An electroencephalography (EEG) study of short-term electromyography (EMG) biofeedback training in patients with myofascial pain syndrome in the upper trapezius

[Purpose] In the present study, electroencephalography was used to explore neural activity related to electromyography biofeedback training, focusing on pain perception before and after electromyography biofeedback. [Participants and Methods] Twenty-seven participants (female=23; mean age: 28.85 ± 4.99 years) with mild-to-moderate myofascial pain syndrome in the upper trapezius were recruited for this study. All participants underwent electroencephalography recording before, during, and after (0 and 15 min) electromyography biofeedback training. Quantitative electroencephalography analysis was performed to obtain the absolute power of the four main frequency bands. Pain scores before and after electromyography biofeedback were also evaluated by subjective rating. [Results] Electromyography biofeedback increased alpha power and decreased delta power 15 minutes after training, suggestive of relaxation. However, although a tendency for scores to decrease was observed, no significant improvements in pain scores were observed following the intervention. Such results may be due to the short duration of the biofeedback session and the subjective nature of pain assessments. [Conclusion] Despite no obvious changes in pain perception, brief electromyography biofeedback training may induce relaxation in patients with myofascial pain syndrome of the upper trapezius muscle.