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

Overview

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).