TENS Therapy for Fibromyalgia
Transcutaneous electrical nerve stimulation – or TENS therapy – is a non-invasive therapeutic modality that involves the use of low-voltage electrical impulses for short-term pain relief. TENS therapy has been promoted for use in relieving pain related to surgery, migraine and other headaches, injuries, arthritis, cancer, and a variety of other conditions and illnesses, as well as to relieve nerve pain. TENS is believed to relieve pain by stimulating pain receptors in the nerves and altering the body’s biochemical response to painful stimuli. In short, TENS is thought to promote the production of endorphins, which are the natural painkillers in the body.
TENS systems contain an electrical power unit that is connected via two wires to a pair of electrodes. The electrodes are attached to the skin near the site of pain, and when the power unit is activated, a mild electrical current travels through the skin and into the body. This often results in a warming or tingling sensation during therapy sessions. TENS therapy can be conducted as often as needed and frequency is usually dictated by the pain severity.
TENS therapy is generally regarded to be safe; however a few potential risks do exist. If the electrical current used is too strong or used incorrectly, it can burn or otherwise irritate the skin. Electrodes should never be placed over the eyes, heart, brain, or in front of the throat, and individuals who have heart problems should not use TENS. Along the same lines, individuals with implanted pacemakers, defibrillators, infusion pumps, or other implanted medical devices should also not use TENS therapy. Finally, pregnant women should avoid using TENS therapy as its effects on the unborn are unknown.
Individuals can use home-based TENS systems by simply obtaining a prescription from their doctor. The US Food and Drug Administration (FDA) has approved over 100 types of TENS units for use in the United States. It is important, however, to be fully informed of the proper use of a TENS system prior to any home-based use. Therefore, individuals who are contemplating using a TENS system as part of their fibromyalgia treatment plan should talk to their doctor or physical therapist about proper use prior to trying it on their own.
TENS Therapy Research and Fibromyalgia
Unfortunately, very few high-quality studies have demonstrated the effectiveness of TENS therapy in general pain relief (Khadilkar et al., 2005; Nnoaham & Kumbang, 2008). Some studies have found TENS to be useful while others have not. Most researchers agree that more well-designed, randomized-controlled studies (the “gold standard” for research study design) are needed in order to more conclusively assess the effectiveness of TENS therapy in relieving pain.
There is an overall lack of research available regarding the use of TENS to treat fibromyalgia pain. A small randomized-controlled trial by Lofgren & Norrbrink (2009) randomly assigned 32 female fibromyalgia patients to receive either three weeks of TENS therapy, or three weeks of superficial warmth stimulations. Superficial warmth therapy, or thermotherapy, has been demonstrated in several studies to effectively improve low back pain, rheumatoid arthritis, and even some fibromyalgia-related pain. Modalities used to deliver therapeutic warmth in these studies have included paraffin wax baths, warm water therapy, and mud packs (Fioravanti et al., 2007; French et al., 2006; Robinson et al., 2002; Ayling & Marks, 2000; Neumann et al., 2001; Offenbacher & Stucki, 2000). In the Lofgren & Norrbrink study, the therapeutic warmth was delivered via a thermal stimulator which produced ‘comfortable warmth’ via four electrodes attached to the body. Electrodes were attached with surgical tape or held in place by tight clothing. Patients in this group were instructed to place the electrodes on their most painful sites and to use the thermal stimulator for as long as desired and comfortable (with a maximum treatment time per day of 45 minutes to two hours). Those in the TENS therapy group were instructed to place the electrodes of their TENS device over their most painful sites for a minimum of 30 minutes each day (but as often as needed), and to increase the amplitude of the device to a strong but tolerable level. After three weeks of therapy, patients in both groups switched to the other therapy for another three week treatment period. The study assessed the impact of TENS therapy and superficial warmth on pain intensity, health status, and preference of therapy (TENS or warmth). Assessments were done prior to the start of the study, after the first three week therapy session (prior to the start of using the second therapy), and at the end of the study. The study found that both TENS therapy and superficial warmth therapy reduced fibromyalgia related pain to equal degrees, and both resulted in significant improvements in pain reduction compared to pre-study measurements. Physical function also improved for individuals in both groups, and with regard to preference 53% of patients indicated they would prefer to continue the warmth therapy versus 31% who preferred the TENS therapy (Lofgren & Norrbrink, 2009).
An earlier study that compared TENS therapy to massage therapy found the latter to be more effective at improving anxiety and depression among fibromyalgia patients, although some effect was seen for those who received TENS therapy (Sunshine et al., 1996). A more recent study compared combination physical therapy (consisting of TENS therapy, ultrasound therapy and infrared therapy) with supplemental balneotherapy (thermal pool baths in mineral water) or hydrotherapy (warm water baths in tap water). The effects of all three treatments on pain, depression, and respiratory symptoms were evaluated. The greatest improvements were found for those treated with combination physical therapy plus balneotherapy; however those who received only combination physical therapy also showed short-term improvements in depression. The findings of this study must be interpreted with caution, however, due to the small sample size (56 patients in total), and the fact that TENS therapy was combined with at least two other therapeutic modalities in each group (Kesiktas et al., 2011).
12. Transcutaneous Electrical Nerve Stimulation. American Cancer Society. Accessed April 16, 2012.