Transcutaneous Electrical Nerve Stimulation (TENS) and Fibromyalgia (FM) (TENS&FM)

Fibromyalgia as a clinical syndrome is defined by chronic widespread muscular pain, fatigue and tenderness with hyperalgesia to pressure over tender points. Pain associated with fibromyalgia can interfere with daily function, work, and social activities. Thus, one of the main treatments for patients with fibromyalgia must focus on pain relief to allow the person to function more independently both at home and at work. Although the etiology of fibromyalgia is unknown, there is clearly enhanced sensitization in the central nervous system pain pathways as demonstrating by decreases in pressure pain thresholds, reduced central inhibition, and enhanced temporal summation. Reducing pain in people with fibromyalgia would help increase the patient's ability to return to work, perform activities of daily living and thus improve the quality of life for the patient. Transcutaneous electrical nerve stimulation (TENS) is a modality utilized in physical therapy that delivers electrical stimulation through the skin and is used for both acute and chronic pain. TENS works by reducing central excitability and increasing central inhibition. Thus, the investigators hypothesize that application of Transcutaneous Electrical Nerve Stimulation (TENS) to patients with Fibromyalgia (FM) will reduce pain, reduce central excitability by restoring diffuse noxious inhibitory controls (DNIC), and reduce temporal summation and that this decrease in pain and/or central excitability will improve function. The primary aim of the study is to test the effectiveness of TENS on pain and central excitability in a crossover design study for patients with Fibromyalgia with random assignment to three treatments: no treatment control, placebo TENS and active high frequency TENS. A secondary aim is to test the effect of decreased pain and central excitability on function in patients with Fibromyalgia.

The study will be a simple crossover design with the following three treatments (1) active TENS, (2) placebo TENS or (3) no treatment control randomly assigned. Subjects will draw the order for treatments (A, B, and C) out of a bowl at the initial testing session. This will determine the order of the testing. Each subject will receive all 3 treatments in random order. The following tools will be used to measure subject characteristics (Fibromyalgia Impact Questionnaire, Tampa Scale of Kinesiophobia), pain (McGill Pain Questionnaire and Visual Analogue Scale), central excitability (pressure pain thresholds, temporal summation and DNIC) and function (6 minute walk test, range of motion, sit to stand test).

Active TENS: 100 Hz, 200 μs at maximal tolerable intensity Placebo TENS: 100 Hz, 200 μs on for 45 seconds and then ramped off No TENS: Participants wore a TENS unit that was turned off for blinding of the outcome assessor

Placebo TENS: 100 Hz, 200 μs on for 45 seconds and then ramped off Active TENS: 100 Hz, 200 μs at maximal tolerable intensity Participants wore a TENS unit that was turned off for blinding of the outcome assessor

No TENS: Participants wore a TENS unit that was turned off for blinding of the outcome assessor Active TENS: 100 Hz, 200 μs at maximal tolerable intensity Placebo TENS: 100 Hz, 200 μs on for 45 seconds and then ramped off

Active TENS: 100 Hz, 200 μs at maximal tolerable intensity No TENS: Participants wore a TENS unit that was turned off for blinding of the outcome assessor Placebo TENS: 100 Hz, 200 μs on for 45 seconds and then ramped off

Placebo TENS: 100 Hz, 200 μs on for 45 seconds and then ramped off Participants wore a TENS unit that was turned off for blinding of the outcome assessor Active TENS: 100 Hz, 200 μs at maximal tolerable intensity

No TENS: Participants wore a TENS unit that was turned off for blinding of the outcome assessor Placebo TENS: 100 Hz, 200 μs on for 45 seconds and then ramped off Active TENS: 100 Hz, 200 μs at maximal tolerable intensity

Visual Analog Scale 0-10 with 0 No Pain and 10 Worst Pain Imaginable Pain was measured at rest before and after intervention.

Visual Analog Scale 0-10 with 0 No Pain and 10 Worst Pain Imaginable Pain was measured at rest before and after intervention.

Visual Analog Scale 0-10 with 0 No Fatigue and 10 Worst Fatigue Imaginable Pain was measured at rest before and after intervention.

Visual Analog Scale 0-10 with 0 No Fatigue and 10 Worst Fatigue Imaginable Pain was measured at rest before and after intervention.

Inclusion Criteria: Fibromyalgia diagnosis by a physician History of cervical or lumbar pain Exclusion Criteria: TENS use in the last 5 years Pacemaker No use of opioids

Dailey DL, Rakel BA, Vance CGT, Liebano RE, Amrit AS, Bush HM, Lee KS, Lee JE, Sluka KA. Transcutaneous electrical nerve stimulation reduces pain, fatigue and hyperalgesia while restoring central inhibition in primary fibromyalgia. Pain. 2013 Nov;154(11):2554-2562. doi: 10.1016/j.pain.2013.07.043. Epub 2013 Jul 27.