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Henderson RD, Shandiz E. Stepping up for a practical biomarker of motor unit loss. Muscle Nerve 2024; 70:1-3. [PMID: 38708833 DOI: 10.1002/mus.28110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 04/23/2024] [Accepted: 04/23/2024] [Indexed: 05/07/2024]
Affiliation(s)
- Robert David Henderson
- Department of Neurology, Royal Brisbane & Women's Hospital, Brisbane, Queensland, Australia
| | - Ehsan Shandiz
- Department of Neurology, Toowoomba Base Hospital, Toowoomba, Queensland, Australia
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Vacchiano V, Morabito F, Faini C, Nocera G, Not R, Scarpini G, Romagnoli M, Pini A, Liguori R. Motor unit number estimation via MScanFit MUNE in spinal muscular atrophy. Muscle Nerve 2024; 70:71-81. [PMID: 38549445 DOI: 10.1002/mus.28091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 03/06/2024] [Accepted: 03/16/2024] [Indexed: 06/06/2024]
Abstract
INTRODUCTION/AIMS MScanFit MUNE (MScanFit) is a novel tool to derive motor unit number estimates (MUNEs) from compound muscle action potential (CMAP) scans. Few studies have explored its utility in 5q spinal muscular atrophy (SMA5q) patients, assessing only the abductor pollicis brevis (APB) muscle. We aimed to assess different distal muscles in pediatric and adult SMA5q patients, further evaluating clinical-electrophysiological correlations. METHODS We analyzed MScanFit parameters reflecting the extent of denervation (MUNE; N50) and parameters of collateral reinnervation in APB, abductor digiti minimi (ADM), and tibialis anterior (TA) muscles. SMA patients were clinically evaluated using standardized motor function clinical scales, including the Hammersmith Functional Motor Scale - Expanded and the Revised Upper Limb Module. RESULTS A total of 23 SMA5q (9 SMA type 2 and 14 SMA type 3) and 12 age-matched healthy controls (HCs) were enrolled. SMA patients showed lower MUNE and N50 values and higher parameters of collateral sprouting in all muscles compared to HC (p < .001). SMA type 2 patients demonstrated lower MUNE and higher collateral reinnervation values in APB and TA compared to SMA type 3 (p < .05). Walker patients showed higher values of MUNE and N50, and lower parameters of reinnervation in all muscles compared to sitters (p < .05). MScanFit parameters showed strong correlations (Rho-values ranging from .72 to .83) with clinical measurements. MUNE values were abnormal in muscles that were not clinically affected. DISCUSSION MScanFit parameters showed promise as an outcome measure. Further studies, particularly longitudinal ones, are needed to evaluate MScanFit in measuring response to treatments.
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Affiliation(s)
- Veria Vacchiano
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Francesca Morabito
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | - Claudia Faini
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - Giovanna Nocera
- UOC Neuropsichiatria Infantile Attività Territoriale (NPIA), Azienda USL di Bologna, Bologna, Italy
| | - Riccardo Not
- UO DATeR Riabilitazione Territoriale, AUSL Bologna, Bologna, Italy
| | - Gaia Scarpini
- Pediatric Neuromuscular Unit, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Martina Romagnoli
- Programma di Neurogenetica, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Antonella Pini
- Pediatric Neuromuscular Unit, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Rocco Liguori
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
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Abd El Mutaleb ANH, Ibrahim FAR, Megahed FAK, Atta A, Ali BA, Omar TEI, Rashad MM. NAIP Gene Deletion and SMN2 Copy Number as Molecular Tools in Predicting the Severity of Spinal Muscular Atrophy. Biochem Genet 2024:10.1007/s10528-023-10657-6. [PMID: 38388850 DOI: 10.1007/s10528-023-10657-6] [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: 09/27/2023] [Accepted: 12/29/2023] [Indexed: 02/24/2024]
Abstract
Spinal muscular atrophy (SMA) is one of the most prevalent autosomal recessive illnesses with type I being the most severe type. Genomic alterations including survival motor neuron (SMN) copy number as well as deletions in SMN and Neuronal Apoptosis Inhibitory Protein (NAIP) are greatly implicated in the emergence of SMA. However, the association of such alterations with the severity of the disease is yet to be investigated. This study was directed to elucidate the molecular assessment of NAIP and SMN genomic alterations as a useful tool in predicting the severity of SMA among patients. This study included 65 SMA pediatric patients (30 type I and 35 type II) and 65 healthy controls. RFLP-PCR was employed to determine the genetic polymorphisms of the SMN1, SMN2, and NAIP genes. In addition, qRT-PCR was used to identify the expression of the SMN1 and SMN2 genes, and serum levels of creatine kinase were measured using a colorimetric method. DNA sequencing was performed on some samples to detect any single nucleotide polymorphisms in SMN1, SMN2, and NAIP genes. All SMA patients had a homozygous deficiency of SMN1 exon 7. The homozygous deficiency of SMN1 exons 7 and 8, with the deletion of NAIP exon 5 was found among the majority of Type I patients. In contrast, patients with the less severe condition (type II) had SMN1 exons 7 and 8 deleted but did not have any deletions in NAIP, additionally; 65.7% of patients had multiple copies of SMN2. Analysis of NAIP deletion alongside assessing SMN2 copy number might enhance the effectiveness of the diagnosis that can predict severity among Spinal Muscular Atrophy patients.
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Affiliation(s)
| | - Fawziya A R Ibrahim
- Department of Applied Medical Chemistry, Medical Research Institute, University of Alexandria, Alexandria, Egypt.
| | - Fayed A K Megahed
- Department of Nucleic Acid Research, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, Alexandria, Egypt
| | - Ahmed Atta
- Department of Nucleic Acid Research, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, Alexandria, Egypt
| | - Bahy A Ali
- Department of Nucleic Acid Research, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, Alexandria, Egypt
| | - Tarek E I Omar
- Department of Pediatric Neurology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Mona M Rashad
- Department of Applied Medical Chemistry, Medical Research Institute, University of Alexandria, Alexandria, Egypt
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Kelly KM, Mizell J, Bigdeli L, Paul S, Tellez MA, Bartlett A, Heintzman S, Reynolds JE, Sterling GB, Rajneesh KF, Kolb SJ, Elsheikh B, Arnold WD. Differential impact on motor unit characteristics across severities of adult spinal muscular atrophy. Ann Clin Transl Neurol 2023; 10:2208-2222. [PMID: 37735861 PMCID: PMC10723249 DOI: 10.1002/acn3.51906] [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: 01/13/2023] [Revised: 08/22/2023] [Accepted: 09/08/2023] [Indexed: 09/23/2023] Open
Abstract
OBJECTIVE To test the hypotheses that decomposition electromyography (dEMG) motor unit action potential (MUAP) amplitude and firing rate are altered in SMA; dEMG parameters are associated with strength and function; dEMG parameters are correlated with traditional electrophysiological assessments. METHODS Ambulatory and non-ambulatory adults with SMA on nusinersen and healthy controls were enrolled. MUAPs were decomposed from multielectrode surface recordings during 30-s maximum contraction of the abductor digiti minimi (ADM). Isometric strength, upper limb function, patient-reported function, and standard electrophysiologic measures of the ADM (compound muscle action potential [CMAP], single motor unit potential [SMUP], motor unit number estimation [MUNE]) were collected. RESULTS dEMG MUAP amplitudes were higher in ambulatory versus control and non-ambulatory groups and were higher in controls versus non-ambulatory SMA. In contrast, dEMG firing rates were higher in ambulatory versus non-ambulatory and control groups but similar between non-ambulatory and control. dEMG parameters showed moderate to strong positive correlation with strength and function whereas CMAP and MUNE better correlated with function than strength. SMUP did not correlate with strength, function, or dEMG MUAP amplitude. dEMG parameters show overall good test-retest reliability. INTERPRETATION dEMG provided reliable, noninvasive measure of MUAP amplitude size and firing rate and revealed divergent patterns across disease severity in adults with SMA. Firing rate enhancement, as seen in milder SMA, may provide a therapeutic avenue for improving function in more severe SMA, where firing rates appear preserved. MUAP amplitude size and firing rate, quantified with dEMG, may be promising monitoring biomarker candidates for noninvasive assessment of SMA.
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Affiliation(s)
- Kristina Marie Kelly
- Department of Physical Medicine & RehabilitationUniversity of MissouriColumbiaMOUSA
- NextGen Precision HealthUniversity of MissouriColumbiaMOUSA
| | - Jordan Mizell
- College of MedicineThe Ohio State UniversityColumbusOHUSA
| | - Ladan Bigdeli
- College of MedicineThe Ohio State UniversityColumbusOHUSA
| | - Samuel Paul
- College of MedicineThe Ohio State UniversityColumbusOHUSA
| | - Marco Antonio Tellez
- Department of NeurologyThe Ohio State University Wexner Medical CenterColumbusOHUSA
| | - Amy Bartlett
- Center for Clinical and Translational ScienceThe Ohio State University Wexner Medical CenterColumbusOHUSA
| | - Sarah Heintzman
- Department of NeurologyThe Ohio State University Wexner Medical CenterColumbusOHUSA
| | | | - Gary Brent Sterling
- Department of NeurologyThe Ohio State University Wexner Medical CenterColumbusOHUSA
| | | | - Stephen James Kolb
- Department of NeurologyThe Ohio State University Wexner Medical CenterColumbusOHUSA
| | - Bakri Elsheikh
- Department of NeurologyThe Ohio State University Wexner Medical CenterColumbusOHUSA
| | - William David Arnold
- Department of Physical Medicine & RehabilitationUniversity of MissouriColumbiaMOUSA
- NextGen Precision HealthUniversity of MissouriColumbiaMOUSA
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Chen M, Lu Z, Li X, Zong Y, Xie Q, Li S, Zhou P. Compound muscle action potential (CMAP) scan examination of paretic and contralateral muscles reveals motor unit alterations after stroke. SCIENCE CHINA. LIFE SCIENCES 2023; 66:2604-2613. [PMID: 37258801 PMCID: PMC11057326 DOI: 10.1007/s11427-022-2308-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/19/2023] [Indexed: 06/02/2023]
Abstract
This study presents a novel compound muscle action potential (CMAP) examination of motor unit changes in paretic muscle post stroke. CMAP scan of the first dorsal interosseous (FDI) muscle was performed bilaterally in 16 chronic stroke subjects. Various parameters were derived from the CMAP scan to examine paretic muscle changes, including CMAP amplitude, D50, step index (STEPIX) and amplitude index (AMPIX). A significant decrease in CMAP amplitude and STEPIX was observed in paretic muscles compared with contralateral muscles (CMAP amplitude: paretic (9.0±0.5) mV, contralateral (11.3±0.9) mV, P=0.024; STEPIX: paretic 101.2±7.6, contralateral 121.9±6.5, P=0.020). No significant difference in D50 and AMPIX was observed between the paretic and contralateral sides (P>0.05). The findings revealed complex paretic muscle changes including motor unit degeneration, muscle fiber denervation, reinnervation and atrophy, providing useful insights to help understand neuromuscular mechanisms associated with weakness and other functional deterioration post stroke. The CMAP scan experimental protocols and the applied processing methods are noninvasive, convenient, and automated, offering practical benefits for clinical application.
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Affiliation(s)
- Maoqi Chen
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao, 266071, China
| | - Zhiyuan Lu
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao, 266071, China.
| | - Xiaoyan Li
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
- Fischell Department of Bioengineering, University of Maryland at College Park, College Park, MD, 20742, USA
| | - Ya Zong
- Department of Rehabilitation Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qing Xie
- Department of Rehabilitation Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center, Houston, TX, 77030, USA
- TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, 77030, USA
| | - Ping Zhou
- School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao, 266071, China
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Ros LA, Sleutjes BT, Stikvoort García DJ, Goedee HS, Asselman FL, van den Berg LH, van der Pol WL, Wadman RI. Feasibility and tolerability of multimodal peripheral electrophysiological techniques in a cohort of patients with spinal muscular atrophy. Clin Neurophysiol Pract 2023; 8:123-131. [PMID: 37554725 PMCID: PMC10404501 DOI: 10.1016/j.cnp.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 05/27/2023] [Accepted: 06/17/2023] [Indexed: 08/10/2023] Open
Abstract
OBJECTIVE Electrophysiological techniques are emerging as an aid in identifying prognostic or therapeutic biomarkers in patients with spinal muscular atrophy (SMA), but electrophysiological assessments may be burdensome for patients. We, therefore, assessed feasibility and tolerability of multimodal peripheral non-invasive electrophysiological techniques in a cohort of patients with SMA. METHODS We conducted a single center, longitudinal cohort study investigating the feasibility and tolerability of applying multimodal electrophysiological techniques to the median nerve unilaterally. Techniques consisted of the compound muscle action potential scan, motor nerve excitability tests, repetitive nerve stimulation and sensory nerve action potential. We assessed tolerability using the numeric rating scale (NRS), ranging from 0 (no pain) to 10 (worst possible pain), and defined the protocol to be tolerable if the NRS score ≤ 3. The protocol was considered feasible if it could be performed according to test and quality standards. RESULTS We included 71 patients with SMA types 1-4 (median 39 years; range 13-67) and 63 patients at follow-up. The protocol was feasible in 98% of patients and was well-tolerated in up to 90% of patients. Median NRS score was 2 (range 0-6 at baseline and range 0-4 at follow-up (p < 0.01)). None of the patients declined follow-up assessment. CONCLUSIONS Multimodal, peripheral, non-invasive, electrophysiological techniques applied to the median nerve are feasible and well-tolerated in adolescents and adults with SMA types 1-4. SIGNIFICANCE Our study supports the use of non-invasive multimodal electrophysiological assessments in adolescents and adults with SMA types 1-4.
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Affiliation(s)
- Leandra A.A. Ros
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Boudewijn T.H.M. Sleutjes
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Diederik J.L. Stikvoort García
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - H. Stephan Goedee
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Fay-Lynn Asselman
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Leonard H. van den Berg
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | | | - Renske I. Wadman
- Corresponding author at: Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
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Ros LAA, Goedee HS, Franssen H, Asselman FL, Bartels B, Cuppen I, van Eijk RPA, Sleutjes BTHM, van der Pol WL, Wadman RI. Longitudinal prospective cohort study to assess peripheral motor function with extensive electrophysiological techniques in patients with Spinal Muscular Atrophy (SMA): the SMA Motor Map protocol. BMC Neurol 2023; 23:164. [PMID: 37095427 PMCID: PMC10124000 DOI: 10.1186/s12883-023-03207-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 04/14/2023] [Indexed: 04/26/2023] Open
Abstract
BACKGROUND Hereditary spinal muscular atrophy (SMA) is a motor neuron disorder with a wide range in severity in children and adults. Two therapies that alter splicing of the Survival Motor Neuron 2 (SMN2) gene, i.e. nusinersen and risdiplam, improve motor function in SMA, but treatment effects vary. Experimental studies indicate that motor unit dysfunction encompasses multiple features, including abnormal function of the motor neuron, axon, neuromuscular junction and muscle fibres. The relative contributions of dysfunction of different parts of the motor unit to the clinical phenotype are unknown. Predictive biomarkers for clinical efficacy are currently lacking. The goals of this project are to study the association of electrophysiological abnormalities of the peripheral motor system in relation to 1) SMA clinical phenotypes and 2) treatment response in patients treated with SMN2-splicing modifiers (nusinersen or risdiplam). METHODS We designed an investigator-initiated, monocentre, longitudinal cohort study using electrophysiological techniques ('the SMA Motor Map') in Dutch children (≥ 12 years) and adults with SMA types 1-4. The protocol includes the compound muscle action potential scan, nerve excitability testing and repetitive nerve stimulation test, executed unilaterally at the median nerve. Part one cross-sectionally assesses the association of electrophysiological abnormalities in relation to SMA clinical phenotypes in treatment-naïve patients. Part two investigates the predictive value of electrophysiological changes at two-months treatment for a positive clinical motor response after one-year treatment with SMN2-splicing modifiers. We will include 100 patients in each part of the study. DISCUSSION This study will provide important information on the pathophysiology of the peripheral motor system of treatment-naïve patients with SMA through electrophysiological techniques. More importantly, the longitudinal analysis in patients on SMN2-splicing modifying therapies (i.e. nusinersen and risdiplam) intents to develop non-invasive electrophysiological biomarkers for treatment response in order to improve (individualized) treatment decisions. TRIAL REGISTRATION NL72562.041.20 (registered at https://www.toetsingonline.nl . 26-03-2020).
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Affiliation(s)
- Leandra A A Ros
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - H Stephan Goedee
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - Hessel Franssen
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - Fay-Lynn Asselman
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - Bart Bartels
- Child Development and Exercise Centre, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Inge Cuppen
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - Ruben P A van Eijk
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
- Biostatistics and Research Support, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Boudewijn T H M Sleutjes
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - W Ludo van der Pol
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands
| | - Renske I Wadman
- Department of Neurology & Neurosurgery, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
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Hjartarson HT, Nathorst-Böös K, Sejersen T. Disease Modifying Therapies for the Management of Children with Spinal Muscular Atrophy (5q SMA): An Update on the Emerging Evidence. Drug Des Devel Ther 2022; 16:1865-1883. [PMID: 35734367 PMCID: PMC9208376 DOI: 10.2147/dddt.s214174] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 06/01/2022] [Indexed: 11/23/2022] Open
Abstract
SMA (5q SMA) is an autosomal recessive neuromuscular disease with an estimated incidence of approximately 1 in 11,000 live births, characterized by progressive degeneration and loss of α-motor neurons in the spinal cord and brain stem, resulting in progressive muscle weakness. The disease spectrum is wide, from a serious congenital to a mild adult-onset disease. SMA is caused by biallelic mutations in the SMN1 gene and disease severity is modified primarily by SMN2 copy number. Before the advent of specific disease altering treatments, SMA was the second most common fatal autosomal recessive disorder after cystic fibrosis and the most common genetic cause of infant mortality. Nusinersen, risdiplam, and onasemnogene abeparvovec are presently the only approved disease modifying therapies for SMA, and the aim of this review is to discuss their mode of action, effects, safety concerns, and results from real-world experience. All exert their action by increasing the level of SMN protein in lower motor neuron. Nusinersen and risdiplam by modifying the SMN2 gene product, and onasemnogene abeparvovec by delivering SMN1 gene copies into cells. All have an established clinical efficacy. An important feature shared by all three is that early intervention is associated with a better treatment outcome, such that in cases where treatment is initiated in an early pre-symptomatic period, it may result in normal - or almost normal - motor development. Thus, early diagnosis followed by swift initiation of treatment is fundamental for the treatment response and consequently long-term prognosis in SMA type 1, and probably SMA type 2. The same principle similarly applies to the milder phenotypes. All three therapies are relatively novel, with risdiplam being the latest addition. Except for nusinersen, real-world data are still scarce, and long-term data are quite naturally lacking.
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Affiliation(s)
- Helgi Thor Hjartarson
- Department of Neuropediatrics, Astrid Lindgren Children´s Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Kristofer Nathorst-Böös
- Department of Neuropediatrics, Astrid Lindgren Children´s Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Sejersen
- Department of Neuropediatrics, Astrid Lindgren Children´s Hospital, Karolinska University Hospital, Stockholm, Sweden
- Department of Women’s and Children’s Health, Karolinska Institute, Stockholm, Sweden
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Islam B, Islam Z, Endtz HP, Jahan I, Jacobs BC, Mohammad QD, Franssen H. Electrophysiology of Guillain-Barré syndrome in Bangladesh: A prospective study of 312 patients. Clin Neurophysiol Pract 2022; 6:155-163. [PMID: 35112034 PMCID: PMC8790160 DOI: 10.1016/j.cnp.2021.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/24/2021] [Accepted: 03/28/2021] [Indexed: 11/27/2022] Open
Abstract
Classification of neurophysiologic subtypes of Guillain-Barré syndrome largely depended on the applied criteria. Anti-GM1 antibodies were not exclusively associated with axonal Guillain-Barré syndrome. Conduction block was not exclusively associated with demyelinating Guillain-Barré syndrome.
Objective To describe the electrophysiological features in relation to clinical and serological findings of Guillain-Barré syndrome (GBS) in the national neuroscience hospital in Bangladesh. This is one of the few studies that investigated GBS patients using standardized electrophysiology in low-income countries. Methods In a prospective and observational study, we investigated 312 GBS patients by standardized clinical, serological and electrophysiological methods. Unilateral motor and sensory nerve conduction studies (NCS) were performed within two weeks of onset of weakness. Follow up NCS were performed in 189 patients and classified according to eight sets of established GBS criteria. Serology included assessment of anti-GM1 antibodies and anti-campylobacter jejuni lipo-oligosaccharide (LOS) antibodies. Results Depending on the criteria used, 44–59% patients had axonal GBS with anti-GM1 antibodies being present in 55–58% and 9–42% patients had demyelinating GBS with anti-GM1 antibodies being present in 7–35%. Conduction block (CB) with demyelinative slowing in the same nerve segment was found in 24% (74/312) patients, and CB without demyelinative slowing in the same nerve segment was found in 18% (56/312) patients, of whom anti-GM1 antibodies were found in 27% and 57% patients respectively. Follow-up NCS showed a change in GBS classification in 11–26% of patients, mainly from demyelinating to axonal GBS. Conclusions The predominant subtype of GBS in Bangladesh is axonal but demyelinating GBS also occurs with classification being strongly dependent on the applied criteria. Significance The present study demonstrates the importance of reaching international agreement on GBS criteria that should be based on the best evidence.
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Affiliation(s)
- Badrul Islam
- Laboratory Sciences and Services Division, icddr,b, Dhaka, Bangladesh
| | - Zhahirul Islam
- Laboratory Sciences and Services Division, icddr,b, Dhaka, Bangladesh
| | - Hubert P Endtz
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Israt Jahan
- Laboratory Sciences and Services Division, icddr,b, Dhaka, Bangladesh
| | - Bart C Jacobs
- Department of Immunology, Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Neurology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Quazi D Mohammad
- National Institute of Neurosciences and Hospital, Dhaka, Bangladesh
| | - Hessel Franssen
- Department of Neuromuscular Disorders, Utrecht Brain Center, the Netherlands
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Oguz-Akarsu E, Sirin NG, Artug T, Erbas B, Orhan EK, Idrisoğlu HA, Ketenci A, Baslo MB, Oge AE. Automatic detection of F-waves and F-MUNE in Two Types of Motor Neuron Diseases. Muscle Nerve 2022; 65:422-432. [PMID: 35020950 DOI: 10.1002/mus.27494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 01/02/2022] [Accepted: 01/06/2022] [Indexed: 11/09/2022]
Abstract
INTRODUCTION/AIMS Motor unit number estimation by F-waves (F-MUNE) is an uncommonly used MUNE technique. The aim of this study was to analyze the sensitivity of F-MUNE values elicited with newly developed software in motor neuron diseases. METHODS F-waves were recorded by 300 submaximal stimuli from abductor digiti minimi (ADM) and abductor pollicis brevis (APB) muscles of 35 patients with amyotrophic lateral sclerosis, 18 with previous poliomyelitis, and 20 controls. The software extracted the surface motor unit action potentials (sMUAP) and calculated the F-MUNE values. CMAP Scans were also recorded to obtain step% and MScanFit. RESULTS sMUAP amplitudes were higher and F-MUNE values were lower in both muscles of the patients than in controls. F-MUNE values were able to distinguish the patients from controls. Significant correlations were found between F-MUNE and MScanFit in patient groups. DISCUSSION The new F-MUNE software gave promising results in revealing motor unit loss caused by motor neuron diseases.
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Affiliation(s)
- Emel Oguz-Akarsu
- Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey.,Department of Neurology, Faculty of Medicine, Bursa Uludag University, Bursa, Turkey
| | - Nermin Gorkem Sirin
- Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Tugrul Artug
- Department of Electrical and Electronics Engineering, Faculty of Engineering, Izmir Democracy University, Izmir, Turkey
| | - Bahar Erbas
- Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey.,Department of Pharmacology, Faculty of Medicine, Demiroglu Bilim University, Istanbul, Turkey
| | - Elif Kocasoy Orhan
- Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Halil Atilla Idrisoğlu
- Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Aysegul Ketenci
- Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Mehmet Baris Baslo
- Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Ali Emre Oge
- Departments of Neurology and Clinical Neurophysiology, Faculty of Medicine, Istanbul University, Istanbul, Turkey
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11
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Stikvoort García DJL, Kovalchuk MO, Goedee HS, van Schelven LJ, van den Berg LH, Franssen H, Sleutjes BTHM. Motor unit integrity in multifocal motor neuropathy: A systematic evaluation with CMAP scans. Muscle Nerve 2021; 65:317-325. [PMID: 34854491 PMCID: PMC9300115 DOI: 10.1002/mus.27469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 11/09/2022]
Abstract
Introduction/Aims Progressive axonal loss in multifocal motor neuropathy (MMN) is often assessed with nerve conduction studies (NCS), by recording maximum compound muscle action potentials (CMAPs). However, reinnervation maintains the CMAP amplitude until a significant portion of the motor unit (MU) pool is lost. Therefore, we performed more informative CMAP scans to study MU characteristics in a large cohort of patients with MMN. Methods We derived the maximum CMAP amplitude (CMAPmax), an MU number estimate (MUNE), and the largest MU amplitude stimulus current required to elicit 5%, 50%, and 95% of CMAPmax (S5, S50, S95) and relative ranges ([S95 − S5] × 100 / S50) from the scans. These metrics were compared with clinical, laboratory, and NCS results. Results Forty MMN patients and 24 healthy controls were included in the study. CMAPmax and MUNE were reduced in MMN patients (both P < .001). Largest MU amplitude as a percentage of CMAPmax was increased in MMN patients (P < .001). Disease duration and treatment duration were not associated with MUNE. Relative range was larger in patients with anti‐GM1 antibodies than in those without anti‐GM1 antibodies (P = .016) and controls (P < .001). The largest MU amplitudes were larger in patients without anti‐GM1 antibodies than in patients with anti‐GM1 antibodies (P = .037) and controls (P = .044). Discussion We found that MU loss is common in MMN and accompanied by enlarged MUs. Presence of anti‐GM1 antibodies was associated with increased relative range of MU thresholds and reduction in largest MU amplitude. Our findings indicate that CMAP scans complement routine NCS, and may have potential for practical monitoring of treatment efficacy and disease progression.
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Affiliation(s)
| | - Maria O Kovalchuk
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - H Stephan Goedee
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Leonard J van Schelven
- Department of Medical Technology and Clinical Physics, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Leonard H van den Berg
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Hessel Franssen
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Boudewijn T H M Sleutjes
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, The Netherlands
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12
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Habets LE, Bartels B, Asselman FL, Hooijmans MT, van den Berg S, Nederveen AJ, van der Pol WL, Jeneson JAL. Magnetic resonance reveals mitochondrial dysfunction and muscle remodelling in spinal muscular atrophy. Brain 2021; 145:1422-1435. [PMID: 34788410 PMCID: PMC9128825 DOI: 10.1093/brain/awab411] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/24/2021] [Accepted: 10/08/2021] [Indexed: 11/14/2022] Open
Abstract
Genetic therapy has changed the prognosis of hereditary proximal spinal muscular atrophy, although treatment efficacy has been variable. There is a clear need for deeper understanding of underlying causes of muscle weakness and exercise intolerance in patients with this disease to further optimize treatment strategies. Animal models suggest that in addition to motor neuron and associated musculature degeneration, intrinsic abnormalities of muscle itself including mitochondrial dysfunction contribute to the disease aetiology. To test this hypothesis in patients, we conducted the first in vivo clinical investigation of muscle bioenergetics. We recruited 15 patients and 15 healthy age and gender-matched control subjects in this cross-sectional clinico-radiological study. MRI and 31P magnetic resonance spectroscopy, the modality of choice to interrogate muscle energetics and phenotypic fibre-type makeup, was performed of the proximal arm musculature in combination with fatiguing arm-cycling exercise and blood lactate testing. We derived bioenergetic parameter estimates including: blood lactate, intramuscular pH and inorganic phosphate accumulation during exercise, and muscle dynamic recovery constants. A linear correlation was used to test for associations between muscle morphological and bioenergetic parameters and clinico-functional measures of muscle weakness. MRI showed significant atrophy of triceps but not biceps muscles in patients. Maximal voluntary contraction force normalized to muscle cross-sectional area for both arm muscles was 1.4-fold lower in patients than in controls, indicating altered intrinsic muscle properties other than atrophy contributed to muscle weakness in this cohort. In vivo31P magnetic resonance spectroscopy identified white-to-red remodelling of residual proximal arm musculature in patients on the basis of altered intramuscular inorganic phosphate accumulation during arm-cycling in red versus white and intermediate myofibres. Blood lactate rise during arm-cycling was blunted in patients and correlated with muscle weakness and phenotypic muscle makeup. Post-exercise metabolic recovery was slower in residual intramuscular white myofibres in patients demonstrating mitochondrial ATP synthetic dysfunction in this particular fibre type. This study provides the first in vivo evidence in patients that degeneration of motor neurons and associated musculature causing atrophy and muscle weakness in 5q spinal muscular atrophy type 3 and 4 is aggravated by disproportionate depletion of myofibres that contract fastest and strongest. Our finding of decreased mitochondrial ATP synthetic function selectively in residual white myofibres provides both a possible clue to understanding the apparent vulnerability of this particular fibre type in 5q spinal muscular atrophy types 3 and 4 as well as a new biomarker and target for therapy.
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Affiliation(s)
- Laura E Habets
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
| | - Bart Bartels
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
| | - Fay-Lynn Asselman
- UMC Utrecht Brain Centre, Department of Neurology and Neurosurgery, University Medical Centre Utrecht Brain Center, Utrecht University, P.O. Box 85500, 3508 GA Utrecht, The Netherlands
| | - Melissa T Hooijmans
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - Sandra van den Berg
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology & Nuclear Medicine, Amsterdam Movement Sciences, Amsterdam University Medical Centre, location AMC, 1105 AZ Amsterdam, The Netherlands
| | - W Ludo van der Pol
- UMC Utrecht Brain Centre, Department of Neurology and Neurosurgery, University Medical Centre Utrecht Brain Center, Utrecht University, P.O. Box 85500, 3508 GA Utrecht, The Netherlands
| | - Jeroen A L Jeneson
- Centre for Child Development, Exercise and Physical Literacy, Wilhelmina Children's Hospital, University Medical Centre Utrecht, P.O. Box 85090 3508 AB Utrecht, The Netherlands
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13
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Sleutjes BTHM, Bystrup Jacobsen A, Tankisi H, Gorkem Sirin N, Emre Oge A, Henderson RD, van Doorn PA, van den Berg LH, van Eijk RPA. Advancing disease monitoring of amyotrophic lateral sclerosis with the compound muscle action potential scan. Clin Neurophysiol 2021; 132:3152-3159. [PMID: 34749234 DOI: 10.1016/j.clinph.2021.09.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/20/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To determine which compound muscle action potential (CMAP) scan-derived electrophysiological markers are most sensitive for monitoring disease progression in amyotrophic lateral sclerosis (ALS), and whether they hold value for clinical trials. METHODS We used four independent patient cohorts to assess longitudinal patterns of a comprehensive set of electrophysiological markers including their association with the ALS functional rating scale (ALSFRS-R). Results were translated to trial sample size requirements. RESULTS In 65 patients, 225 thenar CMAP scan recordings were obtained. Electrophysiological markers showed extensive variation in their longitudinal trajectories. Expressed as standard deviations per month, motor unit number estimation (MUNE) values declined by 0.09 (CI 0.07-0.12), D50, a measure that quantifies CMAP scan discontinuities, declined by 0.09 (CI 0.06-0.13) and maximum CMAP by 0.05 (CI 0.03-0.08). ALSFRS-R declined fastest (0.12, CI 0.08 - 0.15), however the between-patient variability was larger compared to electrophysiological markers, resulting in larger sample sizes. MUNE reduced the sample size by 19.1% (n = 388 vs n = 314) for a 6-month study compared to the ALSFRS-R. CONCLUSIONS CMAP scan-derived markers show promise in monitoring disease progression in ALS patients, where MUNE may be its most suitable derivate. SIGNIFICANCE MUNE may increase clinical trial efficiency compared to clinical endpoints.
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Affiliation(s)
- Boudewijn T H M Sleutjes
- Department of Neurology, Brain Centre Utrecht, Utrecht, the Netherlands; Department of Neurology, Erasmus Medical Center Rotterdam, Rotterdam, the Netherlands.
| | | | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - N Gorkem Sirin
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - A Emre Oge
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Robert D Henderson
- Department of Neurology, Royal Brisbane & Women's Hospital, Brisbane, Australia
| | - Pieter A van Doorn
- Department of Neurology, Erasmus Medical Center Rotterdam, Rotterdam, the Netherlands
| | | | - Ruben P A van Eijk
- Department of Neurology, Brain Centre Utrecht, Utrecht, the Netherlands; Biostatistics and Research Support, Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht, the Netherlands
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14
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Carson VJ, Young M, Brigatti KW, Robinson DL, Reed RM, Sohn J, Petrillo M, Farwell W, Miller F, Strauss KA. Nusinersen by subcutaneous intrathecal catheter for symptomatic spinal muscular atrophy patients with complex spine anatomy. Muscle Nerve 2021; 65:51-59. [PMID: 34606118 DOI: 10.1002/mus.27425] [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: 05/28/2021] [Revised: 09/21/2021] [Accepted: 09/28/2021] [Indexed: 12/18/2022]
Abstract
INTRODUCTION/AIMS Intrathecal administration of nusinersen is challenging in patients with spinal muscular atrophy (SMA) who have spine deformities or fusions. We prospectively studied the safety and efficacy of nusinersen administration via an indwelling subcutaneous intrathecal catheter (SIC) for SMA patients with advanced disease. METHODS Seventeen participants commenced nusinersen therapy between 2.7 and 31.5 years of age and received 9 to 12 doses via SIC. Safety was assessed in all participants. A separate efficacy analysis comprised 11 nonambulatory, treatment-naive SMA patients (18.1 ± 6.8 years) with three SMN2 copies and complex spine anatomy. RESULTS In the safety analysis, 14 treatment-related adverse events (AEs) occurred among 12 (71%) participants; all were related to the SIC and not nusinersen. Device-related AEs interfered with 2.5% of nusinersen doses. Four SICs (24%) required surgical revision due to mechanical malfunction with or without cerebrospinal fluid leak (n = 2), and one (6%) was removed due to Staphylococcus epidermidis meningitis. In the efficacy analysis, mean performance on the nine-hole peg test improved in dominant (15.9%, P = 0.012) and nondominant (19.0%, P = 0.008) hands and grip strength increased by 44.9% (P = 0.031). We observed no significant changes in motor scales, muscle force, pulmonary function, or SMA biomarkers. All participants in the efficacy cohort reported one or more subjective improvement(s) in endurance, purposeful hand use, arm strength, head control, and/or speech. DISCUSSION For SMA patients with complex spine anatomy, the SIC allows for reliable outpatient administration of nusinersen that results in meaningful improvements in upper limb function, but introduces risks of technical malfunction and iatrogenic infection.
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Affiliation(s)
| | - Millie Young
- Clinic for Special Children, Strasburg, Pennsylvania, USA
| | | | | | - Robert M Reed
- University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | | | | | - Freeman Miller
- Department of Orthopedics, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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15
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Schneider C, Wassermann MK, Grether NB, Fink GR, Wunderlich G, Lehmann HC. Motor unit number estimation in adult patients with spinal muscular atrophy treated with nusinersen. Eur J Neurol 2021; 28:3022-3029. [PMID: 34216082 DOI: 10.1111/ene.15005] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/14/2021] [Accepted: 06/30/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE The aim was to assess the organization and short-term changes of motor units in adult patients with spinal muscular atrophy (SMA) treated with nusinersen. METHODS In this single-centre cross-sectional and longitudinal study 15 adult patients with SMA type 3 were assessed and compared to 15 age-matched healthy controls and nine patients with amyotrophic lateral sclerosis. Moreover, 10 patients with SMA were followed up after 4-8 months. All patients were investigated clinically and by the motor unit number estimation method MScanFit of the abductor pollicis brevis muscle. RESULTS The number of motor units (p < 0.001) was significantly lower in patients with SMA compared to healthy controls at study entry. Mean unit amplitude, median amplitude and largest unit (p < 0.001) were significantly increased in patients with SMA. Patients with amyotrophic lateral sclerosis showed a significant reduction of compound muscle action potential (p = 0.005) and number of motor units (p = 0.03) compared to patients with SMA, accompanied by a larger median amplitude (p = 0.03). A prospective analysis identified patients with the ability to walk to improve the number of motor units (p = 0.046) accompanied by a decreased median amplitude (p = 0.03). Electrophysiological measures showed a moderate to strong correlation with clinical scores. CONCLUSION Patients with SMA show loss of motor units in distal muscles. MScanFit variables indicate that compound muscle action potential amplitudes are maintained by collateral sprouting. Prospective analyses suggest that milder affected adult patients with SMA preferentially benefit from nusinersen treatment through recovery of smaller motor units. Correlations with clinical scores underline the potential of MScanFit as a surrogate marker.
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Affiliation(s)
| | | | | | - Gereon R Fink
- Department of Neurology, University of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Jülich, Germany
| | | | - Helmar C Lehmann
- Department of Neurology, University of Cologne, Cologne, Germany
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16
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Zong Y, Lu Z, Chen M, Li X, Stampas A, Deng L, Zhou P. CMAP Scan Examination of the First Dorsal Interosseous Muscle After Spinal Cord Injury. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1199-1205. [PMID: 34106858 PMCID: PMC8780215 DOI: 10.1109/tnsre.2021.3088061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The study assessed motor unit loss in muscles paralyzed by spinal cord injury (SCI) using a novel compound muscle action potential (CMAP) scan examination. The CMAP scan of the first dorsal interosseous (FDI) muscle was applied in tetraplegia (n = 13) and neurologically intact (n = 13) subjects. MScanFit was used for estimating motor unit numbers in each subject. The D50 value of the CMAP scan was also calculated. We observed a significant decrease in both CMAP amplitude and motor unit number estimation (MUNE) in paralyzed FDI muscles, as compared with neurologically intact muscles. Across all subjects, the CMAP (negative peak) amplitude was 8.01 ± 3.97 mV for the paralyzed muscles and 16.75 ± 3.55 mV for the neurologically intact muscles (p < 0.001). The CMAP scan resulted in a MUNE of 59 ± 37 for the paralyzed muscles, much lower than 108 ± 21 for the neurologically intact muscles (p < 0.001). No significant difference in D50 was observed between the two groups (p = 0.2). For the SCI subjects, there was no significant correlation between MUNE and CMAP amplitude, or any of the clinical assessments including pinch force, grip force, the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) score, and SCI duration (p > 0.05). The findings provide an evidence of motor unit loss in the FDI muscles of individuals with tetraplegia, which may contribute to weakness and other hand function deterioration. The CMAP scan offers several practical benefits compared with the traditional MUNE techniques because it is noninvasive, automated and can be performed within several minutes.
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17
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Model-Based Analysis of Muscle Strength and EMG-Force Relation with respect to Different Patterns of Motor Unit Loss. Neural Plast 2021; 2021:5513224. [PMID: 34257638 PMCID: PMC8245245 DOI: 10.1155/2021/5513224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/02/2021] [Accepted: 06/01/2021] [Indexed: 01/07/2023] Open
Abstract
This study presents a model-based sensitivity analysis of the strength of voluntary muscle contraction with respect to different patterns of motor unit loss. A motor unit pool model was implemented including simulation of a motor neuron pool, muscle force, and surface electromyogram (EMG) signals. Three different patterns of motor unit loss were simulated, including (1) motor unit loss restricted to the largest ones, (2) motor unit loss restricted to the smallest ones, and (3) motor unit loss without size restriction. The model outputs including muscle force amplitude, variability, and the resultant EMG-force relation were quantified under two different motor neuron firing strategies. It was found that motor unit loss restricted to the largest ones had the most dominant impact on muscle strength and significantly changed the EMG-force relation, while loss restricted to the smallest motor units had a pronounced effect on force variability. These findings provide valuable insight toward our understanding of the neurophysiological mechanisms underlying experimental observations of muscle strength, force control, and EMG-force relation in both normal and pathological conditions.
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18
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Restoring Protein Expression in Neuromuscular Conditions: A Review Assessing the Current State of Exon Skipping/Inclusion and Gene Therapies for Duchenne Muscular Dystrophy and Spinal Muscular Atrophy. BioDrugs 2021; 35:389-399. [PMID: 34097287 DOI: 10.1007/s40259-021-00486-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2021] [Indexed: 02/06/2023]
Abstract
The debilitating neuromuscular disorders Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), which harm 1 in 5000 newborn males and 1 in 11,000 newborns, respectively, are marked by progressive muscle wasting among other complications. While DMD causes generalized muscle weakness due to the absence of the dystrophin protein, SMA patients generally face motor neuron degeneration because of the lack of the survival motor neuron (SMN) protein. Many of the most promising therapies for both conditions restore the absent proteins dystrophin and SMN. Antisense oligonucleotide-mediated exon skipping and inclusion therapies are advancing clinically with the approved DMD therapies casimersen, eteplirsen, golodirsen, and viltolarsen, and the SMA therapy nusinersen. Existing antisense therapies focus on skeletal muscle for DMD and motor neurons for SMA, respectively. Through innovative techniques, such as peptide conjugation and multi-exon skipping, these therapies could be optimized for efficacy and applicability. By contrast, gene replacement therapy is administered only once to patients during treatment. Currently, only onasemnogene abeparvovec for SMA has been approved. Safety shortcomings remain a major challenge for gene therapy. Nevertheless, gene therapy for DMD has strong potential to restore dystrophin expression in patients. In light of promising functional improvements, antisense and gene therapies stand poised to elevate the lives of patients with DMD and SMA.
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Mendonça RH, Machado LMS, Heise CO, Polido GJ, Matsui C, Silva AMS, Reed UC, Zanoteli E. Motor unit number index (MUNIX) in children and adults with 5q-spinal muscular atrophy: Variability and clinical correlations. Neuromuscul Disord 2021; 31:498-504. [PMID: 33824074 DOI: 10.1016/j.nmd.2021.02.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 02/11/2021] [Accepted: 02/24/2021] [Indexed: 11/25/2022]
Abstract
Spinal muscular atrophy (SMA) is a motor neuron disease associated with progressive muscle weakness and motor disability. The motor unit number index (MUNIX) is a biomarker used to assess loss of motor units in later-onset SMA patients. Twenty SMA patients (SMA types 3 and 4), aged between 7 and 41 years, were clinically evaluated through the Hammersmith Motor Functional Scale Expanded and the Spinal Muscular Atrophy-Functional Rating Scale. The patients underwent compound motor action potential (CMAP) and MUNIX studies of the right abductor pollicis brevis, abductor digiti minimi and tibialis anterior (TA) muscles. Age-matched healthy controls (n = 20) were enrolled to obtain normative CMAP and MUNIX values from the same muscles. Compared to healthy controls, SMA patients showed significant reductions in MUNIX values among all muscles studied, whereas CMAP showed reductions only in the weaker muscles (abductor digiti minimi and TA). MUNIX variability was significantly higher in the SMA group than in the control group. MUNIX variability in TA correlated with CMAP variability. Motor functional scores correlated with TA MUNIX. The MUNIX study is feasible in later-onset SMA patients, and TA MUNIX values correlate with disease severity in patients with mild motor impairment.
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Affiliation(s)
| | | | - Carlos Otto Heise
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Graziela Jorge Polido
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Ciro Matsui
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | | | - Umbertina Conti Reed
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Edmar Zanoteli
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
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20
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Sleutjes BTHM, Ruisch J, Nassi TE, Buitenweg JR, van Schelven LJ, van den Berg LH, Franssen H, Stephan Goedee H. Impact of stimulus duration on motor unit thresholds and alternation in compound muscle action potential scans. Clin Neurophysiol 2021; 132:323-331. [PMID: 33450554 DOI: 10.1016/j.clinph.2020.10.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/30/2020] [Accepted: 10/26/2020] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To investigate the impact of stimulus duration on motor unit (MU) thresholds and alternation within compound muscle action potential (CMAP) scans. METHODS The stimulus duration (0.1, 0.2, 0.6, and 1.0 ms) in thenar CMAP scans and individual MUs of 14 healthy subjects was systematically varied. We quantified variability of individual MU's thresholds by relative spread (RS), MU thresholds by stimulus currents required to elicit target CMAPs of 5% (S5), 50% (S50) and 95% (S95) of the maximum CMAP, and relative range (RR) by 100*[S95-S5]/S50. We further assessed the strength-duration time constant (SDTC). Experimental observations were subsequently simulated to quantify alternation. RESULTS RS, unaffected by stimulus duration, was 1.65% averaged over all recordings. RR increased for longer stimulus duration (11.4% per ms, p < 0.001). SDTC shortened with higher target CMAPs (0.007 ms per 10% CMAP, p < 0.001). Experiments and simulations supported that this may underlie the increased RR. A short compared to long stimulus duration recruited relative more MUs at S50 (more alternation) than at the tails (less alternation). CONCLUSIONS The stimulus duration significantly affects MU threshold distribution and alternation within CMAP scans. SIGNIFICANCE Stimulation settings can be further optimized and their standardization is preferred when using CMAP scans for monitoring neuromuscular diseases.
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Affiliation(s)
- Boudewijn T H M Sleutjes
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, the Netherlands.
| | - Janna Ruisch
- Biomedical Signals and Systems, Technical Medical Centre, University of Twente, Enschede, the Netherlands
| | - Thijs E Nassi
- Biomedical Signals and Systems, Technical Medical Centre, University of Twente, Enschede, the Netherlands
| | - Jan R Buitenweg
- Biomedical Signals and Systems, Technical Medical Centre, University of Twente, Enschede, the Netherlands
| | - Leonard J van Schelven
- Department of Medical Technology and Clinical Physics, University Medical Center Utrecht, the Netherlands
| | - Leonard H van den Berg
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Hessel Franssen
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - H Stephan Goedee
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, the Netherlands
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21
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Goedee HS, Sleutjes BTHM, Bakers JNE, Kruithof WJ, Kruitwagen-van Reenen ET, van der Pol WL. Electrophysiology of fatigue in chronic inflammatory demyelinating polyneuropathy: Can it be useful? Clin Neurophysiol 2020; 131:2912-2914. [PMID: 33250076 DOI: 10.1016/j.clinph.2020.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 09/30/2020] [Indexed: 11/26/2022]
Affiliation(s)
- H Stephan Goedee
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, UMC Utrecht, Utrecht, the Netherlands.
| | - Boudewijn T H M Sleutjes
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, UMC Utrecht, Utrecht, the Netherlands
| | - Jaap N E Bakers
- Department of Rehabilitation, UMC Utrecht Brain Center, UMC Utrecht, Utrecht, the Netherlands
| | - Willeke J Kruithof
- Department of Rehabilitation, UMC Utrecht Brain Center, UMC Utrecht, Utrecht, the Netherlands
| | | | - W Ludo van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, UMC Utrecht, Utrecht, the Netherlands
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Kariyawasam D, D'Silva A, Howells J, Herbert K, Geelan-Small P, Lin CSY, Farrar MA. Motor unit changes in children with symptomatic spinal muscular atrophy treated with nusinersen. J Neurol Neurosurg Psychiatry 2020; 92:jnnp-2020-324254. [PMID: 33106369 PMCID: PMC7803907 DOI: 10.1136/jnnp-2020-324254] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 08/10/2020] [Accepted: 09/02/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To elucidate the motor unit response to intrathecal nusinersen in children with symptomatic spinal muscular atrophy (SMA) using a novel motor unit number estimation technique. METHODS MScanFit MUNE studies were sequentially undertaken from the abductor pollicis brevis muscle after stimulation of the median nerve in a prospective cohort of symptomatic children with SMA, undergoing intrathecal treatment with nusinersen at a single neuromuscular centre from June 2017 to August 2019. Electrophysiological measures included compound muscle action potential (CMAP), motor unit number estimation (MUNE), motor unit number contributing to 50%-100% of CMAP (N50) and measures of collateral reinnervation including largest single motor unit potential (LSMUP) and amplitude of the smallest unit contributing to N50 (A50). RESULTS Twenty children (median age 99 months, range 4-193) were followed for a median of 13.8 (4-33.5) months. Therapeutic intervention was an independent and significant contributor to an increase in CMAP (p = 0.005), MUNE (p = 0.001) and N50 (p = 0.04). The magnitude of this electrophysiological response was increased in children with shorter disease durations (p<0.05). Electrophysiological changes delineated children who were functionally stable from those who attained clinically significant gains in motor function. INTERPRETATION Nusinersen therapy facilitated functional innervation in SMA through recovery of smaller motor units. Delineation of biomechanisms of therapeutic response may be the first step in identifying potential novel targets for disease modification in this and other motor neuropathies. MScanFit MUNE techniques may have a broader role in establishing biomarkers of therapeutic response in similar adult-onset diseases.
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Affiliation(s)
- Didu Kariyawasam
- Neurology, Sydney Children's Hospital Randwick, Randwick, New South Wales, Australia
- School of Women's and Children's Health, UNSW Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Arlene D'Silva
- School of Women's and Children's Health, UNSW Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Karen Herbert
- Physiotherapy, Syndey Children's Hospital, Randwick, Sydney, New South Wales, Australia
| | - Peter Geelan-Small
- Mark Wainwright Analytical Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Cindy Shin-Yi Lin
- Central Clinical School, Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Michelle Anne Farrar
- Neurology, Sydney Children's Hospital Randwick, Randwick, New South Wales, Australia
- School of Women's and Children's Health, UNSW Medicine, University of New South Wales, Sydney, New South Wales, Australia
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