by Dr Dillon Cuppusamy
Many patients have portable TENS units at home, and many who don’t have asked us about them during treatment, so here is some basic information for you.
What is TENS?
TENS or Trans-cutaneous Electrical Nerve Stimulation, makes use of a mobile device that produces electric current, to stimulate the nerves for the relief of pain, and is used by many medical professionals worldwide.
How does TENS work?
The electrodes are often placed on the area of pain or at a pressure point, creating a circuit of electrical impulses that travels along nerve fibers.
When the current is delivered, some people experience less pain. This may be because the electricity from the electrodes stimulates the nerves in an affected area and sends signals to the brain that block or “scramble” normal pain signals. Another theory is that the electrical stimulation of the nerves may help the body to produce natural painkillers called endorphins, which may block the perception of pain, similar to the “runners high“ one can have with long distance running.
You can set a TENS machine for different wavelength frequencies, such as a steady flow of electrical current or a burst of electrical current, as well as modifying the intensity of electrical current. Ideally your physical therapist, acupuncturist, or doctor will determine the appropriate setting for you.
When is TENS used?
The use of TENS is widespread in terms of pain relief. Most commonly, it is used for muscle, joint or bone problems that occur with illnesses such as osteoarthritis or fibromyalgia, or conditions such as low back pain, neck pain and tendinosis.
Are There Contraindications?
Unlike a lot of medication there are virtually no side-effects when using a TENS machine. However, people with the following must not use a TENS machine:
- When the cause of the pain is not known or is not diagnosed.
- Pregnancy (unless specifically medically advised – or in labour).
- Epilepsy or certain types of heart disease.
Is TENS What is Used in the Clinic?
Actually, no. TENS differs from EMS or Electrical Muscle Stimulation in that EMS causes the muscles to contract, sometimes quite strongly, while TENS stimulates the nerves without muscle contraction. In a clinic, an EMS machine offers a wider range of settings based on the use chosen by your doctor or therapist. For safety sake, patients are not generally able to purchase an EMS machine, while TENS units are frequently given as pain management tools for home use.
Evidence Based Care
Although TENS may help relieve pain for some people, its effectiveness has not been proved. Research trials looking at the effectiveness of TENS machines have so far been inconclusive. Further large studies are needed to clarify the precise role and effect of using TENS. TENS devices have proved to be a popular form of pain relief for patients and therapists alike; however it must be known that as with other forms of treatment, the effect can vary from individual to individual, even with the same condition.
Brosseau L., Judd MG., Marchand S., et al. 2003. Transcutaneous electrical nerve stimulation (TENS) for the treatment of Cochrane Database Syst Rev. (3):CD004377.
Dementia. Cochrane Database Syst Rev. (3):CD004032.
Dowswell T., Bedwell C., Lavender T., et al. 2009. Transcutaneous electrical nerve stimulation (TENS) for pain relief in labour. Cochrane Database Syst Rev. (2):CD007214.
Khadilkar A., Odebiyi DO., Brosseau L., et al. 2008. Transcutaneous electrical nerve stimulation (TENS) versus placebo for chronic low-back pain. Cochrane Database Syst Rev. (4):CD003008.
Nnoaham KE., Kumbang J. 2008. Transcutaneous electrical nerve stimulation (TENS) for chronic pain. Cochrane Database Syst Rev. (3):CD003222.
Robb K., Oxberry SG., Bennett MI., et al. 2008. A Cochrane Systematic Review of Transcutaneous Electrical Nerve Stimulation for Cancer Pain. J Pain Symptom Manage.
Rutjes AW., Nuesch E., Sterchi R., et al. 2009. Transcutaneous electrostimulation for osteoarthritis of the knee. Cochrane Database Syst Rev. (4):CD002823.
Walsh DM., Howe TE., Johnson MI., et al. 2009. Transcutaneous electrical nerve stimulation for acute pain. Cochrane Database Syst Rev. (2):CD006142.