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Posa A, Kornhuber M. EMG-Phänomene peripherer motorisch axonaler
Übererregbarkeit. KLIN NEUROPHYSIOL 2021. [DOI: 10.1055/a-1536-9243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
ZusammenfassungBei der Nadel-Elektromyographie (EMG) besitzen Phänomene der vermehrten
Erregbarkeit von Muskelfasern und von motorischen Axonen Bedeutung für
die Diagnostik neuromuskulärer Erkrankungen. Zur motorisch axonalen
Übererregbarkeit gehören spontane Phänomene wie
Faszikulationen, spontane kontinuierliche Einzelentladungen der motorischen
Einheit (SKEME), Myokymien, neuromyotone Entladungsserien und Krampi. Ferner
gehören dazu reizinduzierte Phänomene wie manche A-Wellen,
reizinduzierte komplex repetitive Entladungen oder tetanischen Spasmen bei
Elektrolytstörungen. In der vorliegenden Übersicht wird der
Kenntnisstand zu den verschiedenen Phänomenen motorisch axonaler
Übererregbarkeit referiert. Ein Schwerpunkt liegt dabei auf den SKEME
als neuem Mitglied der Gruppe spontaner Potenziale aus dem motorischen Axon.
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Affiliation(s)
- Andreas Posa
- Universitätsklinik für Neurologie,
Martin-Luther-Universität Halle-Wittenberg, Halle (Saale)
| | - Malte Kornhuber
- Universitätsklinik für Neurologie,
Martin-Luther-Universität Halle-Wittenberg, Halle (Saale)
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Nair AV, Mani A, Vijayaraghavan A, Alexander P, Shaikh A, Ninan R, Prabhakar AT, Sivadasan A, Aaron S, Jude J, Mathew V, Alexander M. Utility of stimulus induced after discharges in the evaluation of peripheral nerve hyperexcitability: Old wine in a new bottle? J Peripher Nerv Syst 2020; 26:90-98. [PMID: 33179828 DOI: 10.1111/jns.12422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/01/2020] [Accepted: 11/05/2020] [Indexed: 01/02/2023]
Abstract
Limited literature is available on stimulus induced after discharges (SIAD) in patients with peripheral nerve hyperexcitability (PNH). The aim of the study was to examine the diagnostic utility of SIAD in the diagnosis and monitoring of primary PNH disorders. In this retrospective study, we studied 26 patients who were admitted with a diagnosis of primary PNH to the department of Neurology from January 2013 to April 2019. Their clinical profile, immunological characteristics were extracted from the database and nerve conduction studies were relooked for the presence of SIAD. 76% of patients in the primary PNH cohort had SIAD with 90% of them being voltage-gated potassium channel complex antibody positive; predominantly against contactin-associated protein-2 antigen and rest being paraneoplastic. There was also resolution of SIAD following treatment indicating reversible hyperexcitability. SIAD is a sensitive marker for Primary PNH syndrome with monitoring and diagnostic implications.
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Affiliation(s)
| | - Arun Mani
- Department of Neurology, Christian Medical College, Vellore, India
| | | | | | - Atif Shaikh
- Department of Neurology, Christian Medical College, Vellore, India
| | - Rohit Ninan
- Department of Neurology, Christian Medical College, Vellore, India
| | - A T Prabhakar
- Department of Neurology, Christian Medical College, Vellore, India
| | - Ajith Sivadasan
- Department of Neurology, Christian Medical College, Vellore, India
| | - Sanjit Aaron
- Department of Neurology, Christian Medical College, Vellore, India
| | - John Jude
- Department of Clinical Microbiology, Christian Medical College, Vellore, India
| | - Vivek Mathew
- Department of Neurology, Christian Medical College, Vellore, India
| | - Mathew Alexander
- Department of Neurology, Christian Medical College, Vellore, India
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A Patient with Double-Negative VGKC, Peripheral Nerve Hyperexcitability, and Central Nervous System Symptoms: A Postinfectious Autoimmune Disease. Case Rep Neurol Med 2020; 2020:3579419. [PMID: 32802532 PMCID: PMC7411456 DOI: 10.1155/2020/3579419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/12/2020] [Accepted: 06/24/2020] [Indexed: 11/18/2022] Open
Abstract
Research in the last few years has indicated that most voltage-gated potassium channel- (VGKC-) complex antibodies without leucine-rich glioma-inactivated protein 1 or contactin-associated protein-like 2 antibody specificity lack pathogenic potential and are not clear markers for autoimmune inflammation. Here we report on a patient with double-negative VGKC who developed severe peripheral nerve hyperexcitability, central nervous system symptoms with agitation and insomnia, dysautonomia, and systemic symptoms with weight loss, itch, and skin lesions. The disease started acutely one month after an episode of enteroviral pericarditis and responded well to immunotherapy. The patient is presumed to have developed a postinfectious immunotherapy-responsive autoimmune disease. In the setting of anti-VGKC positivity, it seems likely that anti-VGKC contributed to the pathogenesis of the patient's symptoms of nerve hyperexcitability and that the disease was caused by an acquired autoimmune effect on the neuronal kinetics of VGKC. It is still unknown whether or not there are unidentified extracellular molecular targets within the VGKC-complex, i.e., a novel surface antigen and a pathogenic antibody that can cause affected individuals to develop a peripheral nerve hyperexcitability syndrome. This case highlights the fact that less well-characterized autoimmune central and peripheral nervous system syndromes may have infectious triggers.
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Supranormal Sensory Nerve Action Potential Amplitude Correlates of Sensory Symptoms. J Clin Neurophysiol 2019; 36:224-228. [DOI: 10.1097/wnp.0000000000000564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
Isaacs syndrome is a peripheral nerve hyperexcitability (PNH) syndrome that presents as continuous motor activity. Clinical findings include cramps, fasciculations, and myokymia. Electrodiagnosis plays a key role in diagnosis by demonstrating after-discharges on nerve conduction studies, and fasciculation potentials, myokymic discharges, neuromyotonic discharges, and other types of abnormal spontaneous activity on needle examination. Etiopathogenesis involves the interaction of genetic, autoimmune, and paraneoplastic factors, which requires a broad-ranging evaluation for underlying causes. Initial treatment is symptomatic, but immune therapy is often needed and can be effective. The purpose of this review is to describe the syndrome and its pathogenesis, assist the reader in evaluating patients with suspected Isaacs syndrome and distinguishing it from other disorders of PNH, and suggest an approach to management, including both symptomatic and immunomodulating therapy.
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Affiliation(s)
- Aiesha Ahmed
- Department of Neurology, Penn State Hershey Medical Center, EC 037, 30 Hope Drive, Hershey, Pennsylvania, 17033, USA
| | - Zachary Simmons
- Department of Neurology, Penn State Hershey Medical Center, EC 037, 30 Hope Drive, Hershey, Pennsylvania, 17033, USA.,Department of Humanities, Penn State Hershey Medical Center, Hershey, Pennyslvania, USA
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Abstract
A patient with Isaacs' syndrome had generalized muscle spasms, twitching, and progressive muscle stiffness for 21 years. Electrodiagnostic study showed continuous spontaneous motor-unit activity and the presence of M-wave afterdischarges. He responded dramatically to treatment with carbamazepine but developed a drug rash; his treatment was changed to gabapentin with continued improvement. Subsequent nerve conduction studies showed decreased amplitude and later an absence of M-wave afterdischarges. Gabapentin thus appears to be an effective treatment for Isaacs' syndrome.
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Affiliation(s)
- Upinder K Dhand
- Department of Neurology, University of Missouri, M178, Columbia, Missouri 65212, USA.
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Scholtes VAB, Becher JG, Beelen A, Lankhorst GJ. Clinical assessment of spasticity in children with cerebral palsy: a critical review of available instruments. Dev Med Child Neurol 2006; 48:64-73. [PMID: 16359597 DOI: 10.1017/s0012162206000132] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/25/2005] [Indexed: 11/06/2022]
Abstract
This study reviews the instruments used for the clinical assessment of spasticity in children with cerebral palsy, and evaluates their compliance with the concept of spasticity, defined as a velocity-dependent increase in muscle tone to passive stretch. Searches were performed in Medline, Embase, and Cinahl, including the keywords 'spasticity', 'child', and 'cerebral palsy', to identify articles in which a clinical method to measure spasticity was reported. Thirteen clinical spasticity assessment instruments were identified and evaluated using predetermined criteria. This review consists of reports on the standardization applied for assessment at different velocities, testing posture, and quantification of spasticity. Results show that most instruments do not comply with the concept of spasticity; standardization of assessment method is often lacking, and scoring systems of most instruments are ambiguous. Only the Tardieu Scale complies with the concept of spasticity, but this instrument has a comprehensive and time-consuming clinical scoring system.
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Affiliation(s)
- Vanessa A B Scholtes
- Department of Rehabilitation Medicine, VU University Medical Centre, Amsterdam, the Netherlands.
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Arimura K, Arimura Y, Ng A, Uehara A, Nakae M, Osame M, Stålberg E. The origin of spontaneous discharges in acquired neuromyotonia. A Macro EMG study. Clin Neurophysiol 2005; 116:1835-9. [PMID: 15979405 DOI: 10.1016/j.clinph.2005.03.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2004] [Revised: 03/23/2005] [Accepted: 03/24/2005] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To study the generator sites of spontaneous discharges in patients with immune-mediated neuromyotonia. METHODS Macro EMGs triggered by both spontaneously and voluntarily activated single action potentials were recorded and the mean peak-to-peak amplitude and area of the macro motor unit potentials were compared in two patients with typical acquired neuromyotonia having positive antibodies against voltage-gated potassium channels. RESULTS Mean peak-to-peak amplitude and area of Macro EMG motor unit potentials (macro MUPs) triggered by spontaneous discharges were significantly smaller than those triggered by voluntary activation in both patients. However, a few macro MUPs triggered by spontaneous discharges resembled those triggered by voluntary activation. CONCLUSIONS Spontaneous discharges in two patients with immune-mediated neuromyotonia seem to be mostly generated at sites distal to the terminal axon branching points. SIGNIFICANCE This finding may provide a new insight in the understanding of spontaneous discharges in immune-mediated neuromyotonia.
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Affiliation(s)
- Kimiyoshi Arimura
- Department of Neurology and Geriatrics, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, 8-35-1 Kagoshima, Japan.
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Mesrati F, Vecchierini MF. F-waves: neurophysiology and clinical value. Neurophysiol Clin 2004; 34:217-43. [PMID: 15639131 DOI: 10.1016/j.neucli.2004.09.005] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Accepted: 09/06/2004] [Indexed: 10/26/2022] Open
Abstract
This review deals with F responses, which are late responses obtained by supramaximal stimulation of virtually all the motor and mixed peripheral nerves. They are recorded over a muscle innervated by the stimulated nerve. The first description of F-waves was published in the fifties. Their neurophysiological mechanisms have been abundantly discussed in the literature leading to a current consensus, whereby F-waves are considered as antidromic responses produced by a pool of motoneurons activated by peripheral nerve stimulation. In the first part of this review, the neurophysiological mechanisms of F-waves as well as the distinction between these and H reflexes are described from a historical point of view. Other late responses are intentionally not reported; nevertheless A-waves are discussed since they are frequently ill-described in a number of conditions. Stimulation and recording procedures as well as F-wave parameters analysis are detailed, with emphasis on measures most useful for clinical purposes. A rigorous F-wave recording method is mandatory for reliable and meaningful analyses. Physiological factors, which influence F-waves such as ageing, drugs and sleep, must be known and their effects discussed. Also, as maturation is an important factor in clinical neurophysiology, data on F-wave ontogenesis are reviewed and discussed. Finally, the different F-wave alterations described so far in the literature, in either peripheral or central disorders, are listed and commented. It is emphasised that F-waves are particularly useful for the diagnosis of polyneuropathies at a very early stage and for the diagnosis of proximal nerve lesions. F-wave recording is indeed one of the rare methods in routine examination allowing at the same time the functional assessment of motor fibres on their proximal segment, and contributing to the evaluation of motoneuronal excitability.
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Affiliation(s)
- F Mesrati
- Service de physiologie, Laboratoire d'explorations fonctionnelles, Groupe hospitalier Bichat-Claude-Bernard, 46, rue Henri-Huchard, 75877 Paris cedex 18, France
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Arimura K, Sonoda Y, Watanabe O, Nagado T, Kurono A, Tomimitsu H, Otsuka R, Kameyama M, Osame M. Isaacs' syndrome as a potassium channelopathy of the nerve. Muscle Nerve 2002; 11:S55-8. [PMID: 12116286 DOI: 10.1002/mus.10148] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Isaacs' syndrome (acquired neuromyotonia) is an antibody-mediated potassium channel disorder (channelopathy). The target channel proteins of the antigens are voltage-gated potassium channels (VGKCs), especially dendrotoxin-sensitive fast potassium channels. The suppression of voltage-gated outward K(+) current by antibodies induces hyperexcitability of the peripheral nerve. Patch clamp studies show that antibodies may not directly block the kinetics of VGKCs but may decrease channel density. Electrophysiological, pharmacological, and immunological findings indicate that the site of origin of spontaneous discharges is principally in the distal portion of the motor nerve and/or within the terminal arborization. The spectrum of potassium channelopathies is expanding. The existence of antibodies against VGKCs should be considered in patients who present with generalized nerve hyperexcitability of undetermined etiology.
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Affiliation(s)
- Kimiyoshi Arimura
- Third Department of Internal Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan.
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