Chronic low back pain is a highly prevalent and disabling musculoskeletal pain condition, especially among older adults. Transcutaneous electrical nerve stimulation (TENS) is a treatment option for this pain, but few studies have assessed how older adults respond to TENS when compared with younger adults. TENS uses a small battery-powered machine to deliver low-volt electrical current through electrodes placed on the skin. It is believed that TENS activates the same receptors in the brain and spinal cord that are targeted by opioid analgesic medication.
As with pain medication, the benefit of TENS is greatest during its application period. “TENS has been available for about 40 years, but recent research suggests a stronger amplitude may be needed” explains Corey B. Simon, DPT, PhD. “TENS is a safe, conservative treatment that is relatively inexpensive and under the current recommended parameters may be comparable to drug treatment.”
In a study published in the Journal of Pain, Dr. Simon and colleagues evaluated the effectiveness of TENS on 60 adults with lower back pain among adults aged 18 to 79. The participants were divided by age group, with 20 being considered young, 20 being middle-aged, and 20 being older. Recipients underwent four 20-minute sessions of TENS therapy over 3 weeks.
An important aspect of the study was that the dose of TENS was based on the perception of “strong, yet tolerable.” Episodic or immediate relief of axial chronic low back pain was assessed after TENS using measures of resting pain, movement-evoked-pain, and self-reported disability. Cumulative or prolonged relief was assessed by comparing daily pain reports across sessions. In addition, Dr. Simon and colleagues assessed for changes in experimental pain response, which are laboratory correlates of pain processing.
“Our results showed that participants of all age groups experienced episodic relief of their back pain after each TENS application, though did not experience cumulative effects,” says Dr. Simon. “Further, all age groups demonstrated improved experimental pain response suggesting improved pain processing. However, older adults were found to have higher TENS amplitude than younger and middle-aged adults. Higher dosage of TENS may necessary for older patients because their response to pain and/or pain relief wanes as they age.”
Findings of the analysis may have important mechanistic and clinical implications for older adults suffering from chronic low back pain. TENS can be a helpful adjunct for these patients and may decrease their need to use pain medications, which can have higher health risks. TENS units are also relatively inexpensive and can be used at home to help patients manage back pain.
However, study findings suggest that clinicians need to consider the amplitude of TENS when treating older adults. Clinicians may also need to assist patients in obtaining a TENS device as both access and prices can vary. “TENS may be an effective alternative to medications and surgery for pain relief,” says Dr. Simon. “It has fewer side effects and can potentially make a big difference with regard to quality of life for patients.”
Readings & Resources (click to view)
Simon CB, Riley III JL, Fillingim RB, Bishop MD, George SZ. Age group comparisons of TENS response among individuals with chronic axial low back pain. J Pain. 2015;16:1268-1279. Available at: http://www.jpain.org/article/S1526-5900(15)00843-3/abstract.
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;129:206-216.
Rakel B, Frantz R. Effectiveness of transcutaneous electrical nerve stimulation on postoperative pain with movement. J Pain. 2003;4:455-464.
Vance CG, Dailey DL, Rakel BA, Sluka KA. Using TENS for pain control: the state of the evidence. Pain Manag. 2014;4:197-209.
Sluka KA, Bjordal JM, Marchand S, Rakel BA. What makes transcutaneous electrical nerve stimulation work? Making sense of the mixed results in the clinical literature. Phys Ther. 2013;93:1397-1402.