INVESTIGATING CHRONIC MYOFASCIAL PAIN SYNDROME USING ADVANCED EMG

Abstract

Chronic Myofascial Pain Syndrome (CMPS) is a complex musculoskeletal condition characterized by myofascial trigger points, persistent pain, and neuromuscular dysfunction. The lack of objective diagnostic tools has contributed to underdiagnosis and ineffective treatment. Advanced electromyography (EMG) techniques offer new opportunities to characterize the underlying pathophysiological mechanisms.This study aimed to investigate neuromuscular and autonomic biomarkers associated with CMPS using high-density surface EMG, intramuscular EMG, and physiological monitoring to provide an objective assessment of muscle and autonomic dysfunction.Sixty participants were enrolled, including 40 patients with CMPS and 20 healthy controls. Tests were made for pain intensity (VAS), pressure pain threshold, muscle unit action potential (MUAP) amplitude and duration, frequency of the EMG signal, muscle coherence, endplate noise, heart rate variability (HRV), and skin conductance. The EMG signals were studied using both time-frequency and wavelet methods. There was a difference in pain severity, which was significantly higher in CMPS patients (mean VAS = 6.5) than in people without CMPS. In the CMPS group, the muscle activity was different since the MUAP amplitude and duration were increased and the EMG signal mean frequency was reduced. The scores for coherence indicated that the patients’ motor control strategies were affected. In CMPS patients, endplate noise seems to increase due to independent muscle activity around the trigger points. Moreover, there was a reduction in HRV and an increase in skin conductance, suggesting the sympathetic nervous system was in control. A relationship was found between pain severity and EMG parameters, coherence, and markers related to the autonomic nervous system. There were differences in both the nervous system and the autonomic nervous system between CMPS patients and normal controls. This supports the value of EMG for clinical work and opens opportunities to adjust medical care in a manner appropriate for every patient.