Combined therapy (ultrasound and interferential current) in patients with fibromyalgia: once or twice in a week?

BACKGROUND AND PURPOSE Combined Therapy (CT) composed of ultrasound and Interferential Therapy has been reported as a cost-effective, local analgesic intervention on tender points in Fibromyalgia (FM). This study aims to investigate the difference between CT applied once a week and twice a week in patients with FM. METHOD Fifty patients with the diagnosis of FM were randomized into two groups (G1 = once a week treatment and G2 = twice a week treatment) with each group containing 25 patients. All eighteen tender points were assessed and treated with CT during each session, over a three-month time period. Interferential Therapy was modulated at 4,000 Hz of current carrier, 100 Hz of amplitude modulated frequency and at a bearable sensorial threshold of intensity. Pulsed ultrasound of 1 MHz at 20% of 2.5 W/cm² was used. For evaluation, the Visual Analogue Scale, Fibromyalgia Impact Questionnaire, Post Sleep Inventory and the tender point count were utilized, and the examiner was blinded to the group assignments. RESULTS G1 and G2 showed a significant improvement in Visual Analogue Scale (p < 0.0001 and p < 0.0005, respectively), Tender Points (p < 0.005 and p < 0.001, respectively), Fibromyalgia Impact Questionnaire and Post Sleep Inventory (p < 0.005 and p < 0.05, respectively). However, there was no significant difference between the two groups in all performed analyses. CONCLUSION There is no advantage in increasing the number of sessions of combined therapy in terms of reducing generalized pain, quality of life and sleep quality for patients with FM.