Effects of transcutaneous electrical nerve stimulation in patients with fibromyalgia syndrome - literature review

Introduction: Fibromyalgia is a chronic disorder characterized by diffuse musculoskeletal pain, fatigue, depression and cognitive impairment. The aim of treatment is to alleviate symptoms, maintain physical function and improve quality of life. One of the recommended methods of a non-pharmacological approach is transcutaneous electrical nerve stimulation (TENS). The aim of the literature review was to determine the effects of TENS in fibromyalgia patients, focusing on the assessment of changes in pain intensity in relation to the minimal clinically important difference. Methods: The literature search was conducted until the end of 2024 in the following databases PubMed, CINAHL and PEDro. Results: Twelve studies were included in the review. Three studies looked at the immediate effects of TENS on pain and nine studies looked at the longer-term effects. The duration of the individual therapies ranged from 20 to 120 minutes, the stimulation frequency from 0.5 to 320 Hz and the intensity from pleasant to very strong but tolerable stimulation. Pain was assessed using a visual analogue scale and a numerical rating scale. Discussion and conclusion: The results indicate that TENS therapy is more effective when applied with sufficient intensity over multiple sessions rather than as a single treatment. While a one-time application may provide temporary pain relief, repeated treatments show more clinically significant effects. People with higher pain sensitivity tend to respond better to TENS. This therapy remains a promising non-pharmacological option for pain management in fibromyalgia, however, caution is needed in generalizing the results as the research has predominantly studied women.