Surface electromyography topography evaluation on low back pain physiotherapy

Abstract

Computer-aided electromyography-analysis has become a practical assessment tool for low back pain (LBP) while current clinical evaluation of LBP physiotherapy greatly relies on patient’s subjective perception of pain and objective measurement of physical impairments. Differences in muscle surface electromyography (SEMG) and pain occurrence during physiological back movements can be particularly useful to connect changes in motion with underlying neuromuscular events. SEMG topography has been developed using amplitude variables to identify patients with LBP from healthy population regarding the significant between-group difference. Interpretation of SEMG topography informs clinicians about the muscle activation pattern which can be used to monitor LBP progress. SEMG topography can further estimate the treatment effect of common physiotherapeutic options including exercise therapy and electrotherapy with reference to the patient’s electromyographic characteristics unveiled. Given limited evidence, the usefulness of SEMG topography in LBP physiotherapy is still to be determined.

Only a few works in literature demonstrate the use of SEMG topography in LBP physiotherapy. This paper began with a short review of the literature regarding conventional physical therapy, exercise therapy and electrotherapy to address the basic framework of physiotherapy management in LBP. Various assessment methods including subjective measures, objective tools, and imaging techniques were discussed to bring some information about the background on clinical evaluation of LBP. Studies focusing on the use of SEMG in LBP assessment were reviewed and the development of SEMG topography an objective measure of LBP was illustrated.

To examine the test consistency of SEMG topography, a study on the reliability of SEMG topography in estimating back muscle activity was preliminarily conducted among thirty patients with non-specific chronic low back pain (NSCLBP). The findings suggested SEMG topography an acceptable and reliable outcome measure for NSCLBP, indicated by good to excellent reliability (intra-class correlation coefficients, ICCs, > 0.8) on root mean square difference (RMSD) of SEMG topographic parameter relative area (RA) at flexion and RA at extension. Followed by three prospective repeated-measures clinical trials recruiting a total of ninety-two patients with NSCLBP, the treatment effects on active stretching exercise (ASE), core stabilization exercise (CSE) and interferential current (IFC) were quantified by SEMG topography and clinical outcomes accordingly. Further comparisons on SEMG topography variables, pain intensity and disability level related to back pain among the three interventions were accomplished. The results supported the use of CSE and IFC in LBP physiotherapy, with interim analgesic effect and reduction of RMSD of RA at flexion shown after intervention.

These studies validated the clinical usefulness of SEMG topography in LBP physiotherapy. Statistically significant change was shown in RMSD of RA at flexion in accordance with the improvement of pain perception, back-related disability, and fear avoidance to move in patients with NSCLBP after CSE and IFC. SEMG topography is deemed a reliable and objective assessment tool for LBP rehabilitation, though the correlation between RMSD of RA at flexion and pain could only be partly established. Future research engaging larger sample is needed to ascertain the clinical application of SEMG topography in LBP rehabilitation.