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El-Wahsh S, Fraser C, Vucic S, Reddel S. Neuromuscular junction disorders: mimics and chameleons. Pract Neurol 2024:pn-2024-004148. [PMID: 39174301 DOI: 10.1136/pn-2024-004148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2024] [Indexed: 08/24/2024]
Abstract
Neuromuscular junction (NMJ) disorders represent a heterogenous group of acquired and congenital disorders that present in variable and distinctive ways. The diagnosis is typically reached through a combination of clinical, serological, pharmacological and electrophysiological evaluation. While the diagnosis can be fairly straightforward in some cases, the overlap with other neurological disorders can make diagnosis challenging, particularly in pure ocular presentations and in seronegative patients. The over-reliance on serological tests and electrophysiological evaluation in isolation can lead to misdiagnosis. In this article, we provide an overview of the NMJ disorders, discuss red flags for the key differential diagnoses (mimics) and report the atypical ways in which NMJ disorders may present (chameleons).
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Affiliation(s)
- Shadi El-Wahsh
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Neurology Department, Concord Hospital, Concord, New South Wales, Australia
| | - Clare Fraser
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Steve Vucic
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Neurology Department, Concord Hospital, Concord, New South Wales, Australia
| | - Stephen Reddel
- Neurology Department, Concord Hospital, Concord, New South Wales, Australia
- Brain and Mind Centre, The University of Sydney, Camperdown, New South Wales, Australia
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Lefaucheur JP, Moro E, Shirota Y, Ugawa Y, Grippe T, Chen R, Benninger DH, Jabbari B, Attaripour S, Hallett M, Paulus W. Clinical neurophysiology in the treatment of movement disorders: IFCN handbook chapter. Clin Neurophysiol 2024; 164:57-99. [PMID: 38852434 DOI: 10.1016/j.clinph.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/02/2024] [Accepted: 05/15/2024] [Indexed: 06/11/2024]
Abstract
In this review, different aspects of the use of clinical neurophysiology techniques for the treatment of movement disorders are addressed. First of all, these techniques can be used to guide neuromodulation techniques or to perform therapeutic neuromodulation as such. Neuromodulation includes invasive techniques based on the surgical implantation of electrodes and a pulse generator, such as deep brain stimulation (DBS) or spinal cord stimulation (SCS) on the one hand, and non-invasive techniques aimed at modulating or even lesioning neural structures by transcranial application. Movement disorders are one of the main areas of indication for the various neuromodulation techniques. This review focuses on the following techniques: DBS, repetitive transcranial magnetic stimulation (rTMS), low-intensity transcranial electrical stimulation, including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), and focused ultrasound (FUS), including high-intensity magnetic resonance-guided FUS (MRgFUS), and pulsed mode low-intensity transcranial FUS stimulation (TUS). The main clinical conditions in which neuromodulation has proven its efficacy are Parkinson's disease, dystonia, and essential tremor, mainly using DBS or MRgFUS. There is also some evidence for Tourette syndrome (DBS), Huntington's disease (DBS), cerebellar ataxia (tDCS), and axial signs (SCS) and depression (rTMS) in PD. The development of non-invasive transcranial neuromodulation techniques is limited by the short-term clinical impact of these techniques, especially rTMS, in the context of very chronic diseases. However, at-home use (tDCS) or current advances in the design of closed-loop stimulation (tACS) may open new perspectives for the application of these techniques in patients, favored by their easier use and lower rate of adverse effects compared to invasive or lesioning methods. Finally, this review summarizes the evidence for keeping the use of electromyography to optimize the identification of muscles to be treated with botulinum toxin injection, which is indicated and widely performed for the treatment of various movement disorders.
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Affiliation(s)
- Jean-Pascal Lefaucheur
- Clinical Neurophysiology Unit, Henri Mondor University Hospital, AP-HP, Créteil, France; EA 4391, ENT Team, Paris-Est Créteil University, Créteil, France.
| | - Elena Moro
- Grenoble Alpes University, Division of Neurology, CHU of Grenoble, Grenoble Institute of Neuroscience, Grenoble, France
| | - Yuichiro Shirota
- Department of Neurology, Division of Neuroscience, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yoshikazu Ugawa
- Department of Human Neurophysiology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Talyta Grippe
- Division of Neurology, University of Toronto, Toronto, Ontario, Canada; Neuroscience Graduate Program, Federal University of Minas Gerais, Belo Horizonte, Brazil; Krembil Brain Institute, Toronto, Ontario, Canada
| | - Robert Chen
- Division of Neurology, University of Toronto, Toronto, Ontario, Canada; Krembil Brain Institute, Toronto, Ontario, Canada
| | - David H Benninger
- Service of Neurology, Department of Clinical Neurosciences, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Bahman Jabbari
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Sanaz Attaripour
- Department of Neurology, University of California, Irvine, CA, USA
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Walter Paulus
- Department of Neurology, Ludwig Maximilians University, Munich, Germany
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Koysuren A, Temucin CM. Concentric needle jitter analysis of the genioglossus muscle in patients with motor neuron disease. Neurol Res 2024; 46:578-582. [PMID: 38591728 DOI: 10.1080/01616412.2024.2339096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/30/2024] [Indexed: 04/10/2024]
Abstract
OBJECTIVES Difficulty relaxing the genioglossus muscle makes the evaluation of spontaneous activity problematic in patients with motor neuron disease (MND). We performed jitter analysis using conventional disposable concentric needle electrodes (CNEs) of the voluntarily activated genioglossus muscle in patients with and without MND to detect the denervation-reinnervation process. METHODS CNE jitter analysis was performed at the genioglossus muscle in 21 MND(+) patients and 22 MND(-) subjects. The jitter analysis was considered abnormal if the jitter values exceeded these limits for the mean consecutive difference (MCD) or the individual MCD in more than 10% of readings. RESULTS Seventeen MND(+) patients (81%) had at least three abnormal individual jitter values whereas denervation findings were obtained in eleven of them during the needle electromyographic examination at genioglossus muscle. None of the MND(-) subjects showed CNE jitter abnormality. CONCLUSION CNE jitter analysis of genioglossus muscle may provide an useful information that may be suggestive of a diagnosis of MND/ALS.
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Affiliation(s)
- Aydan Koysuren
- Department of Neurology, Hacettepe University Medical School, Ankara, Turkey
| | - Cagri Mesut Temucin
- Department of Neurology, Hacettepe University Medical School, Ankara, Turkey
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Kouyoumdjian JA, Graca CR. Muscle fiber conduction velocity in situ revisited: A new approach to an ancient technique. Front Neurol 2023; 14:1118510. [PMID: 36908604 PMCID: PMC9996126 DOI: 10.3389/fneur.2023.1118510] [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: 12/07/2022] [Accepted: 01/18/2023] [Indexed: 02/25/2023] Open
Abstract
The aim of this study was to measure the muscle fiber conduction velocity (MFCV) in situ in the tibialis anterior muscle in healthy subjects. A total of 36 subjects matched for age and sex were studied. The MFCV was measured with a concentric needle by intramuscular monopolar needle electrical activation at a distance of 50 mm. The mean consecutive difference (MCD) of <5 μs was obtained after a median of 62 muscle fiber action potentials (MFAPs), confirming a direct muscle fiber activation. The measuring latency was at the median point of ascending depolarizing line of the MFAP. The calculated MFCV from 784 MFAPs was 4.10 ± 0.66 m/s, 3.99 ± 0.57 for female subjects (95%, 2.85 to 5.13), and 4.20 ± 0.73 for male subjects (95%, 2.74 to 5.67). The MFCV was 5.22% faster in male subjects. The calculated fast-to-slow MFCV ratio (F/S ratio) was 1.47 for female subjects (95%, 1.27 to 2.54) and 1.67 for male subjects (95%, 1.31 to 3.74). Aging significantly increased the F/S ratio. As the MFCVs mainly depend on the muscle diameter, their assessment is a quick and helpful tool for estimating it. Its variability by the F/S ratio is also a powerful tool in the follow-up of some neuromuscular disorders.
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Affiliation(s)
- João Aris Kouyoumdjian
- Neuromuscular Investigation Laboratory, Department of Neurological Sciences, Psychiatry and Medical Psychology, State Medical School (FAMERP), São José do Rio Preto, São Paulo, Brazil
| | - Carla Renata Graca
- Neuromuscular Investigation Laboratory, Department of Neurological Sciences, Psychiatry and Medical Psychology, State Medical School (FAMERP), São José do Rio Preto, São Paulo, Brazil
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Malanda A, Stashuk DW, Navallas J, Rodríguez-Falces J, Rodríguez-Carreño I, Valle C, Garnés-Camarena O. Automatic jitter measurement in needle-detected motor unit potential trains. Comput Biol Med 2022; 149:105973. [DOI: 10.1016/j.compbiomed.2022.105973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 07/28/2022] [Accepted: 08/13/2022] [Indexed: 11/03/2022]
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