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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] [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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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.
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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
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Sørensen DM, Bostock H, Abrahao A, Alaamel A, Alaydin HC, Ballegaard M, Boran E, Cengiz B, de Carvalho M, Dunker Ø, Fuglsang-Frederiksen A, Graffe CC, Jones KE, Kallio M, Kalra S, Krarup C, Krøigård T, Liguori R, Lupescu T, Maitland S, Matamala JM, Moldovan M, Moreno-Roco J, Nilsen KB, Phung L, Santos MO, Themistocleous AC, Uysal H, Vacchiano V, Whittaker RG, Zinman L, Tankisi H. Estimating motor unit numbers from a CMAP scan: Repeatability study on three muscles at 15 centres. Clin Neurophysiol 2023; 151:92-99. [PMID: 37236129 DOI: 10.1016/j.clinph.2023.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/16/2023] [Accepted: 04/15/2023] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To assess the repeatability and suitability for multicentre studies of MScanFit motor unit number estimation (MUNE), which involves modelling compound muscle action potential (CMAP) scans. METHODS Fifteen groups in 9 countries recorded CMAP scans twice, 1-2 weeks apart in healthy subjects from abductor pollicis brevis (APB), abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. The original MScanFit program (MScanFit-1) was compared with a revised version (MScanFit-2), designed to accommodate different muscles and recording conditions by setting the minimal motor unit size as a function of maximum CMAP. RESULTS Complete sets of 6 recordings were obtained from 148 subjects. CMAP amplitudes differed significantly between centres for all muscles, and the same was true for MScanFit-1 MUNE. With MScanFit-2, MUNE differed less between centres but remained significantly different for APB. Coefficients of variation between repeats were 18.0% for ADM, 16.8% for APB, and 12.1% for TA. CONCLUSIONS It is recommended for multicentre studies to use MScanFit-2 for analysis. TA provided the least variable MUNE values between subjects and the most repeatable within subjects. SIGNIFICANCE MScanFit was primarily devised to model the discontinuities in CMAP scans in patients and is less suitable for healthy subjects with smooth scans.
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Affiliation(s)
- D M Sørensen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark
| | - H Bostock
- UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| | - A Abrahao
- Department of Medicine, University of Toronto, Toronto, Canada
| | - A Alaamel
- Department of Neurology, Akdeniz University Hospital, Antalya, Turkey
| | - H C Alaydin
- Department of Neurology, Gazi University, Ankara, Turkey
| | - M Ballegaard
- Department of Clinical Neurology, Zealand University Hospital, Roskilde, Denmark
| | - E Boran
- Department of Neurology, Gazi University, Ankara, Turkey
| | - B Cengiz
- Department of Neurology, Gazi University, Ankara, Turkey
| | - M de Carvalho
- Faculty of Medicine, iMM, Centro de Estudos Egas Moniz, Universidade de Lisboa, Department of Neurosciences and Mental Health, CHULN, Lisbon, Portugal
| | - Ø Dunker
- Department of Neurology and Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Norway
| | - A Fuglsang-Frederiksen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark; Department of Clinical Institute, Aarhus University, Aarhus, Denmark
| | - C C Graffe
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - K E Jones
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - M Kallio
- Department of Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - S Kalra
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - C Krarup
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - T Krøigård
- Department of Neurology, Odense University Hospital, Denmark
| | - R Liguori
- Dipertimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - T Lupescu
- Department of Neurology, Agrippa Ionescu Hospital, Bucharest, Romania
| | - S Maitland
- Translational and Clinical Research Institute, Newcastle University, United Kingdom
| | - J M Matamala
- Translational Neurology and Neurophysiology Lab, Department of Neurological Sciences and Biomedical Neuroscience Institute, University of Chile, Santiago, Chile
| | - M Moldovan
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - J Moreno-Roco
- Translational Neurology and Neurophysiology Lab, Department of Neurological Sciences and Biomedical Neuroscience Institute, University of Chile, Santiago, Chile
| | - K B Nilsen
- Department of Neurology and Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Norway
| | - L Phung
- Department of Medicine, University of Toronto, Toronto, Canada
| | - M O Santos
- Faculty of Medicine, iMM, Centro de Estudos Egas Moniz, Universidade de Lisboa, Department of Neurosciences and Mental Health, CHULN, Lisbon, Portugal
| | - A C Themistocleous
- Nuffield Department of Clinical Neurosciences University of Oxford, Oxford, United Kingdom
| | - H Uysal
- Department of Medicine, University of Toronto, Toronto, Canada
| | - V Vacchiano
- Dipertimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - R G Whittaker
- Translational and Clinical Research Institute, Newcastle University, United Kingdom
| | - L Zinman
- UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| | - H Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark; Department of Clinical Institute, Aarhus University, Aarhus, Denmark.
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Liu Y, Chen YT, Zhang C, Zhou P, Li S, Zhang Y. Motor Unit Number Estimation in Spastic Biceps Brachii Muscles of Chronic Stroke Survivors Before and After BoNT Injection. IEEE Trans Biomed Eng 2023; 70:1045-1052. [PMID: 36126033 PMCID: PMC10676740 DOI: 10.1109/tbme.2022.3208078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The study aims to characterize the motor unit (MU) loss in spastic biceps brachii muscle (BBM) of chronic stroke survivors before and after botulinum neurotoxin (BoNT) injection. METHODS High-density weighted average (HDWA) motor unit number estimation (MUNE) was employed to estimate the number of functioning motor units of BBMs of eight chronic stroke survivors 1-week before (1st visit) and 3-week after (2nd visit) BoNT injection based on the surface electromyography (sEMG) signals recorded during voluntary contraction and supramaximal electrical stimulation. RESULT Significant lower MUNE was estimated from the spastic BBMs compared to the non-spastic MUNEs during two visits. A surprisingly higher MUNE was obtained from the spastic side during the 2nd visit after BoNT injection. CONCLUSIONS The HDWA MUNE technique can be employed to characterize the motor unit loss in spastic muscle caused by upper motor neuro lesions at contraction level up to 30% MVC, but may fail to detect the MU loss caused by the chemodenervation effect of BoNT due to the non-uniform denervation of small and large size MUs. SIGNIFICANCE This study presents the first effort to evaluate the applicability of HDWA MUNE technique to characterize the MU loss in the spastic muscle following stroke and the subsequent BoNT injection for the treatment of post-stroke spasticity. The finding of this study suggests that HDWA MUNE can be a sensitive approach to detect the MU loss in spastic muscles after stroke, but the large inter-subject MUNE variability after the BoNT injection should be interpreted with caution.
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Affiliation(s)
- Yang Liu
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204 USA
| | - Yen-Ting Chen
- (1) Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX 77030, United States; (2) TIRR Memorial Hermann Hospital, Houston, TX 77030, USA; (3) Department of Health and Kinesiology, Northeastern State University, Broken Arrow, OK 74014, USA
| | - Chuan Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204 USA
| | - Ping Zhou
- Faculty of Rehabilitation Engineering, University of Health and Rehabilitation Sciences, Qingdao 266024, China
| | - Sheng Li
- (1) Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX 77030, United States; (2) TIRR Memorial Hermann Hospital, Houston, TX 77030, USA
| | - Yingchun Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204 USA
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Sørensen DM, Bostock H, Ballegaard M, Fuglsang-Frederiksen A, Graffe CC, Grötting A, Jones K, Kallio M, Krarup C, Krøigård T, Lupescu T, Maitland S, Moldovan M, Nilsen KB, Pugdahl K, Santos MO, Themistocleous AC, Zlateva SS, Ööpik M, Tankisi H. Assessing inter-rater reproducibility in MScanFit MUNE in a 6-subject, 12-rater "Round Robin" setup. Neurophysiol Clin 2021; 52:157-169. [PMID: 34906430 DOI: 10.1016/j.neucli.2021.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/20/2021] [Accepted: 11/20/2021] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To assess the inter-rater reliability of MScanFit MUNE using a "Round Robin" research design. METHODS Twelve raters from different centres examined six healthy study participants over two days. Median, ulnar and common peroneal nerves were stimulated, and compound muscle action potential (CMAP)-scans were recorded from abductor pollicis brevis (APB), abductor digiti minimi (ADM) and anterior tibial (TA) muscles respectively. From this we calculated the Motor Unit Number Estimation (MUNE) and "A50", a motor unit size parameter. As statistical analysis we used the measures Limits of Agreement (LOA) and Coefficient of Variation (COV). Study participants scored their perception of pain from the examinations on a rating scale from 0 (no pain) to 10 (unbearable pain). RESULTS Before this study, 41.6% of the raters had performed MScanFit less than five times. The mean MUNE-values were: 99.6 (APB), 131.4 (ADM) and 126.2 (TA), with LOA: 19.5 (APB), 29.8 (ADM) and 20.7 (TA), and COV: 13.4 (APB), 6.3 (ADM) and 5.6 (TA). MUNE-values correlated to CMAP max amplitudes (R2-values were: 0.463 (APB) (p<0.001), 0.421 (ADM) (p<0.001) and 0.645 (TA) (p<0.001)). The average perception of pain was 4. DISCUSSION MScanFit indicates a high level of inter-rater reliability, even with only limited rater experience and is overall reasonably well tolerated by patients. These results may indicate MScanFit as a reliable MUNE method with potential as a biomarker in drug trials.
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Affiliation(s)
| | - Hugh Bostock
- Insitute of Neurology, Queen Square House, London, United Kingdom
| | - Martin Ballegaard
- Deparment of Clinical Neurology, Zealand University Hospital, Roskilde, Denmark
| | | | | | - Arnstein Grötting
- Department of Clinical Neurophysiology, St. Olav Hospital, Trondheim, Norway
| | - Kelvin Jones
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | - Mika Kallio
- Department of Clinical Neurophysiology, Oulu University Hospital, Oulu, Finland
| | - Christian Krarup
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Krøigård
- Department of Neurology, Odense University Hospital, Denmark
| | - Tudor Lupescu
- Department of Neurology, Agrippa Ionescu Hospital, Bucharest, Romania
| | - Stuart Maitland
- Newcastle Biomedical Research Centre, Newcastle upon Tyne, United Kingdom
| | - Mihai Moldovan
- Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark
| | | | - Kirsten Pugdahl
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark
| | - Miguel Oliveira Santos
- Department of Neurosciences and Mental Health, Hospital de Santa Maria, Lisbon, Portugal
| | | | | | - Merle Ööpik
- Deparment of Clinical Neurology, Zealand University Hospital, Roskilde, Denmark
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark.
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Jacobsen AB, Bostock H, Tankisi H. CMAP Scan MUNE (MScan) - A Novel Motor Unit Number Estimation (MUNE) Method. J Vis Exp 2018. [PMID: 29939177 DOI: 10.3791/56805] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Like other methods for motor unit number estimation (MUNE), compound muscle action potential (CMAP) scan MUNE (MScan) is a non-invasive electrophysiologic method to estimate the number of functioning motor units in a muscle. MUNE is an important tool for the assessment of neuropathies and neuronopathies. Unlike most MUNE methods in use, MScan assesses all the motor units in a muscle, by fitting a model to a detailed stimulus-response curve, or CMAP scan. It thereby avoids the bias inherent in all MUNE methods based on extrapolating from a small sample of units. Like 'Bayesian MUNE,' MScan analysis works by fitting a model, made up of motor units with different amplitudes, thresholds, and threshold variabilities, but the fitting method is quite different, and completed within five minutes, rather than several hours. The MScan off-line analysis works in two stages: first, a preliminary model is generated based on the slope and variance of the points in the scan, and second, this model is then refined by adjusting all the parameters to improve the fit between the original scan and scans generated by the model. This new method has been tested for reproducibility and recording time on 22 amyotrophic lateral sclerosis (ALS) patients and 20 healthy controls, with each test repeated twice by two blinded physicians. MScan showed excellent intra- and inter-rater reproducibility with ICC values of >0.98 and a coefficient of variation averaging 12.3 ± 1.6%. There was no difference in the intra-rater reproducibility between the two observers. Average recording time was 6.27 ± 0.27 min. This protocol describes how to record a CMAP scan and how to use the MScan software to derive an estimate of the number and sizes of the functioning motor units. MScan is a fast, convenient, and reproducible method, which may be helpful in diagnoses and monitoring disease progression in neuromuscular disorders.
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Affiliation(s)
- Anna B Jacobsen
- Department of Clinical Neurophysiology, Aarhus University Hospital
| | | | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital;
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7
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Zhang C, Munoz A, Lai HH, Boone T, Zhang Y. Non-invasive electromyographic estimation of motor unit number in the external anal sphincter of the rat. Neurourol Urodyn 2017; 37:115-122. [PMID: 28884835 DOI: 10.1002/nau.23313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 04/24/2017] [Indexed: 11/09/2022]
Abstract
AIMS The external anal sphincter (EAS) is essential for maintaining fecal continence. Neurological disorders or traumatic injuries to muscle and nervous systems could lead to EAS denervation. Currently, there are no techniques available to document global innervation changes in the EAS in vivo. The aim of this study was to develop a novel approach to non-invasively estimate the number of functioning motor units (MUs) in the EAS and validate with immunofluorescent techniques in rats. METHODS Intra-rectal surface electromyography (EMG) signals of the EAS, induced by a series of intra-vaginally delivered pudendal nerve stimulations with different intensities, were recorded. Variation in EMG responses at different intensities was used to estimate the value of a single motor unit potential (SMUP) in order to perform the proposed EAS motor unit number estimation (MUNE) approach. The EAS MUNE was tested in 12 female Sprague-Dawley rats, and validated by comparing against the EAS myofiber counting results achieved by performing immunostaining of acetylcholine receptors in 7 of the 12 rats. RESULTS The mean MU number was 35 ± 9, with an averaged SMUP size of 52.49 ± 20.39 μV. The mean number of successfully identified myofibers was 652.7 ± 130.6 myofiber/EAS. Significance of linear regression between the immunofluorescent results and the MUNE was confirmed (P < 0.01). CONCLUSIONS Our study represents the first effort to non-invasively assess the innervation of the EAS in vivo using the rat as a pre-clinical model. This approach can potentially enable future clinical applications for advanced diagnosis and treatment of neurogenic EAS disorders.
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Affiliation(s)
- Chuan Zhang
- Department of Biomedical Engineering, University of Houston, Houston, Texas.,Guangdong Provincial Work-injury Rehabilitation Hospital, Guangzhou, China.,Regenerative Medicine Program, Houston Methodist Research Institute, and Department of Urology, Houston Methodist Hospital, Houston, Texas
| | - Alvaro Munoz
- Regenerative Medicine Program, Houston Methodist Research Institute, and Department of Urology, Houston Methodist Hospital, Houston, Texas
| | - H Henry Lai
- Division of Urologic Surgery, Department of Surgery and Anesthesiology, Washington University School of Medicine, St Louis, Missouri
| | - Timothy Boone
- Regenerative Medicine Program, Houston Methodist Research Institute, and Department of Urology, Houston Methodist Hospital, Houston, Texas
| | - Yingchun Zhang
- Department of Biomedical Engineering, University of Houston, Houston, Texas.,Guangdong Provincial Work-injury Rehabilitation Hospital, Guangzhou, China.,Regenerative Medicine Program, Houston Methodist Research Institute, and Department of Urology, Houston Methodist Hospital, Houston, Texas
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8
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Reproducibility, and sensitivity to motor unit loss in amyotrophic lateral sclerosis, of a novel MUNE method: MScanFit MUNE. Clin Neurophysiol 2017; 128:1380-1388. [DOI: 10.1016/j.clinph.2017.03.045] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/20/2017] [Accepted: 03/27/2017] [Indexed: 11/18/2022]
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9
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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]
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10
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Gooch CL, Doherty TJ, Chan KM, Bromberg MB, Lewis RA, Stashuk DW, Berger MJ, Andary MT, Daube JR. Motor unit number estimation: A technology and literature review. Muscle Nerve 2014; 50:884-93. [PMID: 25186553 DOI: 10.1002/mus.24442] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Clifton L. Gooch
- Department of Neurology; University of South Florida; Tampa Florida USA
| | - Timothy J. Doherty
- Department of Physical Medicine and Rehabilitation; University of Western Ontario; London Ontario Canada
- Department of Clinical Neurological Sciences; University of Western Ontario; London Ontario Canada
- Schulich School of Medicine and Dentistry; University of Western Ontario; London Ontario Canada
| | - K. Ming Chan
- Division of Physical Medicine and Rehabilitation/Centre for Neuroscience; University of Alberta; Edmonton Alberta Canada
| | - Mark B. Bromberg
- Department of Neurology; University of Utah; Salt Lake City Utah USA
| | - Richard A. Lewis
- Department of Neurology; Cedars-Sinai; Los Angeles California USA
| | - Dan W. Stashuk
- Systems Design Engineering; University of Waterloo; Waterloo Ontario Canada
| | - Michael J. Berger
- School of Kinesiology; University of Western Ontario; London Ontario Canada
- Schulich School of Medicine and Dentistry; University of Western Ontario; London Ontario Canada
| | - Michael T. Andary
- College of Osteopathic Medicine; Michigan State University; East Lansing Michigan USA
| | - Jasper R. Daube
- Department of Neurology; Mayo Clinic; Rochester Minnesota USA
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Simon NG, Lomen-Hoerth C, Kiernan MC. Patterns of clinical and electrodiagnostic abnormalities in early amyotrophic lateral sclerosis. Muscle Nerve 2014; 50:894-9. [DOI: 10.1002/mus.24244] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Neil G. Simon
- Department of Neurology; University of California at San Francisco; San Francisco California USA
- Prince of Wales Clinical School and Neuroscience Research Australia, University of New South Wales; Sydney New South Wales Australia
| | - Catherine Lomen-Hoerth
- Department of Neurology; University of California at San Francisco; San Francisco California USA
| | - Matthew C. Kiernan
- Brain and Mind Research Institute, University of Sydney; 100 Mallett Street Camperdown New South Wales 2050 Australia
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12
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Drovandi CC, Pettitt AN, Henderson RD, McCombe PA. Marginal reversible jump Markov chain Monte Carlo with application to motor unit number estimation. Comput Stat Data Anal 2014. [DOI: 10.1016/j.csda.2013.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Joyce NC, Carter GT. Electrodiagnosis in persons with amyotrophic lateral sclerosis. PM R 2013; 5:S89-95. [PMID: 23523708 DOI: 10.1016/j.pmrj.2013.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 03/15/2013] [Indexed: 12/12/2022]
Abstract
Electrophysiology remains an important tool in the evaluation of patients presenting with signs and symptoms of motor neuron disease. The electrodiagnostic study should include peripheral nerve conduction studies and needle electromyography to both exclude treatable disease and gather evidence regarding a diagnosis of amyotrophic lateral sclerosis (ALS). The recent changes in the revised El Escorial criteria, recommended by the Awaji-shima consensus group, have increased the diagnostic significance of fasciculation potentials to equal that of fibrillation and positive sharp-wave potentials in the needle electromyography examination of patients suspected of having ALS. In addition, electrophysiologic evidence is now considered equivalent to clinical signs and symptoms in reaching a diagnostic certainty of ALS. These changes, strategies for the design, and implementation of an effective electrodiagnostic evaluation, in addition to electrophysiologic techniques and their relationship to the evaluation of a patient with ALS, are reviewed and discussed.
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Affiliation(s)
- Nanette C Joyce
- Department of Physical Medicine and Rehabilitation, University of California, Davis School of Medicine, 4860 Y St, Suite 3850, Sacramento, CA 95817, USA.
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14
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Bromberg MB. MUNIX and MUNE in ALS. Clin Neurophysiol 2013; 124:433-4. [DOI: 10.1016/j.clinph.2012.08.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 08/31/2012] [Accepted: 08/31/2012] [Indexed: 12/14/2022]
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15
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Crone C, Krarup C. Neurophysiological approach to disorders of peripheral nerve. HANDBOOK OF CLINICAL NEUROLOGY 2013; 115:81-114. [PMID: 23931776 DOI: 10.1016/b978-0-444-52902-2.00006-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological methods including nerve conduction studies and electromyography used in the study of patients suspected of having a neuropathy and the significance of the findings are discussed in detail and more novel and experimental methods are mentioned. Diagnostic considerations are based on a flow chart classifying neuropathies into eight categories based on mode of onset, distribution, and electrophysiological findings, and the electrophysiological characteristics in each type of neuropathy are discussed.
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Affiliation(s)
- Clarissa Crone
- Department of Clinical Neurophysiology, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
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dl-3-n-butylphthalide extends survival by attenuating glial activation in a mouse model of amyotrophic lateral sclerosis. Neuropharmacology 2012; 62:1004-10. [DOI: 10.1016/j.neuropharm.2011.10.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 10/13/2011] [Accepted: 10/14/2011] [Indexed: 12/12/2022]
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17
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Tiziano FD, Neri G, Brahe C. Biomarkers in rare disorders: the experience with spinal muscular atrophy. Int J Mol Sci 2010; 12:24-38. [PMID: 21339974 PMCID: PMC3039940 DOI: 10.3390/ijms12010024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/06/2010] [Accepted: 12/16/2010] [Indexed: 12/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by homozygous mutations of the SMN1 gene. Based on clinical severity, three forms of SMA are recognized (type I–III). All patients have at least one (usually 2–4) copies of a highly homologous gene (SMN2) which produces insufficient levels of functional SMN protein, due to alternative splicing of exon7. Recently, evidence has been provided that SMN2 expression can be enhanced by different strategies. The availability of potential candidates to treat SMA has raised a number of issues, including the availability of data on the natural history of the disease, the reliability and sensitivity of outcome measures, the duration of the studies, and the number and clinical homogeneity of participating patients. Equally critical is the availability of reliable biomarkers. So far, different tools have been proposed as biomarkers in SMA, classifiable into two groups: instrumental (the Compound Motor Action Potential, the Motor Unit Number Estimation, and the Dual-energy X-ray absorptiometry) and molecular (SMN gene products dosage, either transcripts or protein). However, none of the biomarkers available so far can be considered the gold standard. Preclinical studies on SMA animal models and double-blind, placebo-controlled studies are crucial to evaluate the appropriateness of biomarkers, on the basis of correlations with clinical outcome.
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Affiliation(s)
- Francesco D Tiziano
- Institute of Medical Genetics, Catholic University of Sacro Cuore, Roma, Italy; E-Mails: (G.N.); (C.B.)
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Blok J, van Dijk J, Drenthen J, Maathuis E, Stegeman D. Size does matter: The influence of motor unit potential size on statistical motor unit number estimates in healthy subjects. Clin Neurophysiol 2010; 121:1772-80. [DOI: 10.1016/j.clinph.2010.03.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 02/17/2010] [Accepted: 03/27/2010] [Indexed: 12/12/2022]
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Ahn SW, Kim SH, Oh DH, Kim SM, Park KS, Hong YH, Kwon OS, Sung JJ, Lee KW. Motor unit number estimation in evaluating disease progression in patients with amyotrophic lateral sclerosis. J Korean Med Sci 2010; 25:1359-63. [PMID: 20808681 PMCID: PMC2923797 DOI: 10.3346/jkms.2010.25.9.1359] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Accepted: 03/16/2010] [Indexed: 11/20/2022] Open
Abstract
We investigated the availability of motor unit number estimation (MUNE) as a quantitative method to assess the severity and clinical progression of amyotrophic lateral sclerosis (ALS). The 143 ALS patients were evaluated by statistical MUNE and the revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). By using mean values of MUNE according to disease duration, regression equation between mean MUNE and disease duration was presented as a formula. The individual MUNE ratio was calculated by dividing individual MUNE value by mean MUNE value. All patients were classified into 2 groups (MUNE ratio <1 vs. MUNE ratio >or=1) according to the MUNE ratio. Comparison between the 2 groups revealed that the patients in MUNE ratio <1 group or MUNE ratio >or=1 group were respectively assigned to rapid progression or slow progression. We recommended informative mean values of MUNE and best regression equation in ALS patients according to disease duration. These values allow us to evaluate the severity and rapidity of progression in ALS.
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Affiliation(s)
- Suk-Won Ahn
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
| | - Su-Hyun Kim
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Dong-Hoon Oh
- Department of Neurology, Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Sung-Min Kim
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Kyung Seok Park
- Department of Neurology, Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Yoon-Ho Hong
- Department of Neurology, Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
| | - Oh-Sang Kwon
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jung-Joon Sung
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Kwang-Woo Lee
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
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Lehky TJ, Chen CJ, di Prospero NA, Rhodes LE, Fischbeck K, Floeter MK. Standard and modified statistical MUNE evaluations in spinal-bulbar muscular atrophy. Muscle Nerve 2009; 40:809-14. [PMID: 19670325 DOI: 10.1002/mus.21399] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Motor unit number estimation (MUNE), a technique used in amyotrophic lateral sclerosis (ALS) clinical trials to quantitatively assess motor neuron loss, should also be valuable in assessing progression in spinal bulbar muscular atrophy (SBMA), an x-linked neuronopathy. In ALS, instability of single motor units (SMUP) prompted Shefner et al.6(6) to modify the statistical MUNE method to exclude SMUPs < or = 40 microV. It is unknown if there is similar SMUP instability in the more chronic degenerative disease of SBMA. In this study the standard parameter of excluding SMUP < 10 microV was compared with the exclusion of SMUP < 40 microV in the calculation of the statistical MUNE. The mean statistical MUNE, using the standard method and the Shefner et al. method, was 60 +/- 21 to 47 +/- 23, respectively. Similar to ALS, SBMA showed an increased proportion (17%) of individual SMUPs < or = 40 microV compared to normal controls. In conclusion, excluding SMUPs < or = 40 microV from the statistical MUNE calculations is appropriate for SBMA subjects because their SMUP, characteristics are similar to ALS. Exclusion of the low-amplitude SMUPs reduces the calculated MUNE.
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Affiliation(s)
- Tanya J Lehky
- EMG Section, NINDS, NIH, Building 10/Room 7-5680, 10 Center Drive, Bethesda, Maryland 20892-1404, USA.
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21
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Zalewska E. Insight into the motor unit activation and structure properties gained from EMG signal analysis. Clin Neurophysiol 2009; 120:449-50. [PMID: 19243991 DOI: 10.1016/j.clinph.2008.12.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2008] [Accepted: 12/23/2008] [Indexed: 11/28/2022]
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22
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Shefner JM. Statistical motor unit number estimation and ALS trials: the effect of motor unit instability. MOTOR UNIT NUMBER ESTIMATION (MUNE) AND QUANTITATIVE EMG - SELECTED PRESENTATIONS FROM THE SECOND INTERNATIONAL SYMPOSIUM ON MUNE AND QEMG, SNOWBIRD, UTAH, USA, 18–20 AUGUST 2006 2009; 60:135-41. [DOI: 10.1016/s1567-424x(08)00013-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Affiliation(s)
- Martin R Turner
- Department of Clinical Neurology, University of Oxford, Oxford, UK.
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24
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Bromberg MB, Brownell AA. Motor unit number estimation in the assessment of performance and function in motor neuron disease. Phys Med Rehabil Clin N Am 2008; 19:509-32, ix. [PMID: 18625413 DOI: 10.1016/j.pmr.2008.02.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Motor unit number estimation (MUNE) is a unique electrophysiologic test used to estimate the number of surviving motor units in a muscle or group of muscles. It is used most frequently to monitor lower motor neuron loss in amyotrophic lateral sclerosis and spinal muscle atrophy. Of particular interest is its use as an endpoint measure in clinical trials for these diseases. This article describes the principles of MUNE and the factors that need to be considered, and reviews several techniques that have been used in clinical trials and in monitoring progression. It then reviews experience with MUNE in clinical trials for amyotrophic lateral sclerosis and spinal muscle atrophy and discusses how MUNE correlates with measures of function.
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Affiliation(s)
- Mark B Bromberg
- Clinical Neuroscience Center, Department of Neurology, University of Utah Health Sciences Center, 175 North Medical Drive, Salt Lake City, UT 84132, USA.
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25
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Santo Neto H, Marques MJ. Estimation of the number and size of motor units in intrinsic laryngeal muscles using morphometric methods. Clin Anat 2008; 21:301-6. [PMID: 18428996 DOI: 10.1002/ca.20624] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The number and size of motor units in the intrinsic laryngeal muscles were estimated by morphometric methods. Laryngeal muscles with their respective nerve branches were obtained from 64 fresh cadavers (32 older than 60 years, mean age 74 +/- 9 years and 32 younger than 60 years, mean age 51 +/- 8 years). Myelinated nerve fibers and the total number of muscle fibers were counted. Motor unit size was estimated by dividing the total number of muscle fibers by the total number of motor units in each case. The mean number of motor units ranged from 268 +/- 1.3 (interarytenoid muscle) to 431 +/- 1.6 (cricothyroid muscle). Thyroarytenoid and cricothyroid muscle presented the smallest (9.8 +/- 0.2) and largest (20.5 +/- 0.9) motor unit size, respectively, suggesting that thyroarytenoid muscle has a greater capacity to fine-tune its total force compared with the other intrinsic laryngeal muscles. No differences in motor unit number or size were observed between the right and left sides or between younger and older subjects. It is suggested that synaptic rearrangements may occur at the level of the neuromuscular junction in the human larynx that may explain the age-related changes in motor units reported by clinical methods.
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Affiliation(s)
- Humberto Santo Neto
- Department of Anatomy, Institute of Biology, State University of Campinas (UNICAMP), Campinas, Brazil.
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26
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Xiong GX, Zhang JW, Hong Y, Guan Y, Guan H. Motor unit number estimation of the tibialis anterior muscle in spinal cord injury. Spinal Cord 2008; 46:696-702. [DOI: 10.1038/sc.2008.7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Daube JR. Motor unit number estimates: A Holy Grail? Clin Neurophysiol 2007; 118:2542-3. [PMID: 17910936 DOI: 10.1016/j.clinph.2007.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 08/11/2007] [Accepted: 08/18/2007] [Indexed: 11/18/2022]
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Hong YH, Sung JJ, Park KS, Kwon O, Min JH, Lee KW. Statistical MUNE: a comparison of two methods of setting recording windows in healthy subjects and ALS patients. Clin Neurophysiol 2007; 118:2605-11. [PMID: 17911043 DOI: 10.1016/j.clinph.2007.05.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 04/18/2007] [Accepted: 05/06/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To address the issue as to how best to perform statistical MUNE, we applied two different approaches and compared results in healthy subjects and ALS patients. METHODS Twelve normal subjects (women 8, mean age 52years) and 11 ALS patients (women 4, mean age 54years) underwent two consecutive MUNE studies, which differed in terms of setting and modifying the recording window. These are referred to as the 'expansion' and 'narrowing' methods, respectively. Size-weighted average (Av) SMUP and MUNE values were obtained using the two methods, and compared in control and patient groups. RESULTS Expansion method-derived Av SMUP sizes and MUNE values differed only slightly from those obtained using the narrowing method in healthy subjects, whereas the narrowing method resulted in significantly larger Av SMUP sizes and smaller MUNE values than the expansion method in ALS patients (Wilcoxon signed ranks test, p=0.003). The sizes of tested areas (mean+/-SD) were significantly larger for the narrowing method than the expansion method in both subject groups with much greater difference in ALS patients; 9.6+/-3.1% vs. 7.9+/-1.7% in healthy subjects and 16.1+/-5.1% vs. 11.2+/-3.0% in ALS patients (Student t-test, p<0.01). CONCLUSIONS The present study shows, unlike that found in normal subjects, that the results of statistical MUNE in ALS patients are heavily dependent on the approach used to set and modify recording windows. SIGNIFICANCE The expansion method using a 10%-sized window is likely to suffer from systemic errors due to the ceiling effect and the sampling of artifactually small motor units in ALS patients. The authors recommend that the narrowing method be considered as an alternative that avoids these problems.
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Affiliation(s)
- Yoon-Ho Hong
- Department of Neurology, Seoul National University College of Medicine, Boramae Hospital, Seoul, Republic of Korea
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29
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Shefner JM, Cudkowicz ME, Zhang H, Schoenfeld D, Jillapalli D. Revised statistical motor unit number estimation in the Celecoxib/ALS trial. Muscle Nerve 2007; 35:228-34. [PMID: 17058270 DOI: 10.1002/mus.20671] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Techniques to estimate motor unit number (MUNE) measure the number of functioning motor units in a muscle. As amyotrophic lateral sclerosis (ALS) is characterized by progressive motor unit loss, this disease offers an ideal setting for the use of MUNE. Statistical MUNE was employed in a recent multicenter trial of creatine in ALS, and was shown to be reliable, reproducible, and to decline with disease progression. However, motor unit amplitude stayed constant over 7 months, a finding believed to reflect an artifact of the method. The statistical method was revised to reflect more accurately the presence of larger motor units and employed in a 12-month study of Celecoxib in ALS. MUNE declined by 49% in 12 months; however, motor unit amplitude again stayed constant over the same period. Statistical MUNE estimates motor unit number based on the variability of response to a repeated stimulus of constant strength, with an underlying assumption that this variability is due solely to the number of motor units responding in an intermittent manner. Based on studies showing that single motor units in ALS display excessive amplitude variability when stimulated repeatedly, we show that response variability in ALS patients is in large part due to single unit changes. Thus, we conclude that the statistical method is not an appropriate measure of motor unit number in any disease associated with motor unit instability.
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Affiliation(s)
- J M Shefner
- Department of Neurology, SUNY Upstate Medical University, Syracuse, New York 13210, USA.
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30
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Hennings K, Kamavuako EN, Farina D. The recruitment order of electrically activated motor neurons investigated with a novel collision technique. Clin Neurophysiol 2006; 118:283-91. [PMID: 17174598 DOI: 10.1016/j.clinph.2006.10.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 09/12/2006] [Accepted: 10/25/2006] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The development of a novel collision technique for assessment of the activation order of electrically activated nerve fibers, which is an important question in functional electrical therapy or for interpretation of results of motor unit number estimates. METHODS Compound muscle action potentials were recorded with the belly-tendon configuration from the abductor digiti minimi. A novel modified Hopf's collision technique was applied on ten healthy male subjects to determine the distributions of conduction velocities (DCV) of all ulnar nerve fibers and of the fibers activated by electrical stimuli eliciting 20%, 50%, and 80% of the maximal muscle response. RESULTS The maximum nerve conduction velocity was (means+/-SE) 64.1+/-0.85m/s. The median conduction velocity of estimated DCV was 58.9+/-0.97m/s (stimulus at 20%), 58.0+/-0.98m/s (50%), 57.2+/-0.91m/s (80%), and 56.5+/-0.84m/s (whole nerve) (all different between each other, P<0.001). CONCLUSIONS The proposed collision technique allows the assessment of nerve conduction velocity distributions at maximal and sub-maximal stimulation levels and provided evidence for an inverse activation order of nerve fibers with electrical stimulation. SIGNIFICANCE The excessive fatigue seen with nerve electrical stimulation can be explained by a preferential activation of large diameter nerve fibers. The motor units first activated with electrical stimulation are likely not representative of the motor unit pool in the muscle, which poses limitations in the reliability of some of the proposed methods for motor unit counting.
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Affiliation(s)
- Kristian Hennings
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7 D-2, DK-9220 Aalborg, Denmark
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Shefner JM, Cudkowicz M, Brown RH. Motor unit number estimation predicts disease onset and survival in a transgenic mouse model of amyotrophic lateral sclerosis. Muscle Nerve 2006; 34:603-7. [PMID: 16892429 DOI: 10.1002/mus.20628] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Motor unit number estimation (MUNE) has proved useful in predicting rate of progression and survival in patients with amyotrophic lateral sclerosis (ALS). In animal models, it has demonstrated physiological effects of experimental medications that were not evident behaviorally. We sought to determine more specifically what aspects of function and survival that MUNE could predict in the G93A transgenic mouse model of ALS. Transgenic mice were examined in two distinct treatment studies, neither of which showed an effect of drug on survival, behavioral measures, or MUNE. MUNE was performed using a modification of the incremental stimulation method by stimulating the sciatic nerve at the sciatic notch, and recording with a circumferential surface electrode around the ipsilateral distal hindlimb. Both limbs were studied and the results averaged. MUNE was performed longitudinally on all animals from near onset to premorbid state. Each study was evaluated separately. For both studies, MUNE at initial study correlated significantly with behavioral determination of disease onset, and MUNE slope from initial to final study correlated significantly with disease duration, as measured from onset to time of death. However, the final MUNE value did not correlate with survival. Thus, in two studies involving animals with quite different disease courses, initial MUNE effectively predicted symptom onset and MUNE slope predicted survival. This suggests that MUNE has potential efficacy as a useful functional outcome measure in both animal and human studies of ALS.
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Affiliation(s)
- Jeremy M Shefner
- Department of Neurology, Upstate Medical University, Syracuse, New York 13210, USA.
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Chapter 2 Physiology and function. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1567-4231(09)70063-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Winhammar JMC, Rowe DB, Henderson RD, Kiernan MC. Assessment of disease progression in motor neuron disease. Lancet Neurol 2005; 4:229-38. [PMID: 15778102 DOI: 10.1016/s1474-4422(05)70042-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Motor neuron disease (MND) is characterised by progressive deterioration of the corticospinal tract, brainstem, and anterior horn cells of the spinal cord. There is no pathognomonic test for the diagnosis of MND, and physicians rely on clinical criteria-upper and lower motor neuron signs-for diagnosis. The presentations, clinical phenotypes, and outcomes of MND are diverse and have not been combined into a marker of disease progression. No single algorithm combines the findings of functional assessments and rating scales, such as those that assess quality of life, with biological markers of disease activity and findings from imaging and neurophysiological assessments. Here, we critically appraise developments in each of these areas and discuss the potential of such measures to be included in the future assessment of disease progression in patients with MND.
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Affiliation(s)
- Jennica M C Winhammar
- Department of Neurology and Multidisciplinary Motor Neurone Disease Clinic, Royal North Shore Hospital, NSW, Australia
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Blok JH, Visser GH, de Graaf S, Zwarts MJ, Stegeman DF. Statistical motor unit number estimation assuming a binomial distribution. Muscle Nerve 2005; 31:182-91. [PMID: 15736298 DOI: 10.1002/mus.20256] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The statistical method of motor unit number estimation (MUNE) uses the natural stochastic variation in a muscle's compound response to electrical stimulation to obtain an estimate of the number of recruitable motor units. The current method assumes that this variation follows a Poisson distribution. We present an alternative that instead assumes a binomial distribution. Results of computer simulations and of a pilot study on 19 healthy subjects showed that the binomial MUNE values are considerably higher than those of the Poisson method, and in better agreement with the results of other MUNE techniques. In addition, simulation results predict that the performance in patients with severe motor unit loss will be better for the binomial than Poisson method. The adapted method remains closer to physiology, because it can accommodate the increase in activation probability that results from rising stimulus intensity. It does not need recording windows as used with the Poisson method, and is therefore less user-dependent and more objective and quicker in its operation. For these reasons, we believe that the proposed modifications may lead to significant improvements in the statistical MUNE technique.
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Affiliation(s)
- Joleen H Blok
- Department of Clinical Neurophysiology, Erasmus Medical Center, Rotterdam, The Netherlands.
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Boe SG, Stashuk DW, Brown WF, Doherty TJ. Decomposition-based quantitative electromyography: Effect of force on motor unit potentials and motor unit number estimates. Muscle Nerve 2005; 31:365-73. [PMID: 15627267 DOI: 10.1002/mus.20266] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Decomposition-based quantitative electromyography (DQEMG) allows for the collection of motor unit potentials (MUPs) over a broad range of force levels. Given the size principle of motor unit recruitment, it may be necessary to control for force when using DQEMG for the purpose of deriving a motor unit number estimate (MUNE). Therefore, this study was performed to examine the effect of force on the physiological characteristics of concentric needle- and surface-detected MUPs and the subsequent impact on MUNEs obtained from the first dorsal interosseous (FDI) muscle sampled using DQEMG. Maximum M waves were elicited in 10 subjects with supramaximal stimulation of the ulnar nerve at the wrist. Intramuscular and surface-detected EMG signals were collected simultaneously during 30-s voluntary isometric contractions performed at specific percentages of maximal voluntary contraction (MVC). Decomposition algorithms were used to identify needle-detected MUPs and their individual MU firing times. These MU firing times were used as triggers to extract their corresponding surface-detected MUPs (S-MUPs) using spike-triggered averaging. A mean S-MUP was then calculated, the size of which was divided into the maximum M-wave size to derive a MUNE. Increased levels of contraction had a significant effect on needle- and surface-detected MUP size, firing rate, and MUNE. These results suggest that force level is an important factor to consider when performing quantitative EMG, including MUNEs with this method.
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Affiliation(s)
- Shaun G Boe
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada
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Shefner JM, Cudkowicz ME, Zhang H, Schoenfeld D, Jillapalli D. The use of statistical MUNE in a multicenter clinical trial. Muscle Nerve 2004; 30:463-9. [PMID: 15316983 DOI: 10.1002/mus.20120] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Techniques to estimate motor unit number (MUNE) measure the number of functioning motor units in a muscle. In diseases characterized by progressive motor unit loss, such as amyotrophic lateral sclerosis (ALS), MUNE may be useful to monitor disease progression or beneficial response to treatment. As part of a multicenter, placebo-controlled, randomized, double-blind clinical trial testing the efficacy of creatine in patients with ALS, statistical MUNE was measured in 104 patients tested monthly for 6 months. The objective was to determine whether MUNE was a reliable and sensitive outcome measure in the context of a multicenter trial. Formal training and reliability testing was required for all MUNE evaluators. Testing of normal controls showed a high degree of test-retest reliability. All patient data were combined as the experimental treatment showed no efficacy. There was a 23% decline in MUNE over 6 months. The technique as employed in this trial overemphasized the presence of small motor units; this problem was partially addressed by poststudy data monitoring and censuring. Thus, MUNE can be used reliably as an outcome measure in multicenter clinical trials; specific remedies are suggested for the difficulties encountered in this study.
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Affiliation(s)
- J M Shefner
- Department of Neurology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, New York 13210, USA.
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Albrecht E, Kuntzer T. Number of Edb motor units estimated using an adapted multiple point stimulation method: normal values and longitudinal studies in ALS and peripheral neuropathies. Clin Neurophysiol 2004; 115:557-63. [PMID: 15036050 DOI: 10.1016/j.clinph.2003.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2003] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To validate the adapted multiple point stimulation (AMPS) method to estimate the number of motor units (MUNE) from the extensor digitorum brevis (Edb) muscle. METHODS Twenty controls (10 young and 10 old) were examined on both sides and 10 patients with amyotrophic lateral sclerosis (ALS) and 5 with acute peripheral neuropathy (PN) were examined longitudinally on one side during a series of repeated electrophysiological sessions. RESULTS In the controls, the median MUNE and size of the motor unit action potentials (S-MUAPs) were found to be age-related (411 and 70 microVms in the young group; 164 and 142 microVms in the old group; P < 0.01), with a coefficient of variation of MUNE values of 27% and 20%, respectively. In the ALS group, the median MUNE value at diagnosis was 31 (P < 0.05 vs. controls), and during a mean follow-up period of 11.5 months a continuous decrease in the MUNE value was seen, together with an initial increase, followed by a later decrease in 4 cases, in S-MUAP size. In the PN group, the MUNE value was initially similar to that in controls, but then decreased, accompanied by an increase in S-MUAP size, and then showed a progressive increase, together with a decrease in S-MUAP size. CONCLUSIONS AMPS, a MUNE method developed in the upper extremity, also appears to be a useful procedure for quantifying changes in the MUNE value in the Edb muscle without specific software in order to study age-related changes or changes in patients with ALS or PN.
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Affiliation(s)
- Eric Albrecht
- Service de Neurologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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Boe SG, Stashuk DW, Doherty TJ. Motor unit number estimation by decomposition-enhanced spike-triggered averaging: Control data, test-retest reliability, and contractile level effects. Muscle Nerve 2004; 29:693-9. [PMID: 15116373 DOI: 10.1002/mus.20031] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Decomposition-enhanced spike-triggered averaging (DE-STA) has been developed as a method for obtaining a motor unit number estimate (MUNE). We describe the method and report control data for the first dorsal interosseous/adductor pollicis and thenar muscles and reliability in the thenar muscles. Seventeen subjects (ages 20-50 years) took part in the study. The maximum M potential was elicited with supramaximal stimulation of the ulnar or median nerve at the wrist. Surface and intramuscularly detected electromyographic signals were then collected simultaneously during mild to moderate contractions. Decomposition algorithms were used to detect and sort the individual motor unit potential (MUP) occurrences of several concurrently active motor units in the needle-detected signals. The MUP occurrences were used as triggering sources to estimate their corresponding surface-detected MUPs (S-MUPs) using STA. The mean S-MUP size was calculated and divided into the maximum M-potential size to derive a MUNE. The MUNE values were consistent with those previously reported with other methods, and thenar MUNEs for the two trials were similar (249 +/- 78 and 246 +/- 90), with high test-retest reliability (r = 0.94, P < 0.05). DE-STA thus appears to be a valid and reliable method to obtain MUNEs.
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Affiliation(s)
- Shaun G Boe
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada
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Bromberg MB. Motor unit number estimation: new techniques and new uses. SUPPLEMENTS TO CLINICAL NEUROPHYSIOLOGY 2004; 57:120-36. [PMID: 16106613 DOI: 10.1016/s1567-424x(09)70350-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
MUNE is a unique neurophysiologic tool because it can quantitatively estimate the number of motor neurons innervating a muscle or group of muscles. All other neurophysiologic techniques are influenced by collateral reinnervation and provide only a qualitative estimate of motor unit loss. Further, the S-MUPs obtained with MUNE provide quantitative information about the whole motor unit. Other routine neurophysiologic techniques provide information restricted to a portion of the motor unit. These unique features of MUNE have been applied to neurogenic disorders to yield a better understanding of disease processes. Various modifications are being developed that will provide more data and ease of use. It is anticipated that the availability of MUNE on EMG machines will grow and it use will expand from a research tool to a routine neurophysiologic test.
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Affiliation(s)
- Mark B Bromberg
- Department of Neurology, University of Utah School of Medicine, Room 3R152, 50 North Medical Drive, Salt Lake City, UT 84109, USA.
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