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Zheng C, Zhu Y, Shao M, Zhu D, Hu H, Qiao K, Jiang J. Split-hand phenomenon quantified by the motor unit number index for distinguishing cervical spondylotic amyotrophy from amyotrophic lateral sclerosis. Neurophysiol Clin 2019; 49:391-404. [DOI: 10.1016/j.neucli.2019.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 09/24/2019] [Accepted: 09/24/2019] [Indexed: 12/13/2022] Open
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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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Yao B, Klein CS, Hu H, Li S, Zhou P. Motor Unit Properties of the First Dorsal Interosseous in Chronic Stroke Subjects: Concentric Needle and Single Fiber EMG Analysis. Front Physiol 2018; 9:1587. [PMID: 30559674 PMCID: PMC6287192 DOI: 10.3389/fphys.2018.01587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 10/23/2018] [Indexed: 02/04/2023] Open
Abstract
The purpose of this study was to better understand changes in motor unit electrophysiological properties in people with chronic stroke based on concentric needle electromyography (EMG) and single fiber EMG recordings. The first dorsal interosseous (FDI) muscle was studied bilaterally in eleven hemiparetic stroke subjects. A significant increase in mean fiber density (FD) was found in the paretic muscle compared with the contralateral side based on single fiber EMG (1.6 ± 0.2 vs. 1.3 ± 0.1, respectively, P = 0.003). There was no statistically significant difference between the paretic and contralateral sides in most concentric needle motor unit action potential (MUAP) parameters, such as amplitude (768.7 ± 441.7 vs. 855.0 ± 289.9 μV), duration (8.9 ± 1.8 vs. 8.68 ± 0.9 ms) and size index (1.2 ± 0.5 vs. 1.1 ± 0.3) (P > 0.18), nor was there a significant difference in single fiber EMG recorded jitter (37.0 ± 9.6 vs. 39.9 ± 10.6 μs, P = 0.45). The increase in FD suggests motor units of the paretic FDI have enlarged due to collateral reinnervation. However, sprouting might be insufficient to result in a statistically significant change in the concentric needle MUAP parameters. Single fiber EMG appears more sensitive than concentric needle EMG to reflect electrophysiological changes in motor units after stroke. Both single fiber and concentric needle EMG recordings may be necessary to better understand muscle changes after stroke, which is important for development of appropriate rehabilitation strategies. The results provide further evidence that motor units are remodeled after stroke, possibly in response to a loss of motoneurons.
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Affiliation(s)
- Bo Yao
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.,Department of Physical Medicine & Rehabilitation, The University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States
| | - Cliff S Klein
- Guangdong Work Injury Rehabilitation Center, Guangzhou, China
| | - Huijing Hu
- Department of Physical Medicine & Rehabilitation, The University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States.,Guangdong Work Injury Rehabilitation Center, Guangzhou, China
| | - Sheng Li
- Department of Physical Medicine & Rehabilitation, The University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States
| | - Ping Zhou
- Department of Physical Medicine & Rehabilitation, The University of Texas Health Science Center at Houston, Houston, TX, United States.,TIRR Memorial Hermann Research Center, Houston, TX, United States
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Neuwirth C, Burkhardt C, Alix J, Castro J, de Carvalho M, Gawel M, Goedee S, Grosskreutz J, Lenglet T, Moglia C, Omer T, Schrooten M, Weber M. Quality Control of Motor Unit Number Index (MUNIX) Measurements in 6 Muscles in a Single-Subject "Round-Robin" Setup. PLoS One 2016; 11:e0153948. [PMID: 27135747 PMCID: PMC4852906 DOI: 10.1371/journal.pone.0153948] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 04/06/2016] [Indexed: 12/12/2022] Open
Abstract
Background Motor Unit Number Index (MUNIX) is a neurophysiological measure that provides an index of the number of lower motor neurons in a muscle. Its performance across centres in healthy subjects and patients with Amyotrophic Lateral Sclerosis (ALS) has been established, but inter-rater variability between multiple raters in one single subject has not been investigated. Objective To assess reliability in a set of 6 muscles in a single subject among 12 examiners (6 experienced with MUNIX, 6 less experienced) and to determine variables associated with variability of measurements. Methods Twelve raters applied MUNIX in six different muscles (abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps brachii (BB), tibialis anterior (TA), extensor dig. brevis (EDB), abductor hallucis (AH)) twice in one single volunteer on consecutive days. All raters visited at least one training course prior to measurements. Intra- and inter-rater variability as determined by the coefficient of variation (COV) between different raters and their levels of experience with MUNIX were compared. Results Mean intra-rater COV of MUNIX was 14.0% (±6.4) ranging from 5.8 (APB) to 30.3% (EDB). Mean inter-rater COV was 18.1 (±5.4) ranging from 8.0 (BB) to 31.7 (AH). No significant differences of variability between experienced and less experienced raters were detected. Conclusion We provide evidence that quality control for neurophysiological methods can be performed with similar standards as in laboratory medicine. Intra- and inter-rater variability of MUNIX is muscle-dependent and mainly below 20%. Experienced neurophysiologists can easily adopt MUNIX and adequate teaching ensures reliable utilization of this method.
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Affiliation(s)
- Christoph Neuwirth
- Neuromuscular Diseases Unit / ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland
- * E-mail:
| | - Christian Burkhardt
- Neuromuscular Diseases Unit / ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland
| | - James Alix
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, England
| | - José Castro
- Department of Neurosciences, Hospital de Santa Maria, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Lisbon, Portugal
| | - Mamede de Carvalho
- Department of Neurosciences, Hospital de Santa Maria, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Lisbon, Portugal
| | - Malgorzata Gawel
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Stephan Goedee
- Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, UMC Utrecht, Utrecht, The Netherlands
| | - Julian Grosskreutz
- Hans-Berger Department of Neurology, University Hospital Jena, Jena, Germany
| | - Timothée Lenglet
- Département de Neurophysiologie, Groupe hospitalier Pitié-Salpêtrière, APHP, Paris, France
| | - Cristina Moglia
- ALS Center of Torino, Department of Neuroscience "Rita Levi Montalcini", University of Torino, Torino, Italy
| | - Taha Omer
- Trinity College Biomedical Science Institute (TBSI) and Beaumont Hospital, Dublin, Ireland
| | - Maarten Schrooten
- Department of Neurology, University Hospital Leuven, Leuven, Belgium
| | - Markus Weber
- Neuromuscular Diseases Unit / ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland
- Department of Neurology, University Hospital Basel, Basel, Switzerland
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Piasecki M, Ireland A, Jones DA, McPhee JS. Age-dependent motor unit remodelling in human limb muscles. Biogerontology 2015; 17:485-96. [PMID: 26667009 PMCID: PMC4889636 DOI: 10.1007/s10522-015-9627-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/26/2015] [Indexed: 12/14/2022]
Abstract
Voluntary control of skeletal muscle enables humans to interact with and manipulate the environment. Lower muscle mass, weakness and poor coordination are common complaints in older age and reduce physical capabilities. Attention has focused on ways of maintaining muscle size and strength by exercise, diet or hormone replacement. Without appropriate neural innervation, however, muscle cannot function. Emerging evidence points to a neural basis of muscle loss. Motor unit number estimates indicate that by age around 71 years, healthy older people have around 40 % fewer motor units. The surviving low- and moderate-threshold motor units recruited for moderate intensity contractions are enlarged by around 50 % and show increased fibre density, presumably due to collateral reinnervation of denervated fibres. Motor unit potentials show increased complexity and the stability of neuromuscular junction transmissions is decreased. The available evidence is limited by a lack of longitudinal studies, relatively small sample sizes, a tendency to examine the small peripheral muscles and relatively few investigations into the consequences of motor unit remodelling for muscle size and control of movements in older age. Loss of motor neurons and remodelling of surviving motor units constitutes the major change in ageing muscles and probably contributes to muscle loss and functional impairments. The deterioration and remodelling of motor units likely imposes constraints on the way in which the central nervous system controls movements.
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Affiliation(s)
- Mathew Piasecki
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - Alex Ireland
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - David A Jones
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK
| | - Jamie S McPhee
- School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, UK.
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Neuwirth C, Barkhaus PE, Burkhardt C, Castro J, Czell D, de Carvalho M, Nandedkar S, Stålberg E, Weber M. Tracking motor neuron loss in a set of six muscles in amyotrophic lateral sclerosis using the Motor Unit Number Index (MUNIX): a 15-month longitudinal multicentre trial. J Neurol Neurosurg Psychiatry 2015; 86:1172-9. [PMID: 25935892 DOI: 10.1136/jnnp-2015-310509] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/15/2015] [Indexed: 11/04/2022]
Abstract
BACKGROUND Motor Unit Number Index (MUNIX) is a novel neurophysiological measure that provides an index of the number of functional lower motor neurons in a given muscle. So far its performance across centres in patients with amyotrophic lateral sclerosis (ALS) has not been investigated. OBJECTIVE To perform longitudinal MUNIX recordings in a set of muscles in a multicentre setting in order to evaluate its value as a marker of disease progression. METHODS Three centres applied MUNIX in 51 ALS patients over 15 months. Six different muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor dig. brevis, abductor hallucis) were measured every 3 months on the less affected side. The decline between MUNIX and ALSFRS-R was compared. RESULTS 31 participants reached month 12. For all participants, ALSFRS-R declined at a rate of 2.3%/month. Using the total score of all muscles, MUNIX declined significantly faster by 3.2%/month (p ≤ 0.02). MUNIX in individual muscles declined between 2.4% and 4.2%, which differed from ASLFRS-R decline starting from month 3 (p ≤ 0.05 to 0.002). Subgroups with bulbar, lower and upper limb onset showed different decline rates of ALSFRS-R between 1.9% and 2.8%/month, while MUNIX total scores showed similar decline rates over all subgroups. Mean intraclass correlation coefficient for MUNIX intra-rater reliability was 0.89 and for inter-rater reliability 0.80. CONCLUSION MUNIX is a reliable electrophysiological biomarker to track lower motor neuron loss in ALS.
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Affiliation(s)
- Christoph Neuwirth
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland
| | | | - Christian Burkhardt
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland
| | - José Castro
- Department of Neurosciences, Faculty of Medicine, Hospital de Santa Maria, Instituto de Medicina Molecular, University of Lisbon, Lisbon, Portugal
| | - David Czell
- Kantonsspital Winterthur, Winterthur, Switzerland
| | - Mamede de Carvalho
- Department of Neurosciences, Faculty of Medicine, Hospital de Santa Maria, Instituto de Medicina Molecular, University of Lisbon, Lisbon, Portugal
| | | | - Erik Stålberg
- Department of Clinical Neurophysiology, Institute of Neurosciences, Uppsala University, University Hospital, Uppsala, Sweden
| | - Markus Weber
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital St.Gallen, St.Gallen, Switzerland Department of Neurology, University Hospital Basel, Basel, Switzerland
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Li X, He W, Li C, Wang YC, Slavens BA, Zhou P. Motor unit number index examination in dominant and non-dominant hand muscles. Laterality 2015; 20:699-710. [PMID: 26227495 DOI: 10.1080/1357650x.2015.1041971] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study investigated the effect of handedness on motor unit number index (MUNIX). Maximal hand strength, compound muscle action potential (CMAP) and voluntary surface electromyography (EMG) signals were measured bilaterally for the first dorsal interosseous (FDI) and thenar muscles in 24 right-handed and 2 left-handed healthy subjects. Mean (±standard error) grip and pinch forces in the dominant hand were 43.99 ± 2.36 kg and 9.36 ± 0.52 kg respectively, significantly larger than those in the non-dominant hand (grip: 41.37 ± 2.29 kg, p < .001; pinch: 8.79 ± 0.46 kg, p < .01). Examination of myoelectric parameters did not show a significant difference among the CMAP area, the MUNIX or motor unit size index (MUSIX) between the two sides in the FDI and thenar muscles. In addition, there was a lack of correlation between the strength and myoelectric parameters in regression analysis. However, strong correlations were observed between dominant and non-dominant hand muscles in both strength and myoelectric measures. Our results indicate that the population of motor units or spinal motor neurons as estimated from MUNIX may not be associated with handedness. Such findings help understand and interpret the MUNIX during its application for clinical or laboratory investigations.
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Affiliation(s)
- Xiaoyan Li
- a 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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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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Shumway KR, Porfirio DJ, Bailey EF. Phonation-related rate coding and recruitment in the genioglossus muscle. Exp Brain Res 2015; 233:2133-40. [PMID: 25899868 DOI: 10.1007/s00221-015-4284-y] [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] [Received: 11/05/2014] [Accepted: 04/10/2015] [Indexed: 11/26/2022]
Abstract
Motor unit recruitment was assessed in two muscles with similar muscle fiber-type compositions and that participate in skilled movements: the tongue muscle, genioglossus (GG), and the hand muscle, first dorsal interosseous (FDI). Our primary objectives were to determine in the framework of a voluntary movement whether muscle force is regulated in tongue as it is in limb, i.e., via processes of rate coding and recruitment. Recruitment in the two muscles was assessed within each subject in the context of ramp force (FDI) and in the tongue (GG) during vowel production and specifically, in the context of ramp increases in loudness, and subsequently expressed relative to the maximal. The principle findings of the study are that the general rules of recruitment and rate coding hold true for both GG and FDI, and second, that average firing rates, firing rates at recruitment and peak firing rates in GG are significantly higher than for FDI (P < 0.001) despite tasks performed across comparable force ranges (~2-40 % of max). The higher firing rates observed in the tongue within the context of phonation may be a function of that muscle's dual role as (prime) mover and hydrostatic support element.
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Affiliation(s)
- K R Shumway
- Department of Physiology, College of Medicine, The University of Arizona, Tucson, AZ, 85721-0093, USA
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Zhou P, Nandedkar SD, Barkhaus PE. Voluntary Contraction Direction Dependence of Motor Unit Number Index in Patients with Amyotrophic Lateral Sclerosis. IEEE Trans Neural Syst Rehabil Eng 2014; 22:992-6. [DOI: 10.1109/tnsre.2014.2314391] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Li X, Liu J, Li S, Wang YC, Zhou P. Examination of hand muscle activation and motor unit indices derived from surface EMG in chronic stroke. IEEE Trans Biomed Eng 2014; 61:2891-8. [PMID: 24967982 DOI: 10.1109/tbme.2014.2333034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this study, we used muscle and motor unit indices, derived from convenient surface electromyography (EMG) measurements, for examination of paretic muscle changes post stroke. For 12 stroke subjects, compound muscle action potential and voluntary surface EMG signals were recorded from paretic and contralateral first dorsal interosseous, abductor pollicis brevis, and abductor digiti minimi muscles. Muscle activation index (AI), motor unit number index (MUNIX), and motor unit size index (MUSIX) were then calculated for each muscle. There was a significant AI reduction for all the three muscles in paretic side compared with contralateral side, providing an evidence of muscle activation deficiency after stroke. The hand MUNIX (defined by summing the values from the three muscles) was significantly reduced in paretic side compared with contralateral side, whereas the hand MUSIX was not significantly different. Furthermore, diverse changes in MUNIX and MUSIX were observed from the three muscles. A major feature of the present examinations is the primary reliance on surface EMG, which offers practical benefits because it is noninvasive, induces minimal discomfort and can be performed quickly.
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Kaya RD, Hoffman RL, Clark BC. Reliability of a modified motor unit number index (MUNIX) technique. J Electromyogr Kinesiol 2013; 24:18-24. [PMID: 24168818 DOI: 10.1016/j.jelekin.2013.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 09/23/2013] [Accepted: 10/07/2013] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION The purpose of this study was to examine the relative and absolute between-day reliability of the motor unit number index (MUNIX). METHODS Young, healthy adults (n=19) attended two testing sessions separated by 4-weeks where their maximal pinch-grip strength, MUNIX, and motor unit size index (MUSIX) were assessed in the abductor pollicis brevis muscle. Reliability was assessed by intraclass correlation coefficients (ICC), coefficient of variation (CV) and limits of agreement (LOA). RESULTS No mean differences were observed for MUNIX or MUSIX. The CV for the MUNIX and MUSIX measures were between 13.5% and 17.5%. The ICC for both measures were moderate to moderately-high (0.73-0.76), The LOA for both indicated a homoscedastic relationship. DISCUSSION Our findings indicate moderate to moderately-high reliability for both MUNIX and MUSIX. Future work is needed to ensure both measures are reliable in other muscles and cohorts, and further investigations are required to examine the validity of MUNIX.
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Affiliation(s)
- Ryan D Kaya
- Ohio Musculoskeletal and Neurological Institute (OMNI) at Ohio University, Athens, OH, United States; School of Applied Health Sciences and Wellness at Ohio University, Athens, OH, United States
| | - Richard L Hoffman
- Ohio Musculoskeletal and Neurological Institute (OMNI) at Ohio University, Athens, OH, United States; Department of Biomedical Sciences at Ohio University, Athens, OH, United States
| | - Brian C Clark
- Ohio Musculoskeletal and Neurological Institute (OMNI) at Ohio University, Athens, OH, United States; Department of Biomedical Sciences at Ohio University, Athens, OH, United States.
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