1
|
Li N, Ou J, He H, He J, Zhang L, Peng Z, Zhong J, Jiang N. Exploration of a machine learning approach for diagnosing sarcopenia among Chinese community-dwelling older adults using sEMG-based data. J Neuroeng Rehabil 2024; 21:69. [PMID: 38725065 PMCID: PMC11080130 DOI: 10.1186/s12984-024-01369-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND In the practical application of sarcopenia screening, there is a need for faster, time-saving, and community-friendly detection methods. The primary purpose of this study was to perform sarcopenia screening in community-dwelling older adults and investigate whether surface electromyogram (sEMG) from hand grip could potentially be used to detect sarcopenia using machine learning (ML) methods with reasonable features extracted from sEMG signals. The secondary aim was to provide the interpretability of the obtained ML models using a novel feature importance estimation method. METHODS A total of 158 community-dwelling older residents (≥ 60 years old) were recruited. After screening through the diagnostic criteria of the Asian Working Group for Sarcopenia in 2019 (AWGS 2019) and data quality check, participants were assigned to the healthy group (n = 45) and the sarcopenic group (n = 48). sEMG signals from six forearm muscles were recorded during the hand grip task at 20% maximal voluntary contraction (MVC) and 50% MVC. After filtering recorded signals, nine representative features were extracted, including six time-domain features plus three time-frequency domain features. Then, a voting classifier ensembled by a support vector machine (SVM), a random forest (RF), and a gradient boosting machine (GBM) was implemented to classify healthy versus sarcopenic participants. Finally, the SHapley Additive exPlanations (SHAP) method was utilized to investigate feature importance during classification. RESULTS Seven out of the nine features exhibited statistically significant differences between healthy and sarcopenic participants in both 20% and 50% MVC tests. Using these features, the voting classifier achieved 80% sensitivity and 73% accuracy through a five-fold cross-validation. Such performance was better than each of the SVM, RF, and GBM models alone. Lastly, SHAP results revealed that the wavelength (WL) and the kurtosis of continuous wavelet transform coefficients (CWT_kurtosis) had the highest feature impact scores. CONCLUSION This study proposed a method for community-based sarcopenia screening using sEMG signals of forearm muscles. Using a voting classifier with nine representative features, the accuracy exceeds 70% and the sensitivity exceeds 75%, indicating moderate classification performance. Interpretable results obtained from the SHAP model suggest that motor unit (MU) activation mode may be a key factor affecting sarcopenia.
Collapse
Affiliation(s)
- Na Li
- The National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
- Medical Equipment Innovation Research Center, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
- The Med-X Center for Manufacturing, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Jiarui Ou
- College of Computer Science, Sichuan University, Chengdu, 610065, China
| | - Haoru He
- The National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
- Medical Equipment Innovation Research Center, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
- The Med-X Center for Manufacturing, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Jiayuan He
- The National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
- Medical Equipment Innovation Research Center, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
- The Med-X Center for Manufacturing, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Le Zhang
- College of Computer Science, Sichuan University, Chengdu, 610065, China
| | - Zhengchun Peng
- School of Electronic Information and ElectricaEngineering, Shanghaijiao Tong University, Shanghai, 200240, China
| | - Junwen Zhong
- Department of Electromechanical Engineering and Centre for Artificial Intelligence and Robotics, University of Macau, Macau, SAR, 999078, China
| | - Ning Jiang
- The National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China.
- Medical Equipment Innovation Research Center, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China.
- The Med-X Center for Manufacturing, Sichuan University, Chengdu, Sichuan, 610041, China.
| |
Collapse
|
2
|
Kouyoumdjian JA, Estephan EDP. Electrophysiological evaluation of the neuromuscular junction: a brief review. ARQUIVOS DE NEURO-PSIQUIATRIA 2023; 81:1040-1052. [PMID: 38157872 PMCID: PMC10756823 DOI: 10.1055/s-0043-1777749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/17/2023] [Indexed: 01/03/2024]
Abstract
The nerve terminal and muscle membrane compose the neuromuscular junction. After opening the voltage-gated calcium channels, action potentials from the motor axons provoke a cascade for the acetylcholine release from synaptic vesicles to the synaptic cleft, where it binds to its receptor at the muscle membrane for depolarization. Low amplitude compound muscle action potential typically presents in presynaptic disorders, increasing by more than 100% after a 10-second effort in the Lambert-Eaton myasthenic syndrome and less in botulism. Needle electromyography may show myopathic motor unit action potentials and morphological instability ("jiggle") due to impulse blocking. Low-frequency repetitive nerve stimulation (RNS) is helpful in postsynaptic disorders, such as myasthenia gravis and most congenital myasthenic syndromes, where the number of functioning acetylcholine receptors is reduced. Low-frequency RNS with a decrement >10% is abnormal when comparing the 4th to the first compound muscle action potential amplitude. High-frequency RNS is helpful in presynaptic disorders like Lambert-Eaton myasthenic syndrome, botulism, and some rare congenital myasthenic syndromes. The high-frequency RNS releases more calcium, increasing the acetylcholine with a compound muscle action potential increment. Concentric needle records apparent single-fiber action potentials (spikes). A voluntary activation measures the jitter between spikes from two endplates. An electrical activation measures the jitter of one spike (one endplate). The jitter is the most sensitive test for detecting a neuromuscular junction dysfunction. Most neuromuscular junction disorders are responsive to treatment.
Collapse
Affiliation(s)
- João Aris Kouyoumdjian
- Faculdade de Medicina de São José do Rio Preto, Departamento de Ciências Neurológicas, Psiquiatria e Psicologia Médica, São José do Rio Preto SP, Brazil.
| | - Eduardo de Paula Estephan
- Faculdade de Medicina de São José do Rio Preto, Departamento de Ciências Neurológicas, Psiquiatria e Psicologia Médica, São José do Rio Preto SP, Brazil.
- Universidade de São Paulo, Departamento de Neurologia, São Paulo SP, Brazil.
- Faculdade de Medicina Santa Marcelina, São Paulo SP, Brazil.
| |
Collapse
|
3
|
Arnold WD, Clark BC. Neuromuscular junction transmission failure in aging and sarcopenia: The nexus of the neurological and muscular systems. Ageing Res Rev 2023; 89:101966. [PMID: 37270145 PMCID: PMC10847753 DOI: 10.1016/j.arr.2023.101966] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/05/2023] [Accepted: 05/29/2023] [Indexed: 06/05/2023]
Abstract
Sarcopenia, or age-related decline in muscle form and function, exerts high personal, societal, and economic burdens when untreated. Integrity and function of the neuromuscular junction (NMJ), as the nexus between the nervous and muscular systems, is critical for input and dependable neural control of muscle force generation. As such, the NMJ has long been a site of keen interest in the context of skeletal muscle function deficits during aging and in the context of sarcopenia. Historically, changes of NMJ morphology during aging have been investigated extensively but primarily in aged rodent models. Aged rodents have consistently shown features of NMJ endplate fragmentation and denervation. Yet, the presence of NMJ changes in older humans remains controversial, and conflicting findings have been reported. This review article describes the physiological processes involved in NMJ transmission, discusses the evidence that supports NMJ transmission failure as a possible contributor to sarcopenia, and speculates on the potential of targeting these defects for therapeutic development. The technical approaches that are available for assessment of NMJ transmission, whether each approach has been applied in the context of aging and sarcopenia, and the associated findings are summarized. Like morphological studies, age-related NMJ transmission deficits have primarily been studied in rodents. In preclinical studies, isolated synaptic electrophysiology recordings of endplate currents or potentials have been mostly used, and paradoxically, have shown enhancement, rather than failure, with aging. Yet, in vivo assessment of single muscle fiber action potential generation using single fiber electromyography and nerve-stimulated muscle force measurements show evidence of NMJ failure in aged mice and rats. Together these findings suggest that endplate response enhancement may be a compensatory response to post-synaptic mechanisms of NMJ transmission failure in aged rodents. Possible, but underexplored, mechanisms of this failure are discussed including the simplification of post-synaptic folding and altered voltage-gated sodium channel clustering or function. In humans, there is limited clinical data that has selectively investigated single synaptic function in the context of aging. If sarcopenic older adults turn out to exhibit notable impairments in NMJ transmission (this has yet to be examined but based on available evidence appears to be plausible) then these NMJ transmission defects present a well-defined biological mechanism and offer a well-defined pathway for clinical implementation. Investigation of small molecules that are currently available clinically or being testing clinically in other disorders may provide a rapid route for development of interventions for older adults impacted by sarcopenia.
Collapse
Affiliation(s)
- W David Arnold
- NextGen Precision Health, University of Missouri System, Columbia, MO, USA; Department of Physical Medicine and Rehabilitation University of Missouri, Columbia, MO, USA.
| | - Brian C Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI) Ohio University, Athens, OH, USA; Department of Biomedical Sciences, Ohio University, Athens, OH, USA.
| |
Collapse
|
4
|
Mandeville R, Sanchez B, Johnston B, Bazarek S, Thum JA, Birmingham A, See RHB, Leochico CFD, Kumar V, Dowlatshahi AS, Brown J, Stashuk D, Rutkove SB. A scoping review of current and emerging techniques for evaluation of peripheral nerve health, degeneration, and regeneration: part 1, neurophysiology. J Neural Eng 2023; 20:041001. [PMID: 37279730 DOI: 10.1088/1741-2552/acdbeb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 06/06/2023] [Indexed: 06/08/2023]
Abstract
Peripheral neuroregeneration research and therapeutic options are expanding exponentially. With this expansion comes an increasing need to reliably evaluate and quantify nerve health. Valid and responsive measures that can serve as biomarkers of the nerve status are essential for both clinical and research purposes for diagnosis, longitudinal follow-up, and monitoring the impact of any intervention. Furthermore, such biomarkers can elucidate regeneration mechanisms and open new avenues for research. Without these measures, clinical decision-making falls short, and research becomes more costly, time-consuming, and sometimes infeasible. As a companion to Part 2, which is focused on non-invasive imaging, Part 1 of this two-part scoping review systematically identifies and critically examines many current and emerging neurophysiological techniques that have the potential to evaluate peripheral nerve health, particularly from the perspective of regenerative therapies and research.
Collapse
Affiliation(s)
- Ross Mandeville
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, United States of America
| | - Benjamin Sanchez
- Department Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Benjamin Johnston
- Department of Neurosurgery, Brigham and Women's Hospital, Boston, MA 02115, United States of America
| | - Stanley Bazarek
- Department of Neurosurgery, Brigham and Women's Hospital, Boston, MA 02115, United States of America
| | - Jasmine A Thum
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, United States of America
| | - Austin Birmingham
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, United States of America
| | - Reiner Henson B See
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, United States of America
| | - Carl Froilan D Leochico
- Department of Physical Medicine and Rehabilitation, St. Luke's Medical Center, Global City, Taguig, The Philippines
- Department of Rehabilitation Medicine, Philippine General Hospital, University of the Philippines Manila, Manila, The Philippines
| | - Viksit Kumar
- Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, United States of America
| | - Arriyan S Dowlatshahi
- Department of Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, United States of America
| | - Justin Brown
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, United States of America
| | - Daniel Stashuk
- Department of Systems Design Engineering, University of Waterloo, Ontario N2L 3G1, Canada
| | - Seward B Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, United States of America
| |
Collapse
|
5
|
Bromberg MB. Quantitative electrodiagnosis of the motor unit. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:271-286. [PMID: 37562872 DOI: 10.1016/b978-0-323-98818-6.00016-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Electromyography (EMG) focuses on assessment of the motor unit (MU), and a given muscle has several hundred MUs, each innervating hundreds of muscle fibers. Assessment is limited by the recording radius of electrodes, 1-2 fibers with single-fiber electrodes and 7-15 fibers with concentric or monopolar electrodes. Routine qualitative EMG studies rely on observing MUs in free-run mode and qualitatively estimating common metrics. In contrast, quantitative EMG (QEMG) applied to routine studies includes assessment of individual MUs by software available in modern EMG machines with extraction of discrete values for common metrics, and also derived metrics. This results in greater precision and statistical interpretation. Other QEMG techniques assess muscle fiber density within the MU and time variability at the neuromuscular junction. The interference pattern can also be assessed. The number of MUs innervating a muscle can be estimated. Advanced signal processing, called near-fiber EMG, allows for extraction of underlying muscle fiber contributions to MU waveforms. It is also possible to use QEMG to make statistical probabilities of the state of a muscle as to whether normal, myopathic, or neuropathic. Time to acquire QEMG data is minimal. QEMG is most useful in situations where pathology is uncertain.
Collapse
Affiliation(s)
- Mark B Bromberg
- Department of Neurology, University of Utah, Salt Lake City, UT, United States.
| |
Collapse
|
6
|
Muceli S, Poppendieck W, Holobar A, Gandevia S, Liebetanz D, Farina D. Blind identification of the spinal cord output in humans with high-density electrode arrays implanted in muscles. SCIENCE ADVANCES 2022; 8:eabo5040. [PMID: 36383647 PMCID: PMC9668292 DOI: 10.1126/sciadv.abo5040] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Invasive electromyography opened a new window to explore motoneuron behavior in vivo. However, the technique is limited by the small fraction of active motoneurons that can be concurrently detected, precluding a population analysis in natural tasks. Here, we developed a high-density intramuscular electrode for in vivo human recordings along with a fully automatic methodology that could detect the discharges of action potentials of up to 67 concurrently active motoneurons with 99% accuracy. These data revealed that motoneurons of the same pool receive common synaptic input at frequencies up to 75 Hz and that late-recruited motoneurons inhibit the discharges of those recruited earlier. These results constitute an important step in the population coding analysis of the human motor system in vivo.
Collapse
Affiliation(s)
- Silvia Muceli
- Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Aleš Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Simon Gandevia
- Neuroscience Research Australia and University of New South Wales, Randwick, Sydney, New South Wales, Australia
| | - David Liebetanz
- Department of Neurology, University Medical Center Göttingen, Georg-August University, Göttingen, Germany
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, UK
| |
Collapse
|
7
|
Inns TB, Bass JJ, Hardy EJ, Wilkinson DJ, Stashuk DW, Atherton PJ, Phillips BE, Piasecki M. Motor unit dysregulation following 15 days of unilateral lower limb immobilisation. J Physiol 2022; 600:4753-4769. [PMID: 36088611 PMCID: PMC9827843 DOI: 10.1113/jp283425] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/19/2022] [Indexed: 01/12/2023] Open
Abstract
Disuse atrophy, caused by situations of unloading such as limb immobilisation, causes a rapid yet diverging reduction in skeletal muscle function when compared to muscle mass. While mechanistic insight into the loss of mass is well studied, deterioration of muscle function with a focus towards the neural input to muscle remains underexplored. This study aimed to determine the role of motor unit adaptation in disuse-induced neuromuscular deficits. Ten young, healthy male volunteers underwent 15 days of unilateral lower limb immobilisation with intramuscular electromyography (iEMG) bilaterally recorded from the vastus lateralis (VL) during knee extensor contractions normalised to maximal voluntary contraction (MVC), pre and post disuse. Muscle cross-sectional area was determined by ultrasound. Individual MUs were sampled and analysed for changes in motor unit (MU) discharge and MU potential (MUP) characteristics. VL CSA was reduced by approximately 15% which was exceeded by a two-fold decrease of 31% in muscle strength in the immobilised limb, with no change in either parameter in the non-immobilised limb. Parameters of MUP size were reduced by 11% to 24% with immobilisation, while neuromuscular junction (NMJ) transmission instability remained unchanged, and MU firing rate decreased by 8% to 11% at several contraction levels. All adaptations were observed in the immobilised limb only. These findings highlight impaired neural input following immobilisation reflected by suppressed MU firing rate which may underpin the disproportionate reductions of strength relative to muscle size. KEY POINTS: Muscle mass and function decline rapidly in situations of disuse such as bed rest and limb immobilisation. The reduction in muscle function commonly exceeds that of muscle mass, which may be associated with the dysregulation of neural input to muscle. We have used intramuscular electromyography to sample individual motor unit and near fibre potentials from the vastus lateralis following 15 days of unilateral limb immobilisation. Following disuse, the disproportionate loss of muscle strength when compared to size coincided with suppressed motor unit firing rate. These motor unit adaptations were observed at multiple contraction levels and in the immobilised limb only. Our findings demonstrate neural dysregulation as a key component of functional loss following muscle disuse in humans.
Collapse
Affiliation(s)
- Thomas B. Inns
- Centre Of Metabolism, Ageing & PhysiologyMRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRCUniversity of NottinghamDerbyUK
| | - Joseph J. Bass
- Centre Of Metabolism, Ageing & PhysiologyMRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRCUniversity of NottinghamDerbyUK
| | - Edward J.O. Hardy
- Centre Of Metabolism, Ageing & PhysiologyMRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRCUniversity of NottinghamDerbyUK
- Department of Surgery and AnaestheticsRoyal Derby HospitalDerbyUK
| | - Daniel J. Wilkinson
- Centre Of Metabolism, Ageing & PhysiologyMRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRCUniversity of NottinghamDerbyUK
| | - Daniel W. Stashuk
- Department of Systems Design EngineeringUniversity of WaterlooOntarioCanada
| | - Philip J. Atherton
- Centre Of Metabolism, Ageing & PhysiologyMRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRCUniversity of NottinghamDerbyUK
| | - Bethan E. Phillips
- Centre Of Metabolism, Ageing & PhysiologyMRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRCUniversity of NottinghamDerbyUK
| | - Mathew Piasecki
- Centre Of Metabolism, Ageing & PhysiologyMRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and NIHR Nottingham BRCUniversity of NottinghamDerbyUK
| |
Collapse
|
8
|
Sarto F, Stashuk DW, Franchi MV, Monti E, Zampieri S, Valli G, Sirago G, Candia J, Hartnell LM, Paganini M, McPhee JS, De Vito G, Ferrucci L, Reggiani C, Narici MV. Effects of short-term unloading and active recovery on human motor unit properties, neuromuscular junction transmission and transcriptomic profile. J Physiol 2022; 600:4731-4751. [PMID: 36071599 PMCID: PMC9828768 DOI: 10.1113/jp283381] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/26/2022] [Indexed: 01/12/2023] Open
Abstract
Electrophysiological alterations of the neuromuscular junction (NMJ) and motor unit potential (MUP) with unloading are poorly studied. We aimed to investigate these aspects and the underlying molecular mechanisms with short-term unloading and active recovery (AR). Eleven healthy males underwent a 10-day unilateral lower limb suspension (ULLS) period, followed by 21-day AR based on resistance exercise. Quadriceps femoris (QF) cross-sectional area (CSA) and isometric maximum voluntary contraction (MVC) were evaluated. Intramuscular electromyographic recordings were obtained during 10% and 25% MVC isometric contractions from the vastus lateralis (VL). Biomarkers of NMJ molecular instability (serum c-terminal agrin fragment, CAF), axonal damage (neurofilament light chain) and denervation status were assessed from blood samples and VL biopsies. NMJ and ion channel transcriptomic profiles were investigated by RNA-sequencing. QF CSA and MVC decreased with ULLS. Increased CAF and altered NMJ transcriptome with unloading suggested the emergence of NMJ molecular instability, which was not associated with impaired NMJ transmission stability. Instead, increased MUP complexity and decreased motor unit firing rates were found after ULLS. Downregulation of ion channel gene expression was found together with increased neurofilament light chain concentration and partial denervation. The AR period restored most of these neuromuscular alterations. In conclusion, the human NMJ is destabilized at the molecular level but shows functional resilience to a 10-day unloading period at least at relatively low contraction intensities. However, MUP properties are altered by ULLS, possibly due to alterations in ion channel dynamics and initial axonal damage and denervation. These changes are fully reversed by 21 days of AR. KEY POINTS: We used integrative electrophysiological and molecular approaches to comprehensively investigate changes in neuromuscular integrity and function after a 10-day unilateral lower limb suspension (ULLS), followed by 21 days of active recovery in young healthy men, with a particular focus on neuromuscular junction (NMJ) and motor unit potential (MUP) properties alterations. After 10-day ULLS, we found significant NMJ molecular alterations in the absence of NMJ transmission stability impairment. These findings suggest that the human NMJ is functionally resilient against insults and stresses induced by short-term disuse at least at relatively low contraction intensities, at which low-threshold, slow-type motor units are recruited. Intramuscular electromyography analysis revealed that unloading caused increased MUP complexity and decreased motor unit firing rates, and these alterations could be related to the observed changes in skeletal muscle ion channel pool and initial and partial signs of fibre denervation and axonal damage. The active recovery period restored these neuromuscular changes.
Collapse
Affiliation(s)
- Fabio Sarto
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Daniel W. Stashuk
- Department of Systems Design EngineeringUniversity of WaterlooOntarioCanada
| | - Martino V. Franchi
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly,CIR‐MYO Myology CenterUniversity of PadovaPadovaItaly
| | - Elena Monti
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Sandra Zampieri
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly,CIR‐MYO Myology CenterUniversity of PadovaPadovaItaly,Department of SurgeryOncology, and GastroenterologyUniversity of PadovaPadovaItaly
| | - Giacomo Valli
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Giuseppe Sirago
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Julián Candia
- Longitudinal Studies SectionTranslational Gerontology BranchNational Institute of AgingNational Institutes of HealthBaltimoreMDUSA
| | - Lisa M. Hartnell
- Longitudinal Studies SectionTranslational Gerontology BranchNational Institute of AgingNational Institutes of HealthBaltimoreMDUSA
| | - Matteo Paganini
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Jamie S. McPhee
- Department of Sport and Exercise SciencesManchester Metropolitan University Institute of SportManchesterUK
| | - Giuseppe De Vito
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly,CIR‐MYO Myology CenterUniversity of PadovaPadovaItaly
| | - Luigi Ferrucci
- Longitudinal Studies SectionTranslational Gerontology BranchNational Institute of AgingNational Institutes of HealthBaltimoreMDUSA
| | - Carlo Reggiani
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly,Science and Research Center KoperInstitute for Kinesiology ResearchKoperSlovenia
| | - Marco V. Narici
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly,CIR‐MYO Myology CenterUniversity of PadovaPadovaItaly,Science and Research Center KoperInstitute for Kinesiology ResearchKoperSlovenia
| |
Collapse
|
9
|
Ely IA, Jones EJ, Inns TB, Dooley S, Miller SBJ, Stashuk DW, Atherton PJ, Phillips BE, Piasecki M. Training induced improvements in knee extensor force accuracy are associated with reduced vastus lateralis motor unit firing variability. Exp Physiol 2022; 107:1061-1070. [PMID: 35923141 PMCID: PMC9542263 DOI: 10.1113/ep090367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/28/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? We aimed to determine levels of bilateral knee extensor force accuracy and any subsequent alterations to central and/or peripheral motor unit features, following 4 weeks of unilateral force accuracy training. What is the main finding and its importance? In the trained limb only, knee extensor force tracking accuracy improved with reduced motor unit firing rate variability in the vastus lateralis, and no change to neuromuscular junction transmission instability. Interventional strategies to improve force accuracy may be directed to older/clinical populations where such improvements may aid performance of daily living activities. ABSTRACT Background Muscle force output during sustained submaximal isometric contractions fluctuates around an average value and is partly influenced by variation in motor unit (MU) firing rates. MU firing rate (FR) variability seemingly reduces following exercise training interventions, however, much less is known with respect to peripheral MU properties. We therefore investigated whether targeted force accuracy training could lead to improved muscle functional capacity and control, in addition to determining any alterations of individual MU features. Methods Ten healthy participants (7 females, 3 males, 27±6 years, 170±8 cm, 69±16kg) underwent a 4-week supervised, unilateral knee extensor force accuracy training intervention. The coefficient of variation for force (FORCECoV ) and sinusoidal wave force tracking accuracy (FORCESinu ) were determined at 25% maximal voluntary contraction (MVC) pre- and post-training. Intramuscular electromyography was utilised to record individual MU potentials from the vastus lateralis (VL) muscles at 25% MVC during sustained contractions, pre- and post-training. Results Knee extensor muscle strength remained unchanged following training, with no improvements in unilateral leg-balance. FORCECoV and FORCESinu significantly improved in only the trained knee extensors by ∼13% (p = 0.01) and ∼30% (p<0.0001) respectively. MU FR variability significantly reduced in the trained VL by ∼16% (n = 8; p = 0.001), with no further alterations to MU FR or neuromuscular junction transmission instability. Conclusion Our results suggest muscle force control and tracking accuracy is a trainable characteristic in the knee extensors, which is likely explained by the reduction in MU FR variability which was apparent in the trained limb only. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Isabel A Ely
- Centre of Metabolism, Ageing and Physiology, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - Eleanor J Jones
- Centre of Metabolism, Ageing and Physiology, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - Thomas B Inns
- Centre of Metabolism, Ageing and Physiology, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - Síobhra Dooley
- School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Sarah B J Miller
- School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Daniel W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Canada
| | - Philip J Atherton
- Centre of Metabolism, Ageing and Physiology, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - Bethan E Phillips
- Centre of Metabolism, Ageing and Physiology, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| | - Mathew Piasecki
- Centre of Metabolism, Ageing and Physiology, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Derby, United Kingdom
| |
Collapse
|
10
|
Sanders DB, Kouyoumdjian JA, Stålberg EV. Single fiber electromyography and measuring jitter with concentric needle electrodes. Muscle Nerve 2022; 66:118-130. [PMID: 35694863 DOI: 10.1002/mus.27573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 05/06/2022] [Indexed: 11/07/2022]
Abstract
This monograph contains descriptions of the single fiber electromyography (SFEMG) method and of the more recently implemented method of recording jitter with concentric needle electrodes (CNEs). SFEMG records action potentials from single muscle fibers (SFAPs), which permits measuring fiber density (FD), a sensitive measure of reinnervation, and jitter, a sensitive measure of abnormal neuromuscular transmission (NMT). With voluntary activation, jitter is measured between two SFAPs with acceptable amplitude and rise time. With activation by axon stimulation, jitter is measured between the stimulus and individual SFAPs. Pitfalls due to unstable triggers and inconstant firing rates during voluntary activation and subliminal stimulation during axon stimulation should be identified and avoided. In CNE recordings, spikes with shoulders or rising phases that are not parallel are produced by summation of SFAPS; these should be excluded and reference values for CNE jitter should be used. CNE and SFEMG have similar and very high sensitivity in detecting increased jitter, as in myasthenia gravis and other myasthenic conditions. However, jitter is also seen in ongoing reinnervation and some myopathic conditions. With SFEMG, these can be identified by increased FD; however, FD cannot be measured with CNE, and conventional electromyography should be performed in muscles with increased jitter to detect neurogenic or myogenic abnormalities. Jitter is abnormal after injections of botulinum toxin, even in muscles remote from the injection site, and can persist for 6 mo or more. This can complicate the detection or exclusion of abnormal NMT.
Collapse
Affiliation(s)
- Donald B Sanders
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA
| | - João A Kouyoumdjian
- Department of Neurological Sciences, State Medical School (FAMERP), São Paulo, Brazil
| | - Erik V Stålberg
- Department of Clinical Neurophysiology, Academic Hospital, Uppsala, Sweden
| |
Collapse
|
11
|
Sanders DB, Kouyoumdjian JA, Stålberg EV. Single fiber EMG and measuring jitter with concentric needle electrodes. Muscle Nerve 2022. [PMID: 35652573 DOI: 10.1002/mus.27572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 05/05/2022] [Indexed: 11/08/2022]
Abstract
This monograph contains descriptions of the single-fiber electromyography (SFEMG) method and of the more recently implemented method of recording jitter with concentric needle electrodes (CNE). SFEMG records action potentials from single muscle fibers (SFAPs), which permits measuring fiber density (FD), a sensitive measure of reinnervation, and jitter, a sensitive measure of abnormal neuromuscular transmission (NMT). With voluntary activation, jitter is measured between two SFAPs with acceptable amplitude and rise time. With activation by axon stimulation, jitter is measured between the stimulus and individual SFAPs. Pitfalls due to unstable triggers and inconstant firing rates during voluntary activation and subliminal stimulation during axon stimulation should be identified and avoided. In CNE recordings, spikes with shoulders or rising phases that are not parallel are produced by summation of SFAPS; these should be excluded and reference values for CNE jitter should be used. CNE and SFEMG have similar and very high sensitivity in detecting increased jitter, as in myasthenia gravis and other myasthenic conditions. However, jitter is also seen in ongoing reinnervation and some myopathic conditions. With SFEMG, these can be identified by increased FD; however, FD cannot be measured with CNE, and conventional EMG should be performed in muscles with increased jitter to detect neurogenic or myogenic abnormalities. Jitter is abnormal after injections of botulinum toxin, even in muscles remote from the injection site, and can persist for 6 mo or more. This can complicate the detection or exclusion of abnormal NMT.
Collapse
Affiliation(s)
- Donald B Sanders
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA
| | - João A Kouyoumdjian
- Department of Neurological Sciences, State Medical School (FAMERP), São Paulo, Brazil
| | - Erik V Stålberg
- Department of Clinical Neurophysiology, Academic Hospital, Uppsala, Sweden
| |
Collapse
|
12
|
Jones EJ, Chiou S, Atherton PJ, Phillips BE, Piasecki M. Ageing and exercise-induced motor unit remodelling. J Physiol 2022; 600:1839-1849. [PMID: 35278221 PMCID: PMC9314090 DOI: 10.1113/jp281726] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 02/14/2022] [Indexed: 11/08/2022] Open
Abstract
A motor unit (MU) comprises the neuron cell body, its corresponding axon and each of the muscle fibres it innervates. Many studies highlight age-related reductions in the number of MUs, yet the ability of a MU to undergo remodelling and to expand to rescue denervated muscle fibres is also a defining feature of MU plasticity. Remodelling of MUs involves two coordinated processes: (i) axonal sprouting and new branching growth from adjacent surviving neurons, and (ii) the formation of key structures around the neuromuscular junction to resume muscle-nerve communication. These processes rely on neurotrophins and coordinated signalling in muscle-nerve interactions. To date, several neurotrophins have attracted focus in animal models, including brain-derived neurotrophic factor and insulin-like growth factors I and II. Exercise in older age has demonstrated benefits in multiple physiological systems including skeletal muscle, yet evidence suggests this may also extend to peripheral MU remodelling. There is, however, a lack of research in humans due to methodological limitations which are easily surmountable in animal models. To improve mechanistic insight of the effects of exercise on MU remodelling with advancing age, future research should focus on combining methodological approaches to explore the in vivo physiological function of the MU alongside alterations of the localised molecular environment.
Collapse
Affiliation(s)
- Eleanor J. Jones
- Centre of Metabolism, Ageing & Physiology (COMAP), MRC–Versus Arthritis Centre of Excellence for Musculoskeletal Ageing ResearchNottingham NIHR Biomedical Research CentreSchool of MedicineUniversity of NottinghamNottinghamUK
| | - Shin‐Yi Chiou
- School of SportExercise, and Rehabilitation Sciences, MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre for Human Brain HealthUniversity of BirminghamBirminghamUK
| | - Philip J. Atherton
- Centre of Metabolism, Ageing & Physiology (COMAP), MRC–Versus Arthritis Centre of Excellence for Musculoskeletal Ageing ResearchNottingham NIHR Biomedical Research CentreSchool of MedicineUniversity of NottinghamNottinghamUK
| | - Bethan E. Phillips
- Centre of Metabolism, Ageing & Physiology (COMAP), MRC–Versus Arthritis Centre of Excellence for Musculoskeletal Ageing ResearchNottingham NIHR Biomedical Research CentreSchool of MedicineUniversity of NottinghamNottinghamUK
| | - Mathew Piasecki
- Centre of Metabolism, Ageing & Physiology (COMAP), MRC–Versus Arthritis Centre of Excellence for Musculoskeletal Ageing ResearchNottingham NIHR Biomedical Research CentreSchool of MedicineUniversity of NottinghamNottinghamUK
| |
Collapse
|
13
|
Herr DW. The Future of Neurotoxicology: A Neuroelectrophysiological Viewpoint. FRONTIERS IN TOXICOLOGY 2021; 3:1. [PMID: 34966904 PMCID: PMC8711081 DOI: 10.3389/ftox.2021.729788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neuroelectrophysiology is an old science, dating to the 18th century when electrical activity in nerves was discovered. Such discoveries have led to a variety of neurophysiological techniques, ranging from basic neuroscience to clinical applications. These clinical applications allow assessment of complex neurological functions such as (but not limited to) sensory perception (vision, hearing, somatosensory function), and muscle function. The ability to use similar techniques in both humans and animal models increases the ability to perform mechanistic research to investigate neurological problems. Good animal to human homology of many neurophysiological systems facilitates interpretation of data to provide cause-effect linkages to epidemiological findings. Mechanistic cellular research to screen for toxicity often includes gaps between cellular and whole animal/person neurophysiological changes, preventing understanding of the complete function of the nervous system. Building Adverse Outcome Pathways (AOPs) will allow us to begin to identify brain regions, timelines, neurotransmitters, etc. that may be Key Events (KE) in the Adverse Outcomes (AO). This requires an integrated strategy, from in vitro to in vivo (and hypothesis generation, testing, revision). Scientists need to determine intermediate levels of nervous system organization that are related to an AO and work both upstream and downstream using mechanistic approaches. Possibly more than any other organ, the brain will require networks of pathways/AOPs to allow sufficient predictive accuracy. Advancements in neurobiological techniques should be incorporated into these AOP-base neurotoxicological assessments, including interactions between many regions of the brain simultaneously. Coupled with advancements in optogenetic manipulation, complex functions of the nervous system (such as acquisition, attention, sensory perception, etc.) can be examined in real time. The integration of neurophysiological changes with changes in gene/protein expression can begin to provide the mechanistic underpinnings for biological changes. Establishment of linkages between changes in cellular physiology and those at the level of the AO will allow construction of biological pathways (AOPs) and allow development of higher throughput assays to test for changes to critical physiological circuits. To allow mechanistic/predictive toxicology of the nervous system to be protective of human populations, neuroelectrophysiology has a critical role in our future.
Collapse
Affiliation(s)
- David W Herr
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, CPHEA/ORD, U.S. Environmental Protection Agency, Washington, NC, United States
| |
Collapse
|
14
|
Tsang P, Larocerie-Salgado J, MacDermid JC, Miller TA, Doherty C, Ross DC. Postoperative management and rehabilitation after the supercharged end-to-side anterior interosseous nerve to ulnar motor nerve transfer: A report of 3 cases. J Hand Ther 2021; 34:469-478. [PMID: 32571598 DOI: 10.1016/j.jht.2020.03.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/23/2020] [Accepted: 03/28/2020] [Indexed: 02/03/2023]
Abstract
INTRODUCTION Compressive ulnar neuropathy at the elbow is the second most common compressive neuropathy. Nerve transfers are used for severe ulnar neuropathies as a means of facilitating recovery. Hand therapy and rehabilitation after nerve transfers have not been extensively explored. PURPOSE OF THE STUDY The aim of this repeated case study was to describe the responses, functional outcome, and neuromuscular health of three participants after the supercharged end-to-side (SETS) anterior interosseous nerve (AIN) to ulnar motor nerve transfer do describe the hand therapy and recovery of 3 cases reflecting different recovery potential mediators, trajectories, and outcomes. STUDY DESIGN Repeated case study. METHODS Three participants of similar age (76-80 years) that had severe ulnar neuropathy who underwent surgical treatment including a SETS AIN to ulnar motor nerve surgery were purposively selected from an ongoing clinical trial, based on their response to the surgical and the rehabilitation intervention (large, moderate, and small improvements). Clinical evaluations included measuring range of motion, strength testing, and clinical tests (ie, Egawa's sign) and, subjective assessment of rehabilitation adherence., Quick Disability of Arm, Shoulder and Hand and decomposition-based quantitative electromyography were performed at >23 months to evaluate patients. RESULTS All the three participants completed the surgical and hand therapy interventions, demonstrating a variable course of recovery and functional outcomes. The Quick Disability of Arm, Shoulder and Hand scores (>23 months) for participants A, B, and C were 68, 30, and 18, respectively. The person with the least improvement had idiopathic Parkinson's disease, dyslipidemia, history of depression, and gout. Comparison across cases suggested that the comorbidities, longer time from neuropathy to the surgical intervention, and psychosocial barriers to exercise and rehabilitation adherence influenced the recovery process. The participants with the best outcomes demonstrated improvements in his lower motor neurons or motor unit counts (109 and 18 motor units in the abductor digiti minimi (ADM) and first dorsal interosseous, respectively) and motor unit stability (39.5% and 37.6% near-fiber jiggle in the ADM and first dorsal interosseous, respectively). The participant with moderate response to the interventions had a motor unit count of 93 for the ADM muscle. We were unable to determine motor unit counts and measurements from the participant with the poorest outcomes due to his physical limitations. CONCLUSIONS SETS AIN to ulnar motor nerve followed by multimodal hand therapy provides measurable improvements in neurophysiology and function, although engagement in hand therapy and outcomes appear to be mediated by comorbid physical and psychosocial health.
Collapse
Affiliation(s)
- Philemon Tsang
- Department of Health and Rehabilitation Sciences, Western University, London, Ontario, Canada; Hand and Upper Limb Centre Clinical Research Lab, St. Joseph's Health Centre, London, Ontario, Canada.
| | | | - Joy C MacDermid
- Department of Health and Rehabilitation Sciences, Western University, London, Ontario, Canada; Hand and Upper Limb Centre Clinical Research Lab, St. Joseph's Health Centre, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada
| | - Thomas A Miller
- Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Christopher Doherty
- Division of Plastic Surgery, University of British Columbia, London, Ontario, Canada
| | - Douglas C Ross
- Division of Plastic Surgery, Department of Surgery, Roth-McFarlane Hand & Upper Limb Centre, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| |
Collapse
|
15
|
Pratt J, De Vito G, Narici M, Boreham C. Neuromuscular Junction Aging: A Role for Biomarkers and Exercise. J Gerontol A Biol Sci Med Sci 2021; 76:576-585. [PMID: 32832976 DOI: 10.1093/gerona/glaa207] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related skeletal muscle degradation known as "sarcopenia" exerts considerable strain on public health systems globally. While the pathogenesis of such atrophy is undoubtedly multifactorial, disruption at the neuromuscular junction (NMJ) has recently gained traction as a key explanatory factor. The NMJ, an essential communicatory link between nerve and muscle, undergoes profound changes with advancing age. Ascertaining whether such changes potentiate the onset of sarcopenia would be paramount in facilitating a timely implementation of targeted therapeutic strategies. Hence, there is a growing level of importance to further substantiate the effects of age on NMJs, in parallel with developing measures to attenuate such changes. As such, this review aimed to establish the current standpoint on age-related NMJ deterioration and consequences for skeletal muscle, while illuminating a role for biomarkers and exercise in ameliorating these alterations. Recent insights into the importance of key biomarkers for NMJ stability are provided, while the stimulative benefits of exercise in preserving NMJ function are demonstrated. Further elucidation of the diagnostic and prognostic relevance of biomarkers, coupled with the therapeutic benefits of regular exercise may be crucial in combating age-related NMJ and skeletal muscle degradation.
Collapse
Affiliation(s)
- Jedd Pratt
- Institute for Sport and Health, University College Dublin, Ireland.,Genuity Science, Dublin, Ireland
| | - Giuseppe De Vito
- Department of Biomedical Sciences, CIR-Myo Myology Centre, Neuromuscular Physiology Laboratory, University of Padua, Italy
| | - Marco Narici
- Department of Biomedical Sciences, CIR-Myo Myology Centre, Neuromuscular Physiology Laboratory, University of Padua, Italy
| | - Colin Boreham
- Institute for Sport and Health, University College Dublin, Ireland
| |
Collapse
|
16
|
Allen MD, Dalton BH, Gilmore KJ, McNeil CJ, Doherty TJ, Rice CL, Power GA. Neuroprotective effects of exercise on the aging human neuromuscular system. Exp Gerontol 2021; 152:111465. [PMID: 34224847 DOI: 10.1016/j.exger.2021.111465] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 05/31/2021] [Accepted: 06/30/2021] [Indexed: 12/23/2022]
Abstract
Human biological aging from maturity to senescence is associated with a gradual loss of muscle mass and neuromuscular function. It is not until very old age (>80 years) however, that these changes often manifest into functional impairments. A driving factor underlying the age-related loss of muscle mass and function is the reduction in the number and quality of motor units (MUs). A MU consists of a single motoneuron, located either in the spinal cord or the brain stem, and all of the muscle fibres it innervates via its peripheral axon. Throughout the adult lifespan, MUs are slowly, but progressively lost. The compensatory process of collateral reinnervation attempts to recapture orphaned muscle fibres following the death of a motoneuron. Whereas this process helps mitigate loss of muscle mass during the latter decades of adult aging, the neuromuscular system has fewer and larger MUs, which have lower quality connections between the axon terminal and innervated muscle fibres. Whether this process of MU death and degradation can be attenuated with habitual physical activity has been a challenging question of great interest. This review focuses on age-related alterations of the human neuromuscular system, with an emphasis on the MU, and presents findings on the potential protective effects of lifelong physical activity. Although there is some discrepancy across studies of masters athletes, if one considers all experimental limitations as well as the available literature in animals, there is compelling evidence of a protective effect of chronic physical training on human MUs. Our tenet is that high-levels of physical activity can mitigate the natural trajectory of loss of quantity and quality of MUs in old age.
Collapse
Affiliation(s)
- Matti D Allen
- Department of Physical Medicine and Rehabilitation, School of Medicine, Faculty of Health Sciences, Queen's University, Kingston, ON K7L 4X3, Canada; School of Kinesiology and Health Studies, Faculty of Arts and Sciences, Queen's University, Kingston, ON K7L 4X3, Canada
| | - Brian H Dalton
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada
| | - Kevin J Gilmore
- Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Chris J McNeil
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada
| | - Timothy J Doherty
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada; Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Charles L Rice
- School of Kinesiology, The University of Western Ontario, London, ON, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| |
Collapse
|
17
|
Near-fiber electromyography. Clin Neurophysiol 2021; 132:1089-1104. [PMID: 33774377 DOI: 10.1016/j.clinph.2021.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/28/2021] [Accepted: 02/05/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Describe and evaluate the concepts of near fiber electromyography (NFEMG), the features used, including near fiber motor unit potential (NFMUP) duration and dispersion, which relate to motor unit distal axonal branch and muscle fiber conduction time dispersion, and NFMUP segment jitter, a new measure of the temporal variability of neuromuscular junction transmission (NMJ), and axonal branch and muscle fibre conduction for the near fibres (i.e. NF jitter), and the methods for obtaining their values. METHODS Trains of high-pass filtered motor unit potentials (MUPs) (i.e. NFMUP trains) were extracted from needle-detected EMG signals to assess changes in motor unit (MU) morphology and electrophysiology caused by neuromuscular disorders or ageing. Evaluations using simulated needle-detected EMG data were completed and example human data are presented. RESULTS NFEMG feature values can be used to detect axonal sprouting, conduction slowing and NMJ transmission delay as well as changes in MU fiber diameter variability, and NF jitter. These changes can be detected prior to alterations of MU size or numbers. CONCLUSIONS The evaluations clearly demonstrate and the example data support that NFMUP duration and dispersion reflect MU distal axonal branching, conduction slowing and NMJ transmission delay and/or MU fiber diameter variability and that NFMUP jiggle and segment jitter reflect NF jitter. SIGNIFICANCE NFEMG can detect early changes in MU morphology and/or electrophysiology and has the potential to augment clinical diagnosis and tracking of neuromuscular disorders.
Collapse
|
18
|
Assessment of age-related differences in decomposition-based quantitative EMG in the intrinsic hand muscles: A multivariate approach. Clin Neurophysiol 2020; 131:2192-2199. [DOI: 10.1016/j.clinph.2020.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/06/2020] [Accepted: 06/02/2020] [Indexed: 01/17/2023]
|
19
|
Kamali T, Stashuk DW. Transparent Electrophysiological Muscle Classification From EMG Signals Using Fuzzy-Based Multiple Instance Learning. IEEE Trans Neural Syst Rehabil Eng 2020; 28:842-849. [PMID: 32149647 DOI: 10.1109/tnsre.2020.2979412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although a well-established body of literature has examined electrophysiological muscle classification methods and systems, ways to enhance their transparency is still an important challenge and requires further study. In this work, a transparent semi-supervised electrophysiological muscle classification system which uses needle-detected EMG signals to classify muscles as normal, myopathic, or neurogenic is proposed. The electrophysiological muscle classification (EMC) problem is naturally formulated using multiple instance learning (MIL) and needs an adaptation of standard supervised classifiers for the purpose of training and evaluating bags of instances. Here, a novel MIL-based EMC system in which the muscle classifier uses predictions based on motor unit potentials (MUPs) to infer muscle labels is described. This system uses morphological, stability, near fiber and spectral MUP features. Quantitative results obtained from applying the proposed transparent system to four electrophysiologically different groups of muscles, composed of proximal and distal hand and leg muscles, resulted in an average classification accuracy of 95.85%. The findings show the superior and stable performance of the proposed EMC system compared to previous works using other supervised, semi-supervised and unsupervised methods.
Collapse
|
20
|
Panchabhai TS, Mireles Cabodevila E, Pioro EP, Wang X, Han X, Aboussouan LS. Pattern of lung function decline in patients with amyotrophic lateral sclerosis: implications for timing of noninvasive ventilation. ERJ Open Res 2019; 5:00044-2019. [PMID: 31579678 PMCID: PMC6759589 DOI: 10.1183/23120541.00044-2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/20/2019] [Indexed: 12/11/2022] Open
Abstract
Background The course of lung function decline in amyotrophic lateral sclerosis (ALS) and the effect of noninvasive positive-pressure ventilation (NIPPV) on that decline are uncertain. We sought to model lung function decline, determine when NIPPV is initiated along that course, and assess its impact on the course of decline. Methods An observed sigmoid pattern of forced vital capacity decline was reproduced with a four-parameter nonlinear mixed-effects logistic model. Results Analyses were performed on 507 patients overall and in 353 patients for whom a determination of adherence to NIPPV was ascertained. A sigmoid bi-asymptotic model provided a statistical fit of the data and showed a period of stable vital capacity, followed by an accelerated decline, an inflection point, then a slowing in decline to a plateau. By the time NIPPV was initiated in accordance with reimbursement guidelines, vital capacity had declined by ≥85% of the total range. Nearly half of the total loss of vital capacity occurred over 6.2 months centred at an inflection point occurring 17 months after disease onset and 5.2 months before initiation of NIPPV at a vital capacity of about 60%. Fewer bulbar symptoms and a faster rate of decline of lung function predicted adherence to NIPPV, but the intervention had no impact on final vital capacity. Conclusions In patients with ALS, vital capacity decline is rapid but slows after an inflection point regardless of NIPPV. Initiating NIPPV along reimbursement guidelines occurs after ≥85% of vital capacity loss has already occurred. In patients with amyotrophic lateral sclerosis, vital capacity decline is rapid but slows after an inflection point regardless of NIPPV. Initiation of NIPPV according to guidelines occurs when >85% of vital capacity loss has already occurred.http://bit.ly/2JOiEZG
Collapse
Affiliation(s)
- Tanmay S Panchabhai
- Section of Interventional Pulmonology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | | | - Erik P Pioro
- Dept of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Xiaofeng Wang
- Dept of Qualitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Xiaozhen Han
- Dept of Qualitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Loutfi S Aboussouan
- Dept of Pulmonary Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, OH, USA.,Dept of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| |
Collapse
|
21
|
Bromberg MB. The motor unit and quantitative electromyography. Muscle Nerve 2019; 61:131-142. [PMID: 31579956 DOI: 10.1002/mus.26718] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 12/13/2022]
Abstract
Electromyography (EMG) assesses the anatomic motor unit (A-MU), but knowledge of its anatomy, physiology, and changes with pathology is limited. The electrophysiological motor unit (E-MU) and its motor unit potential (E-MUP) represents a fraction of the A-MU. Routine EMG assesses a limited number of E-MUP waveform characteristics (metrics) and their magnitudes qualitatively scaled in a nonlinear manner. Another approach is quantitative EMG (QEMG), whereby 20+ E-MUPs are extracted and both basic and derived metrics obtained and values expressed quantitatively. In diseased muscle, many E-MUP metrics may be normal, which complicates diagnostic interpretation. In QEMG, E-MUP metrics can be clustered and statistical analyses performed to assign probabilities that E-MUPs (and the muscle) are normal, neuropathic, or myopathic. In this article we review what is known about the A-MU, the restricted E-MU, E-MUP metrics, and what QEMG offers currently and in the future.
Collapse
Affiliation(s)
- Mark B Bromberg
- Department of Neurology, University of Utah, Salt Lake City, Utah
| |
Collapse
|
22
|
Tsang P, MacDermid JC, Eventov M, Miller TA, Doherty TJ, Ross DC, Doherty CD. Test-retest reliability of near-fibre jiggle in the ulnar intrinsic hand muscles. J Electromyogr Kinesiol 2019; 49:102349. [PMID: 31476613 DOI: 10.1016/j.jelekin.2019.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/03/2019] [Accepted: 08/10/2019] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE Near-fibre (NF) jiggle is one method of measuring the shape variability of motor unit potentials (MUPs) from successive firings during voluntary contractions. MUP shape variability has been associated with neuromuscular stability and health. The purpose of this study was to analyze the test-retest reliability of NF jiggle in the ulnar nerve innervated intrinsic hand muscles of healthy subjects. METHODS Twenty healthy adult were tested (Mean age = 23.2 ± 1.9; 8 females). Measurements of NF jiggle were assessed with a standard concentric needle during mild-moderate contractions from the first dorsal interosseous (FDI), the abductor digiti minimi (ADM), and the forth dorsal interosseous (4DI) muscles. Test-retest reliability were evaluated using intraclass-correlation coefficient (ICC). RESULTS NF jiggle showed good test-retest reliability in the FDI, ADM and 4DI muscles with ICC values of 0.86, 0.85, and 0.87, respectively. The SEM for the FDI, ADM, and 4DI were 1.9%, 2.1%, and 2.5%. Finally, the MDC of the FDI, ADM and 4DI were 4.4%, 5.0%, and 7.1%. CONCLUSION To date, this is the first investigation to explore NF jiggle in the intrinsic hand muscles. NF Jiggle demonstrates good test-retest reliability coefficients and with low measurement error.
Collapse
Affiliation(s)
- Philemon Tsang
- Department of Health and Rehabilitation Sciences, Western University, London, Ontario, Canada.
| | - Joy C MacDermid
- Department of Health and Rehabilitation Sciences, Western University, London, Ontario, Canada; Hand and Upper Limb Centre Clinical Research Lab, St. Joseph's Health Centre, Canada; Department of Surgery, Division of Plastic Surgery, Roth-McFarlane Hand & Upper Limb Centre, Schulich School of Medicine and Dentistry, Western University, Canada
| | - Michelle Eventov
- Department of Health and Rehabilitation Sciences, Western University, London, Ontario, Canada
| | - Thomas A Miller
- Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, Western University, Canada
| | - Timothy J Doherty
- Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, Western University, Canada; Lawson Health Research Institute, Canada
| | - Douglas C Ross
- Department of Surgery, Division of Plastic Surgery, Roth-McFarlane Hand & Upper Limb Centre, Schulich School of Medicine and Dentistry, Western University, Canada
| | - Christopher D Doherty
- Department of Surgery, Division of Plastic Surgery, Roth-McFarlane Hand & Upper Limb Centre, Schulich School of Medicine and Dentistry, Western University, Canada
| |
Collapse
|
23
|
Stålberg E, van Dijk H, Falck B, Kimura J, Neuwirth C, Pitt M, Podnar S, Rubin DI, Rutkove S, Sanders DB, Sonoo M, Tankisi H, Zwarts M. Standards for quantification of EMG and neurography. Clin Neurophysiol 2019; 130:1688-1729. [DOI: 10.1016/j.clinph.2019.05.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/07/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022]
|
24
|
Sanders DB. Neuromuscular transmission in myopathies. Muscle Nerve 2019; 60:E8. [DOI: 10.1002/mus.26501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 02/16/2019] [Indexed: 11/07/2022]
|
25
|
Sanders DB, Arimura K, Cui L, Ertaş M, Farrugia ME, Gilchrist J, Kouyoumdjian JA, Padua L, Pitt M, Stålberg E. Guidelines for single fiber EMG. Clin Neurophysiol 2019; 130:1417-1439. [PMID: 31080019 DOI: 10.1016/j.clinph.2019.04.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/30/2019] [Accepted: 04/06/2019] [Indexed: 12/13/2022]
Abstract
This document is the consensus of international experts on the current status of Single Fiber EMG (SFEMG) and the measurement of neuromuscular jitter with concentric needle electrodes (CNE - CN-jitter). The panel of authors was chosen based on their particular interests and previous publications within a specific area of SFEMG or CN-jitter. Each member of the panel was asked to submit a section on their particular area of interest and these submissions were circulated among the panel members for edits and comments. This process continued until a consensus was reached. Donald Sanders and Erik Stålberg then edited the final document.
Collapse
Affiliation(s)
| | - Kimiyoshi Arimura
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
| | - LiYing Cui
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
| | | | | | - James Gilchrist
- Southern Illinois University School of Medicine, Springfield, IL USA.
| | | | - Luca Padua
- Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Department of Geriatrics, Neurosciences and Orthopaedics, Università Cattolica del Sacro Cuore, Rome, Italy.
| | - Matthew Pitt
- Department of Clinical Neurophysiology, Great Ormond Street Hospital, London, UK.
| | - Erik Stålberg
- Department of Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.
| |
Collapse
|
26
|
Amin Lari A, Ghavanini AA, Bokaee HR. A review of electrophysiological studies of lower motor neuron involvement in amyotrophic lateral sclerosis. Neurol Sci 2019; 40:1125-1136. [PMID: 30877611 DOI: 10.1007/s10072-019-03832-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/07/2019] [Indexed: 02/08/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease involving both the upper and lower motor neuron diseases. In this review, we studied and compared different articles regarding the electrodiagnostic criteria for diagnosis of lower motor neuron pathology in ALS. We reviewed the most recent articles and metaanalysis regarding various lower motor neuron electrodiagnostic methods for ALS and their sensitivities. We concluded that Awaji Shima criteria is by far the most sensitive criteria for diagnosis of ALS.
Collapse
Affiliation(s)
- Ali Amin Lari
- Canadian Neurologic Center, Mississauga, ON, Canada.
| | | | | |
Collapse
|
27
|
Juel VC. Clinical neurophysiology of neuromuscular junction disease. HANDBOOK OF CLINICAL NEUROLOGY 2019; 161:291-303. [PMID: 31307607 DOI: 10.1016/b978-0-444-64142-7.00055-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The neuromuscular junction (NMJ) is a cholinergic synapse where quantal release of acetylcholine (ACh) from motor nerve terminals generates a local endplate potential (EPP) on the muscle fiber. EPPs that reach threshold depolarize the entire muscle fiber and initiate the process of excitation-contraction coupling. Deficits of neuromuscular transmission result in clinical weakness that is fatigable and may fluctuate. Repetitive nerve stimulation (RNS) testing can unmask the reduced safety factor common to all NMJ disorders via depletion of immediate ACh stores at the presynaptic motor nerve terminal with decremental responses to low-frequency RNS (LF-RNS). The facilitated responses characterizing presynaptic NMJ disorders can be revealed by brief exercise or high stimulation rates that augment presynaptic calcium levels. Activation with isometric exercise may increase the sensitivity of RNS testing. Attention to technical detail and reproducibility of findings are essential in generating valid results in RNS testing. Motor unit potential (MUP) instability or jiggle is the main finding seen in NMJ disorders on conventional needle EMG and reflects the moment-to-moment variability in the number and synchrony of muscle fiber action potentials (MFAPs) that compose a MUP. Single fiber EMG (SFEMG) is a highly selective technique that assesses jitter, the temporal variability in MFAPs generated in response to motor nerve action potentials.
Collapse
Affiliation(s)
- Vern C Juel
- Department of Neurology, Duke University School of Medicine, Durham, NC, United States.
| |
Collapse
|
28
|
Normal and abnormal voluntary activity. HANDBOOK OF CLINICAL NEUROLOGY 2019; 160:281-301. [PMID: 31277854 DOI: 10.1016/b978-0-444-64032-1.00018-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
An important component of needle EMG entails recording and interpreting the electrical signals generated from motor units during voluntary contraction. The recorded motor unit potentials (MUPs) reflect the number of motor units within a muscle and the distribution and density of muscle fibers within a motor unit within a portion of a muscle. Various MUP parameters are assessed to determine the integrity of the motor units, including recruitment, stability, phases and turns, duration, and amplitude. Each of these parameters is altered in a different way in various neuromuscular diseases. In neurogenic disorders, the earliest changes occur in the recruitment pattern of motor units followed by MUP morphologic changes (increased MUP phases and duration) as reinnervation occurs. MUP instability, indicating impaired neuromuscular transmission, also occurs in reinnervating neurogenic disorders as well as in neuromuscular junction disorders. In myopathies, a reduction in the size of the motor unit is manifested by MUPs of low amplitude and short duration. Interpreting the voluntary MUP changes along with spontaneous activity helps to determine the type, severity, and temporal course of neuromuscular diseases.
Collapse
|
29
|
|
30
|
Stålberg E, Kouyoumdjian JA, Paiva GP, Yanaze LL, Sanders DB. Problems in Comparing Jitter Values Obtained with Voluntary Activation and Electrical Stimulation. J Neuromuscul Dis 2018; 5:225-230. [DOI: 10.3233/jnd-170289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Erik Stålberg
- Department of Clinical Neurophysiology, Institute of Neurosciences, Uppsala University, Sweden
| | - João Aris Kouyoumdjian
- Faculdade Medicina Sao Jose do Rio Preto, Investigation Neuromuscular Laboratory, Sao Jose do Rio Preto SP, Brazil
| | - Gabriel Pina Paiva
- Faculdade Medicina Sao Jose do Rio Preto, Investigation Neuromuscular Laboratory, Sao Jose do Rio Preto SP, Brazil
| | - Larissa Luri Yanaze
- Faculdade Medicina Sao Jose do Rio Preto, Investigation Neuromuscular Laboratory, Sao Jose do Rio Preto SP, Brazil
| | - Donald B. Sanders
- Department of Neurology, Duke University Medical Center, Durham, NC, USA
| |
Collapse
|
31
|
Malanda-Trigueros A, Navallas J, Rodriguez-Falces J, Rodriguez-Carreño I, Porta S, Fernández-Martínez M, Gila L. Sliding window averaging in normal and pathological motor unit action potential trains. Clin Neurophysiol 2018; 129:1170-1181. [PMID: 29649769 DOI: 10.1016/j.clinph.2018.02.134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 02/12/2018] [Accepted: 02/25/2018] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To evaluate the performance of a recently proposed motor unit action potential (MUAP) averaging method based on a sliding window, and compare it with relevant published methods in normal and pathological muscles. METHODS Three versions of the method (with different window lengths) were compared to three relevant published methods in terms of signal analysis-based merit figures and MUAP waveform parameters used in the clinical practice. 218 MUAP trains recorded from normal, myopathic, subacute neurogenic and chronic neurogenic muscles were analysed. Percentage scores of the cases in which the methods obtained the best performance or a performance not significantly worse than the best were computed. RESULTS For signal processing figures of merit, the three versions of the new method performed better (with scores of 100, 86.6 and 66.7%) than the other three methods (66.7, 25 and 0%, respectively). In terms of MUAP waveform parameters, the new method also performed better (100, 95.8 and 91.7%) than the other methods (83.3, 37.5 and 25%). CONCLUSIONS For the types of normal and pathological muscle studied, the sliding window approach extracted more accurate and reliable MUAP curves than other existing methods. SIGNIFICANCE The new method can be of service in quantitative EMG.
Collapse
Affiliation(s)
| | - Javier Navallas
- Electrical and Electronics Engineering Dept., Public University of Navarre, Spain
| | | | | | - Sonia Porta
- Electrical and Electronics Engineering Dept., Public University of Navarre, Spain
| | | | - Luis Gila
- Neurophysiology Service, Navarre Hospital Complex, Spain
| |
Collapse
|
32
|
Artuğ NT, Goker I, Bolat B, Osman O, Orhan EK, Baslo MB. New features for scanned bioelectrical activity of motor unit in health and disease. Biomed Signal Process Control 2018. [DOI: 10.1016/j.bspc.2017.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
33
|
Kamali T, Stashuk DW. Electrophysiological Muscle Classification Using Multiple Instance Learning and Unsupervised Time and Spectral Domain Analysis. IEEE Trans Biomed Eng 2018; 65:2494-2502. [PMID: 29993485 DOI: 10.1109/tbme.2018.2802200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Electrophysiological muscle classification (EMC) is a crucial step in the diagnosis of neuromuscular disorders. Existing quantitative techniques are not sufficiently robust and accurate to be reliably clinically used. Here, EMC is modeled as a multiple instance learning (MIL) problem and a system to infer unsupervised motor unit potential (MUP) labels and create supervised muscle classifications is presented. METHODS The system has five main steps: MUP representation using morphological, stability, and near fiber parameters as well as spectral features extracted from wavelet coefficients; MUP feature selection using unsupervised Laplacian scores; MUP clustering using neighborhood distance entropy consistency to find representations of MUP normality and abnormality; muscle representation by embedding its MUP cluster associations in a feature vector; and muscle classification using support vector machines or random forests. RESULTS The evaluation data consist of 63, 83, 93, and 84 sets of MUPs recorded in deltoid, vastus medialis, first dorsal interosseous, and tibialis anterior muscles, respectively. The proposed system discovered representations of normal, myopathic, and neurogenic MUPs for each specific muscle type and resulted in an average classification accuracy of 98%, which is higher than in previous works. CONCLUSION Modeling EMC as an instance of the MIL solves the traditional problem of characterizing MUPs without full supervision. Furthermore, finding representations of MUP normality and abnormality using morphological, stability, near fiber, and spectral features improve muscle classification. SIGNIFICANCE The proposed method is able to characterize MUPs with respect to disease categories, with no a priori information.
Collapse
|
34
|
Piasecki M, Ireland A, Coulson J, Stashuk DW, Hamilton-Wright A, Swiecicka A, Rutter MK, McPhee JS, Jones DA. Motor unit number estimates and neuromuscular transmission in the tibialis anterior of master athletes: evidence that athletic older people are not spared from age-related motor unit remodeling. Physiol Rep 2017; 4:4/19/e12987. [PMID: 27694526 PMCID: PMC5064139 DOI: 10.14814/phy2.12987] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 09/06/2016] [Indexed: 11/24/2022] Open
Abstract
Muscle motor unit numbers decrease markedly in old age, while remaining motor units are enlarged and can have reduced neuromuscular junction transmission stability. However, it is possible that regular intense physical activity throughout life can attenuate this remodeling. The aim of this study was to compare the number, size, and neuromuscular junction transmission stability of tibialis anterior (TA) motor units in healthy young and older men with those of exceptionally active master runners. The distribution of motor unit potential (MUP) size was determined from intramuscular electromyographic signals recorded in healthy male Young (mean ± SD, 26 ± 5 years), Old (71 ± 4 years) and Master Athletes (69 ± 3 years). Relative differences between groups in numbers of motor units was assessed using two methods, one comparing MUP size and muscle cross-sectional area (CSA) determined with MRI, the other comparing surface recorded MUPs with maximal compound muscle action potentials and commonly known as a "motor unit number estimate (MUNE)". Near fiber (NF) jiggle was measured to assess neuromuscular junction transmission stability. TA CSA did not differ between groups. MUNE values for the Old and Master Athletes were 45% and 40%, respectively, of the Young. Intramuscular MUPs of Old and Master Athletes were 43% and 56% larger than Young. NF jiggle was slightly higher in the Master Athletes, with no difference between Young and Old. These results show substantial and similar motor unit loss and remodeling in Master Athletes and Old individuals compared with Young, which suggests that lifelong training does not attenuate the age-related loss of motor units.
Collapse
Affiliation(s)
- Mathew Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - Alex Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - Jessica Coulson
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - Dan W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Andrew Hamilton-Wright
- Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada
| | - Agnieszka Swiecicka
- Andrology Research Unit, Cardiovascular, Metabolic and Nutritional Sciences Domain, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Martin K Rutter
- Manchester Diabetes Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Jamie S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - David A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| |
Collapse
|
35
|
Johansson MT, Ellegaard HR, Tankisi H, Fuglsang-Frederiksen A, Qerama E. Fasciculations in nerve and muscle disorders - A prospective study of muscle ultrasound compared to electromyography. Clin Neurophysiol 2017; 128:2250-2257. [PMID: 29028499 DOI: 10.1016/j.clinph.2017.08.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 08/15/2017] [Accepted: 08/28/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVES We examined the clinical utility of muscle ultrasound (MUS) in detecting fasciculations in patients with nerve and muscle disorders (NMD) and investigated the impact on diagnostic sensitivity when combining electromyography (EMG) and MUS. METHODS We included 58 consecutive patients suspected to have NMD and 38 healthy subjects (HS). Patients and HS underwent MUS in 14 skeletal and two bulbar muscles and the video recordings of the MUS were anonymised. Only patients underwent EMG. RESULTS The follow-up diagnoses were: 15 Amyotrophic lateral sclerosis (ALS), 15 polyneuropathy, 14 patients had other diagnoses (disease-control group) and 14 patients had no pathological findings. MUS detected more muscles with fasciculations among ALS patients compared to all other groups. In ALS patients, the dominating pattern of fasciculations was continuous (45%). More proximal muscles showed fasciculations among ALS patients compared to all other patient groups. MUS was more sensitive than EMG in detecting fasciculations (58% vs. 48%). When combining the two methods, the sensitivity in detecting fasciculations increased to 65%. Fasciculations in nine muscles could predict the ALS diagnosis with high sensitivity and specificity. CONCLUSIONS MUS is a sensitive tool in detecting fasciculations in patients with NMD and performs well compared to EMG in diagnosing ALS. SIGNIFICANCE MUS may add valuable information in the clinic, especially in diagnosing ALS.
Collapse
Affiliation(s)
- M T Johansson
- Department of Neurophysiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus, Denmark
| | - H R Ellegaard
- Department of Neurophysiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus, Denmark
| | - H Tankisi
- Department of Neurophysiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus, Denmark
| | - A Fuglsang-Frederiksen
- Department of Neurophysiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus, Denmark
| | - E Qerama
- Department of Neurophysiology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus, Denmark.
| |
Collapse
|
36
|
Power GA, Dalton BH, Gilmore KJ, Allen MD, Doherty TJ, Rice CL. Maintaining Motor Units into Old Age: Running the Final Common Pathway. Eur J Transl Myol 2017; 27:6597. [PMID: 28458809 PMCID: PMC5391523 DOI: 10.4081/ejtm.2017.6597] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Invited Letter to the Editor. This article is a commentary on the recently published manuscript "Use it or lose it: tonic activity of slow motoneurons promotes their survival and preferentially increases slow fiber-type groupings in muscles of old lifelong recreational sportsmen". Mosole S, Carraro U, Kern H, Loefler S, Zampieri S. Use it or lose it: tonic activity of slow motoneurons promotes their survival and preferentially increases slow fiber-type groupings in muscles of old lifelong recreational sportsmen. Eur J Transl Myol 2016;26:5972. doi: 10.4081/ejtm.2016.5972. We offer some unique perspectives on masters athletes and the role of physical activity in maintaining the number and function of motor units into old age.
Collapse
Affiliation(s)
- Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Brian H Dalton
- School of Health and Exercise Sciences, The University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Kevin J Gilmore
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Matti D Allen
- Schools of Medicine and Kinesiology and Health Studies, Faculty of Health Sciences, Queen's University, Kingston, Ontario, Canada
| | - Timothy J Doherty
- Departments of Physical Medicine and Rehabilitation and Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Charles L Rice
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
37
|
Gilmore KJ, Allen MD, Doherty TJ, Kimpinski K, Rice CL. Electrophysiological and neuromuscular stability of persons with chronic inflammatory demyelinating polyneuropathy. Muscle Nerve 2017; 56:413-420. [DOI: 10.1002/mus.25516] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/07/2016] [Accepted: 12/09/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Kevin J. Gilmore
- School of Kinesiology; The University of Western Ontario; London ON Canada
| | - Matti D. Allen
- School of Medicine Queen's University Kingston ON Canada
| | - Timothy J. Doherty
- Department of Clinical Neurological Sciences; Schulich School of Medicine and Dentistry, The University of Western Ontario; London ON Canada
- Department of Physical Medicine and Rehabilitation; Schulich School of Medicine and Dentistry, The University of Western Ontario; London ON Canada
| | - Kurt Kimpinski
- School of Kinesiology; The University of Western Ontario; London ON Canada
- Department of Clinical Neurological Sciences; Schulich School of Medicine and Dentistry, The University of Western Ontario; London ON Canada
| | - Charles L. Rice
- School of Kinesiology; The University of Western Ontario; London ON Canada
- Department of Anatomy and Cell Biology; Schulich School of Medicine and Dentistry, The University of Western Ontario; London ON Canada
| |
Collapse
|
38
|
Liu MS, Niu JW, Li Y, Guan YZ, Cui LY. Quantitating Changes in Jitter and Spike Number Using Concentric Needle Electrodes in Amyotrophic Lateral Sclerosis Patients. Chin Med J (Engl) 2017; 129:1036-40. [PMID: 27098787 PMCID: PMC4852669 DOI: 10.4103/0366-6999.180533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background: Single-fiber electromyography (SFEMG) has been suggested as a quantitative method for supporting chronic partial denervation in amyotrophic lateral sclerosis (ALS) by the revised EI Escorial criteria. Although concentric needle (CN) electrodes have been used to assess jitter in myasthenia gravis patients and healthy controls, there are few reports using CN electrodes to assess motor unit instability and denervation in neurogenic diseases. The aim of this study was to determine whether quantitative changes in jitter and spike number using CN electrodes could be used for ALS studies. Methods: Twenty-seven healthy controls and 23 ALS patients were studied using both CN and single-fiber needle (SFN) electrodes on the extensor digitorum communis muscle with an SFEMG program. The SFN-jitter and SFN-fiber density data were measured using SFN electrodes. The CN-jitter and spike number were measured using CN electrodes. Results: The mean CN-jitter was significantly increased in ALS patients (47.3 ± 17.0 μs) than in healthy controls (27.4 ± 3.3 μs) (P < 0.001). Besides, the mean spike number was significantly increased in ALS patients (2.5 ± 0.5) than in healthy controls (1.7 ± 0.3) (P < 0.001). The sensitivity and specificity in the diagnosis of ALS were 82.6% and 92.6% for CN-jitter (cut-off value: 32 μs), and 91.3% and 96.3% for the spike number (cut-off value: 2.0), respectively. There was no significant difference between the SFN-jitter and CN-jitter in ALS patients; meanwhile, there was no significant difference between the SFN-jitter and CN-jitter in healthy controls. Conclusion: CN-jitter and spike number could be used to quantitatively evaluate changes due to denervation-reinnervation in ALS.
Collapse
Affiliation(s)
| | | | | | | | - Li-Ying Cui
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| |
Collapse
|
39
|
Gilmore KJ, Morat T, Doherty TJ, Rice CL. Motor unit number estimation and neuromuscular fidelity in 3 stages of sarcopenia. Muscle Nerve 2017; 55:676-684. [DOI: 10.1002/mus.25394] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 08/23/2016] [Accepted: 08/29/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Kevin J. Gilmore
- School of Kinesiology; Faculty of Health Sciences, The University of Western Ontario; London Ontario Canada
| | - Tobias Morat
- German Sport University Cologne, Institute of Movement and Sport Gerontology; Cologne Germany
| | - Timothy J. Doherty
- Department of Clinical Neurological Sciences; The University of Western Ontario; London Ontario Canada
- Department of Physical Medicine and Rehabilitation; The University of Western Ontario; London Ontario Canada
| | - Charles L. Rice
- School of Kinesiology; Faculty of Health Sciences, The University of Western Ontario; London Ontario Canada
- Department of Anatomy and Cell Biology; Schulich School of Medicine and Dentistry, The University of Western Ontario; London Ontario N6G 1H1 Canada
| |
Collapse
|
40
|
Abstract
The motor unit comprises the anterior horn cell, its axon, and the muscle fibers that it innervates. Although the true number of motor units is unknown, the number of motor units appears to vary greatly between different muscles and between different individuals. Assessment of the number and function of motor units is needed in diseases of the anterior horn cell and other motor nerve disorders. Amyotrophic lateral sclerosis is the most important disease of anterior horn cells. The need for an effective biomarker for assessing disease progression and for use in clinical trials in amyotrophic lateral sclerosis has stimulated the study of methods to measure the number of motor units. Since 1970 a number of different methods, including the incremental, F-wave, multipoint, and statistical methods, have been developed but none has achieved widespread applicability. Two methods (MUNIX and the multipoint incremental method) are in current use across multiple centres and are discussed in detail in this review, together with other recently published methods. Imaging with magnetic resonance and ultrasound is increasingly being applied to this area. Motor unit number estimates have also been applied to other neuromuscular diseases such as spinal muscular atrophy, compression neuropathies, and prior poliomyelitis. The need for an objective measure for the assessment of motor units remains tantalizingly close but unfulfilled in 2016.
Collapse
Affiliation(s)
- Robert D Henderson
- Department of Neurology, Royal Brisbane & Women's Hospital and University of Queensland Centre for Clinical Research, Herston, Brisbane, 4006, Australia.
| | - Pamela A McCombe
- Department of Neurology, Royal Brisbane & Women's Hospital and University of Queensland Centre for Clinical Research, Herston, Brisbane, 4006, Australia
| |
Collapse
|
41
|
Hunter SK, Pereira HM, Keenan KG. The aging neuromuscular system and motor performance. J Appl Physiol (1985) 2016; 121:982-995. [PMID: 27516536 PMCID: PMC5142309 DOI: 10.1152/japplphysiol.00475.2016] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/08/2016] [Indexed: 12/25/2022] Open
Abstract
Age-related changes in the basic functional unit of the neuromuscular system, the motor unit, and its neural inputs have a profound effect on motor function, especially among the expanding number of old (older than ∼60 yr) and very old (older than ∼80 yr) adults. This review presents evidence that age-related changes in motor unit morphology and properties lead to impaired motor performance that includes 1) reduced maximal strength and power, slower contractile velocity, and increased fatigability; and 2) increased variability during and between motor tasks, including decreased force steadiness and increased variability of contraction velocity and torque over repeat contractions. The age-related increase in variability of motor performance with aging appears to involve reduced and more variable synaptic inputs that drive motor neuron activation, fewer and larger motor units, less stable neuromuscular junctions, lower and more variable motor unit action potential discharge rates, and smaller and slower skeletal muscle fibers that coexpress different myosin heavy chain isoforms in the muscle of older adults. Physical activity may modify motor unit properties and function in old men and women, although the effects on variability of motor performance are largely unknown. Many studies are of cross-sectional design, so there is a tremendous opportunity to perform high-impact and longitudinal studies along the continuum of aging that determine 1) the influence and cause of the increased variability with aging on functional performance tasks, and 2) whether lifestyle factors such as physical exercise can minimize this age-related variability in motor performance in the rapidly expanding numbers of very old adults.
Collapse
Affiliation(s)
- Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin; and
| | - Hugo M Pereira
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin; and
| | - Kevin G Keenan
- Department of Kinesiology, College of Health Sciences, University of Wisconsin, Milwaukee, Wisconsin
| |
Collapse
|
42
|
de Carvalho M, Swash M. Lower motor neuron dysfunction in ALS. Clin Neurophysiol 2016; 127:2670-81. [DOI: 10.1016/j.clinph.2016.03.024] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 02/08/2016] [Accepted: 03/01/2016] [Indexed: 12/11/2022]
|
43
|
Power GA, Allen MD, Gilmore KJ, Stashuk DW, Doherty TJ, Hepple RT, Taivassalo T, Rice CL. Motor unit number and transmission stability in octogenarian world class athletes: Can age-related deficits be outrun? J Appl Physiol (1985) 2016; 121:1013-1020. [PMID: 27013605 DOI: 10.1152/japplphysiol.00149.2016] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 03/18/2016] [Indexed: 11/22/2022] Open
Abstract
Our group has shown a greater number of functioning motor units (MU) in a cohort of highly active older (∼65 yr) masters runners relative to age-matched controls. Because of the precipitous loss in the number of functioning MUs in the eighth and ninth decades of life it is unknown whether older world class octogenarian masters athletes (MA) would also have greater numbers of functioning MUs compared with age-matched controls. We measured MU numbers and neuromuscular transmission stability in the tibialis anterior of world champion MAs (∼80 yr) and compared the values with healthy age-matched controls (∼80 yr). Decomposition-enhanced spike-triggered averaging was used to collect surface and intramuscular electromyography signals during dorsiflexion at ∼25% of maximum voluntary isometric contraction. Near fiber (NF) MU potential analysis was used to assess neuromuscular transmission stability. For the MAs compared with age-matched controls, the amount of excitable muscle mass (compound muscle action potential) was 14% greater (P < 0.05), there was a trend (P = 0.07) toward a 27% smaller surface-detected MU potential representative of less collateral reinnervation, and 28% more functioning MUs (P < 0.05). Additionally, the MAs had greater MU neuromuscular stability than the controls, as indicated by lower NF jitter and jiggle values (P < 0.05). These results demonstrate that high-performing octogenarians better maintain neuromuscular stability of the MU and mitigate the loss of MUs associated with aging well into the later decades of life during which time the loss of muscle mass and strength becomes functionally relevant. Future studies may identify the concomitant roles genetics and exercise play in neuroprotection.
Collapse
Affiliation(s)
- Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph Ontario, Canada;
| | - Matti D Allen
- School of Medicine and School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Kevin J Gilmore
- Faculty of Health Sciences, School of Kinesiology, Canadian Centre for Activity and Aging, The University of Western Ontario, Ontario, Canada
| | - Daniel W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Timothy J Doherty
- Faculty of Health Sciences, School of Kinesiology, Canadian Centre for Activity and Aging, The University of Western Ontario, Ontario, Canada.,Department of Physical Medicine and Rehabilitation, The University of Western Ontario, London, Ontario, Canada
| | - Russell T Hepple
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Meakins Christie Laboratories, McGill University, Montreal, Quebec, Canada; and
| | - Tanja Taivassalo
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | - Charles L Rice
- Faculty of Health Sciences, School of Kinesiology, Canadian Centre for Activity and Aging, The University of Western Ontario, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
44
|
Krarup C, Boeckstyns M, Ibsen A, Moldovan M, Archibald S. Remodeling of motor units after nerve regeneration studied by quantitative electromyography. Clin Neurophysiol 2016; 127:1675-1682. [DOI: 10.1016/j.clinph.2015.08.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 07/16/2015] [Accepted: 08/13/2015] [Indexed: 10/23/2022]
|
45
|
Hepple RT, Rice CL. Innervation and neuromuscular control in ageing skeletal muscle. J Physiol 2015; 594:1965-78. [PMID: 26437581 DOI: 10.1113/jp270561] [Citation(s) in RCA: 209] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/28/2015] [Indexed: 12/28/2022] Open
Abstract
Changes in the neuromuscular system affecting the ageing motor unit manifest structurally as a reduction in motor unit number secondary to motor neuron loss; fibre type grouping due to repeating cycles of denervation-reinnervation; and instability of the neuromuscular junction that may be due to either or both of a gradual perturbation in postsynaptic signalling mechanisms necessary for maintenance of the endplate acetylcholine receptor clusters or a sudden process involving motor neuron death or traumatic injury to the muscle fibre. Functionally, these changes manifest as a reduction in strength and coordination that precedes a loss in muscle mass and contributes to impairments in fatigue. Regular muscle activation in postural muscles or through habitual physical activity can attenuate some of these structural and functional changes up to a point along the ageing continuum. On the other hand, regular muscle activation in advanced age (>75 years) loses its efficacy, and at least in rodents may exacerbate age-related motor neuron death. Transgenic mouse studies aimed at identifying potential mechanisms of motor unit disruptions in ageing muscle are not conclusive due to many different mechanisms converging on similar motor unit alterations, many of which phenocopy ageing muscle. Longitudinal studies of ageing models and humans will help clarify the cause and effect relationships and thus, identify relevant therapeutic targets to better preserve muscle function across the lifespan.
Collapse
Affiliation(s)
- Russell T Hepple
- Department of Kinesiology & Physical Education, McGill University, Montreal, Québec, Canada.,McGill Research Centre for Physical Activity and Health, Montreal, Québec, Canada.,Centre for Translational Biology, Research Institute of the McGill University Health Centre, Montreal, Québec, Canada
| | - Charles L Rice
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada.,Canadian Centre for Activity and Aging, London, Ontario, Canada.,Department of Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
46
|
Piasecki M, Ireland A, Stashuk D, Hamilton-Wright A, Jones DA, McPhee JS. Age-related neuromuscular changes affecting human vastus lateralis. J Physiol 2015; 594:4525-36. [PMID: 26486316 PMCID: PMC4983624 DOI: 10.1113/jp271087] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 10/12/2015] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS Skeletal muscle size and strength decline in older age. The vastus lateralis, a large thigh muscle, undergoes extensive neuromuscular remodelling in healthy ageing, as characterized by a loss of motor neurons, enlargement of surviving motor units and instability of neuromuscular junction transmission. The loss of motor axons and changes to motor unit potential transmission precede a clinically-relevant loss of muscle mass and function. ABSTRACT The anterior thigh muscles are particularly susceptible to muscle loss and weakness during ageing, although how this is associated with changes to neuromuscular structure and function in terms of motor unit (MU) number, size and MU potential (MUP) stability remains unclear. Intramuscular (I.M.) and surface electromyographic signals were recorded from the vastus lateralis (VL) during voluntary contractions held at 25% maximal knee extensor strength in 22 young (mean ± SD, 25.3 ± 4.8 years) and 20 physically active older men (71.4 ± 6.2 years). MUP size, firing rates, phases, turns and near fibre (NF) jiggle were determined and MU number estimates (MUNEs) were made by comparing average surface MUP with maximal electrically-evoked compound muscle action potentials. Quadriceps cross-sectional area was measured by magnetic resonance imaging. In total, 379 individual MUs were sampled in younger men and 346 in older men. Compared to the MU in younger participants, those in older participants had 8% lower firing rates and larger MUP size (+25%), as well as increased complexity, as indicated by phases (+13%), turns (+20%) and NF jiggle (+11%) (all P < 0.0005). The MUNE values (derived from the area of muscle in range of the surface-electrode) in older participants were ∼70% of those in the young (P < 0.05). Taking into consideration the 30% smaller cross-sectional area of the VL, the total number of MUs in the older muscles was between 50% and 60% lower compared to in young muscles (P < 0.0005). A large portion of the VL MU pool is lost in older men and those recruited during moderate intensity contractions were enlarged and less stable. These MU changes were evident before clinically relevant changes to muscle function were apparent; nevertheless, the changes in MU number and size are probably a prelude to future movement problems.
Collapse
Affiliation(s)
- M Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - A Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - D Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - A Hamilton-Wright
- Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada
| | - D A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| | - J S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, UK
| |
Collapse
|
47
|
Piasecki M, Ireland A, Jones DA, McPhee JS. Age-dependent motor unit remodelling in human limb muscles. Biogerontology 2015; 17:485-96. [PMID: 26667009 PMCID: PMC4889636 DOI: 10.1007/s10522-015-9627-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/26/2015] [Indexed: 12/14/2022]
Abstract
Voluntary control of skeletal muscle enables humans to interact with and manipulate the environment. Lower muscle mass, weakness and poor coordination are common complaints in older age and reduce physical capabilities. Attention has focused on ways of maintaining muscle size and strength by exercise, diet or hormone replacement. Without appropriate neural innervation, however, muscle cannot function. Emerging evidence points to a neural basis of muscle loss. Motor unit number estimates indicate that by age around 71 years, healthy older people have around 40 % fewer motor units. The surviving low- and moderate-threshold motor units recruited for moderate intensity contractions are enlarged by around 50 % and show increased fibre density, presumably due to collateral reinnervation of denervated fibres. Motor unit potentials show increased complexity and the stability of neuromuscular junction transmissions is decreased. The available evidence is limited by a lack of longitudinal studies, relatively small sample sizes, a tendency to examine the small peripheral muscles and relatively few investigations into the consequences of motor unit remodelling for muscle size and control of movements in older age. Loss of motor neurons and remodelling of surviving motor units constitutes the major change in ageing muscles and probably contributes to muscle loss and functional impairments. The deterioration and remodelling of motor units likely imposes constraints on the way in which the central nervous system controls movements.
Collapse
Affiliation(s)
- Mathew Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - Alex Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - David A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - Jamie S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK.
| |
Collapse
|
48
|
|
49
|
Leon-Sarmiento FE, Rizzo-Sierra CV, Leon-Ariza JS, Leon-Ariza DS, Sobota R, Prada DG. A new neurometric dissection of the area-under-curve-associated jiggle of the motor evoked potential induced by transcranial magnetic stimulation. Physiol Behav 2015; 141:111-9. [DOI: 10.1016/j.physbeh.2015.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 01/09/2015] [Accepted: 01/13/2015] [Indexed: 10/24/2022]
|
50
|
Hourigan ML, McKinnon NB, Johnson M, Rice CL, Stashuk DW, Doherty TJ. Increased motor unit potential shape variability across consecutive motor unit discharges in the tibialis anterior and vastus medialis muscles of healthy older subjects. Clin Neurophysiol 2015; 126:2381-9. [PMID: 25727901 DOI: 10.1016/j.clinph.2015.02.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 01/31/2015] [Accepted: 02/02/2015] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To study the potential utility of using near fiber (NF) jiggle as an assessment of neuromuscular transmission stability in healthy older subjects using decomposition-based quantitative electromyography (DQEMG). METHODS The tibialis anterior (TA) and vastus medialis (VM) muscles were tested in 9 older men (77 ± 5 years) and 9 young male control subjects (23 ± 0.3 years). Simultaneous surface and needle-detected electromyographic (EMG) signals were collected during voluntary contractions, and then analyzed using DQEMG. Motor unit potential (MUP) and NF MUP parameters were analyzed. RESULTS NF jiggle was significantly increased for both the TA and VM in the old age group relative to the younger controls (P<0.05). NF jiggle was significantly higher in the TA compared to VM (P<0.05). For TA, NF jiggle was negatively correlated with MUNE, and positively correlated with S-MUP amplitude, NF count, MUP duration, MUP peak-to-peak voltage, and MUP area (P<0.05). For VM, NF jiggle was positively correlated with NF count and MUP area (P<0.05), and no significant correlations were found between NF jiggle and S-MUP amplitude, MUP duration, or MUP peak-to-peak voltage (MUNE was not calculated for VM, so no correlation could be made). CONCLUSIONS Healthy aging is associated with neuromuscular transmission instability (increased NF jiggle) and MU remodeling, which can be measured using DQEMG. SIGNIFICANCE NF jiggle derived from DQEMG can be a useful method of identifying neuromuscular dysfunction at various stages of MU remodeling and aging.
Collapse
Affiliation(s)
- Maddison L Hourigan
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Neal B McKinnon
- School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada
| | - Marjorie Johnson
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Charles L Rice
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada
| | - Daniel W Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Timothy J Doherty
- School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada; Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
| |
Collapse
|