Academic Journal
Maximal motor unit firing rates decline with amyotrophic lateral sclerosis progression.
| Τίτλος: | Maximal motor unit firing rates decline with amyotrophic lateral sclerosis progression. |
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| Συγγραφείς: | Fernandes GL; Physical Activity, Sport and Exercise Research (PASER) Theme, Faculty of Health, Southern Cross University, Gold Coast, 4227, Australia. Electronic address: gabriel.fernandes@scu.edu.au., Orssatto LBR; Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, 4072, Australia., Pinto MD; School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, 4059, Australia; Exercise Medicine Research Institute, Edith Cowan University, Joondalup, Western Australia, 6027, Australia., Henkin JS; School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, 4059, Australia., Shandiz E; Department of Neurology, Royal Brisbane & Women's Hospital, Brisbane, 4006, Australia., McCombe PA; Department of Neurology, Royal Brisbane & Women's Hospital, Brisbane, 4006, Australia; Centre for Clinical Research, The University of Queensland, Brisbane, 4006, Australia., Henderson RD; Department of Neurology, Royal Brisbane & Women's Hospital, Brisbane, 4006, Australia; Centre for Clinical Research, The University of Queensland, Brisbane, 4006, Australia., Trajano GS; School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, 4059, Australia. Electronic address: g.trajano@qut.edu.au. |
| Πηγή: | Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology [Clin Neurophysiol] 2026 May; Vol. 185, pp. 2111697. Date of Electronic Publication: 2026 Feb 19. |
| Τύπος έκδοσης: | Journal Article |
| Γλώσσα: | English |
| Στοιχεία περιοδικού: | Publisher: Elsevier Country of Publication: Netherlands NLM ID: 100883319 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1872-8952 (Electronic) Linking ISSN: 13882457 NLM ISO Abbreviation: Clin Neurophysiol Subsets: MEDLINE |
| Imprint Name(s): | Original Publication: Amsterdam : Elsevier, c1999- |
| Ιατρικοί όροι (MeSH): | Amyotrophic Lateral Sclerosis*/physiopathology , Amyotrophic Lateral Sclerosis*/diagnosis , Motor Neurons*/physiology , Muscle, Skeletal*/physiopathology , Recruitment, Neurophysiological*/physiology , Action Potentials*/physiology, Electromyography/methods ; Muscle Strength/physiology ; Humans ; Middle Aged ; Male ; Disease Progression ; Female ; Aged |
| Περίληψη: | Objective: Amyotrophic lateral sclerosis (ALS) is characterised by progressive degeneration of upper and lower motor neurons and their motor units (MUs). MU loss is compensated by collateral sprouting and reinnervation of muscle fibres. There is limited information about the properties of these surviving MUs as these processes take place. High-density surface electromyography (HD-sEMG) decomposition enables non-invasive analysis of individual MU firing behaviour during maximal voluntary contractions and assess their changes with ALS progression. Methods: Thirty-nine individuals with ALS (24 men; mean age 63 ± 16 years) completed up to five visits (interval 20.0 ± 7.9 weeks). Tibialis anterior HD-sEMG recordings during maximal contractions were decomposed into individual MU spike trains, from which maximal firing rates were quantified. Muscle strength was assessed with the Medical Research Council (MRC) scale, and global function with the revised ALS Functional Rating Scale (ALSFRS-R). Results: Maximal MU firing rates declined significantly over time [-0.32 Hz/month, (95% CI -0.44; -0.19)], regardless of MRC scores. Across participants, maximal firing rates decreased by 2.38 Hz (1.78; 2.98) for each 1-point reduction in MRC and by 0.54 Hz for each ALSFRS-R point (-0.83; -0.26). Conclusion: These findings demonstrate that maximal MU firing rates decline as ALS progresses, suggesting that the surviving motor unit undergo progressive pathophysiological changes as motor neurons degenerate. HD-sEMG MU firing-rates analysis appeared more sensitive than MRC in detecting early deterioration in muscle decline. Significance: Maximal firing rates analysis has the potential to serve as a quantitative clinical biomarker of neuromotor system degeneration, complementing global functional scales in clinical monitoring. (Copyright © 2026 The Author(s). Published by Elsevier B.V. All rights reserved.) |
| Competing Interests: | Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. |
| Contributed Indexing: | Keywords: ALS; Collateral reinnervation; HD-sEMG; Motoneuron; Motor neuron disease; Motor unit discharge rate |
| Entry Date(s): | Date Created: 20260226 Date Completed: 20260709 Latest Revision: 20260709 |
| Update Code: | 20260711 |
| DOI: | 10.1016/j.clinph.2026.2111697 |
| PMID: | 41747658 |
| Βάση Δεδομένων: | MEDLINE |
| ISSN: | 1872-8952 |
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| DOI: | 10.1016/j.clinph.2026.2111697 |