APPLICATION OF SINGLE WIRELESS HOLTER TO SIMULTANEOUS EMG, MMG AND EIM MEASUREMENT OF HUMAN MUSCLES ACTIVITY

This paper describes application and design of wireless holter with innovative functionality, used it in field of human muscle monitoring. In our experiments we monitored EMG (electromyography), MMG (mechanomyography) and EIM (electrical impedance myography) all by single device. It is first time when these all parameters were monitored simultaneously taking advantage of the holter device data output in order to find the signals interconnection. Our data were compared with normally used medical device and signal quality was verified

IMPACT OF SKINFOLD THICKNESS ON WAVELET-BASED MECHANOMYOGRAPHIC SIGNAL

Surface mechanography (MMG) is a non-invasive technique that captures signs of low-frequency vibrations of skeletal muscles through the skin. However, subcutaneous structures may interfere with the acquisition of MMG signals. The objective of this study was to verify the influence of skinfold thickness (ST) on the MMG wavelet-based signal in the rectus femoris muscle during maximal voluntary contraction in two groups of individuals: group I (n = 10, ST 20 mm). Negative correlation was observed between the 19 Hz, 28 Hz and 39 Hz frequency bands with ST. There was a statistical difference in almost all frequency bands, especially in the X and Y axes. All MMG axes in group II presented higher magnitudes in frequency bands 2 and 6 Hz (like low-pass filter). Thus, these results can be applied to calibrate MMG responses as biofeedback systems

Mechanomyographic Parameter Extraction Methods: An Appraisal for Clinical Applications

The research conducted in the last three decades has collectively demonstrated that the skeletal muscle performance can be alternatively assessed by mechanomyographic signal (MMG) parameters. Indices of muscle performance, not limited to force, power, work, endurance and the related physiological processes underlying muscle activities during contraction have been evaluated in the light of the signal features. As a non-stationary signal that reflects several distinctive patterns of muscle actions, the illustrations obtained from the literature support the reliability of MMG in the analysis of muscles under voluntary and stimulus evoked contractions. An appraisal of the standard practice including the measurement theories of the methods used to extract parameters of the signal is vital to the application of the signal during experimental and clinical practices, especially in areas where electromyograms are contraindicated or have limited application. As we highlight the underpinning technical guidelines and domains where each method is well-suited, the limitations of the methods are also presented to position the state of the art in MMG parameters extraction, thus providing the theoretical framework for improvement on the current practices to widen the opportunity for new insights and discoveries. Since the signal modality has not been widely deployed due partly to the limited information extractable from the signals when compared with other classical techniques used to assess muscle performance, this survey is particularly relevant to the projected future of MMG applications in the realm of musculoskeletal assessments and in the real time detection of muscle activity

Advances and perspectives of mechanomyography

INTRODUCTION: The evaluation of muscular tissue condition can be accomplished with mechanomyography (MMG), a technique that registers intramuscular mechanical waves produced during a fiber's contraction and stretching that are sensed or interfaced on the skin surface. OBJECTIVE: Considering the scope of MMG measurements and recent advances involving the technique, the goal of this paper is to discuss mechanomyography updates and discuss its applications and potential future applications. METHODS: Forty-three MMG studies were published between the years of 1987 and 2013. RESULTS: MMG sensors are developed with different technologies such as condenser microphones, accelerometers, laser-based instruments, etc. Experimental protocols that are described in scientific publications typically investigated the condition of the vastus lateralis muscle and used sensors built with accelerometers, third and fourth order Butterworth filters, 5-100Hz frequency bandpass, signal analysis using Root Mean Square (RMS) (temporal), Median Frequency (MDF) and Mean Power Frequency (MPF) (spectral) features, with epochs of 1 s. CONCLUSION: Mechanomyographic responses obtained in isometric contractions differ from those observed during dynamic contractions in both passive and functional electrical stimulation evoked movements. In the near future, MMG features applied to biofeedback closed-loop systems will help people with disabilities, such as spinal cord injury or limb amputation because they may improve both neural and myoelectric prosthetic control. Muscular tissue assessment is a new application area enabled by MMG; it can be useful in evaluating the muscular tonus in anesthetic blockade or in pathologies such as myotonic dystrophy, chronic obstructive pulmonary disease, and disorders including dysphagia, myalgia and spastic hypertonia. New research becomes necessary to improve the efficiency of MMG systems and increase their application in rehabilitation, clinical and other health areas304384401CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPsem informaçã

Markers of physical functioning and neuromuscular fatigue for the post-discharge follow-up of subjects already assisted in intensive care for COVID-19 and non-communicable diseases.

L'insorgenza di malattie non trasmissibili con incidenza neuromuscolare e il prolungato ricovero in terapia intensiva comportano implicazioni negative sulla capacità funzionale e l'autonomia dei pazienti. Queste alterazioni sono causate da fattori come l'immobilità prolungata, l'infiammazione sistemica, le disfunzioni neuromuscolari e gli effetti diretti della patologia stessa. Ciò porta a fatica e debolezza muscolare, contribuendo a un significativo declino nelle abilità motorie, ostacolando il recupero e peggiorando la qualità della vita dei pazienti. Le principali disfunzioni motorie si manifestano con l’alterata deambulazione, limitando l'autonomia nelle attività quotidiane. Tali disfunzioni sono causate dalla compromissione delle vie motorie del sistema nervoso e si manifestano già durante la fase acuta della malattia, peggiorando successivamente con il suo evolversi. Tale quadro clinico è aggravato ulteriormente dalla conseguente inattività fisica, favorita dalle condizioni psicofisiche dei singoli. Di conseguenza, tutto ciò incide notevolmente sulle proprietà contrattili dei muscoli, portando ad alterazioni critiche che influenzano la capacità del sistema nervoso centrale e periferico di reclutare e modulare l'attività delle unità motorie. Date le complessità associate a queste considerazioni, diventa fondamentale identificare marcatori in grado di quantificare e caratterizzare l’alterazione della capacità funzionale e l’insorgenza della debolezza muscolare e della fatica. Ciò faciliterebbe una diagnosi precoce e, in modo cruciale, il monitoraggio continuo di tali problematiche. Pertanto, l'obiettivo primario di questa ricerca di Dottorato è identificare e analizzare marcatori in grado di supportare efficacemente gli operatori sanitari nella progettazione e nell'implementazione di approcci terapeutici personalizzati per accelerare il recupero di questi individui. Nonostante, infatti, la pratica clinica attualmente in uso negli ospedali offra continui miglioramenti, questa presenta ancora delle limitazioni. Sebbene le valutazioni attualmente impiegate riescano ad identificare la presenza di fatica e debolezza muscolare nei pazienti post-ricovero in terapia intensiva o in soggetti affetti da malattie non trasmissibili, non riescono tuttavia ad indagare a fondo su quali siano le effettive cause che innescano la perdita della forza muscolare o ad esaminare in modo esaustivo i fattori centrali e/o periferici che contribuiscono all'insorgenza della fatica. Per colmare in modo esaustivo questa lacuna, lo studio ha condotto un'ampia ricerca combinando l'elettromiografia di superficie con la capacità di generare forza muscolare in diverse condizioni patologiche, includendo attivazioni muscolari sia volontarie che indotte elettricamente. Il muscolo oggetto di studio è stato il tibiale anteriore, scelto per il suo ruolo cruciale nella biomeccanica della deambulazione e quindi fondamentale per il mantenimento dell’autonomia motoria. I risultati hanno mostrato che le variazioni nella forza e nei parametri delle unità motorie possono servire da indicatori per le alterazioni neuromuscolari e il recupero progressivo, facilitando il monitoraggio a breve e lungo termine. Questo studio ha quindi un'importanza fondamentale per le popolazioni coinvolte e può suggerire approcci più ampi per la gestione delle alterazioni neuromuscolari in diversi contesti clinici. In particolare, sottolinea l'importanza di programmi di riabilitazione personalizzati e soggettivati alle esigenze specifiche di ciascun individuo.The onset of non-communicable neuromuscular diseases and prolonged stays in the intensive care unit have deep implications for physical functioning and neuromuscular health. These repercussions arise from muscle deconditioning, systemic inflammation, and the direct impact of the pathology. Moreover, resulting fatigue and acquired muscle weakness contribute to reduced muscular performance, significantly hampering recovery and diminishing overall quality of life. The predominant motor impairments observed in these patients primarily manifest in their ability to perform correct walking, substantially limiting their independent execution of daily activities. This compromised excitability in descending motor pathways becomes evident during the acute phase of the disease and intensifies as the condition progresses chronically, exacerbated by prolonged physical inactivity. Consequently, this significantly affects the muscle's contractile properties, leading to critical alterations that influence the nervous systems' capacity to recruit and modulate the activity of motor units, the fundamental functional units responsible for planning, executing, and maintaining motor gestures. Given these considerations, it becomes crucial to identify markers that enable the quantification and characterization of physical functioning impairment, muscle weakness and fatigue. This would facilitate early diagnosis and, crucially, the ongoing monitoring of these issues. Thus, the primary goal of this PhD research is to identify and analyze markers that can effectively support healthcare practitioners in devising and delivering personalized therapeutic approaches to expedite the recovery of these individuals. The overarching objective is to optimize the current clinical practice commonly employed in hospitals. Despite ongoing refinements, these practices still exhibit limitations. While standard assessments succeed in identifying the presence of fatigue and muscle weakness in ICU patients or those afflicted by non-communicable diseases, they fall short of investigating the root causes of muscle strength deterioration or thoroughly probing the central and/or peripheral factors contributing to the emergence of pathological fatigue. To comprehensively bridge this existing gap, the study undertook an extensive exploration by measuring concurrent joint torques and surface electromyography across various pathological conditions, encompassing both voluntary and electrically induced muscle activations. The focal point was the tibialis anterior muscle, chosen for its pivotal role in gait patterns and consequential influence on individual autonomy. The presented results were mainly achieved through the decomposition of signals recorded using the High-Density Surface EMG technique. This technique enabled the analysis of individual motor units recruited during motor tasks administered to patients within the studied populations. The process of data collection and analysis revealed that variations in muscle strength values and motor unit parameters can serve as indicators of neuromuscular system alterations and progressive recovery. These factors are pivotal for subsequent follow-up procedures. Indeed, by establishing a robust framework of markers, is possible to contribute to the development of evidence-based protocols that enhance the post-discharge care of these individuals. This study is not only pivotal for these specific cohorts but also holds the potential to inform broader strategies for managing physical impairment and neuromuscular challenges in diverse clinical settings. Notably, the study highlights that hospitalization in intensive care, as well as the onset of non-communicable pathologies with high motor impact, leads to specific alterations in parameters of both central and peripheral neuromuscular pathways. This underscores the imperative for devising personalized rehabilitation regimens tailored to each patient's needs