Complexity Analysis of Surface Electromyography for Assessing the Myoelectric Manifestation of Muscle Fatigue: A Review

The surface electromyography (sEMG) records the electrical activity of muscle fibers during contraction: one of its uses is to assess changes taking place within muscles in the course of a fatiguing contraction to provide insights into our understanding of muscle fatigue in training protocols and rehabilitation medicine. Until recently, these myoelectric manifestations of muscle fatigue (MMF) have been assessed essentially by linear sEMG analyses. However, sEMG shows a complex behavior, due to many concurrent factors. Therefore, in the last years, complexity-based methods have been tentatively applied to the sEMG signal to better individuate the MMF onset during sustained contractions. In this review, after describing concisely the traditional linear methods employed to assess MMF we present the complexity methods used for sEMG analysis based on an extensive literature search. We show that some of these indices, like those derived from recurrence plots, from entropy or fractal analysis, can detect MMF efficiently. However, we also show that more work remains to be done to compare the complexity indices in terms of reliability and sensibility; to optimize the choice of embedding dimension, time delay and threshold distance in reconstructing the phase space; and to elucidate the relationship between complexity estimators and the physiologic phenomena underlying the onset of MMF in exercising muscles

Complexity analysis of surface electromyography for assessing the myoelectric manifestation of muscle fatigue: A review

The surface electromyography (sEMG) records the electrical activity of muscle fibers during contraction: one of its uses is to assess changes taking place within muscles in the course of a fatiguing contraction to provide insights into our understanding of muscle fatigue in training protocols and rehabilitation medicine. Until recently, these myoelectric manifestations of muscle fatigue (MMF) have been assessed essentially by linear sEMG analyses. However, sEMG shows a complex behavior, due to many concurrent factors. Therefore, in the last years, complexity-based methods have been tentatively applied to the sEMG signal to better individuate the MMF onset during sustained contractions. In this review, after describing concisely the traditional linear methods employed to assess MMF we present the complexity methods used for sEMG analysis based on an extensive literature search. We show that some of these indices, like those derived from recurrence plots, from entropy or fractal analysis, can detect MMF efficiently. However, we also show that more work remains to be done to compare the complexity indices in terms of reliability and sensibility; to optimize the choice of embedding dimension, time delay and threshold distance in reconstructing the phase space; and to elucidate the relationship between complexity estimators and the physiologic phenomena underlying the onset of MMF in exercising muscles

Degraded Synergistic Recruitment of sEMG Oscillations for Cerebral Palsy Infants Crawling

Background: Synergistic recruitment of muscular activities is a generally accepted mechanism for motor function control, and motor dysfunction, such as cerebral palsy (CP), destroyed the synergistic electromyography activities of muscle group for limb movement. However, very little is known how motor dysfunction of CP affects the organization of the myoelectric frequency components due to the abnormal motor unit recruiting patterns.Objectives: Exploring whether the myoelectric activity can be represented with synergistic recruitment of surface electromyography (sEMG) frequency components; evaluating the effect of CP motor dysfunction on the synergistic recruitment of sEMG oscillations.Methods: Twelve CP infants and 17 typically developed (TD) infants are recruited for self-paced crawling on hands and knees. sEMG signals have been recorded from bilateral biceps brachii (BB) and triceps brachii (TB) muscles. Multi-scale oscillations are extracted via multivariate empirical mode decomposition (MEMD), and non-negative matrix factorization (NMF) method is employed to obtain synergistic pattern of these sEMG oscillations. The coefficient curve of sEMG oscillation synergies are adopted to quantify the time-varying recruitment of BB and TB myoelectric activity during infants crawling.Results: Three patterns of sEMG oscillation synergies with specific frequency ranges are extracted in BB and TB of CP or TD infants. The contribution of low-frequency oscillation synergy of BB in CP group is significantly less than that in TD group (p < 0.05) during forward swing phase for slow contraction; however, this low-frequency oscillation synergy keep higher level during the backward swing phase crawling. For the myoelectric activities of TB, there is not enough high-frequency oscillation recruitment of sEMG for the fast contraction in propulsive phase of CP infants crawling.Conclusion: Our results reveal that, the myoelectric activities of a muscle can be manifested as sEMG oscillation synergies, and motor dysfunction of CP degrade the synergistic recruitment of sEMG oscillations due to the impaired CNS regulation and destroyed MU/muscle fiber. Our preliminary work suggests that time-varying coefficient curve of sEMG oscillation synergies is a potential index to evaluate the abnormal recruitment of electromyography activities affected by CP disorders

Changes in surface electromyography characteristics and foot-tapping rate of force development as measures of spasticity in patients with multiple sclerosis

Spasticity is a common symptom experienced by individuals with upper motor neuron lesions such as those with stroke, spinal cord injury, traumatic brain injury, cerebral palsy, amyotrophic lateral sclerosis, and multiple sclerosis. Although the etiology and progression of spasticity differs between these clinical populations, it shares many of the same consequences: muscle pain, weakness, fatigue, increased disability, depression, medication side effects, and a reduced quality of life. For this reason, there has been increased interest in the measurement and treatment of spasticity symptoms. Subjective measures of spasticity like the Modified Ashworth Scale (MAS) and Tardieu Scale have shown questionable validity/reliability and poorly correlate to functional outcome measures but continue to be used in clinical and research settings. Objective measures like myotonometry, electrogoniometry, and inertial sensors on the other hand provide much more reliable measures but at the expense of increased costs, time, and equipment. Therefore, to properly assess and treat spasticity symptoms, a timelier and cost-effective objective measure of spasticity is needed. PURPOSE: To reexamine a previously collected dataset from a sample of patients with multiple sclerosis before and after dry-needling and functional electrically stimulated walking spasticity treatments. Specifically, we wished to know whether there were: 1.) Acute (within visit) and chronic (between visit) changes in sEMG and Foot-tapping rate of force development measures after treatment, 2.) Between leg differences before and after treatments, 3.) significant correlations between EMG, foot-tapping, and functional outcome measures. METHODS: 16 MS patients (10 relapsing-remitting and 6 progressive MS) participated in the original study. The study consisted of 14 visits: 2 pre/post visits, 4 visits of dry-needling + functional electrically stimulated walking (FESW), and 8 visits with FESW only. The more spastic leg (involved leg) was given the treatment, making the other the control. Dry-needling was performed on the involved leg’s gastrocnemius medial and lateral heads by inserting monofilament needles and electrically stimming the muscles until visible twitches occurred. Dry-needling was done 30 seconds on and 30 seconds off for a total of 90 seconds of treatment. FESW was performed on the involved leg by attaching electrodes to the tibialis anterior and gastrocnemius muscles. Patients walked 20-minutes at a self-selected pace while the involved leg was stimmed. sEMG was collected before and after each treatment by having the patient perform a single maximal heel raise. Foot-tapping ability was assessed using the 10-second foot-tapping test (FTT) and a small force plate. Functional measures also included the 25-foot walk test (25FWT) 6-minute walk test (6MWT), modified fatigue impact score (MFIS), and number of heel raises performed. RESULTS: No significant between leg differences were noted for any of the sEMG measures (p>0.05). No significant chronic changes occurred in any of the sEMG measures. For the Dry-needling + FESW visits, sEMG sample entropy was significantly increased in the involved leg at post-needling (p = 0.035) and post-FESW (p = 0.027). The non-involved leg’s sample entropy was significantly higher at post-FESW only (p = 0.017). The non-involved leg’s, mean frequency was significantly higher at post-FESW compared pre-needling (p = 0.033) and post-needling (p = 0.032). For the FESW only visits, there were no significant changes in the involved leg. The Non-involved leg’s mean frequency was significantly higher at Post-FESW (p = 0.006). Median frequency was significantly higher at Post-FESW (p = 0.009). The number of foot-taps was significantly increased from Pre to Post-intervention in both the Involved (p = 0.006) and Non-involved legs (p 0.002). There was a significantly higher number of foot-taps in the Non-involved leg compared to the Involved leg at both Pre (p =0.008) and Post (p = 0.015) timepoints. AUC was significantly higher in the Involved leg at Post-treatment (p = 0.030). Time to peak was found to be higher in the Involved leg compared to the Non-involved leg at both Pre (p = 0.037) and Post-intervention (p = 0.019). Time to base was higher in the Involved leg compared to the Non-involved leg at both Pre (p = 0.031) and Post-intervention (p = 0.004). Total tap time was higher in the Involved leg at both Pre (p = 0.010) and Post-intervention (p = 0.007). Percent time to peak was significantly lower in the involved limb at Pre-intervention (p = 0.026) and Post intervention (p = 0.037). Percent time to base was significantly higher in the Involved leg at Pre-intervention (p = 0.026) and Post intervention (p = 0.037). The sEMG measures tended to poorly or non-significantly correlate with the functional outcome measures. The foot-tapping measures, especially the involved leg, tended to exhibit stronger correlations with the functional outcome measures. CONCLUSION: sEMG Sample entropy and foot-tapping ability are significantly improved by dry-needling treatments and walking. sEMG measures did not tend to correlate well with functional outcome measures but the foot-tapping measures did. This suggests that foot-tapping rate and related measures may be a useful measure of spasticity and treatment effects

Applications of EMG in Clinical and Sports Medicine

This second of two volumes on EMG (Electromyography) covers a wide range of clinical applications, as a complement to the methods discussed in volume 1. Topics range from gait and vibration analysis, through posture and falls prevention, to biofeedback in the treatment of neurologic swallowing impairment. The volume includes sections on back care, sports and performance medicine, gynecology/urology and orofacial function. Authors describe the procedures for their experimental studies with detailed and clear illustrations and references to the literature. The limitations of SEMG measures and methods for careful analysis are discussed. This broad compilation of articles discussing the use of EMG in both clinical and research applications demonstrates the utility of the method as a tool in a wide variety of disciplines and clinical fields

Non-Invasive Investigation of Human Foot Muscles Function

Appropriate functioning of the human foot is fundamental for good quality of life. The intrinsic foot muscles (IFM) are a crucial component of the foot, but their natural behaviour and contribution to good foot health is currently poorly understood. Recording muscle activation from IFM has been attempted with invasive techniques, but these generally only allow assessment of one muscle at a time and are not much used in many clinical populations (e.g. children, patients with peripheral neuropathy or on blood thinning medication). Here a novel application of multi-channel surface electromyography (sEMG) electrodes is presented to non-invasively, record sEMG and quantify activation patterns of IFMs from across the plantar region of the foot. sEMG (13×5 array), kinematics and force plate data were recorded from 30 healthy adult volunteers who completed six postural balance tasks (e.g. bipedal stance, one-foot stance, two-foot tip-toe). Linear (amplitude based) and non-linear (entropy based) methodologies were used to evaluate the physiological features of the sEMG, the patterns of activation, the association with whole body and foot biomechanics and the neuromuscular drive to the IFM. EMG signals features (amplitude and frequency) were shown to be in the physiological ranges reported in the literature (Basmajian and De Luca, 1985), with spatially clustered patterns of high activation corresponding to the Flexor digitorum brevis muscle. IFMs responded differently based on the direction of postural sway, with greater activations associated with sways in the mediolateral direction. Entropy based, non-linear analysis revealed that neuromuscular drive to IFM depends on the balance demand of the postural task, with greater drive evident for more challenging tasks (i.e. standing on tiptoe). Combining non-invasive measures of IFM activation and entropy based assessment of temporal organisation (or structure) of EMG signal variability is therefore revealing of IFM function and will enable a more detailed assessment of IFM function across healthy and clinical populations

Proceedings XXIII Congresso SIAMOC 2023

Il congresso annuale della Società Italiana di Analisi del Movimento in Clinica (SIAMOC), giunto quest’anno alla sua ventitreesima edizione, approda nuovamente a Roma. Il congresso SIAMOC, come ogni anno, è l’occasione per tutti i professionisti che operano nell’ambito dell’analisi del movimento di incontrarsi, presentare i risultati delle proprie ricerche e rimanere aggiornati sulle più recenti innovazioni riguardanti le procedure e le tecnologie per l’analisi del movimento nella pratica clinica. Il congresso SIAMOC 2023 di Roma si propone l’obiettivo di fornire ulteriore impulso ad una già eccellente attività di ricerca italiana nel settore dell’analisi del movimento e di conferirle ulteriore respiro ed impatto internazionale. Oltre ai qualificanti temi tradizionali che riguardano la ricerca di base e applicata in ambito clinico e sportivo, il congresso SIAMOC 2023 intende approfondire ulteriori tematiche di particolare interesse scientifico e di impatto sulla società. Tra questi temi anche quello dell’inserimento lavorativo di persone affette da disabilità anche grazie alla diffusione esponenziale in ambito clinico-occupazionale delle tecnologie robotiche collaborative e quello della protesica innovativa a supporto delle persone con amputazione. Verrà infine affrontato il tema dei nuovi algoritmi di intelligenza artificiale per l’ottimizzazione della classificazione in tempo reale dei pattern motori nei vari campi di applicazione

Computational Intelligence in Electromyography Analysis

Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG may be used clinically for the diagnosis of neuromuscular problems and for assessing biomechanical and motor control deficits and other functional disorders. Furthermore, it can be used as a control signal for interfacing with orthotic and/or prosthetic devices or other rehabilitation assists. This book presents an updated overview of signal processing applications and recent developments in EMG from a number of diverse aspects and various applications in clinical and experimental research. It will provide readers with a detailed introduction to EMG signal processing techniques and applications, while presenting several new results and explanation of existing algorithms. This book is organized into 18 chapters, covering the current theoretical and practical approaches of EMG research

Proceedings XXI Congresso SIAMOC 2021

XXI Congresso Annuale della SIAMOC, modalità telematica il 30 settembre e il 1° ottobre 2021. Come da tradizione, il congresso vuole essere un’occasione di arricchimento e mutuo scambio, dal punto di vista scientifico e umano. Verranno toccati i temi classici dell’analisi del movimento, come lo sviluppo e l’applicazione di metodi per lo studio del movimento nel contesto clinico, e temi invece estremamente attuali, come la teleriabilitazione e il telemonitoraggio