A Randomized Controlled Trial to Evaluate the Effectiveness of Electromyography (EMG)-Biofeedback in Patients With Fibromyalgia

The primary outcome measure was the Fibromyalgia Impact Questionnaire (FIQ). The FIQ is a disease specific multidimensional self-administered instrument that covers the dimensions physical functioning (11 items), well-being (1 item), work situation (2 items), pain (1 item), fatigue /sleep (2 items), stiffness (2 items) and psychological symptoms (2 items). Scoring ranges from 0 to 80 with the latter number being the worst case. The FIQ Total Score gives a summary of patients' impairment and is recommended as a highly sensitive measure of change in Fibromyalgia treatment programs and clinical studies. In this study the validated German version was used.

The SF-36 is a widely used measure of health-related quality of life with 36 items. It yields an eight-scale profile of scores which are Physical Functioning, Role-Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role-Emotional and Mental Health.

Change of health was directly measured by the self-rated Patients' Global Clinical Impression of Change Score, which is a validated measure of overall change compared with study onset, including six possible scores from "very much worse" (score 1) to "very much better" (score 6).

This questionnaire was developed and validated for patients with depression and has been applied in clinical trials of patients with Fibromyalgia as well. It contains 21 items that assess the cognitive, affective and neurovegetative factors associated with depression.

the Symptom Checklist 90 Revised (SCL-90-R) was used for measuring psychological distress. It generates 9 specific scales, one additional unspecific scale and three general scores. The 9 dimensions of the scale are as follows: SCL 1 = somatization; SCL 2 = obsessive-compulsive symptoms; SCL 3 = interpersonal sensitivity; SCL 4 = depression; SCL 5 = anxiety; SCL 6 = hostility; SCL 7 = phobic anxiety; SCL 8 = paranoid ideation; SCL 9 = psychoticism. The Global Severity Index serves as a measure of psychological distress.

It consists of a body diagram, where patients can rate the pain intensity at 24 locations of the front and the back side of the body. It allows calculating a total score for the whole body, as well as specific local scores.

According to the Tender point manual the examiner applied discrete pressure of 4 kg/cm² to each of the 18 Fibromyalgia typical Tender Points. When the patients expressed pain, the tender point was considered positive.

For measuring the Pressure Pain Threshold, the assessor first searched for an induration with pressure pain in the trapezius muscle pars descendens on each side of the muscle. The palpated part of the muscle was always located above or on a line between the acromioclavicular joint and the spinous process of vertebrae C 7. These two structures also served as coordinates to write down the exact place of the palpated taut band. Second, using a Fischer dolorimeter with a stamp of 1 cm², the examiner applied vertical pressure to the selected point and successively augmented the pressure until the patient signalled pain. In this way, the pressure pain threshold was measured in kg/cm².