Electromyogram (EMG) biofeedback is used in chronic pain but its effectiveness in patients with fibromyalgia is unclear. The objective of this randomized controlled clinical trial was to evaluate the effectiveness of EMG biofeedback in patients with fibromyalgia.
Patients were recruited from a waiting list at the fibromyalgia day care clinic at the University Hospital Munich. The study intervention comprised 14 sessions of EMG biofeedback during 8 weeks in addition to the usual care. The control intervention was usual care alone. Assessments were scheduled before intervention (T0), after intervention (T1), and 3 months after the end of intervention (T2). The primary outcome measure was the Fibromyalgia Impact Questionnaire (FIQ). Secondary outcome measures included additional patient-oriented measures and the pressure-pain threshold in the trapezius muscles. Effectiveness was analyzed by significance tests and standardized effect sizes (ES).
36 patients completed the study. EMG biofeedback did not improve the health status (FIQ, T1: p = 0.95, ES = 0.02; T2: p = 0.52, ES = 0.26). Among the secondary outcome measures, only the pressure-pain threshold at the trapezius muscles showed an improvement in the intervention group (T1: p = 0.016, ES = 0.84).
EMG biofeedback showed no health status improvement in patients with fibromyalgia.