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Shin-Yi Lin C, Howells J, Rutkove S, Nandedkar S, Neuwirth C, Noto YI, Shahrizaila N, Whittaker RG, Bostock H, Burke D, Tankisi H. Neurophysiological and imaging biomarkers of lower motor neuron dysfunction in motor neuron diseases/amyotrophic lateral sclerosis: IFCN handbook chapter. Clin Neurophysiol 2024; 162:91-120. [PMID: 38603949 DOI: 10.1016/j.clinph.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/07/2024] [Accepted: 03/12/2024] [Indexed: 04/13/2024]
Abstract
This chapter discusses comprehensive neurophysiological biomarkers utilised in motor neuron disease (MND) and, in particular, its commonest form, amyotrophic lateral sclerosis (ALS). These encompass the conventional techniques including nerve conduction studies (NCS), needle and high-density surface electromyography (EMG) and H-reflex studies as well as novel techniques. In the last two decades, new methods of assessing the loss of motor units in a muscle have been developed, that are more convenient than earlier methods of motor unit number estimation (MUNE),and may use either electrical stimulation (e.g. MScanFit MUNE) or voluntary activation (MUNIX). Electrical impedance myography (EIM) is another novel approach for the evaluation that relies upon the application and measurement of high-frequency, low-intensity electrical current. Nerve excitability techniques (NET) also provide insights into the function of an axon and reflect the changes in resting membrane potential, ion channel dysfunction and the structural integrity of the axon and myelin sheath. Furthermore, imaging ultrasound techniques as well as magnetic resonance imaging are capable of detecting the constituents of morphological changes in the nerve and muscle. The chapter provides a critical description of the ability of each technique to provide neurophysiological insight into the complex pathophysiology of MND/ALS. However, it is important to recognise the strengths and limitations of each approach in order to clarify utility. These neurophysiological biomarkers have demonstrated reliability, specificity and provide additional information to validate and assess lower motor neuron dysfunction. Their use has expanded the knowledge about MND/ALS and enhanced our understanding of the relationship between motor units, axons, reflexes and other neural circuits in relation to clinical features of patients with MND/ALS at different stages of the disease. Taken together, the ultimate goal is to aid early diagnosis, distinguish potential disease mimics, monitor and stage disease progression, quantify response to treatment and develop potential therapeutic interventions.
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Affiliation(s)
- Cindy Shin-Yi Lin
- Faculty of Medicine and Health, Central Clinical School, Brain and Mind Centre, University of Sydney, Sydney 2006, Australia.
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Seward Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sanjeev Nandedkar
- Natus Medical Inc, Middleton, Wisconsin, USA and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Christoph Neuwirth
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
| | - Yu-Ichi Noto
- Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Nortina Shahrizaila
- Division of Neurology, Department of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Roger G Whittaker
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University., Newcastle Upon Tyne, United Kingdom
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, United Kingdom
| | - David Burke
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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Chan Y, Alix JJP, Neuwirth C, Barkhaus PE, Castro J, Jenkins TM, McDermott CJ, Shaw PJ, de Carvalho M, Nandedkar S, Stålberg E, Weber M. Reinnervation as measured by the motor unit size index is associated with preservation of muscle strength in amyotrophic lateral sclerosis, but not all muscles reinnervate. Muscle Nerve 2021; 65:203-210. [PMID: 34687220 DOI: 10.1002/mus.27444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 11/11/2022]
Abstract
INTRODUCTION/AIMS The motor unit size index (MUSIX) may provide insight into reinnervation patterns in diseases such as amyotrophic lateral sclerosis (ALS). However, it is not known whether MUSIX detects clinically relevant changes in reinnervation, or if all muscles manifest changes in MUSIX in response to reinnervation after motor unit loss. METHODS Fifty-seven patients with ALS were assessed at 3-month intervals for 12 months in four centers. Muscles examined were abductor pollicis brevis, abductor digiti minimi, biceps brachii, and tibialis anterior. Results were split into two groups: muscles with increases in MUSIX and those without increases. Longitudinal changes in MUSIX, motor unit number index (MUNIX), compound muscle action potential amplitude, and Medical Research Council strength score were investigated. RESULTS One hundred thirty-three muscles were examined. Fifty-nine percent of the muscles exhibited an increase in MUSIX during the study. Muscles with MUSIX increases lost more motor units (58% decline in MUNIX at 12 months, P < .001) than muscles that did not increase MUSIX (34.6% decline in MUNIX at 12 months, P < .001). However, longitudinal changes in muscle strength were similar. When motor unit loss was similar, the absence of a MUSIX increase was associated with a significantly greater loss of muscle strength (P = .002). DISCUSSION MUSIX increases are associated with greater motor unit loss but relative preservation of muscle strength. Thus, MUSIX appears to be measuring a clinically relevant response that can provide a quantitative outcome measure of reinnervation in clinical trials. Furthermore, MUSIX suggests that reinnervation may play a major role in determining the progression of weakness.
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Affiliation(s)
- Young Chan
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - James J P Alix
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Christoph Neuwirth
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
| | | | - José Castro
- Department of Neurosciences, Centro Hospitalar Lisboa Norte-Hospital de Santa Maria, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Lisboa, Portugal
| | - Thomas M Jenkins
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | | | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Mamede de Carvalho
- Department of Neurosciences, Centro Hospitalar Lisboa Norte-Hospital de Santa Maria, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Lisboa, Portugal
| | | | - Erik Stålberg
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
| | - Markus Weber
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
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Nandedkar S. Workshop 4: Advanced Neurophysiology Techniques WS4.1. My Approach to Motor Unit Number Estimation (with Demonstration). Clin Neurophysiol 2021. [DOI: 10.1016/j.clinph.2021.02.089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Alix JJP, Neuwirth C, Gelder L, Burkhardt C, Castro J, de Carvalho M, Gawel M, Goedee S, Grosskreutz J, Lenglet T, Moglia C, Omer T, Schrooten M, Nandedkar S, Stalberg E, Barkhaus PE, Furtula J, van Dijk JP, Baldinger R, Costa J, Otto M, Sandberg A, Weber M. Assessment of the reliability of the motor unit size index (MUSIX) in single subject "round-robin" and multi-centre settings. Clin Neurophysiol 2019; 130:666-674. [PMID: 30870802 DOI: 10.1016/j.clinph.2019.01.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 11/16/2018] [Accepted: 01/03/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The motor unit size index (MUSIX) is incorporated into the motor unit number index (MUNIX). Our objective was to assess the intra-/inter-rater reliability of MUSIX in healthy volunteers across single subject "round robin" and multi-centre settings. METHODS Data were obtained from (i) a round-robin assessment in which 12 raters (6 with prior experience and 6 without) assessed six muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor digitorum brevis and abductor hallucis) and (ii) a multi-centre study with 6 centres studying the same muscles in 66 healthy volunteers. Intra/inter-rater data were provided by 5 centres, 1 centre provided only intra-rater data. Intra/inter-rater variability was assessed using the coefficient of variation (COV), Bland-Altman plots, bias and 95% limits of agreement. RESULTS In the round-robin assessment intra-rater COVs for MUSIX ranged from 7.8% to 28.4%. Inter-rater variability was between 7.8% and 16.2%. Prior experience did not impact on MUSIX values. In the multi-centre study MUSIX was more consistent than the MUNIX. Abductor hallucis was the least reliable muscle. CONCLUSIONS The MUSIX is a reliable neurophysiological biomarker of reinnervation. SIGNIFICANCE MUSIX could provide insights into the pathophysiology of a range of neuromuscular disorders, providing a quantitative biomarker of reinnervation.
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Affiliation(s)
- James J P Alix
- Sheffield Institute for Translational Neuroscience, University of Sheffield, 385A Glossop Road, Sheffield S10 2HQ, UK.
| | - Christoph Neuwirth
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
| | - Lucy Gelder
- Statistical Services Unit, University of Sheffield, UK
| | - Christian Burkhardt
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
| | - José Castro
- Department of Neurosciences, Hospital de Santa Maria, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal
| | - Mamede de Carvalho
- Department of Neurosciences, Hospital de Santa Maria, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal
| | - Malgorzata Gawel
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Stephan Goedee
- Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, Utrecht, The Netherlands
| | - Julian Grosskreutz
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Timothée Lenglet
- Département de Neurophysiologie, Groupe hospitalier Pitié-Salpêtrière, APHP, Paris, France
| | - Cristina Moglia
- ALS Centre of Torino, Department of Neuroscience "Rita Levi Montalcini", University of Torino, Torino, Italy
| | - Taha Omer
- Trinity College Biomedical Science Institute (TBSI) and Beaumont Hospital, Dublin, Ireland
| | - Maarten Schrooten
- Department of Neurology, University Hospital Leuven, Leuven, Belgium
| | - Sanjeev Nandedkar
- Natus Medical, Inc., 15 Dartantra Drive, Hopewell Junction, NY 12533, USA
| | - Erik Stalberg
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Sweden
| | - Paul E Barkhaus
- Milwaukee Veterans Administration Medical Center and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jasna Furtula
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | | | - Reto Baldinger
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
| | - Joao Costa
- Department of Neurosciences, Hospital de Santa Maria, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal
| | - Marit Otto
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Arne Sandberg
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Sweden
| | - Markus Weber
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
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Nandedkar S. S71 Motor unit number index (MUNIX). Clin Neurophysiol 2017. [DOI: 10.1016/j.clinph.2017.07.082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Saboisky JP, Stashuk DW, Hamilton-Wright A, Trinder J, Nandedkar S, Malhotra A. Correction: Effects of Aging on Genioglossus Motor Units in Humans. PLoS One 2016; 11:e0164252. [PMID: 27695099 PMCID: PMC5047479 DOI: 10.1371/journal.pone.0164252] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Neuwirth C, Barkhaus PE, Burkhardt C, Castro J, Czell D, de Carvalho M, Nandedkar S, Stålberg E, Weber M. Tracking motor neuron loss in a set of six muscles in amyotrophic lateral sclerosis using the Motor Unit Number Index (MUNIX): a 15-month longitudinal multicentre trial. J Neurol Neurosurg Psychiatry 2015; 86:1172-9. [PMID: 25935892 DOI: 10.1136/jnnp-2015-310509] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/15/2015] [Indexed: 11/04/2022]
Abstract
BACKGROUND Motor Unit Number Index (MUNIX) is a novel neurophysiological measure that provides an index of the number of functional lower motor neurons in a given muscle. So far its performance across centres in patients with amyotrophic lateral sclerosis (ALS) has not been investigated. OBJECTIVE To perform longitudinal MUNIX recordings in a set of muscles in a multicentre setting in order to evaluate its value as a marker of disease progression. METHODS Three centres applied MUNIX in 51 ALS patients over 15 months. Six different muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor dig. brevis, abductor hallucis) were measured every 3 months on the less affected side. The decline between MUNIX and ALSFRS-R was compared. RESULTS 31 participants reached month 12. For all participants, ALSFRS-R declined at a rate of 2.3%/month. Using the total score of all muscles, MUNIX declined significantly faster by 3.2%/month (p ≤ 0.02). MUNIX in individual muscles declined between 2.4% and 4.2%, which differed from ASLFRS-R decline starting from month 3 (p ≤ 0.05 to 0.002). Subgroups with bulbar, lower and upper limb onset showed different decline rates of ALSFRS-R between 1.9% and 2.8%/month, while MUNIX total scores showed similar decline rates over all subgroups. Mean intraclass correlation coefficient for MUNIX intra-rater reliability was 0.89 and for inter-rater reliability 0.80. CONCLUSION MUNIX is a reliable electrophysiological biomarker to track lower motor neuron loss in ALS.
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Affiliation(s)
- Christoph Neuwirth
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland
| | | | - Christian Burkhardt
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland
| | - José Castro
- Department of Neurosciences, Faculty of Medicine, Hospital de Santa Maria, Instituto de Medicina Molecular, University of Lisbon, Lisbon, Portugal
| | - David Czell
- Kantonsspital Winterthur, Winterthur, Switzerland
| | - Mamede de Carvalho
- Department of Neurosciences, Faculty of Medicine, Hospital de Santa Maria, Instituto de Medicina Molecular, University of Lisbon, Lisbon, Portugal
| | | | - Erik Stålberg
- Department of Clinical Neurophysiology, Institute of Neurosciences, Uppsala University, University Hospital, Uppsala, Sweden
| | - Markus Weber
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland Department of Neurology, University Hospital Basel, Basel, Switzerland
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Saboisky JP, Stashuk DW, Hamilton-Wright A, Trinder J, Nandedkar S, Malhotra A. Effects of aging on genioglossus motor units in humans. PLoS One 2014; 9:e104572. [PMID: 25111799 PMCID: PMC4128697 DOI: 10.1371/journal.pone.0104572] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/10/2014] [Indexed: 11/21/2022] Open
Abstract
The genioglossus is a major upper airway dilator muscle thought to be important in obstructive sleep apnea pathogenesis. Aging is a risk factor for obstructive sleep apnea although the mechanisms are unclear and the effects of aging on motor unit remodeled in the genioglossus remains unknown. To assess possible changes associated with aging we compared quantitative parameters related to motor unit potential morphology derived from EMG signals in a sample of older (n = 11; >55 years) versus younger (n = 29; <55 years) adults. All data were recorded during quiet breathing with the subjects awake. Diagnostic sleep studies (Apnea Hypopnea Index) confirmed the presence or absence of obstructive sleep apnea. Genioglossus EMG signals were analyzed offline by automated software (DQEMG), which estimated a MUP template from each extracted motor unit potential train (MUPT) for both the selective concentric needle and concentric needle macro (CNMACRO) recorded EMG signals. 2074 MUPTs from 40 subjects (mean±95% CI; older AHI 19.6±9.9 events/hr versus younger AHI 30.1±6.1 events/hr) were extracted. MUPs detected in older adults were 32% longer in duration (14.7±0.5 ms versus 11.1±0.2 ms; P = 0.05), with similar amplitudes (395.2±25.1 µV versus 394.6±13.7 µV). Amplitudes of CNMACRO MUPs detected in older adults were larger by 22% (62.7±6.5 µV versus 51.3±3.0 µV; P<0.05), with areas 24% larger (160.6±18.6 µV.ms versus 130.0±7.4 µV.ms; P<0.05) than those detected in younger adults. These results confirm that remodeled motor units are present in the genioglossus muscle of individuals above 55 years, which may have implications for OSA pathogenesis and aging related upper airway collapsibility.
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Affiliation(s)
- Julian P. Saboisky
- Division of Sleep Medicine, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Prince of Wales Clinical School, Faculty of Medicine University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
| | - Daniel W. Stashuk
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada
| | - Andrew Hamilton-Wright
- Mathematics and Computer Science, Mount Allison University, Sackville, New Brunswick, Canada
| | - John Trinder
- School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | | | - Atul Malhotra
- Division of Sleep Medicine, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
- University of California San Diego, La Jolla, California, United States of America
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Saboisky JP, Stashuk DW, Hamilton-Wright A, Carusona AL, Campana LM, Trinder J, Eckert DJ, Jordan AS, McSharry DG, White DP, Nandedkar S, David WS, Malhotra A. Neurogenic changes in the upper airway of patients with obstructive sleep apnea. Am J Respir Crit Care Med 2011; 185:322-9. [PMID: 22016445 DOI: 10.1164/rccm.201106-1058oc] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Controversy persists regarding the presence and importance of hypoglossal nerve dysfunction in obstructive sleep apnea (OSA). OBJECTIVES We assessed quantitative parameters related to motor unit potential (MUP) morphology derived from electromyographic (EMG) signals in patients with OSA versus control subjects and hypothesized that signs of neurogenic remodeling would be present in the patients with OSA. METHODS Participants underwent diagnostic sleep studies to obtain apnea-hypopnea indices. Muscle activity was detected with 50-mm concentric needle electrodes. The concentric needle was positioned at more than 10 independent sites per subject, after the local anatomy of the upper airway musculature was examined by ultrasonography. All activity was quantified with subjects awake, during supine eupneic breathing while wearing a nasal mask connected to a pneumotachograph. Genioglossus EMG signals were analyzed offline by automated software (DQEMG), which extracted motor unit potential trains (MUPTs) contributed by individual motor units from the composite EMG signals. Quantitative measurements of MUP templates, including duration, peak-to-peak amplitude, area, area-to-amplitude ratio, and size index, were compared between the untreated patients with OSA and healthy control subjects. MEASUREMENTS AND MAIN RESULTS A total of 1,655 MUPTs from patients with OSA (n = 17; AHI, 55 ± 6/h) and control subjects (n = 14; AHI, 4 ± 1/h) were extracted from the genioglossus muscle EMG signals. MUP peak-to-peak amplitudes in the patients with OSA were not different compared with the control subjects (397.5 ± 9.0 vs. 382.5 ± 10.0 μV). However, the MUPs of the patients with OSA were longer in duration (11.5 ± 0.1 vs. 10.3 ± 0.1 ms; P < 0.001) and had a larger size index (4.09 ± 0.02 vs. 3.92 ± 0.02; P < 0.001) compared with control subjects. CONCLUSIONS These results confirm and quantify the extent and existence of structural neural remodeling in OSA.
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Affiliation(s)
- Julian P Saboisky
- Sleep Disorders Program, Division of Sleep Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA.
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Neuwirth C, Nandedkar S, Stålberg E, Barkhaus PE, Carvalho MD, Furtula J, van Dijk JP, Baldinger R, Castro J, Costa J, Otto M, Sandberg A, Weber M. Motor Unit Number Index (MUNIX): reference values of five different muscles in healthy subjects from a multi-centre study. Clin Neurophysiol 2011; 122:1895-8. [PMID: 21689981 DOI: 10.1016/j.clinph.2011.05.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 05/10/2011] [Accepted: 05/12/2011] [Indexed: 12/14/2022]
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Neuwirth C, Nandedkar S, Stålberg E, Weber M. Motor unit number index (MUNIX): A novel neurophysiological technique to follow disease progression in amyotrophic lateral sclerosis. Muscle Nerve 2010; 42:379-84. [PMID: 20589888 DOI: 10.1002/mus.21707] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Christoph Neuwirth
- Neuromuscular Diseases Unit and Kantonsspital St. Gallen, St. Gallen, Switzerland.
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Nandedkar S. BS10 Signal analysis in neurophysiology. Clin Neurophysiol 2006. [DOI: 10.1016/j.clinph.2006.07.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
A better appreciation of the specific spatial recording characteristics of the single fiber and concentric needle electrode can result in more accurate physiologic and theoretical interpretations of single fiber and quantitative motor unit action potential analysis. We demonstrate by physical modeling that the 90% and 99% amplitude sensitivity envelopes are not simple hemispherical shapes. The 90% sensitivity concentric electrode volume does not extend beyond the insulated portion of the 15 degree beveled surface between the core and cannula and extends only 280 microm perpendicularly from the center of the core's surface. The 99% envelope extends approximately 830 microm perpendicularly from the core's center. This is a much smaller volume of sensitivity than exists for a similarly modeled monopolar electrode. The 90% and 99% envelopes extend to 110 and 320 microm perpendicularly from the exposed single fiber core. Both the single fiber and concentric needle volumes of sensitivity have specific asymmetries described.
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Affiliation(s)
- J C King
- Department of Rehabilitation Medicine, University of Texas Health Science Center at San Antonio, 78284-7798, USA
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Abstract
An electromyographic technique is presented that has been developed in an effort to quantitate the number of motor units in the urinary sphincter. Sphincter contraction was provoked by electrical stimulation and recorded with a catheter mounted electrode. Incremental stimulation produced corresponding increments of sphincter contraction that were recorded as the magnitude of the sphincter electromyogram. Estimates of the number of motor units in the sphincter were made by analysis of variance of a Poisson distribution. Using this method, the mean number of motor units in the sphincter of five dogs was estimated to be 129 with values ranging from 80 to 182. Anatomical correlation was sought by infiltrating this sphincter with horseradish peroxidase, which is taken up by axonal transport to stain the motor neurons in the spinal cord. The mean number of motor neurons was 229 with values ranging from 116 to 358. There are technical and physiologic explanations for the observed differences between the predicted and the actual number of motor neurons stained and this is addressed in the discussion.
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Affiliation(s)
- J A Mekras
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710
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Aquilonius SM, Askmark H, Gillberg PG, Nandedkar S, Olsson Y, Stålberg E. Topographical localization of motor endplates in cryosections of whole human muscles. Muscle Nerve 1984; 7:287-93. [PMID: 6203034 DOI: 10.1002/mus.880070406] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The distribution of motor endplates in biceps brachii, tibialis anterior, and sartorius muscles from human adults was studied by staining longitudinal cryosections of whole muscle for cholinesterase. A special freezing technique was used to prevent the muscle from cracking before sectioning on a heavy cryostat microtome. The results from a large number of cryosections from biceps brachii and tibialis anterior muscles were analyzed by a computer and the topographical distributions of endplates in different views of the muscles were reconstructed. In the biceps brachii muscle, the endplates formed a fairly distinct, slightly V-shaped band through the middle of the two heads. In the tibialis anterior muscle, the majority of the endplates were superficially distributed along the whole muscle. In the longitudinal sections from the middle part of the muscle, they gave the pattern of a parabola with its apex at the proximal end of the muscle. In the sartorius muscle, the endplates were scattered throughout the muscle and no endplate band was observed. The findings are in accordance with results obtained 30 years ago in investigations of muscle from small children and stillborn infants.
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Stålberg E, Chu J, Bril V, Nandedkar S, Stålberg S, Ericsson M. Automatic analysis of the EMG interference pattern. Electroencephalogr Clin Neurophysiol 1983; 56:672-81. [PMID: 6197286 DOI: 10.1016/0013-4694(83)90035-4] [Citation(s) in RCA: 156] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A method is described for the automatic analysis of EMG interference patterns obtained at optional non-controlled force levels. It is a modification of Willison's method of measuring turns and amplitude of the signal. In the method, the mean amplitude is plotted against turns obtained during 300 msec for each of 20 recording sites. Different voluntary strengths are used and a scatter of points is obtained. Confidence limits enclosing these points are constructed for healthy subjects for 4 different muscles with concentric and monopolar electrodes. The normal values differ with age, muscle, sex and electrode. The method is tested on patients with myopathic or neurogenic EMG and a high diagnostic yield is obtained. The method is objective, reproducible, fast and needs relatively small computer facilities.
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Abstract
Macro EMG motor unit potentials (MUPs) have been simulated. The effects on MUP parameters of number of fibres, fibre diameter, end-plate scatter, nerve branch delay, motor unit territory and electrode position have been studied. The MUP shape is sensitive to electrode position in the vicinity of the end-plates. It is mainly reflecting the end-plate scatter and the nerve delays. Away from the end-plates the wave shape is principally determined by the fibre diameter distribution. Total number of muscle fibres and their mean diameter act as gain factors at all recording positions. In the simulations the area of the signal appears to be a better measure of the strength of the motor unit than the amplitude. Macro EMG offers a much less selective recording than conventional EMG and single fibre EMG and therefore new aspects of the motor unit can be quantified. Preliminary results from simulations of neuromuscular disorders are consistent with actual findings.
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