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Shefner JM, Musaro A, Ngo ST, Lunetta C, Steyn FJ, Robitaille R, De Carvalho M, Rutkove S, Ludolph AC, Dupuis L. Skeletal muscle in amyotrophic lateral sclerosis. Brain 2023; 146:4425-4436. [PMID: 37327376 PMCID: PMC10629757 DOI: 10.1093/brain/awad202] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/16/2023] [Accepted: 05/30/2023] [Indexed: 06/18/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS), the major adult-onset motor neuron disease, has been viewed almost exclusively as a disease of upper and lower motor neurons, with muscle changes interpreted as a consequence of the progressive loss of motor neurons and neuromuscular junctions. This has led to the prevailing view that the involvement of muscle in ALS is only secondary to motor neuron loss. Skeletal muscle and motor neurons reciprocally influence their respective development and constitute a single functional unit. In ALS, multiple studies indicate that skeletal muscle dysfunction might contribute to progressive muscle weakness, as well as to the final demise of neuromuscular junctions and motor neurons. Furthermore, skeletal muscle has been shown to participate in disease pathogenesis of several monogenic diseases closely related to ALS. Here, we move the narrative towards a better appreciation of muscle as a contributor of disease in ALS. We review the various potential roles of skeletal muscle cells in ALS, from passive bystanders to active players in ALS pathophysiology. We also compare ALS to other motor neuron diseases and draw perspectives for future research and treatment.
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Affiliation(s)
- Jeremy M Shefner
- Barrow Neurological Institute, Phoenix, AZ, USA
- College of Medicine, University of Arizona, Phoenix, AZ, USA
- College of Medicine, Creighton University, Phoenix, AZ, USA
| | - Antonio Musaro
- DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia—Fondazione Cenci Bolognetti, Scuola Superiore di Studi Avanzati Sapienza (SSAS), Rome, Italy
| | - Shyuan T Ngo
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
| | - Christian Lunetta
- Neurorehabilitation Department, Istituti Clinici Scientifici Maugeri IRCCS, Milan, Italy
| | - Frederik J Steyn
- Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Richard Robitaille
- Département de neurosciences, CIRCA, Université de Montréal, Montréal H7G 1T7, Canada
| | - Mamede De Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Seward Rutkove
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Albert C Ludolph
- Department of Neurology, University of Ulm, Ulm, Germany
- Deutsches Zentrum für neurodegenerative Erkrankungen (DZNE), Ulm, Germany
| | - Luc Dupuis
- Université de Strasbourg, Inserm, UMR-S1118, Mécanismes centraux et périphériques de la neurodégénérescence, CRBS, Strasbourg, France
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Kesim-Sahin O, Sirin NG, Erbas B, Artug T, Oguz-Akarsu E, Kocasoy-Orhan E, Baslo MB, Mammadova N, Emekli U, Oge AE. Compound muscle action potential scan and MScanFit motor unit number estimation during Wallerian degeneration after nerve transections. Muscle Nerve 2020; 62:239-246. [PMID: 32415858 DOI: 10.1002/mus.26923] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND Compound muscle action potential (CMAP) scan and MScanFit have been used to understand the consequences of denervation and reinnervation. This study aimed to monitor these parameters during Wallerian degeneration (WD) after acute nerve transections (ANT). METHODS Beginning after urgent surgery, CMAP scans were recorded at 1-2 day intervals in 12 patients with ANT of the ulnar or median nerves, by stimulating the distal stump (DS). Stimulus intensities (SI), steps, returners, and MScanFit were calculated. Studies were grouped according to the examination time after ANT. Results were compared with those of 27 controls. RESULTS CMAP amplitudes and MScanFit progressively declined, revealing a positive correlation with one another. SIs were higher in WD groups than controls. Steps appeared or disappeared in follow-up scans. The late WD group had higher returner% than the early WD and control groups. CONCLUSIONS MScanFit can monitor neuromuscular dysfunction during WD. SIs revealed excitability changes in DS.
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Affiliation(s)
- Ozlem Kesim-Sahin
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Nermin Gorkem Sirin
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Bahar Erbas
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.,Department of Pharmacology, Istanbul Bilim University, Istanbul, Turkey
| | - Tugrul Artug
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.,Department of Electrical and Electronics Engineering, Istanbul Arel University, Istanbul, Turkey
| | - Emel Oguz-Akarsu
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Elif Kocasoy-Orhan
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Mehmet Baris Baslo
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Nermin Mammadova
- Department of Reconstructive and Plastic Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Ufuk Emekli
- Department of Reconstructive and Plastic Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Ali Emre Oge
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
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3
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Kumar RI, Mallette MM, Cheung SS, Stashuk DW, Gabriel DA. A method for editing motor unit potential trains obtained by decomposition of surface electromyographic signals. J Electromyogr Kinesiol 2020; 50:102383. [DOI: 10.1016/j.jelekin.2019.102383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 12/04/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022] Open
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Harrigan ME, Filous AR, Tosolini AP, Morris R, Schwab JM, Arnold WD. Assessing Rat Forelimb and Hindlimb Motor Unit Connectivity as Objective and Robust Biomarkers of Spinal Motor Neuron Function. Sci Rep 2019; 9:16699. [PMID: 31723233 PMCID: PMC6853930 DOI: 10.1038/s41598-019-53235-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/29/2019] [Indexed: 12/13/2022] Open
Abstract
Sensitive and objective biomarkers of neuronal injury, degeneration, and regeneration can help facilitate translation of experimental findings into clinical testing. Whereas measures of upper motor neuron connectivity have been readily established, functional assessments of lower motor neuron (LMN) innervation of forelimb muscles are lacking. Compound muscle action potential (CMAP) and motor unit (MU) number estimation (MUNE) are well-established methods that allow longitudinal MU integrity monitoring in patients. In analogy we refined CMAP and MUNE methods for assessing spinal MU input in the rat forelimb and hindlimb. Repeated CMAP and MUNE recordings are robust (coefficients of variability: 4.5-11.3%), and MUNE measurements from forelimb wrist flexor muscles (415 ± 8 [SEM]) align with back-traced anatomical LMN counts (336 ± 16 [SEM]). For disease validation, cross-sectional blinded electrophysiological and muscle contractility measurements were obtained in a cohort of G93A SOD1 mutant overexpressing rats and compared with controls. Longitudinal assessment of mutant animals demonstrated progressive motor unit decline in the hindlimb to a greater extent than the forelimb. Hindlimb CMAP and MUNE demonstrated strong correlations with plantarflexion muscle contractility. Cross-species assessment of upper/fore- limb and lower/hind- limb motor units using objective electrophysiological CMAP and MUNE values as biomarkers will guide and improve bi-directional translation.
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Affiliation(s)
- Markus E Harrigan
- Department of Neurology, Spinal Cord Injury Medicine (Paraplegiology), The Ohio State University, Wexner Medical Center, Columbus, OH, USA
| | - Angela R Filous
- Department of Neurology, Spinal Cord Injury Medicine (Paraplegiology), The Ohio State University, Wexner Medical Center, Columbus, OH, USA
| | - Andrew P Tosolini
- Department of Neuromuscular Diseases, Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Renee Morris
- Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Jan M Schwab
- Department of Neurology, Spinal Cord Injury Medicine (Paraplegiology), The Ohio State University, Wexner Medical Center, Columbus, OH, USA
- Belford Center for Spinal Cord Injury, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
- Department of Physical Medicine and Rehabilitation, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
- Department of Neuroscience, The Ohio State University, Wexner Medical Center, Columbus, OH, USA
| | - W David Arnold
- Department of Neurology, Neuromuscular Division, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- Department of Physical Medicine and Rehabilitation, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- Department of Neuroscience, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
- Department of Physiology and Cell Biology, The Ohio State University, Wexner Medical Center, Columbus, OH, USA.
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Verber NS, Shepheard SR, Sassani M, McDonough HE, Moore SA, Alix JJP, Wilkinson ID, Jenkins TM, Shaw PJ. Biomarkers in Motor Neuron Disease: A State of the Art Review. Front Neurol 2019; 10:291. [PMID: 31001186 PMCID: PMC6456669 DOI: 10.3389/fneur.2019.00291] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/06/2019] [Indexed: 12/17/2022] Open
Abstract
Motor neuron disease can be viewed as an umbrella term describing a heterogeneous group of conditions, all of which are relentlessly progressive and ultimately fatal. The average life expectancy is 2 years, but with a broad range of months to decades. Biomarker research deepens disease understanding through exploration of pathophysiological mechanisms which, in turn, highlights targets for novel therapies. It also allows differentiation of the disease population into sub-groups, which serves two general purposes: (a) provides clinicians with information to better guide their patients in terms of disease progression, and (b) guides clinical trial design so that an intervention may be shown to be effective if population variation is controlled for. Biomarkers also have the potential to provide monitoring during clinical trials to ensure target engagement. This review highlights biomarkers that have emerged from the fields of systemic measurements including biochemistry (blood, cerebrospinal fluid, and urine analysis); imaging and electrophysiology, and gives examples of how a combinatorial approach may yield the best results. We emphasize the importance of systematic sample collection and analysis, and the need to correlate biomarker findings with detailed phenotype and genotype data.
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Affiliation(s)
- Nick S Verber
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Stephanie R Shepheard
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Matilde Sassani
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Harry E McDonough
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Sophie A Moore
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - James J P Alix
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Iain D Wilkinson
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Tom M Jenkins
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
| | - Pamela J Shaw
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom
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6
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Amin Lari A, Ghavanini AA, Bokaee HR. A review of electrophysiological studies of lower motor neuron involvement in amyotrophic lateral sclerosis. Neurol Sci 2019; 40:1125-1136. [PMID: 30877611 DOI: 10.1007/s10072-019-03832-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/07/2019] [Indexed: 02/08/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease involving both the upper and lower motor neuron diseases. In this review, we studied and compared different articles regarding the electrodiagnostic criteria for diagnosis of lower motor neuron pathology in ALS. We reviewed the most recent articles and metaanalysis regarding various lower motor neuron electrodiagnostic methods for ALS and their sensitivities. We concluded that Awaji Shima criteria is by far the most sensitive criteria for diagnosis of ALS.
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Affiliation(s)
- Ali Amin Lari
- Canadian Neurologic Center, Mississauga, ON, Canada.
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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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8
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Nicholson KA, Cudkowicz ME, Berry JD. Clinical Trial Designs in Amyotrophic Lateral Sclerosis: Does One Design Fit All? Neurotherapeutics 2015; 12:376-83. [PMID: 25700798 PMCID: PMC4404442 DOI: 10.1007/s13311-015-0341-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The last 2 decades have seen a surge in the number of amyotrophic lateral sclerosis (ALS) clinical trials with the hope of finding successful treatments. Clinical trialists aim to repurpose existing drugs and test novel compounds to target potential ALS disease pathophysiology. Recent technological advancements have led to the discovery of new causative genetic agents and modes of delivering potential therapy, calling for increasingly sophisticated trial design. The standard ALS clinical trial design may be modified depending on study needs: type of therapy; route of therapy delivery; phase of therapy development; applicable subpopulation; market availability of therapy; and utility of telemedicine. Novel biomarkers of diagnostic, predictive, prognostic, and pharmacodynamic value are undergoing development and validation for use in clinical trials. Design modifications build on the traditional clinical trial design and may be employed in either the learning or confirming trial phase. Novel designs aim to minimize patient risk, study duration, and sample size, while improving efficiency and promoting statistical power to herald an exciting era for clinical research in ALS.
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Affiliation(s)
- Katharine A Nicholson
- Massachusetts General Hospital, Department of Neurology, Neurological Clinical Research Institute, 165 Cambridge Street, Suite 600, Boston, MA, 02114, USA,
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9
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Ives CT, Findlater K, Shoesmith CL, Doherty TJ. Preliminary evaluation of the sensitivity to change of DE-STA motor unit number estimation in the upper trapezius muscle in amyotrophic lateral sclerosis. Clin Neurophysiol 2014; 126:1427-34. [PMID: 25453610 DOI: 10.1016/j.clinph.2014.10.013] [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: 12/20/2013] [Revised: 09/13/2014] [Accepted: 10/06/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To compare the sensitivity to change of decomposition-enhanced spike-triggered averaging (DE-STA) motor unit number estimation (MUNE) in the upper trapezius (UT) to that of various clinical outcome measures in subjects with amyotrophic lateral sclerosis (ALS). METHODS Ten patients with clinically probable or definite ALS were assessed at baseline, 2, 4 and 6months with the following outcome measures: manual muscle testing in five upper extremity muscle groups, scapular elevation and elbow flexion peak force measured with hand-held dynamometry, MUNE, forced vital capacity and the Revised ALS Functional Rating Scale (ALSFRS-R). RESULTS ALSFRS-R was the only outcome measure for which there was a significant difference between baseline and 6months (p=0.034). ALSFRS-R had the largest standardized response mean (SRM), and was thus the most sensitive to change. MUNE demonstrated a decline over 6months and a moderate SRM (-0.63). CONCLUSIONS This study has demonstrated a moderate degree of sensitivity to change for DE-STA MUNE as applied to the UT in subjects with ALS. SIGNIFICANCE In this preliminary study, DE-STA MUNE detected motor unit loss over 6months, with a moderate degree of sensitivity, in the upper trapezius of subjects with ALS.
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Affiliation(s)
- Colleen T Ives
- Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada
| | - Karen Findlater
- Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada
| | - Christen L Shoesmith
- Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada
| | - Timothy J Doherty
- Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada; Department of Physical Medicine and Rehabilitation, Western University, London, Ontario, Canada.
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10
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Abstract
Motor unit number estimation (MUNE) is an electrophysiological method designed to quantify motor unit loss in target muscles of interest. Most of the techniques are noninvasive and are therefore well suited for longitudinal monitoring. In this brief review, we describe the more commonly used techniques and their applications in amyotrophic lateral sclerosis, poliomyelitis, spinal muscular atrophy and hereditary sensorimotor neuropathies. Findings in some of these studies offer important pathophysiological insights. Since conventional electrophysiologic methods are not sensible measures of motor neuronal loss, MUNE could play a potentially important role in the diagnosis, monitoring of disease progression and response to treatment in neuromuscular diseases in which motor unit loss is a major feature.
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11
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Gooch CL, Doherty TJ, Chan KM, Bromberg MB, Lewis RA, Stashuk DW, Berger MJ, Andary MT, Daube JR. Motor unit number estimation: A technology and literature review. Muscle Nerve 2014; 50:884-93. [PMID: 25186553 DOI: 10.1002/mus.24442] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Clifton L. Gooch
- Department of Neurology; University of South Florida; Tampa Florida USA
| | - Timothy J. Doherty
- Department of Physical Medicine and Rehabilitation; University of Western Ontario; London Ontario Canada
- Department of Clinical Neurological Sciences; University of Western Ontario; London Ontario Canada
- Schulich School of Medicine and Dentistry; University of Western Ontario; London Ontario Canada
| | - K. Ming Chan
- Division of Physical Medicine and Rehabilitation/Centre for Neuroscience; University of Alberta; Edmonton Alberta Canada
| | - Mark B. Bromberg
- Department of Neurology; University of Utah; Salt Lake City Utah USA
| | - Richard A. Lewis
- Department of Neurology; Cedars-Sinai; Los Angeles California USA
| | - Dan W. Stashuk
- Systems Design Engineering; University of Waterloo; Waterloo Ontario Canada
| | - Michael J. Berger
- School of Kinesiology; University of Western Ontario; London Ontario Canada
- Schulich School of Medicine and Dentistry; University of Western Ontario; London Ontario Canada
| | - Michael T. Andary
- College of Osteopathic Medicine; Michigan State University; East Lansing Michigan USA
| | - Jasper R. Daube
- Department of Neurology; Mayo Clinic; Rochester Minnesota USA
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12
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Shefner JM, Mihaila D. Assessment of disease progression and functional benefit in neurodegenerative disease: can we tell the difference? Amyotroph Lateral Scler Frontotemporal Degener 2014; 15:337-43. [PMID: 24918689 DOI: 10.3109/21678421.2014.918150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Therapeutic strategies for neurodegenerative diseases include modalities intended to modulate disease progression as well as those whose intent is to improve or maintain functional capacity. As the search for pharmacodynamic markers has proved elusive, treatment outcomes most commonly reflect patient function. As a result, even when clinical trials show a beneficial effect, the underlying etiology of that benefit can be difficult to determine. This review summarizes recent trials in ALS and Parkinson's disease, with the goal of increasing understanding of how the choice of outcome measures influences what can be concluded from the results. Although most ALS trials have been negative in recent years, outcomes are reviewed in terms of potential conclusions that could have been drawn. Functional benefit has been established in a number of recent trials; however, the outcomes used have lead to uncertainty as to whether specific agents modify disease or alter function. In the absence of specific markers sensitive to alteration of disease specific pathways, the distinction between agents that alter underlying disease versus those that affect function may depend on underlying hypotheses rather than clinical trial results.
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Affiliation(s)
- Jeremy M Shefner
- Department of Neurology, SUNY Upstate Medical University , Syracuse, New York , USA
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13
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Unlusoy Acar Z, Yalinay Dikmen P, Yayla V, Başaran K, Emekli U, Öge AE. Decline of compound muscle action potentials and statistical MUNEs during Wallerian degeneration. Neurophysiol Clin 2014; 44:257-65. [PMID: 25240559 DOI: 10.1016/j.neucli.2014.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 01/21/2014] [Accepted: 04/12/2014] [Indexed: 12/12/2022] Open
Abstract
AIM OF THE STUDY In two previous studies, we found that the compound muscle action potential (CMAP) amplitude loss was significantly higher than the loss of estimated motor unit numbers in the course of Wallerian degeneration (WD). In order to overcome some drawbacks of the method previously used, we performed a similar CMAP vs MUNE comparison by using the statistical motor unit number estimation (MUNE) method. PATIENTS AND METHODS Initial electrophysiological studies on 6 patients were performed between 22 and 98 hours after the injuries; it was possible to make repeated examinations, four times in 1 nerve, twice in 1 nerve and three times in 4 nerves, before the eventual complete disappearance of the CMAPs. RESULTS The transected/intact (T/I) side CMAP ratios declined steeply as WD evolved. They were significantly lower than the relatively stable MUNE ratios 48 hours after the injury. CONCLUSION This study, performed with the use of statistical MUNE, strengthens our previous observation by the incremental method that might have some relevance to the pathophysiology of early WD. CMAP amplitude loss that is more than expected from the amount of axonal degeneration may indicate a considerable amount of inactive muscle fibers in the motor units innervated by the nerve fibers, which are undergoing degeneration but still retain their excitability. Although technical sources of error cannot be totally excluded, our findings could more likely be explained by the failing of neuromuscular synapses in an asynchronous order before complete unresponsiveness of the motor unit ensues.
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Affiliation(s)
- Z Unlusoy Acar
- Department of Neurology, TDV 29 May Hospital, 34091 Istanbul, Turkey
| | - P Yalinay Dikmen
- Department of Neurology, Acıbadem University School of Medicine, 34140 Istanbul, Turkey.
| | - V Yayla
- Department of Neurology, Dr. Sadi Konuk Bakırköy Education and Research Hospital, 34147 Istanbul, Turkey
| | - K Başaran
- Department of Plastic and Reconstructive Surgery, Istanbul University, Istanbul Faculty of Medicine, 34390 Istanbul, Turkey
| | - U Emekli
- Department of Plastic and Reconstructive Surgery, Istanbul University, Istanbul Faculty of Medicine, 34390 Istanbul, Turkey
| | - A E Öge
- Department of Neurology, Istanbul University, Istanbul Faculty of Medicine, 34390 Istanbul, Turkey
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14
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Arezzo JC, Seto S, Schaumburg HH. Sensory-motor assessment in clinical research trials. HANDBOOK OF CLINICAL NEUROLOGY 2014; 115:265-78. [PMID: 23931786 DOI: 10.1016/b978-0-444-52902-2.00016-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
The assessment of changes in sensory-motor function in clinical research presents a unique set of difficulties. Clinimetrics is the science of measurement as related to the identification of a clinical disorder, the tracing of the progression of the condition under study, and calculation of its impact. The selection of appropriate measures for clinical studies of sensory-motor function must consider validity, sensitivity, specificity, responsiveness, reliability, and feasibility. Reasonable measures of motor function in clinical research include manual examination of muscle strength, electrophysiology, functional scales, patient-reported outcomes (e.g., quality of life), and for severe conditions such as ALS, survival. The assessment of sensory function includes targeted electrophysiology and QOL, as well as more focused measures such as quantitative sensory testing and the scoring of positive symptoms. Each individual measure and each combination of endpoints has its strengths and limitations.
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Affiliation(s)
- Joseph C Arezzo
- Department of Neuroscience, Albert Einstein College of Medicine, New York, USA; Department of Neurology, Albert Einstein College of Medicine, New York, USA.
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15
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Paganoni S, Cudkowicz M, Berry JD. Outcome measures in amyotrophic lateral sclerosis clinical trials. CLINICAL INVESTIGATION 2014; 4:605-618. [PMID: 28203356 PMCID: PMC5305182 DOI: 10.4155/cli.14.52] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with an average survival of 3-5 years. While therapies for ALS remain limited, basic and translational ALS research has been host to numerous influential discoveries in recent years. These discoveries have led to a large pipeline of potential therapies that await testing in clinical trials. Until recently, ALS clinical trials have relied on a limited cadre of 'traditional' outcome measures, including survival and measures of function. These measures have proven useful, although imperfect, in Phase III ALS trials. However, their utility in early-phase ALS trials is limited. For these early trials, outcome measures focused on target engagement or biological pathway analysis might improve trial outcomes and better support the drug development process.
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Affiliation(s)
- Sabrina Paganoni
- Harvard Medical School, Department of Neurology, Neurological Clinical Research Institute (NCRI), Massachusetts Genera Hospital, MA, USA
- Harvard Medical School, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA, USA
| | - Merit Cudkowicz
- Harvard Medical School, Department of Neurology, Neurological Clinical Research Institute (NCRI), Massachusetts Genera Hospital, MA, USA
| | - James D Berry
- Harvard Medical School, Department of Neurology, Neurological Clinical Research Institute (NCRI), Massachusetts Genera Hospital, MA, USA
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Handgrip maximal voluntary isometric contraction does not correlate with thenar motor unit number estimation. Neurol Res Int 2012; 2012:187947. [PMID: 22649725 PMCID: PMC3357599 DOI: 10.1155/2012/187947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 02/09/2012] [Accepted: 02/21/2012] [Indexed: 12/11/2022] Open
Abstract
In slowly progressive conditions, such as motor neurone disease (MND), 50-80% of motor units may be lost before weakness becomes clinically apparent. Despite this, maximal voluntary isometric contraction (MVIC) has been reported as a clinically useful, reliable, and reproducible measure for monitoring disease progression in MND. We performed a study on a group of asymptomatic subjects that showed a lack of correlation between isometric grip strength and thenar MUNE. Motor unit number estimation (MUNE) estimates the number of functioning lower motor neurones innervating a muscle or a group of muscles. We used the statistical electrophysiological technique of MUNE to estimate the number of motor units in thenar group of muscles in 69 subjects: 19 asymptomatic Cu, Zn superoxide dismutase 1 (SOD 1) mutation carriers, 34 family controls, and 16 population controls. The Jamar hand dynamometer was used to measure isometric grip strength. This study suggests that MUNE is more sensitive for monitoring disease progression than maximal voluntary isometric contraction (MVIC), as MUNE correlates with the number of functional motor neurones. This supports the observation that patients with substantial chronic denervation can maintain normal muscle twitch tension until 50-80% of motor units are lost and weakness is detectable.
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Ngo ST, Baumann F, Ridall PG, Pettitt AN, Henderson RD, Bellingham MC, McCombe PA. The relationship between Bayesian motor unit number estimation and histological measurements of motor neurons in wild-type and SOD1(G93A) mice. Clin Neurophysiol 2012; 123:2080-91. [PMID: 22521362 DOI: 10.1016/j.clinph.2012.01.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 12/19/2011] [Accepted: 01/27/2012] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To assess the relationship between Bayesian MUNE and histological motor neuron counts in wild-type mice and in an animal model of ALS. METHODS We performed Bayesian MUNE paired with histological counts of motor neurons in the lumbar spinal cord of wild-type mice and transgenic SOD1(G93A) mice that show progressive weakness over time. We evaluated the number of acetylcholine endplates that were innervated by a presynaptic nerve. RESULTS In wild-type mice, the motor unit number in the gastrocnemius muscle estimated by Bayesian MUNE was approximately half the number of motor neurons in the region of the spinal cord that contains the cell bodies of the motor neurons supplying the hindlimb crural flexor muscles. In SOD1(G93A) mice, motor neuron numbers declined over time. This was associated with motor endplate denervation at the end-stage of disease. CONCLUSION The number of motor neurons in the spinal cord of wild-type mice is proportional to the number of motor units estimated by Bayesian MUNE. In SOD1(G93A) mice, there is a lower number of estimated motor units compared to the number of spinal cord motor neurons at the end-stage of disease, and this is associated with disruption of the neuromuscular junction. SIGNIFICANCE Our finding that the Bayesian MUNE method gives estimates of motor unit numbers that are proportional to the numbers of motor neurons in the spinal cord supports the clinical use of Bayesian MUNE in monitoring motor unit loss in ALS patients.
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Affiliation(s)
- S T Ngo
- University of Queensland Centre for Clinical Research, University of Queensland, Australia
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Asymmetry of motor unit number estimate and its rate of decline in patients with amyotrophic lateral sclerosis. J Clin Neurophysiol 2012; 28:528-32. [PMID: 21946374 DOI: 10.1097/wnp.0b013e318231c9e0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This study was performed to investigate the asymmetry of motor unit number estimate (MUNE) and its longitudinal course in patients with amyotrophic lateral sclerosis. A modified statistical MUNE was performed at the hypothenar muscles bilaterally in a total of 135 patients, and 18 of these patients underwent a follow-up study. The degree of asymmetry varied considerably among those patients whose average MUNE of both sides was moderately reduced, whereas it tended to be low in those whose average MUNE was either severely reduced or close to normal. The rate of motor unit loss was also asymmetric, and two distinct patterns were identified. In patients whose MUNE was greater than 30 in both sides (n = 7), the rate of motor unit loss tended to be greater in the initially more affected side compared with the contralateral one, yielding the so-called lead phenomenon. In contrast, the other patients (n = 11) tended to show the opposite pattern of "catch-up," that is, MUNE declined faster in the initially less affected side compared with the contralateral one. This study shows that not only the MUNE but also the rate of motor unit loss are frequently asymmetric in amyotrophic lateral sclerosis patients.
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dl-3-n-butylphthalide extends survival by attenuating glial activation in a mouse model of amyotrophic lateral sclerosis. Neuropharmacology 2012; 62:1004-10. [DOI: 10.1016/j.neuropharm.2011.10.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 10/13/2011] [Accepted: 10/14/2011] [Indexed: 12/12/2022]
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Moldovan M, Alvarez S, Pinchenko V, Marklund S, Graffmo KS, Krarup C. Nerve excitability changes related to axonal degeneration in amyotrophic lateral sclerosis: Insights from the transgenic SOD1G127X mouse model. Exp Neurol 2012; 233:408-20. [DOI: 10.1016/j.expneurol.2011.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 09/16/2011] [Accepted: 11/07/2011] [Indexed: 12/13/2022]
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Bowser R, Turner MR, Shefner J. Biomarkers in amyotrophic lateral sclerosis: opportunities and limitations. Nat Rev Neurol 2011; 7:631-8. [DOI: 10.1038/nrneurol.2011.151] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Motor Unit Number Index (MUNIX): A novel neurophysiological marker for neuromuscular disorders; test–retest reliability in healthy volunteers. Clin Neurophysiol 2011; 122:1867-72. [PMID: 21396884 DOI: 10.1016/j.clinph.2011.02.017] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 02/10/2011] [Accepted: 02/16/2011] [Indexed: 12/13/2022]
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Shefner JM, Watson ML, Simionescu L, Caress JB, Burns TM, Maragakis NJ, Benatar M, David WS, Sharma KR, Rutkove SB. Multipoint incremental motor unit number estimation as an outcome measure in ALS. Neurology 2011; 77:235-41. [PMID: 21676915 DOI: 10.1212/wnl.0b013e318225aabf] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Improved outcome measures are necessary to reduce sample size and increase power in amyotrophic lateral sclerosis (ALS) clinical trials. Motor unit number estimation (MUNE) is a potentially attractive tool. MUNE methods previously employed in multicenter trials exhibited excessive variability and were prone to artifact. OBJECTIVE To evaluate a modification of standard incremental MUNE in a multicenter natural history study of subjects with ALS. METHODS Fifty healthy subjects were evaluated twice and 71 subjects with ALS were studied repeatedly for up to 500 days. Side and nerve studied was based on clinical examination findings. Nerves were stimulated at 3 specified locations and 3 increments were obtained at each location. Average single motor unit action potential (SMUP) amplitude was calculated by adding the amplitude of the third increment at each location and dividing by 9; SMUP was divided into maximum CMAP amplitude to determine the MUNE. RESULTS Test-retest variability was 9% in normal subjects. Average MUNE for normal subjects was 225 (±87), and was 41.9 (±39) among subjects with ALS at baseline. Subjects with ALS showed clear decrements over time, with an overage rate of decline of approximately 9% per month. SMUP amplitude increased with time in a fashion consistent with the known pathophysiology of ALS. CONCLUSION Multipoint incremental MUNE has a number of attributes that make it attractive as an outcome measure in ALS and other diseases characterized by motor unit loss. It can be rapidly performed on any EMG machine and has repeatability and rates of decline that favorably compare to other previously described methods.
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Affiliation(s)
- J M Shefner
- Department of Neurology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
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Blok J, van Dijk J, Drenthen J, Maathuis E, Stegeman D. Size does matter: The influence of motor unit potential size on statistical motor unit number estimates in healthy subjects. Clin Neurophysiol 2010; 121:1772-80. [DOI: 10.1016/j.clinph.2010.03.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 02/17/2010] [Accepted: 03/27/2010] [Indexed: 12/12/2022]
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Neuwirth C, Nandedkar S, Stålberg E, Weber M. Motor unit number index (MUNIX): A novel neurophysiological technique to follow disease progression in amyotrophic lateral sclerosis. Muscle Nerve 2010; 42:379-84. [PMID: 20589888 DOI: 10.1002/mus.21707] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Christoph Neuwirth
- Neuromuscular Diseases Unit and Kantonsspital St. Gallen, St. Gallen, Switzerland.
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David WS, Goyal N, Henry FP, Baldassari LE, Redmond RW. Validation of an incremental motor unit number estimation technique in rabbits. Muscle Nerve 2010; 41:794-9. [PMID: 20169589 DOI: 10.1002/mus.21590] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Motor unit number estimation (MUNE) allows for quantitative assessment of functional motor units in a nerve. Several techniques have been applied to human studies. Although MUNE has been performed in animals to study neurological disorders, reproducibility has not been addressed. We analyzed the test-retest reproducibility of an incremental MUNE technique in rabbits and performed histological correlation. A peroneal MUNE was performed in 9 rabbits on two occasions separated by 30 days. MUNE was then performed on 18 rabbits prior to euthanize. A count of total fibers and a second count of large myelinated fibers were performed on nerve cross-sections. Test-retest reproducibility revealed an intraclass correlation coefficient (ICC) of 0.75. The average test-retest relative difference was 26.6%. Comparison of MUNE and histomorphometrical counts revealed a correlation coefficient (r) of 0.21 (total fiber counts) and 0.27 (large fibers). Although incremental MUNE has a high degree of reproducibility in rabbits, there is poor correlation with histological fiber counts.
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Affiliation(s)
- William S David
- Neuromuscular Diagnostics Center, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge Street, Suite 820, Boston, Massachusetts 02114, USA
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van Dijk JP, Schelhaas HJ, Van Schaik IN, Janssen HMHA, Stegeman DF, Zwarts MJ. Monitoring disease progression using high-density motor unit number estimation in amyotrophic lateral sclerosis. Muscle Nerve 2010; 42:239-44. [PMID: 20544934 DOI: 10.1002/mus.21680] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Johannes P van Dijk
- Department of Neurology, Clinical Neurophysiology-920, Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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Lehky TJ, Chen CJ, di Prospero NA, Rhodes LE, Fischbeck K, Floeter MK. Standard and modified statistical MUNE evaluations in spinal-bulbar muscular atrophy. Muscle Nerve 2009; 40:809-14. [PMID: 19670325 DOI: 10.1002/mus.21399] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Motor unit number estimation (MUNE), a technique used in amyotrophic lateral sclerosis (ALS) clinical trials to quantitatively assess motor neuron loss, should also be valuable in assessing progression in spinal bulbar muscular atrophy (SBMA), an x-linked neuronopathy. In ALS, instability of single motor units (SMUP) prompted Shefner et al.6(6) to modify the statistical MUNE method to exclude SMUPs < or = 40 microV. It is unknown if there is similar SMUP instability in the more chronic degenerative disease of SBMA. In this study the standard parameter of excluding SMUP < 10 microV was compared with the exclusion of SMUP < 40 microV in the calculation of the statistical MUNE. The mean statistical MUNE, using the standard method and the Shefner et al. method, was 60 +/- 21 to 47 +/- 23, respectively. Similar to ALS, SBMA showed an increased proportion (17%) of individual SMUPs < or = 40 microV compared to normal controls. In conclusion, excluding SMUPs < or = 40 microV from the statistical MUNE calculations is appropriate for SBMA subjects because their SMUP, characteristics are similar to ALS. Exclusion of the low-amplitude SMUPs reduces the calculated MUNE.
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Affiliation(s)
- Tanya J Lehky
- EMG Section, NINDS, NIH, Building 10/Room 7-5680, 10 Center Drive, Bethesda, Maryland 20892-1404, USA.
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Shefner JM. Statistical motor unit number estimation and ALS trials: the effect of motor unit instability. MOTOR UNIT NUMBER ESTIMATION (MUNE) AND QUANTITATIVE EMG - SELECTED PRESENTATIONS FROM THE SECOND INTERNATIONAL SYMPOSIUM ON MUNE AND QEMG, SNOWBIRD, UTAH, USA, 18–20 AUGUST 2006 2009; 60:135-41. [DOI: 10.1016/s1567-424x(08)00013-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Abstract
Clinical trials in amyotrophic lateral sclerosis have significantly evolved over the last decade. New outcome measures have been developed that have reduced the sample size requirement as compared with survival studies. There has been increasing recognition that dose-ranging studies are crucial to full evaluation of experimental agents. While the requirements of late stage trials have not changed, many new designs have been suggested for earlier phase development. While no design achieves the perfect balance of sensitivity and efficiency, clinical trialists continue to work toward the goals of smaller and shorter trials so that more compounds can be studied concurrently.
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Yamamoto M, Tanaka F, Tatsumi H, Sobue G. A strategy for developing effective amyotropic lateral sclerosis pharmacotherapy: from clinical trials to novel pharmacotherapeutic strategies. Expert Opin Pharmacother 2008; 9:1845-57. [PMID: 18627324 DOI: 10.1517/14656566.9.11.1845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND The pathomechanism of sporadic amyotropic lateral sclerosis is not clearly understood, although a proportion of familial amyotropic lateral sclerosis is caused by superoxide dismutase 1 mutations. Theories based on studies of human post-mortem tissue, research on animal models and in vitro work have been proposed for the pathogenesis of amyotropic lateral sclerosis, but the pathogenesis is not the same between sporadic and familial amyotropic lateral sclerosis. OBJECTIVE/METHODS Drug candidates were tested using superoxide dismutase 1 mutant mice. Although the candidates were shown to be effective in mice, clinical trials in humans have failed to identify any truly effective pharmacotherapies in sporadic amyotropic lateral sclerosis, with only riluzole providing a modest improvement in survival. Ongoing or planned trials are exploring the value of antiglutamatergic drugs, antioxidants, neurotrophic factors, anti-inflammatory drugs and anti-aggregation drugs. RESULTS/CONCLUSIONS A combination of drugs acting on different mechanisms is needed for effective therapy. Moreover, gene expression profiling and genome-wide association studies, together with inhibitory RNA techniques, are helpful for developing new pharmacotherapeutic strategies including gene therapy. It is also likely that the recently advanced generation of induced pluripotent stem cells will lead to the development of cell therapy for amyotropic lateral sclerosis. In addition to finding effective therapies, research is also needed in order to detect early disease markers since pharmacotherapy is most beneficial when given early in the course of sporadic amyotropic lateral sclerosis.
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Affiliation(s)
- Masahiko Yamamoto
- Nagoya University Graduate School of Medicine, Department of Neurology, Nagoya 466-8550, Aichi, Japan
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Bromberg MB, Brownell AA. Motor unit number estimation in the assessment of performance and function in motor neuron disease. Phys Med Rehabil Clin N Am 2008; 19:509-32, ix. [PMID: 18625413 DOI: 10.1016/j.pmr.2008.02.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Motor unit number estimation (MUNE) is a unique electrophysiologic test used to estimate the number of surviving motor units in a muscle or group of muscles. It is used most frequently to monitor lower motor neuron loss in amyotrophic lateral sclerosis and spinal muscle atrophy. Of particular interest is its use as an endpoint measure in clinical trials for these diseases. This article describes the principles of MUNE and the factors that need to be considered, and reviews several techniques that have been used in clinical trials and in monitoring progression. It then reviews experience with MUNE in clinical trials for amyotrophic lateral sclerosis and spinal muscle atrophy and discusses how MUNE correlates with measures of function.
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Affiliation(s)
- Mark B Bromberg
- Clinical Neuroscience Center, Department of Neurology, University of Utah Health Sciences Center, 175 North Medical Drive, Salt Lake City, UT 84132, USA.
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Daube JR. Motor unit number estimates: A Holy Grail? Clin Neurophysiol 2007; 118:2542-3. [PMID: 17910936 DOI: 10.1016/j.clinph.2007.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 08/11/2007] [Accepted: 08/18/2007] [Indexed: 11/18/2022]
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Attarian S, Verschueren A, Pouget J. Magnetic stimulation including the triple-stimulation technique in amyotrophic lateral sclerosis. Muscle Nerve 2007; 36:55-61. [PMID: 17443663 DOI: 10.1002/mus.20789] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To study the relative importance of upper motor neuron (UMN) dysfunction in the weakness of amyotrophic lateral sclerosis (ALS) and to compare the sensitivity of several transcranial magnetic stimulation (TMS) parameters as means of assessing UMN impairment in ALS, we used TMS to evaluate one upper limb of 63 patients. The triple-stimulation technique (TST) and silent period (SP) were found to be the most frequently abnormal parameters (55.6% and 47.6%, respectively), without significant difference in their diagnostic sensitivity. The SP was found to be a useful parameter in patients with suspected or possible ALS. A positive correlation was found between weakness and the TST amplitude ratio, indicating that weakness may partly be caused by UMN dysfunction. Thus, the TST provides a quantitative tool for assessing UMN conduction failure. When used in association with the SP, the TST provides a sensitive diagnostic tool for use on ALS patients.
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Affiliation(s)
- Shahram Attarian
- Department of Neurology and Neuromuscular Diseases, CHU La Timone, 264 rue Saint-Pierre, 13385 Marseille, France.
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Henderson RD, Ridall PG, Hutchinson NM, Pettitt AN, McCombe PA. Bayesian statistical MUNE method. Muscle Nerve 2007; 36:206-13. [PMID: 17487869 DOI: 10.1002/mus.20805] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have developed a new method of motor unit number estimation (MUNE) for assessing diseases such as amyotrophic lateral sclerosis (ALS). We used data from the whole stimulus-response curve and then performed a Bayesian statistical analysis. The Bayesian method uses mathematical equations that express the basic elements of motor unit activation after electrical stimulation and allows for the sources of variability and uncertainty in this formulation. The Bayesian MUNE method was used to determine the most probable number of motor units in 8 normal subjects, 49 ALS subjects, and 3 subjects with progressive lower motor neuron (LMN) weakness. In normals the number of motor units was calculated to be 75-85 in hand and 40-58 in foot muscles. In ALS subjects the number of motor units per muscle was less than in normal subjects. In 17 ALS subjects and 3 subjects with LMN weakness the median, ulnar, or peroneal nerve was studied on repeated occasions over an average of 189 days (range 63-1,071) and the number of motor units progressively declined, with a half-life ranging from 62-834 days. The results of our MUNE technique were reproducible on replicate studies. A Bayesian statistical MUNE method is a new approach that can be used to study ALS patients serially for assessment and treatment trials.
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Affiliation(s)
- Robert D Henderson
- Department of Neurology, Royal Brisbane and Women's Hospital, Department of Medicine, University of Queensland, Butterfield Street, Herston 4029, Queensland, Australia.
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