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Pavey N, Hannaford A, van den Bos M, Kiernan MC, Menon P, Vucic S. Distinct neuronal circuits mediate cortical hyperexcitability in amyotrophic lateral sclerosis. Brain 2024; 147:2344-2356. [PMID: 38374770 DOI: 10.1093/brain/awae049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/16/2024] [Accepted: 01/27/2024] [Indexed: 02/21/2024] Open
Abstract
Cortical hyperexcitability is an important pathophysiological mechanism in amyotrophic lateral sclerosis (ALS), reflecting a complex interaction of inhibitory and facilitatory interneuronal processes that evolves in the degenerating brain. The advances in physiological techniques have made it possible to interrogate progressive changes in the motor cortex. Specifically, the direction of transcranial magnetic stimulation (TMS) stimulus within the primary motor cortex can be utilized to influence descending corticospinal volleys and to thereby provide information about distinct interneuronal circuits. Cortical motor function and cognition was assessed in 29 ALS patients with results compared to healthy volunteers. Cortical dysfunction was assessed using threshold-tracking TMS to explore alterations in short interval intracortical inhibition (SICI), short interval intracortical facilitation (SICF), the index of excitation and stimulus response curves using a figure-of-eight coil with the coil oriented relative to the primary motor cortex in a posterior-anterior, lateral-medial and anterior-posterior direction. Mean SICI, between interstimulus interval of 1-7 ms, was significantly reduced in ALS patients compared to healthy controls when assessed with the coil oriented in posterior-anterior (P = 0.044) and lateral-medial (P = 0.005) but not the anterior-posterior (P = 0.08) directions. A significant correlation between mean SICI oriented in a posterior-anterior direction and the total Edinburgh Cognitive and Behavioural ALS Screen score (Rho = 0.389, P = 0.037) was evident. In addition, the mean SICF, between interstimulus interval 1-5 ms, was significantly increased in ALS patients when recorded with TMS coil oriented in posterior-anterior (P = 0.035) and lateral-medial (P < 0.001) directions. In contrast, SICF recorded with TMS coil oriented in the anterior-posterior direction was comparable between ALS and controls (P = 0.482). The index of excitation was significantly increased in ALS patients when recorded with the TMS coil oriented in posterior-anterior (P = 0.041) and lateral-medial (P = 0.003) directions. In ALS patients, a significant increase in the stimulus response curve gradient was evident compared to controls when recorded with TMS coil oriented in posterior-anterior (P < 0.001), lateral-medial (P < 0.001) and anterior-posterior (P = 0.002) directions. The present study has established that dysfunction of distinct interneuronal circuits mediates the development of cortical hyperexcitability in ALS. Specifically, complex interplay between inhibitory circuits and facilitatory interneuronal populations, that are preferentially activated by stimulation in posterior-to-anterior or lateral-to-medial directions, promotes cortical hyperexcitability in ALS. Mechanisms that underlie dysfunction of these specific cortical neuronal circuits will enhance understanding of the pathophysiological processes in ALS, with the potential to uncover focussed therapeutic targets.
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Affiliation(s)
- Nathan Pavey
- Brain and Nerve Research Centre, Concord Clinical School, The University of Sydney, Concord Hospital, Sydney, NSW 2139, Australia
| | - Andrew Hannaford
- Brain and Nerve Research Centre, Concord Clinical School, The University of Sydney, Concord Hospital, Sydney, NSW 2139, Australia
| | - Mehdi van den Bos
- Brain and Nerve Research Centre, Concord Clinical School, The University of Sydney, Concord Hospital, Sydney, NSW 2139, Australia
| | - Matthew C Kiernan
- Brain and Mind Centre, The University of Sydney, Sydney, NSW 2139, Australia
- Department of Neurology, Royal Prince Alfred Hospital, Sydney, NSW 2139, Australia
| | - Parvathi Menon
- Brain and Nerve Research Centre, Concord Clinical School, The University of Sydney, Concord Hospital, Sydney, NSW 2139, Australia
| | - Steve Vucic
- Brain and Nerve Research Centre, Concord Clinical School, The University of Sydney, Concord Hospital, Sydney, NSW 2139, Australia
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Issa NP, Aydin S, Polley E, Carberry N, Garret MA, Smith S, Habib AA, Baumgartner NW, Soliven B, Rezania K. Intermuscular coherence as an early biomarker for amyotrophic lateral sclerosis: The protocol for a prospective, multicenter study. PLoS One 2024; 19:e0303053. [PMID: 38776297 PMCID: PMC11111088 DOI: 10.1371/journal.pone.0303053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 04/18/2024] [Indexed: 05/24/2024] Open
Abstract
OBJECTIVE To describe the protocol of a prospective study to test the validity of intermuscular coherence (IMC) as a diagnostic tool and biomarker of upper motor neuron degeneration in amyotrophic lateral sclerosis (ALS). METHODS This is a multicenter, prospective study. IMC of muscle pairs in the upper and lower limbs is gathered in ∼650 subjects across three groups using surface electrodes and conventional electromyography (EMG) machines. The following subjects will be tested: 1) neurotypical controls; 2) patients with symptomatology suggestive for early ALS but not meeting probable or definite ALS by Awaji Criteria; 3) patients with a known ALS mimic. The recruitment period is between 3/31/2021 and 12/31/2025. Written consent will be sought from the subject or the subject's legally authorized representative during enrollment. RESULTS The endpoints of this study include: 1) whether adding IMC to the Awaji ALS criteria improve its sensitivity in early ALS and can allow for diagnosis earlier; 2) constructing a database of IMC across different ages, genders, and ethnicities. SIGNIFICANCE This study may validate a new inexpensive, painless, and widely available tool for the diagnosis of ALS.
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Affiliation(s)
- Naoum P. Issa
- University of Chicago Medical Center, Chicago, IL, United States of America
| | - Serdar Aydin
- University of Chicago Medical Center, Chicago, IL, United States of America
| | - Eric Polley
- University of Chicago Medical Center, Chicago, IL, United States of America
| | - Nathan Carberry
- University of Miami, Coral Gables, FL, United States of America
| | - Mark A. Garret
- Massachusetts General Hospital, Boston, MA, United States of America
| | - Sean Smith
- Washington University, St. Louis, MO, United States of America
| | - Ali A. Habib
- University of California, Irvine, Irvine, CA, United States of America
| | | | - Betty Soliven
- University of Chicago Medical Center, Chicago, IL, United States of America
| | - Kourosh Rezania
- University of Chicago Medical Center, Chicago, IL, United States of America
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de Souza PVS, Serrano PDL, Farias IB, Machado RIL, Badia BDML, de Oliveira HB, Barbosa AS, Pereira CA, Moreira VDF, Chieia MAT, Barbosa AR, Braga VL, Pinto WBVDR, Oliveira ASB. Clinical and Genetic Aspects of Juvenile Amyotrophic Lateral Sclerosis: A Promising Era Emerges. Genes (Basel) 2024; 15:311. [PMID: 38540369 PMCID: PMC10969870 DOI: 10.3390/genes15030311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 02/22/2024] [Accepted: 02/27/2024] [Indexed: 06/14/2024] Open
Abstract
Juvenile Amyotrophic Lateral Sclerosis is a genetically heterogeneous neurodegenerative disorder, which is frequently misdiagnosed due to low clinical suspicion and little knowledge about disease characteristics. More than 20 different genetic loci have been associated with both sporadic and familial juvenile Amyotrophic Lateral Sclerosis. Currently, almost 40% of cases have an identifiable monogenic basis; type 6, associated with FUS gene variants, is the most prevalent globally. Despite several upper motor neuron-dominant forms being generally associated with long-standing motor symptoms and slowly progressive course, certain subtypes with lower motor neuron-dominant features and early bulbar compromise lead to rapidly progressive motor handicap. For some monogenic forms, there is a well-established genotypic-phenotypic correlation. There are no specific biochemical and neuroimaging biomarkers for the diagnosis of juvenile Amyotrophic Lateral Sclerosis. There are several inherited neurodegenerative and neurometabolic disorders which can lead to the signs of motor neuron impairment. This review emphasizes the importance of high clinical suspicion, assessment, and proper diagnostic work-up for juvenile Amyotrophic Lateral Sclerosis.
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Affiliation(s)
- Paulo Victor Sgobbi de Souza
- Motor Neuron Disease Unit, Division of Neuromuscular Diseases, Federal University of Sao Paulo (UNIFESP), Sao Paulo 04039-060, Brazil; (P.d.L.S.); (W.B.V.d.R.P.)
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Moreno-Roco J, del Valle L, Jiménez D, Acosta I, Castillo JL, Dharmadasa T, Kiernan MC, Matamala JM. Diagnostic utility of transcranial magnetic stimulation for neurodegenerative disease: a critical review. Dement Neuropsychol 2024; 17:e20230048. [PMID: 38189033 PMCID: PMC10768644 DOI: 10.1590/1980-5764-dn-2023-0048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/13/2023] [Accepted: 09/24/2023] [Indexed: 01/09/2024] Open
Abstract
Neurodegenerative diseases pose significant challenges due to their impact on brain structure, function, and cognition. As life expectancy rises, the prevalence of these disorders is rapidly increasing, resulting in substantial personal, familial, and societal burdens. Efforts have been made to optimize the diagnostic and therapeutic processes, primarily focusing on clinical, cognitive, and imaging characterization. However, the emergence of non-invasive brain stimulation techniques, specifically transcranial magnetic stimulation (TMS), offers unique functional insights and diagnostic potential. TMS allows direct evaluation of brain function, providing valuable information inaccessible through other methods. This review aims to summarize the current and potential diagnostic utility of TMS in investigating neurodegenerative diseases, highlighting its relevance to the field of cognitive neuroscience. The findings presented herein contribute to the growing body of research focused on improving our understanding and management of these debilitating conditions, particularly in regions with limited resources and a pressing need for innovative approaches.
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Affiliation(s)
- Javier Moreno-Roco
- Universidad de Chile, Facultad de Medicina, Laboratorio de Neurología y Neurofisiología Traslacional, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Centro de Investigación Clínica Avanzado (CICA) Oriente, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Departamento de Ciencias Neurológicas Oriente, Santiago, Chile
| | - Lucía del Valle
- Universidad de Chile, Facultad de Medicina, Laboratorio de Neurología y Neurofisiología Traslacional, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Centro de Investigación Clínica Avanzado (CICA) Oriente, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Departamento de Ciencias Neurológicas Oriente, Santiago, Chile
| | - Daniel Jiménez
- Universidad de Chile, Facultad de Medicina, Laboratorio de Neurología y Neurofisiología Traslacional, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Centro de Investigación Clínica Avanzado (CICA) Oriente, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Departamento de Ciencias Neurológicas Oriente, Santiago, Chile
- Hospital del Salvador, Servicio de Neurología, Santiago, Chile
| | - Ignacio Acosta
- Universidad de Chile, Facultad de Medicina, Laboratorio de Neurología y Neurofisiología Traslacional, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Centro de Investigación Clínica Avanzado (CICA) Oriente, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Departamento de Ciencias Neurológicas Oriente, Santiago, Chile
- Hospital del Salvador, Servicio de Neurología, Santiago, Chile
| | - José Luis Castillo
- Universidad de Chile, Facultad de Medicina, Laboratorio de Neurología y Neurofisiología Traslacional, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Departamento de Ciencias Neurológicas Oriente, Santiago, Chile
| | - Thanuja Dharmadasa
- University of Melbourne, The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- The Royal Melbourne Hospital, Department of Neurology, Parkville, Victoria, Australia
- University of Sydney, Brain and Mind Centre, Sydney, Australia
| | - Matthew C. Kiernan
- University of Sydney, Brain and Mind Centre, Sydney, Australia
- Royal Prince Alfred Hospital, Department of Neurology, Sydney, AustraliaArgento
| | - José Manuel Matamala
- Universidad de Chile, Facultad de Medicina, Laboratorio de Neurología y Neurofisiología Traslacional, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Centro de Investigación Clínica Avanzado (CICA) Oriente, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Departamento de Ciencias Neurológicas Oriente, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Departamento de Neurociencias, Santiago, Chile
- Universidad de Chile, Facultad de Medicina, Instituto de Neurociencia Biomédica (BNI), Santiago, Chile
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Stikvoort García DJL, Sleutjes BTHM, van Schelven LJ, Goedee HS, van den Berg LH. Diagnostic accuracy of nerve excitability and compound muscle action potential scan derived biomarkers in amyotrophic lateral sclerosis. Eur J Neurol 2023; 30:3068-3078. [PMID: 37354059 DOI: 10.1111/ene.15954] [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: 04/03/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/26/2023]
Abstract
BACKGROUND AND PURPOSE The lack of reliable early biomarkers still causes substantial diagnostic delays in amyotrophic lateral sclerosis (ALS). The aim was to assess the diagnostic accuracy of a novel electrophysiological protocol in patients with suspected motor neuron disease (MND). METHODS Consecutive patients with suspected MND were prospectively recruited at our tertiary referral centre for MND in Utrecht, The Netherlands. Procedures were performed in accordance with the Standards for Reporting of Diagnostic Accuracy. In addition to the standard diagnostic workup, an electrophysiological protocol of compound muscle action potential (CMAP) scans and nerve excitability tests was performed on patients' thenar muscles. The combined diagnostic yield of nerve excitability and CMAP scan based motor unit number estimation was compared to the Awaji and Gold Coast criteria and their added value was determined. RESULTS In all, 153 ALS or progressive muscular atrophy patients, 63 disease controls and 43 healthy controls were included. Our electrophysiological protocol had high diagnostic accuracy (area under the curve [AUC] 0.85, 95% confidence interval [95% CI] 0.80-0.90), even in muscles with undetectable axon loss (AUC 0.78, 95% CI 0.70-0.85) and in bulbar-onset patients (AUC 0.85, 95% CI 0.73-0.95). Twenty-four of 33 (73%) ALS patients who could not be diagnosed during the same visit were correctly identified, as well as 8/13 (62%) ALS patients not meeting the Gold Coast criteria and 49/59 (83%) ALS patients not meeting the Awaji criteria during this first visit. CONCLUSIONS Our practical and non-invasive electrophysiological protocol may improve early diagnosis in clinically challenging patients with suspected ALS. Routine incorporation may boost early diagnosis, enhance patient selection and generate baseline measures for clinical trials.
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Affiliation(s)
- D J L Stikvoort García
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - B T H M Sleutjes
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - L J van Schelven
- Department of Medical Technology and Clinical Physics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - H S Goedee
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - L H van den Berg
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
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Genç B, Jara JH, Sanchez SS, Lagrimas AKB, Gözütok Ö, Koçak N, Zhu Y, Hande Özdinler P. Upper motor neurons are a target for gene therapy and UCHL1 is necessary and sufficient to improve cellular integrity of diseased upper motor neurons. Gene Ther 2022; 29:178-192. [PMID: 34853443 PMCID: PMC9018479 DOI: 10.1038/s41434-021-00303-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/15/2022]
Abstract
There are no effective cures for upper motor neuron (UMN) diseases, such as amyotrophic lateral sclerosis (ALS), primary lateral sclerosis, and hereditary spastic paraplegia. Here, we show UMN loss occurs independent of spinal motor neuron degeneration and that UMNs are indeed effective cellular targets for gene therapy, which offers a potential solution especially for UMN disease patients. UCHL1 (ubiquitin C-terminal hydrolase-L1) is a deubiquitinating enzyme crucial for maintaining free ubiquitin levels. Corticospinal motor neurons (CSMN, a.k.a UMNs in mice) show early, selective, and profound degeneration in Uchl1nm3419 (UCHL1-/-) mice, which lack all UCHL1 function. When UCHL1 activity is ablated only from spinal motor neurons, CSMN remained intact. However, restoring UCHL1 specifically in CSMN of UCHL1-/- mice via directed gene delivery was sufficient to improve CSMN integrity to the healthy control levels. In addition, when UCHL1 gene was delivered selectively to CSMN that are diseased due to misfolded SOD1 toxicity and TDP-43 pathology via AAV-mediated retrograde transduction, the disease causing misfolded SOD1 and mutant human TDP-43 were reduced in hSOD1G93A and prpTDP-43A315T models, respectively. Diseased CSMN retained their neuronal integrity and cytoarchitectural stability in two different mouse models that represent two distinct causes of neurodegeneration in ALS.
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Affiliation(s)
- Barış Genç
- Davee Department of Neurology and Clinical Neurological Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Javier H Jara
- Davee Department of Neurology and Clinical Neurological Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Santana S Sanchez
- Davee Department of Neurology and Clinical Neurological Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Amiko K B Lagrimas
- Davee Department of Neurology and Clinical Neurological Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Öge Gözütok
- Davee Department of Neurology and Clinical Neurological Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Nuran Koçak
- Davee Department of Neurology and Clinical Neurological Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Yongling Zhu
- Departments of Ophthalmology and Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - P Hande Özdinler
- Davee Department of Neurology and Clinical Neurological Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA.
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Soni N, Ora M, Bathla G, Nagaraj C, Boles Ponto LL, Graham MM, Saini J, Menda Y. Multiparametric magnetic resonance imaging and positron emission tomography findings in neurodegenerative diseases: Current status and future directions. Neuroradiol J 2021; 34:263-288. [PMID: 33666110 PMCID: PMC8447818 DOI: 10.1177/1971400921998968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neurodegenerative diseases (NDDs) are characterized by progressive neuronal loss, leading to dementia and movement disorders. NDDs broadly include Alzheimer's disease, frontotemporal lobar degeneration, parkinsonian syndromes, and prion diseases. There is an ever-increasing prevalence of mild cognitive impairment and dementia, with an accompanying immense economic impact, prompting efforts aimed at early identification and effective interventions. Neuroimaging is an essential tool for the early diagnosis of NDDs in both clinical and research settings. Structural, functional, and metabolic imaging modalities, including magnetic resonance imaging (MRI) and positron emission tomography (PET), are widely available. They show encouraging results for diagnosis, monitoring, and treatment response evaluation. The current review focuses on the complementary role of various imaging modalities in relation to NDDs, the qualitative and quantitative utility of newer MRI techniques, novel radiopharmaceuticals, and integrated PET/MRI in the setting of NDDs.
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Affiliation(s)
- Neetu Soni
- University of Iowa Hospitals and Clinics, USA
| | - Manish Ora
- Department of Nuclear Medicine, SGPGIMS, India
| | - Girish Bathla
- Neuroradiology Department, University of Iowa Hospitals and
Clinics, USA
| | - Chandana Nagaraj
- Department of Neuro Imaging and Interventional Radiology,
NIMHANS, India
| | | | - Michael M Graham
- Division of Nuclear Medicine, University of Iowa Hospitals and
Clinics, USA
| | - Jitender Saini
- Department of Neuro Imaging and Interventional Radiology,
NIMHANS, India
| | - Yusuf Menda
- University of Iowa Hospitals and Clinics, USA
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Lipidomics study of plasma from patients suggest that ALS and PLS are part of a continuum of motor neuron disorders. Sci Rep 2021; 11:13562. [PMID: 34193885 PMCID: PMC8245424 DOI: 10.1038/s41598-021-92112-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 12/14/2020] [Indexed: 12/04/2022] Open
Abstract
Motor neuron disorders (MND) include a group of pathologies that affect upper and/or lower motor neurons. Among them, amyotrophic lateral sclerosis (ALS) is characterized by progressive muscle weakness, with fatal outcomes only in a few years after diagnosis. On the other hand, primary lateral sclerosis (PLS), a more benign form of MND that only affects upper motor neurons, results in life-long progressive motor dysfunction. Although the outcomes are quite different, ALS and PLS present with similar symptoms at disease onset, to the degree that both disorders could be considered part of a continuum. These similarities and the lack of reliable biomarkers often result in delays in accurate diagnosis and/or treatment. In the nervous system, lipids exert a wide variety of functions, including roles in cell structure, synaptic transmission, and multiple metabolic processes. Thus, the study of the absolute and relative concentrations of a subset of lipids in human pathology can shed light into these cellular processes and unravel alterations in one or more pathways. In here, we report the lipid composition of longitudinal plasma samples from ALS and PLS patients initially, and after 2 years following enrollment in a clinical study. Our analysis revealed common aspects of these pathologies suggesting that, from the lipidomics point of view, PLS and ALS behave as part of a continuum of motor neuron disorders.
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Vucic S, Pavey N, Haidar M, Turner BJ, Kiernan MC. Cortical hyperexcitability: Diagnostic and pathogenic biomarker of ALS. Neurosci Lett 2021; 759:136039. [PMID: 34118310 DOI: 10.1016/j.neulet.2021.136039] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 03/04/2021] [Accepted: 06/01/2021] [Indexed: 02/06/2023]
Abstract
Cortical hyperexcitability is an early and intrinsic feature of both sporadic and familial forms of amyotrophic lateral sclerosis (ALS).. Importantly, cortical hyperexcitability appears to be associated with motor neuron degeneration, possibly via an anterograde glutamate-mediated excitotoxic process, thereby forming a pathogenic basis for ALS. The presence of cortical hyperexcitability in ALS patients may be readily determined by transcranial magnetic stimulation (TMS), a neurophysiological tool that provides a non-invasive and painless method for assessing cortical function. Utilising the threshold tracking TMS technique, cortical hyperexcitability has been established as a robust diagnostic biomarker that distinguished ALS from mimicking disorders at early stages of the disease process. The present review discusses the pathophysiological and diagnostic utility of cortical hyperexcitability in ALS.
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Affiliation(s)
- Steve Vucic
- Western Clinical School, University of Sydney, Sydney, Australia.
| | - Nathan Pavey
- Western Clinical School, University of Sydney, Sydney, Australia
| | - Mouna Haidar
- Florey Institute of Neuroscieace and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Bradley J Turner
- Florey Institute of Neuroscieace and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Matthew C Kiernan
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia
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Fernández V. The Use of Motor-Evoked Potentials in Clinical Trials in Multiple Sclerosis. J Clin Neurophysiol 2021; 38:166-170. [PMID: 33958566 DOI: 10.1097/wnp.0000000000000734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SUMMARY Motor-evoked potentials (MEPs) can be used to assess the integrity of the descending corticospinal tract in the laboratory. Evoked potentials (EPs) have been widely used in the past for the diagnosis of multiple sclerosis (MS), but they are now becoming more useful in assessing the prognosis of the disease. Motor-evoked potentials have been included in EP scales that have demonstrated good correlations with clinical disability. Soon after the onset of MS, it is possible to detect an ongoing process of neurodegeneration and axonal loss. Axonal loss is probably responsible for the disability and disease progression that occurs in MS. Given the good correlations of EPs in detecting disease progression in MS, they have been used to monitor the effects of drugs used to treat the disease. Several clinical trials used MEPs as part of their EP evaluation, but MEPs have never been used as a measure of efficacy in clinical trials testing neuroprotective agents, although MEPs could be a very promising tool to measure neuroprotection and remyelination resulting from these drugs. To be used in multicenter clinical trials, MEP readings should be comparable between centers. Standardized multicenter EP assessment with central reading has been demonstrated to be feasible and reliable. Although MEP measurements have been correlated with clinical scores and other measures of neurodegeneration, further validation of MEP amplitude measurements is needed regarding their validity, reliability, and sensitivity before they can be routinely used in clinical drug trials in MS.
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Affiliation(s)
- Victoria Fernández
- Service of Clinical Neurophysiology, University Regional Hospital of Malaga, Malaga, Spain
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Rawji V, Latorre A, Sharma N, Rothwell JC, Rocchi L. On the Use of TMS to Investigate the Pathophysiology of Neurodegenerative Diseases. Front Neurol 2020; 11:584664. [PMID: 33224098 PMCID: PMC7669623 DOI: 10.3389/fneur.2020.584664] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/05/2020] [Indexed: 12/22/2022] Open
Abstract
Neurodegenerative diseases are a collection of disorders that result in the progressive degeneration and death of neurons. They are clinically heterogenous and can present as deficits in movement, cognition, executive function, memory, visuospatial awareness and language. Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation tool that allows for the assessment of cortical function in vivo. We review how TMS has been used for the investigation of three neurodegenerative diseases that differ in their neuroanatomical axes: (1) Motor cortex-corticospinal tract (motor neuron diseases), (2) Non-motor cortical areas (dementias), and (3) Subcortical structures (parkinsonisms). We also make four recommendations that we hope will benefit the use of TMS in neurodegenerative diseases. Firstly, TMS has traditionally been limited by the lack of an objective output and so has been confined to stimulation of the motor cortex; this limitation can be overcome by the use of concurrent neuroimaging methods such as EEG. Given that neurodegenerative diseases progress over time, TMS measures should aim to track longitudinal changes, especially when the aim of the study is to look at disease progression and symptomatology. The lack of gold-standard diagnostic confirmation undermines the validity of findings in clinical populations. Consequently, diagnostic certainty should be maximized through a variety of methods including multiple, independent clinical assessments, imaging and fluids biomarkers, and post-mortem pathological confirmation where possible. There is great interest in understanding the mechanisms by which symptoms arise in neurodegenerative disorders. However, TMS assessments in patients are usually carried out during resting conditions, when the brain network engaged during these symptoms is not expressed. Rather, a context-appropriate form of TMS would be more suitable in probing the physiology driving clinical symptoms. In all, we hope that the recommendations made here will help to further understand the pathophysiology of neurodegenerative diseases.
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Affiliation(s)
| | | | | | | | - Lorenzo Rocchi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
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12
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Electrodiagnosis of Amyotrophic Lateral Sclerosis: A Review of Existing Guidelines. J Clin Neurophysiol 2020; 37:294-298. [DOI: 10.1097/wnp.0000000000000682] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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Higashihara M, Van den Bos MA, Menon P, Kiernan MC, Vucic S. Interneuronal networks mediate cortical inhibition and facilitation. Clin Neurophysiol 2020; 131:1000-1010. [DOI: 10.1016/j.clinph.2020.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/23/2020] [Accepted: 02/04/2020] [Indexed: 12/13/2022]
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Bashford JA, Wickham A, Iniesta R, Drakakis EM, Boutelle MG, Mills KR, Shaw CE. The rise and fall of fasciculations in amyotrophic lateral sclerosis. Brain Commun 2020; 2:fcaa018. [PMID: 32901231 PMCID: PMC7425399 DOI: 10.1093/braincomms/fcaa018] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Amyotrophic lateral sclerosis is a devastating neurodegenerative disease with a median survival of 3 years from symptom onset. Accessible and reliable biomarkers of motor neuron decline are urgently needed to quicken the pace of drug discovery. Fasciculations represent an early pathophysiological hallmark of amyotrophic lateral sclerosis and can be reliably detected by high-density surface electromyography. We set out to quantify fasciculation potentials prospectively over 14 months, seeking comparisons with established markers of disease progression. Twenty patients with amyotrophic lateral sclerosis and five patients with benign fasciculation syndrome underwent up to seven assessments each. At each assessment, we performed the amyotrophic lateral sclerosis-functional rating scale, sum power score, slow vital capacity, 30-min high-density surface electromyography recordings from biceps and gastrocnemius and the motor unit number index. We employed the Surface Potential Quantification Engine, which is an automated analytical tool to detect and characterize fasciculations. Linear mixed-effect models were employed to account for the pseudoreplication of serial measurements. The amyotrophic lateral sclerosis-functional rating scale declined by 0.65 points per month (P < 0.0001), 35% slower than average. A total of 526 recordings were analysed. Compared with benign fasciculation syndrome, biceps fasciculation frequency in amyotrophic lateral sclerosis was 10 times greater in strong muscles and 40 times greater in weak muscles. This was coupled with a decline in fasciculation frequency among weak muscles of -7.6/min per month (P = 0.003), demonstrating the rise and fall of fasciculation frequency in biceps muscles. Gastrocnemius behaved differently, whereby strong muscles in amyotrophic lateral sclerosis had fasciculation frequencies five times greater than patients with benign fasciculation syndrome while weak muscles were increased by only 1.5 times. Gastrocnemius demonstrated a significant decline in fasciculation frequency in strong muscles (2.4/min per month, P < 0.0001), which levelled off in weak muscles. Fasciculation amplitude, an easily quantifiable surrogate of the reinnervation process, was highest in the biceps muscles that transitioned from strong to weak during the study. Pooled analysis of >900 000 fasciculations revealed inter-fasciculation intervals <100 ms in the biceps of patients with amyotrophic lateral sclerosis, particularly in strong muscles, consistent with the occurrence of doublets. We hereby present the most comprehensive longitudinal quantification of fasciculation parameters in amyotrophic lateral sclerosis, proposing a unifying model of the interactions between motor unit loss, muscle power and fasciculation frequency. The latter showed promise as a disease biomarker with linear rates of decline in strong gastrocnemius and weak biceps muscles, reflecting the motor unit loss that drives clinical progression.
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Affiliation(s)
- James A Bashford
- UK Dementia Research Institute, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
- Correspondence to: James A. Bashford, MRCP, PhD UK Dementia Research Institute, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, 5 Cutcombe Road, King’s College London, London SE5 9RT, UK E-mail:
| | - Aidan Wickham
- Department of Bioengineering, Imperial College London, London, UK
| | - Raquel Iniesta
- Department of Biostatistics and Health Informatics, King’s College London, London, UK
| | | | | | - Kerry R Mills
- UK Dementia Research Institute, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Chris E Shaw
- UK Dementia Research Institute, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
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Pathophysiology and Diagnosis of ALS: Insights from Advances in Neurophysiological Techniques. Int J Mol Sci 2019; 20:ijms20112818. [PMID: 31185581 PMCID: PMC6600525 DOI: 10.3390/ijms20112818] [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: 05/01/2019] [Revised: 05/27/2019] [Accepted: 06/06/2019] [Indexed: 12/28/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal neurodegenerative disorder of the motor neurons, characterized by focal onset of muscle weakness and incessant disease progression. While the presence of concomitant upper and lower motor neuron signs has been recognized as a pathognomonic feature of ALS, the pathogenic importance of upper motor neuron dysfunction has only been recently described. Specifically, transcranial magnetic stimulation (TMS) techniques have established cortical hyperexcitability as an important pathogenic mechanism in ALS, correlating with neurodegeneration and disease spread. Separately, ALS exhibits a heterogeneous clinical phenotype that may lead to misdiagnosis, particularly in the early stages of the disease process. Cortical hyperexcitability was shown to be a robust diagnostic biomarker if ALS, reliably differentiating ALS from neuromuscular mimicking disorders. The present review will provide an overview of key advances in the understanding of ALS pathophysiology and diagnosis, focusing on the importance of cortical hyperexcitability and its relationship to advances in genetic and molecular processes implicated in ALS pathogenesis.
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