531 results match your criteria Single-Fiber EMG


Motor Unit Properties of the First Dorsal Interosseous in Chronic Stroke Subjects: Concentric Needle and Single Fiber EMG Analysis.

Front Physiol 2018 3;9:1587. Epub 2018 Dec 3.

Department of Physical Medicine & Rehabilitation, The University of Texas Health Science Center at Houston, Houston, TX, United States.

The purpose of this study was to better understand changes in motor unit electrophysiological properties in people with chronic stroke based on concentric needle electromyography (EMG) and single fiber EMG recordings. The first dorsal interosseous (FDI) muscle was studied bilaterally in eleven hemiparetic stroke subjects. A significant increase in mean fiber density (FD) was found in the paretic muscle compared with the contralateral side based on single fiber EMG (1. Read More

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http://dx.doi.org/10.3389/fphys.2018.01587DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6287192PMC
December 2018

Concentric or monopolar electrode for jitter determination in orbicularis oculi.

Clin Neurophysiol 2018 Dec 26;129(12):2552-2556. Epub 2018 Oct 26.

Institute of Physiology Unit, Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Portugal; Department of Neurosciences and Mental Health, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, Portugal. Electronic address:

Objectives: To investigate if monopolar (MN) and concentric (CN) electrodes are equivalent for volitional contraction jitter estimation in orbicularis oculi (OO), and to study the effect of selecting a specific high-pass filter.

Methods: We studied neuromuscular jitter in OO on both sides in 100 consecutive patients with a clinical diagnosis of ocular myasthenia gravis (MG). We used either MN (50 patients) or CN (50 patients) electrodes in individual patients, according to a randomised protocol, with a 1kH high pass filter on one side and a 3kH filter on the other. Read More

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http://dx.doi.org/10.1016/j.clinph.2018.09.024DOI Listing
December 2018
11 Reads

Glioneuronal brainstem tumor - It's all in the eyes.

J Clin Neurosci 2018 Oct 23. Epub 2018 Oct 23.

Alfred Hospital, Department of Neurology, Melbourne, Australia. Electronic address:

A previously well man presented with several months' history of neurological symptoms including diplopia and balance difficulties. Examination revealed fluctuating neurological deficits, fatigable weakness and slowed saccades. Extensive testing revealed mildly elevated cerebrospinal fluid protein, strongly positive single fiber electromyography and a dorsal pontine lesion at the floor of the 4th ventricle. Read More

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http://dx.doi.org/10.1016/j.jocn.2018.10.084DOI Listing
October 2018
7 Reads

Identification of components from distant fibers in a recorded single muscle fiber potential (SFP) - a new approach to the SFP criteria.

Neurophysiol Clin 2018 Oct 13. Epub 2018 Oct 13.

Department of Neurology, Medical University of Warsaw, Banacha 1A str., 02-097 Warsaw, Poland. Electronic address:

Objectives: The aim of our study was to verify the effectiveness of single fiber potential (SFP) criteria in cases when the potential recorded using single fiber electrode (SFE) or concentric needle electrode (CNE) is contaminated by distant fibers.

Methods: Morphological counterparts of SFP were studied using computer simulations. In this study, we examined triphasic potentials using a model of a linear source of SFP. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S09877053183005
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http://dx.doi.org/10.1016/j.neucli.2018.09.003DOI Listing
October 2018
2 Reads

Stimulated single-fiber electromyography (sSFEMG) in Lambert-Eaton syndrome.

Clin Neurophysiol Pract 2018 13;3:148-150. Epub 2018 Aug 13.

I Division of Neurology and Neurophysiopathology, University of Campania "Luigi Vanvitelli", Naples, Italy.

Objective: To report the clinical features and the neurophysiological approach of a patient with Lambert-Eaton myasthenic syndrome (LEMS), highlighting the diagnostic role of the stimulated single fiber electromyography (sSFEMG).

Case Report: A 60-year-old woman presenting with the LEMS triad (proximal and axial weakness, autonomic dysfunction and areflexia) was evaluated by neurophysiological tests (electroneuromyography, repetitive stimulation test (TSR), voluntary and stimulated SFEMG). We reported: ) increase of compound muscle action potential (CMAP) amplitude (>60%) following brief isometric exercise compared to the rest (baseline); ) decremental/incremental response of CMAP amplitude at low- (3 Hz) and high-frequency (30 Hz) repetitive stimulation test (RST), respectively; ) increased neuromuscular jitter and blocking at voluntary single-fiber electromyography (vSFEMG); ) stimulation rate-dependent reduction of the neuromuscular jitter and blocking at sSFEMG. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S2467981X183002
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http://dx.doi.org/10.1016/j.cnp.2018.07.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6134173PMC
August 2018
5 Reads

Serial Stimulated Jitter Analysis In Juvenile Myasthenia Gravis.

Muscle Nerve 2018 Nov 2;58(5):729-732. Epub 2018 Oct 2.

Division of Pediatric Neurology, Department of Pediatrics, Emory University School of Medicine, Atlanta, 1605 Chantilly Drive NE, Suite 300, Atlanta, Georgia, 30324, USA.

Introduction: Clinical and electrophysiological studies to measures disease activity in juvenile myasthenia gravis (JMG) are limited.

Methods: Retrospective review of the clinical profile, Myasthenia Gravis Foundation of America (MGFA) scores, serial stimulated jitter analysis (Stim-JA) of the orbicularis oculi muscle, grip strength, and spirometry of patients with JMG who were followed in a multidisciplinary clinic was performed.

Results: Thirteen patients with JMG (9 females) with mean age of 13. Read More

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http://doi.wiley.com/10.1002/mus.26319
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http://dx.doi.org/10.1002/mus.26319DOI Listing
November 2018
20 Reads

Electromyography in Pediatric Population.

Noro Psikiyatr Ars 2018 Mar 19;55(1):36-39. Epub 2018 Mar 19.

Department of Neurology, Istanbul University Faculty of Medicine, İstanbul, Turkey.

Introduction: Electrodiagnostic evaluation provides an important extension to the neurological examination for the evaluation of pediatric neuromuscular disease. Many pediatric neuromuscular diseases are analogous to those seen in the adult. However, the relative frequency of these illnesses varies greatly when different age populations are compared. Read More

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http://dx.doi.org/10.5152/npa.17023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6045805PMC
March 2018
17 Reads

Role of concentric needle Single Fiber Electromyography in detection of subclinical motor involvement in carpal tunnel syndrome.

Egypt J Neurol Psychiatr Neurosurg 2018 25;54(1). Epub 2018 Apr 25.

1Clinical Neurophysiology Unit, Kasr Alainy Hospital, Faculty of Medicine, Cairo University, Cairo, Egypt.

Background: Conventional motor nerve conduction studies are usually normal in early and mild carpal tunnel syndrome (CTS). Single-fiber electromyography (SFEMG) measures the mean consecutive difference (MCD) as an expression of the variability in impulse transmission over the motor endplates and along the nerve fibers distally to the last branching point and along the muscle fibers.Application of concentric needle SFEMG in a group of CTS patients who showed pure sensory abnormalities in nerve conduction studies to examine for subclinical motor involvement. Read More

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http://dx.doi.org/10.1186/s41983-018-0004-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5954771PMC
April 2018
1 Read

Diagnosis of Myasthenia Gravis.

Neurol Clin 2018 May;36(2):261-274

Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 2012, Kansas City, KS 66160, USA.

Myasthenia gravis (MG) diagnosis is primarily clinically based. By the end of the clinical evaluation, clinicians have a sense as to whether presenting symptoms and elicited signs are weakly or strongly supportive of MG. Diagnostic tests can reaffirm the clinicians' impression. Read More

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http://dx.doi.org/10.1016/j.ncl.2018.01.010DOI Listing
May 2018
12 Reads

Needle electromyography practice patterns in patients taking novel oral anticoagulants: A survey-based study.

Muscle Nerve 2018 Aug 25;58(2):307-309. Epub 2018 Mar 25.

Department of Neurology and Rehabilitation Medicine, University of Cincinnati, 260 Stetson Street Suite 2300, ML 0525, Cincinnati, Ohio, USA.

Introduction: This study sought to evaluate needle electromyography (EMG) practice patterns among electromyographers with patients taking novel oral anticoagulants (NOAC).

Methods: A survey questionnaire was sent to members of the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) via email web link. Anonymous survey responses were collected through an online website. Read More

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http://dx.doi.org/10.1002/mus.26119DOI Listing
August 2018
4 Reads

Increased Single-Fiber Jitter Level Is Associated With Reduction in Motor Function With Aging.

Am J Phys Med Rehabil 2018 Aug;97(8):551-556

From the Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, Maryland (TC, YT); Department of Medicine, Division of Geriatric Medicine and Gerontology, Johns Hopkins School of Medicine, Baltimore, Maryland (JW); and Department of Neurology, Neuromuscular Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland (TC, AH).

Objective: Age-associated skeletal muscle weakness is a major contributing factor to an increased late life mortality and morbidity, but its neurobiology is poorly understood. Previously, we provided histological evidence of dying-back axonal degeneration of motor neurons and denervation of neuromuscular junctions in age-associated muscle weakness. Given this, we aimed to evaluate the relation between impaired neuromuscular transmission and various aspects of age-associated muscle weakness. Read More

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http://dx.doi.org/10.1097/PHM.0000000000000915DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051904PMC
August 2018
2 Reads

Repetitive nerve stimulation and jitter measurement with disposable concentric needle electrode in newly diagnosed myasthenia gravis patients.

Neurophysiol Clin 2018 Oct 25;48(5):261-267. Epub 2018 Feb 25.

Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey.

Introduction: The aim of this study was to define the diagnostic accuracy of concentric needle (CN)-jitter in newly diagnosed myasthenia gravis (MG) patients and to compare CN-jitter with repetitive nerve stimulation.

Methods: In 30 MG patients, repetitive nerve stimulation in 4 muscles (orbicularis oculi, nasalis, trapezius and abductor digiti minimi) and CN-jitter of extensor digitorum (ED) and frontalis muscles were evaluated.

Results: Twenty-eight of 30 patients (93%) had high jitter in at least one muscle. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S09877053173027
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http://dx.doi.org/10.1016/j.neucli.2018.01.003DOI Listing
October 2018
15 Reads

Presynaptic congenital myasthenic syndrome with altered synaptic vesicle homeostasis linked to compound heterozygous sequence variants in RPH3A.

Mol Genet Genomic Med 2018 05 14;6(3):434-440. Epub 2018 Feb 14.

Department of Anesthesiology and Pain Medicine, University of California Davis, Sacramento, CA, USA.

Background: Monogenic defects of synaptic vesicle (SV) homeostasis have been implicated in many neurologic diseases, including autism, epilepsy, and movement disorders. In addition, abnormal vesicle exocytosis has been associated with several endocrine dysfunctions.

Methods: We report an 11 year old girl with learning disabilities, tremors, ataxia, transient hyperglycemia, and muscle fatigability responsive to albuterol sulfate. Read More

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http://dx.doi.org/10.1002/mgg3.370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014458PMC
May 2018
13 Reads

Coexisting myasthenia gravis, myositis, and polyneuropathy induced by ipilimumab and nivolumab in a patient with non-small-cell lung cancer: A case report and literature review.

Medicine (Baltimore) 2017 Dec;96(50):e9262

Department of Neurology.

Rationale: Immune checkpoint inhibitors have led to the development of new approaches for cancer treatment with positive outcomes. However, checkpoint blockade is associated with a unique spectrum of immune-related adverse events (irAEs), which may cause irreversible neurological deficits and even death.

Patient Concerns: We presented a case of a 57-year-old man with non-small-cell lung cancer. Read More

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http://dx.doi.org/10.1097/MD.0000000000009262DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5815782PMC
December 2017
6 Reads

Clinical and CN-SFEMG evaluation of neostigmine test in myasthenia gravis.

Neurol Sci 2018 Feb 12;39(2):341-345. Epub 2018 Jan 12.

Department "G. F. Ingrassia", Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.

Neostigmine test (NT) is a pharmacological test, demonstrating a clinical improvement in patients affected by myasthenia gravis (MG). We aim to compare clinical evaluation and neurophysiological recordings by concentric-needle single-fiber electromyography (CN-SFEMG) in response to acute administration of neostigmine in ocular and generalized MG patients. Twenty-three MG patients (10 with ocular MG and 13 with generalized MG) were evaluated before and after 90 min neostigmine 0. Read More

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http://link.springer.com/10.1007/s10072-017-3194-0
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http://dx.doi.org/10.1007/s10072-017-3194-0DOI Listing
February 2018
14 Reads

Extending knowledge of the clinical picture of Balkan adder (Vipera berus bosniensis) envenoming: The first photographically-documented neurotoxic case from South-Western Hungary.

Toxicon 2018 Mar 2;143:29-35. Epub 2018 Jan 2.

"Moritz Kaposi" General Hospital, Department of Surgery, Tallián Gyula u. 20-32, H-7400 Kaposvár, Hungary.

We report a severe envenoming associated with minimal local symptoms following a Balkan adder (Vipera berus bosniensis) bite in South-Western Hungary. A 63-year-old male with a history of hypertension and sinus bradycardia (45/min) was bitten by a sub-adult specimen of V. b. Read More

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http://dx.doi.org/10.1016/j.toxicon.2017.12.053DOI Listing
March 2018
14 Reads

Correlating motor unit morphology with bioelectrical activity - A simulation study.

Clin Neurophysiol 2018 01 16;129(1):271-279. Epub 2017 Nov 16.

Neuromuscular Unit, Mossakowski Medical Research Center, Polish Academy of Sciences, 02-106 Warsaw, Pawinskiego 5, Poland.

Objectives: The aim was to determine motor unit morphology underpinning the various MUP waveforms using MUP analysis.

Method: The simulation method is based on the decomposition of MUP into single fiber potentials. Number of fibers, fiber diameters and fiber to electrode distances were determined. Read More

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http://dx.doi.org/10.1016/j.clinph.2017.11.003DOI Listing
January 2018
6 Reads

Confirmed Ceylon krait (Bungarus ceylonicus) envenoming in Sri Lanka resulting in neuromuscular paralysis: a case report.

J Med Case Rep 2017 Nov 24;11(1):330. Epub 2017 Nov 24.

Department of Medicine, University of Peradeniya, Peradeniya, Sri Lanka.

Background: Ceylon krait (Bungarus ceylonicus) is a venomous elapid snake endemic to Sri Lanka. It inhabits shaded home gardens and forests in the wet zone of Sri Lanka and might creep into houses in the night. Despite frequent encounters with humans, reports of envenoming are very rare. Read More

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https://jmedicalcasereports.biomedcentral.com/articles/10.11
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http://dx.doi.org/10.1186/s13256-017-1503-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5701456PMC
November 2017
12 Reads

Deriving muscle fiber diameter from recorded single fiber potential.

Authors:
Ewa Zalewska

Neurophysiol Clin 2017 Dec 20;47(5-6):413-417. Epub 2017 Nov 20.

Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks. Trojdena 4 str., 02-109 Warsaw, Poland. Electronic address:

Objective: The aim of the study was to estimate muscle fiber diameters through analysis of single muscle fiber potentials (SFPs) recorded in the frontalis muscle of a healthy subject.

Methods: Our previously developed analytical and graphic method to derive fiber diameter from the analysis of the negative peak duration and the amplitude of SFP, was applied to a sample of ten SFPs recorded in vivo.

Results: Muscle fiber diameters derived from the simulation method for the sample of frontalis muscle SFPs are consistent with anatomical data for this muscle. Read More

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http://dx.doi.org/10.1016/j.neucli.2017.10.058DOI Listing
December 2017
4 Reads

Mechanism hypotheses for the electrophysiological manifestations of two cases of endplate acetylcholinesterase deficiency related congenital myasthenic syndrome.

J Clin Neurosci 2018 Feb 14;48:229-232. Epub 2017 Nov 14.

Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China; Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100730, China. Electronic address:

Objective: To summarize the electrophysiological characteristics of two cases of endplate acetylcholinesterase deficiency (EAD) related congenital myasthenic syndrome (CMS) caused by COLQ mutation and to discuss the possible mechanism of these electrophysiological phenomena.

Methods: Electrophysiological examinations were conducted including nerve conduction studies, routine electromyography (EMG), repetitive nerve stimulation (RNS) and single fiber EMG (SFEMG). The ulnar nerve was also stimulated at 50 Hz followed by 0. Read More

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http://dx.doi.org/10.1016/j.jocn.2017.10.084DOI Listing
February 2018
8 Reads

Congenital Myasthenic Syndrome due to mutations in a family from Chile.

Eur J Transl Myol 2017 06 20;27(3):6832. Epub 2017 Sep 20.

Department of Neurology, University of California Davis, Davis CA, USA

Congenital myasthenic syndromes (CMS) are neuromuscular transmission disorders caused by mutations in genes encoding neuromuscular junction proteins. A 61-year-old female and her older sister showed bilateral ptosis, facial and proximal limb weakness, and scoliosis since childhood. Another female sibling had milder signs, while other family members were asymptomatic. Read More

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http://www.pagepressjournals.org/index.php/bam/article/view/
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http://dx.doi.org/10.4081/ejtm.2017.6832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5658635PMC
June 2017
13 Reads

Pitfalls and errors in measuring jitter.

Clin Neurophysiol 2017 11 21;128(11):2233-2241. Epub 2017 Sep 21.

Faculdade Medicina Sao Jose do Rio Preto, Investigation Neuromuscular Laboratory, 15090-000 Sao Jose do Rio Preto, SP, Brazil. Electronic address:

The safety factor of neuromuscular transmission can be assessed by measuring the neuromuscular jitter, which reflects the time variability of processes in the motor end-plate. Jitter is increased in any condition with disturbed end-plate function, such as myasthenic conditions and ongoing reinnervation. Jitter is increasingly being measured with concentric needle (CN) electrodes, which are more prone to artefacts than single fiber EMG recordings. Read More

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http://dx.doi.org/10.1016/j.clinph.2017.09.001DOI Listing
November 2017
4 Reads

Single-fiber electromyography in the orbicularis oculi muscle in patients with ocular myasthenia gravis symptoms: does abnormal jitter predict response to treatment?

BMC Neurol 2017 Jun 7;17(1):108. Epub 2017 Jun 7.

EMG Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.

Background: Seronegative ocular myasthenia gravis (OMG) is diagnosed by ocular symptoms with supporting SFEMG, typically of frontalis or extensor digitorum muscles. We aimed to determine the sensitivity and specificity of orbicularis oculi SFEMG to diagnose and exclude myasthenia gravis and predict response to therapy.

Methods: Orbicularis oculi SFEMG studies were conducted in 142 consecutive patients with symptoms and/or findings of OMG and negative AChR antibody during the period of 5 years. Read More

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http://dx.doi.org/10.1186/s12883-017-0891-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5463377PMC
June 2017
19 Reads

Selective or predominant triceps muscle weakness in African-American patients with myasthenia gravis.

Neuromuscul Disord 2017 Jul 21;27(7):646-649. Epub 2017 Apr 21.

Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada.

Myasthenia gravis (MG) can lead to weakness in different patterns of muscle groups. Limb muscle weakness is most typically seen in a limb girdle pattern, although variants exist. In the current study, we aimed to describe a unique MG phenotype consisting of selective or predominant triceps muscle weakness. Read More

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http://dx.doi.org/10.1016/j.nmd.2017.04.009DOI Listing
July 2017
11 Reads

Use of stimulated electromyography in the analysis of the neuromuscular junction in children.

Authors:
Matthew C Pitt

Muscle Nerve 2017 Nov 22;56(5):841-847. Epub 2017 May 22.

Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom.

A screening test is required to diagnose disorders of the neuromuscular junction (NMJ) in children. This Review describes the development of stimulation potential analysis with concentric needle electrodes (SPACE). This nomenclature was chosen to distinguish the technique from single-fiber methodology because of the difficulties in identifying single-fiber potentials in most studies, particularly those with the most severe abnormalities of the NMJ. Read More

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http://dx.doi.org/10.1002/mus.25685DOI Listing
November 2017
4 Reads

A reappraisal of diagnostic tests for myasthenia gravis in a large Asian cohort.

J Neurol Sci 2017 May 14;376:153-158. Epub 2017 Mar 14.

Duke-NUS Graduate Medical School, Singapore; Singapore Eye Research Institute, Singapore; Singapore National Eye Centre, Singapore.

Background: Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease characterized by weakness of bodily skeletal muscles. Office-based diagnostic tests such as repetitive nerve stimulation (RNS), single fiber electromyography (SFEMG), and the ice test, are used to refine the differential clinical diagnosis of this disease. Evaluating the clinical sensitivity and specificity of these tests, however, may be confounded by lack of a gold standard, non-blinding, incorporation bias, use of non-representative populations and retrospective data. Read More

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http://dx.doi.org/10.1016/j.jns.2017.03.016DOI Listing
May 2017
10 Reads

Hinge-deleted IgG4 blocker therapy for acetylcholine receptor myasthenia gravis in rhesus monkeys.

Sci Rep 2017 04 20;7(1):992. Epub 2017 Apr 20.

Genmab, Utrecht, The Netherlands.

Autoantibodies against ion channels are the cause of numerous neurologic autoimmune disorders. Frequently, such pathogenic autoantibodies have a restricted epitope-specificity. In such cases, competing antibody formats devoid of pathogenic effector functions (blocker antibodies) have the potential to treat disease by displacing autoantibodies from their target. Read More

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http://dx.doi.org/10.1038/s41598-017-01019-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5430546PMC
April 2017
15 Reads

Jitter Values on Voluntary Active Periocular Muscles of Healthy Subjects with Conventional (37 mm) Concentric Needle Electrode.

Noro Psikiyatr Ars 2016 Jun 1;53(2):126-129. Epub 2016 Jun 1.

Department of Neurology and Clinical Neurophysiology, İstanbul University İstanbul School of Medicine, İstanbul, Turkey.

Introduction: The aim of this study was to re-evaluate jitter values of healthy subjects in whom pairs of single-fiber-like potentials were recorded from voluntary activated periocular muscles using a disposable 37-mm concentric needle electrode (CNE) with 2-kHz low-cut filtering.

Methods: We reviewed the recordings of 129 subjects (85 women; 44 men; mean age, 43.8±15. Read More

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http://dx.doi.org/10.5152/npa.2015.12390DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5353016PMC
June 2016
15 Reads

Low-Density Lipoprotein Receptor-Related Protein 4-Positive Myasthenia Gravis in a Double-Seronegative, Electromyography-Negative Patient.

J Neuroophthalmol 2017 09;37(3):285-286

Department of Ophthalmology (JMK), Hadassah Medical Center, Kiryat Hadassah, Jerusalem, Israel; Neuroimmunology and Cell Therapy Unit (DK, PP), Neurology Department, Hadassah-Hebrew University Medical Center, Jerusalem, Israel; and Department of Neurobiology (PZ), Hellenic Pasteur Institute, Greece and Tzartos NeuroDiagnostics, Athens, Greece.

We describe a patient with ocular myasthenia gravis, where single-fiber electromyography and testing for acetylcholine receptor and muscle-specific kinase antibodies were negative. However, antibodies to low-density lipoprotein receptor-related protein 4 (LRP4) were positive, and this prompted appropriate management. We recommend that testing for LRP4 antibodies be considered when the clinical suspicion for myasthenia gravis is high despite negative conventional diagnostic tests. Read More

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http://dx.doi.org/10.1097/WNO.0000000000000499DOI Listing
September 2017
10 Reads

Head drop after botox: Electrodiagnostic evaluation of iatrogenic botulinum toxicity.

Clin Neurol Neurosurg 2017 May 6;156:1-3. Epub 2017 Mar 6.

Department of Neurology, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston Salem, NC 27157, USA. Electronic address:

Background: Botulinum is a potent neurotoxin with increasing indications for neurologic disorders. While clinical benefit manifests primarily due to local actions at the neuromuscular junction, regional and systemic effects do occur. Rarely, systemic symptoms including weakness, dysarthria, dysphagia and other side effects occur as a result of iatrogenic botulinum neurotoxicity. Read More

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http://dx.doi.org/10.1016/j.clineuro.2017.02.012DOI Listing
May 2017
11 Reads

Detection of myasthenia gravis using electrooculography signals.

Conf Proc IEEE Eng Med Biol Soc 2016 08;2016:896-899

Myasthenia gravis (MG) is an autoimmune neuromuscular disorder resulting from skeletal muscle weakness and fatigue. An early common symptom is fatigable weakness of the extrinsic ocular muscles; if symptoms remain confined to the ocular muscles after a few years, this is classified as ocular myasthenia gravis (OMG). Diagnosis of MG when there are mild, isolated ocular symptoms can be difficult, and currently available diagnostic techniques are insensitive, non-specific or technically cumbersome. Read More

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http://dx.doi.org/10.1109/EMBC.2016.7590845DOI Listing
August 2016
7 Reads

Seronegative myasthenia gravis associated with malignant thymoma.

Neuromuscul Disord 2017 May 2;27(5):417-418. Epub 2017 Feb 2.

Department of Neurology, The University of North Carolina, Chapel Hill, NC 27514.

Myasthenia gravis (MG) is generally caused by antibodies directed against the neuromuscular junction, including antibodies against the postsynaptic nicotinic acetylcholine receptor (AChR). Pathologic abnormalities of the thymus gland, including thymoma, are associated with MG. We report a 56-year-old woman who presented with double vision. Read More

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http://dx.doi.org/10.1016/j.nmd.2017.01.023DOI Listing
May 2017
5 Reads

Motor Unit Potential Jitter: A New Measure of Neuromuscular Transmission Instability.

IEEE Trans Neural Syst Rehabil Eng 2017 07 9;25(7):1018-1025. Epub 2017 Feb 9.

A new measure of neuromuscular transmission instability, motor unit potential (MUP) jitter, is introduced. MUP jitter can be estimated quickly using MUP trains (MUPTs) extracted from electromyographic (EMG) signals acquired using conventional clinical equipment and needle EMG electrodiagnostic protocols. The primary motivation for developing MUP jitter is to avoid the technical demands associated with estimating jitter using conventional single fiber EMG techniques. Read More

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http://dx.doi.org/10.1109/TNSRE.2017.2666741DOI Listing
July 2017
8 Reads

Electrophysiological testing is correlated with myasthenia gravis severity.

Muscle Nerve 2017 09 23;56(3):445-448. Epub 2017 Mar 23.

Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto General Hospital, 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.

Introduction: Electrophysiological studies play an important role in the diagnosis of myasthenia gravis (MG). The objectives of this study was to explore the correlation of jitter and decrement with various clinical symptoms and signs and disease severity.

Methods: We performed a retrospective chart review of 75 MG patients who attended the neuromuscular clinic from April 2013 to May 2014. Read More

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http://dx.doi.org/10.1002/mus.25539DOI Listing
September 2017
12 Reads

Single-fiber EMG with concentric electrodes in lambert-eaton myasthenia.

Muscle Nerve 2017 08 12;56(2):253-257. Epub 2017 Apr 12.

Department of Neurology, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing, Dongcheng, Beijing, China, 100730.

Introduction: We analyzed jitter recordings made with concentric needle electrode (CNE) single-fiber electromyography (SFEMG) in Lambert-Eaton myasthenia (LEM).

Methods: Fifteen subjects diagnosed with LEM were studied using CNE-SFEMG in the extensor digitorum (ED) and tibialis anterior (TA) muscles. CNE-SFEMG in the ED and TA was also used to evaluate 12 and 10 healthy controls (HCs), respectively. Read More

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http://dx.doi.org/10.1002/mus.25500DOI Listing
August 2017
13 Reads

Does change in neuromuscular jitter predict or correlate with clinical change in MG?

Muscle Nerve 2017 07 15;56(1):45-50. Epub 2017 Feb 15.

Neuromuscular Section, Department of Neurology, Box 3403, Duke University Medical Center, Durham, North Carolina, 27710, USA.

Introduction: The objective of this study was to determine if single-fiber electromyography (SFEMG) jitter accurately reflects change in severity in myasthenia gravis (MG).

Methods: We reviewed jitter and outcome data from all MG patients in our clinic who had at least 2 jitter measurements in the extensor digitorum or frontalis muscle.

Results: Change in all parameters of jitter measured with SFEMG electrodes predicted clinical change with acceptable accuracy. Read More

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http://dx.doi.org/10.1002/mus.25440DOI Listing
July 2017
15 Reads

Determining jitter values in the very young by use of the e-norms methodology.

Muscle Nerve 2017 01 18;55(1):51-54. Epub 2016 Oct 18.

Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.

Introduction: The diagnosis of myasthenia gravis in very young infants is a challenging one. In young infants, stimulated single-fiber electromyography (StimSFEMG) is the most appropriate technique, but it has serious limitations due to the absence of reference values in this subpopulation. Here we present our efforts to derive a reference range of jitter in a patient cohort of infants <3 years of age using the extrapolated norms, or e-norms, technique. Read More

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http://dx.doi.org/10.1002/mus.25191DOI Listing
January 2017
6 Reads

Diagnostic Accuracy of Single Fiber Electromyography for Myasthenia Gravis in Patients Followed Longitudinally.

J Clin Neurophysiol 2016 Oct;33(5):469-474

*Neuromuscular Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, U.S.A.; and †Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH.

Introduction: The literature lacks data on accuracy of single fiber electromyography (SFEMG) for myasthenia gravis (MG) patients followed longitudinally.

Methods: We included patients with a clinical suspicion of MG who received SFEMG and follow-up at our institution between 2003 and 2013. Data collected included demographics, symptom details, clinical deficits, other diagnostic testing results, MG medication regimen, duration on treatment, response to therapy, and ultimate diagnosis after follow-up. Read More

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http://dx.doi.org/10.1097/WNP.0000000000000285DOI Listing
October 2016
10 Reads

Neuromuscular transmission abnormalities in myotonic dystrophy type 1: A neurophysiological study.

Clin Neurol Neurosurg 2016 Nov 29;150:84-88. Epub 2016 Aug 29.

Neuromuscular and Neurological Rare Diseases Centre, Neurology and Neurophysiology Unit, S. Camillo Forlanini Hospital, C. Gianicolense, 87-00152, Rome, Italy. Electronic address:

Objectives: Weakness and fatigue are frequent symptoms in myotonic dystrophy type 1 (DM1), mainly as a result of muscle impairment. However, neuromuscular junction (NMJ) abnormalities could play an additional role in determining these manifestations. We aimed to document the possible NMJ involvement in DM1. Read More

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http://dx.doi.org/10.1016/j.clineuro.2016.08.020DOI Listing
November 2016
6 Reads

Repetitive facial nerve stimulation in myasthenia gravis 1min after muscle activation is inferior to testing a second muscle at rest.

Clin Neurophysiol 2016 Oct 12;127(10):3294-7. Epub 2016 Aug 12.

Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, University of Toronto, Toronto, Canada. Electronic address:

Objectives: To explore the increased diagnostic yield of repetitive nerve stimulation (RNS) following activation for myasthenia gravis (MG) diagnosis, and compare with testing an additional muscle at rest only.

Methods: We performed a retrospective chart review of patients diagnosed with MG attending the neuromuscular clinic from 2013 to 2015 and extracted data on electrophysiological studies, including frequency of decrement of 10% or above, with facial RNS at rest, and following activation.

Results: The total cohort included 102 patients with MG, 65 with generalized, and 37 with ocular MG. Read More

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http://dx.doi.org/10.1016/j.clinph.2016.08.004DOI Listing
October 2016
8 Reads

Evidence for dying-back axonal degeneration in age-associated skeletal muscle decline.

Muscle Nerve 2017 06 1;55(6):894-901. Epub 2017 Apr 1.

Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, 21205, USA.

Introduction: Age-associated muscle strength decline is a major contributing factor to increased late-life functional decline and comorbidity, and is strongly associated with early mortality. Although all parts of the neuromuscular system seem to be affected by aging, dying-back of motor axons likely plays a major role.

Methods: We compared the degeneration in ventral roots and neuromuscular junction denervation in young and aged mice and correlated the findings with strength and electrophysiological measures. Read More

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http://dx.doi.org/10.1002/mus.25267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5489232PMC
June 2017
5 Reads

Repetitive nerve stimulation cutoff values for the diagnosis of myasthenia gravis.

Muscle Nerve 2017 02 16;55(2):166-170. Epub 2016 Nov 16.

Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Division of Neurology, Department of Medicine, University Health Network, Toronto General Hospital 200 Elizabeth Street, Room 5 EB 309, Toronto, Ontario, Canada, M5G 2C4.

Introduction: Repetitive nerve stimulation (RNS) showing ≥ 10% decrement is considered the cutoff for myasthenia gravis (MG), but this has never been validated. The objective of this study was to find an optimal validated cutoff value for decrement on RNS.

Methods: We performed retrospective chart review of patients who had electrophysiological assessment for possible MG from 2013 to 2015. Read More

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http://dx.doi.org/10.1002/mus.25214DOI Listing
February 2017
7 Reads

Single-Fiber Recordings of Nociceptive Fibers in Patients With HSAN Type V With Congenital Insensitivity to Pain.

Clin J Pain 2016 07;32(7):636-42

*Section of Clinical Neurophysiology, Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway †Department of Clinical Neurophysiology, Uppsala University, Uppsala ‡Department of Surgery, Unit of Orthopedics, Perioperative Sciences, Umeå University Hospital, Umeå, Sweden §Department of Physiology and Experimental Pathophysiology, University of Erlangen, Erlangen ∥Department of Anaesthesiology and Operative Intensive Care, Heidelberg University, Mannheim, Germany.

Objectives: Nerve growth factor (NGF) is a protein important for growth and survival, but also for modulation of sensitivity of nociceptors and sympathetic neurons. The purpose of the present study was to investigate the effects of reduced NGF signaling in patients with hereditary sensory and autonomic neuropathies type V, congenital insensitivity to pain, caused by a mutation of the NGFβ gene, including a characterization of single nociceptive fibers using microneurography (MNG).

Materials And Methods: One homozygote and 2 heterozygote patients with this mutation were examined with electromyography/neurography, thermal testing, quantitative sudomotor axon reflex test, and electrically induced axon reflex erythema in addition to MNG. Read More

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http://dx.doi.org/10.1097/AJP.0000000000000303DOI Listing
July 2016
19 Reads

What's in the Literature?

J Clin Neuromuscul Dis 2016 Jun;17(4):227-38

*Department of Neurology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, SUNY, Buffalo, NY; †Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT; Departments of ‡Neurology and §Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA.

One of the first questions asked by patients and family members when a diagnosis of amyotrophic lateral sclerosis is made is "what about stem cells?" The term "stem cells" has attractiveness to it, with the assumption that stem cell treatment (stem nerve cells) can replace lost nerve cells. There are perhaps 2 types of stem cell trials, those that are vetted by the Food and Drug Administration and those that have no official oversight and whose results are infrequently published. The issue of the latter was discussed in the last edition of this column. Read More

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http://dx.doi.org/10.1097/CND.0000000000000134DOI Listing
June 2016
7 Reads

The effect of different low-frequency filters on concentric needle jitter in stimulated orbicularis oculi.

Muscle Nerve 2016 08 26;54(2):317-9. Epub 2016 May 26.

Department of Clinical Neurophysiology, Great Ormond Street Hospital For Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK.

Introduction: Our objective was to compare the effect of different low-frequency filters on jitter parameters when stimulating the orbicularis oculi.

Methods: Ten healthy volunteers were studied. Jitter was expressed as the mean consecutive difference (MCD). Read More

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http://doi.wiley.com/10.1002/mus.25178
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http://dx.doi.org/10.1002/mus.25178DOI Listing
August 2016
5 Reads

Single fiber EMG as a prognostic tool in myasthenia gravis.

Muscle Nerve 2016 12 11;54(6):1034-1040. Epub 2016 Oct 11.

University Medical Centre Ljubljana, Department of Neurology, Zaloška cesta 2,1000, Ljubljana, Slovenia.

Introduction: Single fiber electromyography (SFEMG) is the most sensitive diagnostic tool for diagnosis of myasthenia gravis (MG). Its prognostic value is not known.

Methods: We retrospectively analyzed the clinical course of 232 MG patients who presented with only mild symptoms and had SFEMG of the orbicularis oculi muscle. Read More

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http://dx.doi.org/10.1002/mus.25174DOI Listing
December 2016
15 Reads

Characterization of patients with ocular myasthenia gravis - A case series.

eNeurologicalSci 2016 Sep 25;4:30-33. Epub 2016 Apr 25.

Neuro-ophthalmology Unit of the Department of Ophthalmology, Tel Aviv Sourasky Medical Center, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.

Ocular myasthenia gravis (OMG) is sometimes difficult to diagnose and is probably both under-diagnosed and misdiagnosed. We studied the epidemiological parameters, relevant serology, electromyographic (EMG) findings, and the relationship between OMG and thymoma, thymus hyperplasia and other autoimmune disorders compared to generalized MG (GMG) in a case control study of 133 patients with MG (32 patients with OMG and 101 patients with GMG). The proportion of OMG among all MG patients was relatively high (24. Read More

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http://dx.doi.org/10.1016/j.ensci.2016.04.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5803088PMC
September 2016
5 Reads

Quantitating Changes in Jitter and Spike Number Using Concentric Needle Electrodes in Amyotrophic Lateral Sclerosis Patients.

Chin Med J (Engl) 2016 May;129(9):1036-40

Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.

Background: Single-fiber electromyography (SFEMG) has been suggested as a quantitative method for supporting chronic partial denervation in amyotrophic lateral sclerosis (ALS) by the revised EI Escorial criteria. Although concentric needle (CN) electrodes have been used to assess jitter in myasthenia gravis patients and healthy controls, there are few reports using CN electrodes to assess motor unit instability and denervation in neurogenic diseases. The aim of this study was to determine whether quantitative changes in jitter and spike number using CN electrodes could be used for ALS studies. Read More

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http://dx.doi.org/10.4103/0366-6999.180533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4852669PMC
May 2016
8 Reads

Determination of the normative values of the masseter muscle by single-fiber electromyography in myasthenia gravis patients.

Int J Clin Exp Med 2015 15;8(10):19424-9. Epub 2015 Oct 15.

Department of Neurology, The First Affiliated Hospital of Zhengzhou University Zhengzhou 450000, Henan, China.

The purpose of this study is to obtain normative values of the masseter muscle of myasthenia gravis (MG) patients and healthy volunteers by single-fiber electromyography (SFEMG). Stimulation of SFEMG in the masseter muscle was studied in 15 healthy volunteers (men 8, women 7; mean age 40.2, range 21-77) and 30 patients affected by MG (men 16, women 14; mean age 42. Read More

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4694486PMC
January 2016
7 Reads

Single-fiber Electromyography in the Extensor Digitorum Communis for the Predictive Prognosis of Ocular Myasthenia Gravis: A Retrospective Study of 102 Cases.

Chin Med J (Engl) 2015 Oct;128(20):2783-6

Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730; Neuroscience Center, Chinese Academy of Medical Sciences, Beijing 100730, China.

Background: Single-fiber electromyography (SFEMG) abnormality in the extensor digitorum communis (EDC) was reported in ocular myasthenia gravis (OMG), which indicated subclinical involvement beyond extraocular muscles in OMG patients. The relationship between the abnormal findings of SFEMG in EDC and the probability for OMG to develop generalized myasthenia gravis (GMG) is unknown. This retrospective study aimed to determine the predictive value of abnormality of SFEMG in EDC of OMG patients. Read More

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http://dx.doi.org/10.4103/0366-6999.167354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4736893PMC
October 2015
10 Reads