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McMackin R, Bede P, Ingre C, Malaspina A, Hardiman O. Biomarkers in amyotrophic lateral sclerosis: current status and future prospects. Nat Rev Neurol 2023; 19:754-768. [PMID: 37949994 DOI: 10.1038/s41582-023-00891-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2023] [Indexed: 11/12/2023]
Abstract
Disease heterogeneity in amyotrophic lateral sclerosis poses a substantial challenge in drug development. Categorization based on clinical features alone can help us predict the disease course and survival, but quantitative measures are also needed that can enhance the sensitivity of the clinical categorization. In this Review, we describe the emerging landscape of diagnostic, categorical and pharmacodynamic biomarkers in amyotrophic lateral sclerosis and their place in the rapidly evolving landscape of new therapeutics. Fluid-based markers from cerebrospinal fluid, blood and urine are emerging as useful diagnostic, pharmacodynamic and predictive biomarkers. Combinations of imaging measures have the potential to provide important diagnostic and prognostic information, and neurophysiological methods, including various electromyography-based measures and quantitative EEG-magnetoencephalography-evoked responses and corticomuscular coherence, are generating useful diagnostic, categorical and prognostic markers. Although none of these biomarker technologies has been fully incorporated into clinical practice or clinical trials as a primary outcome measure, strong evidence is accumulating to support their clinical utility.
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Affiliation(s)
- Roisin McMackin
- Discipline of Physiology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Peter Bede
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- Computational Neuroimaging Group, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- Department of Neurology, St James's Hospital, Dublin, Ireland
| | - Caroline Ingre
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden
| | - Andrea Malaspina
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Orla Hardiman
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland.
- Department of Neurology, Beaumont Hospital, Dublin, Ireland.
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2
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Xu Q, Xue S, Gao F, Wu Q, Zhang Q. Evaluation method of motor unit number index based on optimal muscle strength combination. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2023; 20:3854-3872. [PMID: 36899608 DOI: 10.3934/mbe.2023181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Repeatability is an important attribute of motor unit number index (MUNIX) technology. This paper proposes an optimal contraction force combination for MUNIX calculation in an effort to improve the repeatability of this technology. In this study, the surface electromyography (EMG) signals of the biceps brachii muscle of eight healthy subjects were initially recorded with high-density surface electrodes, and the contraction strength was the maximum voluntary contraction force of nine progressive levels. Then, by traversing and comparing the repeatability of MUNIX under various combinations of contraction force, the optimal combination of muscle strength is determined. Finally, calculate MUNIX using the high-density optimal muscle strength weighted average method. The correlation coefficient and the coefficient of variation are utilized to assess repeatability. The results show that when the muscle strength combination is 10, 20, 50 and 70% of the maximum voluntary contraction force, the repeatability of MUNIX is greatest, and the correlation between MUNIX calculated using this combination of muscle strength and conventional methods is high (PCC > 0.99), the repeatability of the MUNIX method improved by 11.5-23.8%. The results indicate that the repeatability of MUNIX differs for various combinations of muscle strength and that MUNIX, which is measured with a smaller number and lower-level contractility, has greater repeatability.
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Affiliation(s)
- Qun Xu
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Suqi Xue
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Farong Gao
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Qiuxuan Wu
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Qizhong Zhang
- School of Artificial Intelligence, Hangzhou Dianzi University, Hangzhou 310018, China
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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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Fathi D, Nafissi S, Attarian S, Neuwirth C, Fatehi F. An overview of motor unit number index reproducibility in amyotrophic lateral sclerosis. IRANIAN JOURNAL OF NEUROLOGY 2019; 18:119-126. [PMID: 31749933 PMCID: PMC6858602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Motor unit number index (MUNIX) is an electrophysiological technique to give an estimate of functioning motor neurons in a muscle. For any given neurophysiological technique for the use in clinical or research studies, reproducibility between different operators and in a single operator in different times is one of the most important qualities, which must be evaluated and approved by different examiners and centers. After its introduction, testing the reproducibility of MUNIX was the aim of many studies to show this quality of the technique. In this review, we aimed to summarize all the studies, which have been performed up to now to approve MUNIX reproducibility in amyotrophic lateral sclerosis comparing healthy individuals.
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Affiliation(s)
- Davood Fathi
- Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran,Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahriar Nafissi
- Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahram Attarian
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, Marseille, France
| | - Christoph Neuwirth
- Neuromuscular Disease Unit/ALS Clinic, Kantonspital St. Gallen, St. Gallen, Switzerland
| | - Farzad Fatehi
- Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran,Iranian Center of Neurological Research, Tehran University of Medical Sciences, Tehran, Iran
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5
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Wier CG, Crum AE, Reynolds AB, Iyer CC, Chugh D, Palettas MS, Heilman PL, Kline DM, Arnold WD, Kolb SJ. Muscle contractility dysfunction precedes loss of motor unit connectivity in SOD1(G93A) mice. Muscle Nerve 2018; 59:254-262. [PMID: 30370671 DOI: 10.1002/mus.26365] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/17/2018] [Accepted: 10/22/2018] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Electrophysiological measurements are used in longitudinal clinical studies to provide insight into the progression of amyotrophic lateral sclerosis (ALS) and the relationship between muscle weakness and motor unit (MU) degeneration. Here, we used a similar longitudinal approach in the Cu/Zn superoxide dismutase (SOD1[G93A]) mouse model of ALS. METHODS In vivo muscle contractility and MU connectivity assays were assessed longitudinally in SOD1(G93A) and wild type mice from postnatal days 35 to 119. RESULTS In SOD1(G93A) males, muscle contractility was reduced by day 35 and preceded MU loss. Muscle contractility and motor unit reduction were delayed in SOD1(G93A) females compared with males, but, just as with males, muscle contractility reduction preceded MU loss. DISCUSSION The longitudinal contractility and connectivity paradigm employed here provides additional insight into the SOD1(G93A) mouse model and suggests that loss of muscle contractility is an early finding that may precede loss of MUs and motor neuron death. Muscle Nerve 59:254-262, 2019.
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Affiliation(s)
- Christopher G Wier
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Alexander E Crum
- Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, 395 West 12th Avenue, Columbus, Ohio, 43210, USA
| | - Anthony B Reynolds
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Chitra C Iyer
- Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, 395 West 12th Avenue, Columbus, Ohio, 43210, USA
| | - Deepti Chugh
- Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, 395 West 12th Avenue, Columbus, Ohio, 43210, USA
| | - Marilly S Palettas
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio, USA
| | - Patrick L Heilman
- Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, 395 West 12th Avenue, Columbus, Ohio, 43210, USA
| | - David M Kline
- Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio, USA
| | - W David Arnold
- Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, 395 West 12th Avenue, Columbus, Ohio, 43210, USA.,Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Stephen J Kolb
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, 395 West 12th Avenue, Columbus, Ohio, 43210, USA
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Fatehi F, Grapperon AM, Fathi D, Delmont E, Attarian S. The utility of motor unit number index: A systematic review. Neurophysiol Clin 2018; 48:251-259. [PMID: 30287192 DOI: 10.1016/j.neucli.2018.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 09/04/2018] [Accepted: 09/11/2018] [Indexed: 12/11/2022] Open
Abstract
The need for a valid biomarker for assessing disease progression and for use in clinical trials on amyotrophic lateral sclerosis (ALS) has stimulated the study of methods that could measure the number of motor units. Motor unit number index (MUNIX) is a newly developed neurophysiological technique that was demonstrated to have a good correlation with the number of motor units in a given muscle, even though it does not necessarily accurately express the actual number of viable motor neurons. Several studies demonstrated the technique is reproducible and capable of following motor neuron loss in patients with ALS and peripheral polyneuropathies. The main goal of this review was to conduct an extensive review of the literature using MUNIX. We conducted a systematic search in English medical literature published in two databases (PubMed and SCOPUS). In this review, we aimed to answer the following queries: Comparison of MUNIX with other MUNE techniques; the reproducibility of MUNIX; the utility of MUNIX in ALS and preclinical muscles, peripheral neuropathies, and other neurological disorders.
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Affiliation(s)
- Farzad Fatehi
- Reference Center for Neuromuscular Diseases and ALS, Timone University Hospital, 13385 Marseille, France; Department of Neurology, Iranian Center of Neurological Research, Neuroscience Institute, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Aude-Marie Grapperon
- Reference Center for Neuromuscular Diseases and ALS, Timone University Hospital, 13385 Marseille, France
| | - Davood Fathi
- Department of Neurology, Iranian Center of Neurological Research, Neuroscience Institute, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran; Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Emilien Delmont
- Reference Center for Neuromuscular Diseases and ALS, Timone University Hospital, 13385 Marseille, France
| | - Shahram Attarian
- Reference Center for Neuromuscular Diseases and ALS, Timone University Hospital, 13385 Marseille, France; Inserm, GMGF, Aix-Marseille University, Marseille, 13385 France.
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7
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Peng Y, Zhang Y. Improving the repeatability of Motor Unit Number Index (MUNIX) by introducing additional epochs at low contraction levels. Clin Neurophysiol 2017; 128:1158-1165. [PMID: 28511128 DOI: 10.1016/j.clinph.2017.03.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/25/2017] [Accepted: 03/27/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To evaluate the repeatability of (Motor Unit Number Index) MUNIX under repeatability conditions, specify the origin of variations and provide strategies for quality control. METHODS MUNIX calculations were performed on the bicep brachii muscles of eight healthy subjects. Negative effect of suboptimal electrode positions on MUNIX accuracy was eliminated by employing the high-density surface electromyography technique. MUNIX procedures that utilized a variety of surface interferential pattern (SIP) epoch recruitment strategies (including the original MUNIX procedure, two proposed improvement strategies and their combinations) were described. For each MUNIX procedure, ten thousands of different SIP pools were constructed by randomly recruiting necessary SIP epochs from a large SIP epoch pool (3 datasets, 9 independent electromyography recordings at different contraction levels per dataset and 10 SIP epochs per recording) and implemented for MUNIX calculation. The repeatability of each MUNIX procedure was assessed by summarizing the resulting MUNIX distribution and compared to investigate the effect of SIP epoch selection strategy on repeatability performance. RESULTS SIP epochs selected at lower contraction levels have a stronger influence on the repeatability of MUNIX than those selected at higher contraction levels. MUNIX under repeatability conditions follows a normal distribution and the standard deviation can be significantly reduced by introducing more epochs near the MUNIX definition line. CONCLUSIONS The MUNIX technique shows an inherent variation attributable to SIP epochs at low contraction levels. It is recommended that more epochs should be sampled at these low contraction levels to improve the repeatability. SIGNIFICANCE The present study thoroughly documented the inherent variation of MUNIX and the causes, and offered practical solutions to improve the repeatability of MUNIX.
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Affiliation(s)
- Yun Peng
- Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, TX 77204, USA
| | - Yingchun Zhang
- Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, TX 77204, USA; Guangdong Provincial Work Injury Rehabilitation Center, Guangzhou, Guangdong 510000, China.
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8
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Swash M. MUNIX in the clinic in ALS: MUNE comes of age. Clin Neurophysiol 2017; 128:482-483. [DOI: 10.1016/j.clinph.2016.12.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 12/21/2016] [Indexed: 12/12/2022]
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Zhou P, Li X, Li S, Nandedkar SD. A dilemma in stroke application: Standard or modified motor unit number index? Clin Neurophysiol 2016; 127:2756-2759. [PMID: 27417048 DOI: 10.1016/j.clinph.2016.05.185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 04/25/2016] [Accepted: 05/16/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Ping Zhou
- Guangdong Provincial Work Injury Rehabilitation Center, Guangzhou, China; Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston and TIRR Memorial Hermann Research Center, Houston, TX, USA.
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston and TIRR Memorial Hermann Research Center, Houston, TX, USA
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston and TIRR Memorial Hermann Research Center, Houston, TX, USA
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Mahato NK, Montuelle S, Cotton J, Williams S, Thomas J, Clark B. Development of a morphology-based modeling technique for tracking solid-body displacements: examining the reliability of a potential MRI-only approach for joint kinematics assessment. BMC Med Imaging 2016; 16:38. [PMID: 27189195 PMCID: PMC4870733 DOI: 10.1186/s12880-016-0140-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 05/03/2016] [Indexed: 11/25/2022] Open
Abstract
Background Single or biplanar video radiography and Roentgen stereophotogrammetry (RSA) techniques used for the assessment of in-vivo joint kinematics involves application of ionizing radiation, which is a limitation for clinical research involving human subjects. To overcome this limitation, our long-term goal is to develop a magnetic resonance imaging (MRI)-only, three dimensional (3-D) modeling technique that permits dynamic imaging of joint motion in humans. Here, we present our initial findings, as well as reliability data, for an MRI-only protocol and modeling technique. Methods We developed a morphology-based motion-analysis technique that uses MRI of custom-built solid-body objects to animate and quantify experimental displacements between them. The technique involved four major steps. First, the imaging volume was calibrated using a custom-built grid. Second, 3-D models were segmented from axial scans of two custom-built solid-body cubes. Third, these cubes were positioned at pre-determined relative displacements (translation and rotation) in the magnetic resonance coil and scanned with a T1 and a fast contrast-enhanced pulse sequences. The digital imaging and communications in medicine (DICOM) images were then processed for animation. The fourth step involved importing these processed images into an animation software, where they were displayed as background scenes. In the same step, 3-D models of the cubes were imported into the animation software, where the user manipulated the models to match their outlines in the scene (rotoscoping) and registered the models into an anatomical joint system. Measurements of displacements obtained from two different rotoscoping sessions were tested for reliability using coefficient of variations (CV), intraclass correlation coefficients (ICC), Bland-Altman plots, and Limits of Agreement analyses. Results Between-session reliability was high for both the T1 and the contrast-enhanced sequences. Specifically, the average CVs for translation were 4.31 % and 5.26 % for the two pulse sequences, respectively, while the ICCs were 0.99 for both. For rotation measures, the CVs were 3.19 % and 2.44 % for the two pulse sequences with the ICCs being 0.98 and 0.97, respectively. A novel biplanar imaging approach also yielded high reliability with mean CVs of 2.66 % and 3.39 % for translation in the x- and z-planes, respectively, and ICCs of 0.97 in both planes. Conclusions This work provides basic proof-of-concept for a reliable marker-less non-ionizing-radiation-based quasi-dynamic motion quantification technique that can potentially be developed into a tool for real-time joint kinematics analysis.
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Affiliation(s)
- Niladri K Mahato
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, 45701, USA. .,Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA.
| | - Stephane Montuelle
- Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA
| | - John Cotton
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, 45701, USA.,Department of Mechanical Engineering, Ohio University, Athens, OH, 45701, USA
| | - Susan Williams
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, 45701, USA.,Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA
| | - James Thomas
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, 45701, USA.,School of Rehabilitation and Communication Sciences, Ohio University, Athens, OH, 45701, USA
| | - Brian Clark
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, 45701, USA.,Department of Biomedical Sciences, Ohio University, Athens, OH, 45701, USA.,Department of Geriatric Medicine, Ohio University, Athens, OH, 45701, USA
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11
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Li X, Nandedkar SD, Zhou P. Modified motor unit number index: A simulation study of the first dorsal interosseous muscle. Med Eng Phys 2015; 38:115-20. [PMID: 26639774 DOI: 10.1016/j.medengphy.2015.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 10/23/2015] [Accepted: 11/06/2015] [Indexed: 12/14/2022]
Abstract
The motor unit number index (MUNIX) technique has provided a quick and convenient approach to estimating motor unit population changes in a muscle. Reduction in motor unit action potential (MUAP) amplitude can lead to underestimation of motor unit numbers using the standard MUNIX technique. This study aims to overcome this limitation by developing a modified MUNIX (mMUNIX) technique. The mMUNIX uses a variable that is associated with the area of compound muscle action potential (CMAP) rather than an arbitrary fixed value (20 mV ms) as used in the standard MUNIX to define the output. The performance of the mMUNIX was evaluated using motoneuron pool and surface electromyography (EMG) models. With a fixed motor unit number, the mMUNIX output remained relatively constant with varying degrees of MUAP amplitude changes, while the standard MUNIX substantially underestimated the motor unit number in such cases. However, when MUAP amplitude remained unchanged, the mMUNIX showed less sensitivity than the standard MUNIX in tracking motor unit loss. The current simulation study demonstrated both the advantages and limitations of the standard and modified MUNIX techniques, which can help guide appropriate application and interpretation of MUNIX measurements.
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Affiliation(s)
- Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, 1333B Moursund St., Houston, TX, USA; TIRR Memorial Hermann Research Center, Houston, TX, USA.
| | | | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, 1333B Moursund St., Houston, TX, USA; TIRR Memorial Hermann Research Center, Houston, TX, USA; Guangdong Work Injury Rehabilitation Center, Guangzhou, China
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12
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Swash M, Kiernan MC. Measuring change in amyotrophic lateral sclerosis. J Neurol Neurosurg Psychiatry 2015; 86:1169-70. [PMID: 25999409 DOI: 10.1136/jnnp-2015-311051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/05/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Michael Swash
- Department of Neurology, The Royal London Hospital, London, UK
| | - Matthew C Kiernan
- Brain and Mind Research Institute, The University of Sydney, Sydney, New South Wales, Australia
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13
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Li L, Li X, Liu J, Zhou P. Alterations in multidimensional motor unit number index of hand muscles after incomplete cervical spinal cord injury. Front Hum Neurosci 2015; 9:238. [PMID: 26005410 PMCID: PMC4424856 DOI: 10.3389/fnhum.2015.00238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 04/13/2015] [Indexed: 12/13/2022] Open
Abstract
The objective of this study was to apply a novel multidimensional motor unit number index (MD-MUNIX) technique to examine hand muscles in patients with incomplete cervical spinal cord injury (SCI). The MD-MUNIX was estimated from the compound muscle action potential (CMAP) and different levels of surface interference pattern electromyogram (EMG) at multiple directions of voluntary isometric muscle contraction. The MD-MUNIX was applied in the first dorsal interosseous (FDI), thenar and hypothenar muscles of SCI (n = 12) and healthy control (n = 12) subjects. The results showed that the SCI subjects had significantly smaller CMAP and MD-MUNIX in all the three examined muscles, compared to those derived from the healthy control subjects. The multidimensional motor unit size index (MD-MUSIX) demonstrated significantly larger values for the FDI and hypothenar muscles in SCI subjects than those from healthy control subjects, whereas the MD-MUSIX enlargement was marginally significant for the thenar muscles. The findings from the MD-MUNIX analyses provide an evidence of motor unit loss in hand muscles of cervical SCI patients, contributing to hand function deterioration.
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Affiliation(s)
- Le Li
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-Sen University Guangzhou, China ; Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA
| | - Jie Liu
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago Chicago, IL, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Hermann Research Center Houston, TX, USA ; Biomedical Engineering Program, University of Science and Technology of China Hefei, China
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Marciniak C, Li X, Zhou P. An examination of motor unit number index in adults with cerebral palsy. J Electromyogr Kinesiol 2015; 25:444-50. [PMID: 25840713 DOI: 10.1016/j.jelekin.2015.02.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 01/22/2015] [Accepted: 02/13/2015] [Indexed: 12/14/2022] Open
Abstract
Spinal motor neuron loss may be a factor contributing to weakness in central disorders. The aim of this study was to assess whether motor unit numbers are reduced in the hand musculature of adults with cerebral palsy (CP) using the motor unit number index (MUNIX) technique. In this prospective, case-control study, 10 adults with CP were matched with healthy controls. MUNIX was computed using area and power of voluntary surface hypothenar electromyographic (EMG) signals and the compound muscle action potential (CMAP) recorded with ulnar nerve stimulation. The motor unit size index (MUSIX) was calculated based on maximum CMAP amplitude and MUNIX value. Gross Motor Function Classification Scale (GMFCS) and Manual Abilities Classification Scale (MACS) levels were rated for CP subjects. MUNIX was significantly lower for CP participants (Mean 167.8 vs. 214.4, p=.022). MUNIX values did not correlate with GMFCS or MACS. MUSIX values were higher, though not significantly, for CP subjects (p=.11). MUSIX increased with increasing MACS levels (r(2)=.4017, p=.049). Thus, motor unit numbers in ulnar hand muscles may be decreased with CP. MUSIX values are associated with greater hand impairment. Therefore, peripheral motor unit loss as a component of the weakness found with CP deserves further evaluation.
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Affiliation(s)
- Christina Marciniak
- Department of Physical Medicine and Rehabilitation and the Department of Neurology, Northwestern University Feinberg Medical School and the Rehabilitation Institute of Chicago.
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, and TIRR Memorial Hermann Research Center, Houston, TX 77030, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, and TIRR Memorial Hermann Research Center, Houston, TX 77030, USA; Biomedical Engineering Program, University of Science and Technology of China, Hefei, 230027, China
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