214.pub2. PMID: 19370680; PMCID: PMC4297467.
Johnson M. (2007). Transcutaneous Electrical Nerve Stimulation: Mechanisms, Clinical Application and Evidence. Reviews in pain, 1(1), 7–11. https://doi.org/10.1177/204946370700100103
Facci LM, Nowotny JP, Tormem F, Trevisani VF. Effects of transcutaneous electrical nerve stimulation (TENS) and interferential currents (IFC) in patients with nonspecific chronic low back pain: randomized clinical trial. Sao Paulo Med J. 2011;129(4):206-16. doi: 10.1590/s1516-31802011000400003. PMID: 21971895.
Chellappa D, Thirupathy M. Comparative efficacy of low-Level laser and TENS in the symptomatic relief of temporomandibular joint disorders: A randomized clinical trial. Indian J Dent Res. 2020 Jan-Feb;31(1):42-47. doi: 10.4103/ijdr.IJDR_735_18. PMID: 32246680.
Antony AB, Mazzola AJ, Dhaliwal GS, Hunter CW. Neurostimulation for the Treatment of Chronic Head and Facial Pain: A Literature Review. Pain Physician. 2019 Sep;22(5):447-477. PMID: 31561646.
Ferreira AP, Costa DR, Oliveira AI, Carvalho EA, Conti PC, Costa YM, Bonjardim LR. Short-term transcutaneous electrical nerve stimulation reduces pain and improves the masticatory muscle activity in temporomandibular disorder patients: a randomized controlled trial. J Appl Oral Sci. 2017 Mar-Apr;25(2):112-120. doi: 10.1590/1678-77572016-0173. PMID: 28403351; PMCID: PMC5393531.
Peng WW, Tang ZY, Zhang FR, Li H, Kong YZ, Iannetti GD, Hu L. Neurobiological mechanisms of TENS-induced analgesia. Neuroimage. 2019 Jul 15;195:396-408. doi: 10.1016/j.neuroimage.2019.03.077. Epub 2019 Apr 1. PMID: 30946953; PMCID: PMC6547049.
Zayan K, Felix ER, Galor A. Transcutaneous Electrical Nerve Stimulation for Facial Pain. Prog Neurol Surg. 2020;35:35-44. doi: 10.1159/000509620. Epub 2020 Jul 21. PMID: 32694253.
Sluka KA, Deacon M, Stibal A, Strissel S, Terpstra A. Spinal blockade of opioid receptors prevents the analgesia produced by TENS in arthritic rats. J Pharmacol Exp Ther. 1999 May;289(2):840-6. PMID: 10215661.