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Calma AD, van den Bos M, Pavey N, Santos Silva C, Menon P, Vucic S. Physiological Biomarkers of Upper Motor Neuron Dysfunction in ALS. Brain Sci 2024; 14:760. [PMID: 39199454 PMCID: PMC11352893 DOI: 10.3390/brainsci14080760] [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: 06/03/2024] [Revised: 07/24/2024] [Accepted: 07/26/2024] [Indexed: 09/01/2024] Open
Abstract
Upper motor neuron (UMN) dysfunction is an important feature of amyotrophic lateral sclerosis (ALS) for the diagnosis and understanding of pathogenesis. The identification of UMN signs forms the basis of ALS diagnosis, although may be difficult to discern, especially in the setting of severe muscle weakness. Transcranial magnetic stimulation (TMS) techniques have yielded objective physiological biomarkers of UMN dysfunction in ALS, enabling the interrogation of cortical and subcortical neuronal networks with diagnostic, pathophysiological, and prognostic implications. Transcranial magnetic stimulation techniques have provided pertinent pathogenic insights and yielded novel diagnostic and prognostic biomarkers. Cortical hyperexcitability, as heralded by a reduction in short interval intracortical inhibition (SICI) and an increase in short interval intracortical facilitation (SICF), has been associated with lower motor neuron degeneration, patterns of disease evolution, as well as the development of specific ALS clinical features including the split hand phenomenon. Reduction in SICI has also emerged as a potential diagnostic aid in ALS. More recently, physiological distinct inhibitory and facilitatory cortical interneuronal circuits have been identified, which have been shown to contribute to ALS pathogenesis. The triple stimulation technique (TST) was shown to enhance the diagnostic utility of conventional TMS measures in detecting UMN dysfunction. Resting-state EEG is a novel neurophysiological technique developed for directly interrogating cortical neuronal networks in ALS, that have yielded potentially useful physiological biomarkers of UMN dysfunction. The present review discusses physiological biomarkers of UMN dysfunction in ALS, encompassing conventional and novel TMS techniques developed to interrogate the functional integrity of the corticomotoneuronal system, focusing on pathogenic, diagnostic, and prognostic utility.
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Affiliation(s)
- Aicee Dawn Calma
- Brain and Nerve Research Center, The University of Sydney, Sydney 2139, Australia (C.S.S.)
| | - Mehdi van den Bos
- Brain and Nerve Research Center, The University of Sydney, Sydney 2139, Australia (C.S.S.)
| | - Nathan Pavey
- Brain and Nerve Research Center, The University of Sydney, Sydney 2139, Australia (C.S.S.)
| | - Cláudia Santos Silva
- Brain and Nerve Research Center, The University of Sydney, Sydney 2139, Australia (C.S.S.)
- Department of Neurosciences and Mental Health, Unidade Local de Saúde de Santa Maria, 1649-028 Lisbon, Portugal
- Faculdade de Medicina-Instituto de Medicina Molecular, Centro de Estudos Egas Moniz, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Parvathi Menon
- Brain and Nerve Research Center, The University of Sydney, Sydney 2139, Australia (C.S.S.)
| | - Steve Vucic
- Brain and Nerve Research Center, The University of Sydney, Sydney 2139, Australia (C.S.S.)
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Dharmadasa T, Pavey N, Tu S, Menon P, Huynh W, Mahoney CJ, Timmins HC, Higashihara M, van den Bos M, Shibuya K, Kuwabara S, Grosskreutz J, Kiernan MC, Vucic S. Novel approaches to assessing upper motor neuron dysfunction in motor neuron disease/amyotrophic lateral sclerosis: IFCN handbook chapter. Clin Neurophysiol 2024; 163:68-89. [PMID: 38705104 DOI: 10.1016/j.clinph.2024.04.010] [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: 10/01/2023] [Revised: 02/08/2024] [Accepted: 04/14/2024] [Indexed: 05/07/2024]
Abstract
Identifying upper motor neuron (UMN) dysfunction is fundamental to the diagnosis and understanding of disease pathogenesis in motor neuron disease (MND). The clinical assessment of UMN dysfunction may be difficult, particularly in the setting of severe muscle weakness. From a physiological perspective, transcranial magnetic stimulation (TMS) techniques provide objective biomarkers of UMN dysfunction in MND and may also be useful to interrogate cortical and network function. Single, paired- and triple pulse TMS techniques have yielded novel diagnostic and prognostic biomarkers in MND, and have provided important pathogenic insights, particularly pertaining to site of disease onset. Cortical hyperexcitability, as heralded by reduced short interval intracortical inhibition (SICI) and increased short interval intracortical facilitation, has been associated with the onset of lower motor neuron degeneration, along with patterns of disease spread, development of specific clinical features such as the split hand phenomenon, and may provide an indication about the rate of disease progression. Additionally, reduction of SICI has emerged as a potential diagnostic aid in MND. The triple stimulation technique (TST) was shown to enhance the diagnostic utility of conventional TMS measures in detecting UMN dysfunction in MND. Separately, sophisticated brain imaging techniques have uncovered novel biomarkers of neurodegeneration that have bene associated with progression. The present review will discuss the utility of TMS and brain neuroimaging derived biomarkers of UMN dysfunction in MND, focusing on recently developed TMS techniques and advanced neuroimaging modalities that interrogate structural and functional integrity of the corticomotoneuronal system, with an emphasis on pathogenic, diagnostic, and prognostic utility.
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Affiliation(s)
- Thanuja Dharmadasa
- Department of Neurology, The Royal Melbourne Hospital City Campus, Parkville, Victoria, Australia
| | - Nathan Pavey
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia
| | - Sicong Tu
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Parvathi Menon
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia
| | - William Huynh
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Colin J Mahoney
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Hannah C Timmins
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Mana Higashihara
- Department of Neurology, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan
| | - Mehdi van den Bos
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia
| | - Kazumoto Shibuya
- Neurology, Chiba University, Graduate School of Medicine, Chiba, Japan
| | - Satoshi Kuwabara
- Neurology, Chiba University, Graduate School of Medicine, Chiba, Japan
| | - Julian Grosskreutz
- Precision Neurology, Excellence Cluster Precision Medicine in Inflammation, University of Lübeck, University Hospital Schleswig-Holstein Campus, Lübeck, Germany
| | - Matthew C Kiernan
- Brain and Mind Centre, The University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Australia
| | - Steve Vucic
- Brain and Nerve Research Center, The University of Sydney, Sydney, Australia.
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Higashihara M, Pavey N, Menon P, van den Bos M, Shibuya K, Kuwabara S, Kiernan MC, Koinuma M, Vucic S. Reduction in short interval intracortical inhibition from the early stage reflects the pathophysiology in amyotrophic lateral sclerosis: A meta-analysis study. Eur J Neurol 2024; 31:e16281. [PMID: 38504632 PMCID: PMC11235657 DOI: 10.1111/ene.16281] [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: 10/29/2023] [Revised: 02/13/2024] [Accepted: 03/05/2024] [Indexed: 03/21/2024]
Abstract
BACKGROUND AND PURPOSE Cortical hyperexcitability has been identified as a diagnostic and pathogenic biomarker of amyotrophic lateral sclerosis (ALS). Cortical excitability is assessed by transcranial magnetic stimulation (TMS), a non-invasive neurophysiological technique. The TMS biomarkers exhibiting highest sensitivity for cortical hyperexcitability in ALS remain to be elucidated. A meta-analysis was performed to determine the TMS biomarkers exhibiting the highest sensitivity for cortical hyperexcitability in ALS. METHODS A systematic literature review was conducted of all relevant studies published in the English language by searching PubMed, MEDLINE, Embase and Scopus electronic databases from 1 January 2006 to 28 February 2023. Inclusion criteria included studies reporting the utility of threshold tracking TMS (serial ascending method) in ALS and controls. RESULTS In total, more than 2500 participants, incorporating 1530 ALS patients and 1102 controls (healthy, 907; neuromuscular, 195) were assessed with threshold tracking TMS across 25 studies. Significant reduction of mean short interval intracortical inhibition (interstimulus interval 1-7 ms) exhibited the highest standardized mean difference with moderate heterogeneity (-0.994, 95% confidence interval -1.12 to -0.873, p < 0.001; Q = 38.61, p < 0.05; I2 = 40%). The reduction of cortical silent period duration along with an increase in motor evoked potential amplitude and intracortical facilitation also exhibited significant, albeit smaller, standardized mean differences. CONCLUSION This large meta-analysis study disclosed that mean short interval intracortical inhibition reduction exhibited the highest sensitivity for cortical hyperexcitability in ALS. Combined findings from this meta-analysis suggest that research strategies aimed at understanding the cause of inhibitory interneuronal circuit dysfunction could enhance understanding of ALS pathogenesis.
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Affiliation(s)
- Mana Higashihara
- Department of NeurologyTokyo Metropolitan Institute for Geriatrics and GerontologyTokyoJapan
| | - Nathan Pavey
- Brain and Nerve Research CenterUniversity of SydneySydneyNew South WalesAustralia
| | - Parvathi Menon
- Brain and Nerve Research CenterUniversity of SydneySydneyNew South WalesAustralia
| | - Mehdi van den Bos
- Brain and Nerve Research CenterUniversity of SydneySydneyNew South WalesAustralia
| | - Kazumoto Shibuya
- Neurology, Graduate School of MedicineChiba UniversityChibaJapan
| | - Satoshi Kuwabara
- Neurology, Graduate School of MedicineChiba UniversityChibaJapan
| | - Matthew C. Kiernan
- Neuroscience Resarch AustraliaUniversity of New South WalesSydneyNew South WalesAustralia
- Department of NeurologyRoyal Prince Alfred HospitalSydneyNew South WalesAustralia
| | - Masayoshi Koinuma
- Faculty of Pharmaceutical SciencesTeikyo Heisei UniversityTokyoJapan
- Healthy Aging Innovation CenterTokyo Metropolitan Institute for Geriatrics and GerontologyTokyoJapan
| | - Steve Vucic
- Brain and Nerve Research CenterUniversity of SydneySydneyNew South WalesAustralia
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Jacobsen AB, Bostock H, Howells J, Cengiz B, Samusyte G, Koltzenburg M, Pia H, Fuglsang‐Frederiksen A, Blicher J, Obál I, Andersen H, Tankisi H. Threshold tracking transcranial magnetic stimulation and neurofilament light chain as diagnostic aids in ALS. Ann Clin Transl Neurol 2024; 11:1887-1896. [PMID: 38894662 PMCID: PMC11251469 DOI: 10.1002/acn3.52095] [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: 03/25/2024] [Revised: 04/21/2024] [Accepted: 05/04/2024] [Indexed: 06/21/2024] Open
Abstract
OBJECTIVE There is a need for sensitive biomarkers in amyotrophic lateral sclerosis (ALS), to enable earlier diagnosis and to help assess potential treatments. The main objective of this study was to compare two potential biomarkers, threshold-tracking short-interval cortical inhibition (T-SICI), which has shown promise as a diagnostic aid, and neurofilament light chains (NfL). METHODS Ninety-seven patients with ALS (mean age 67.1 ± 11.5 years) and 53 ALS mimics (aged 62.4 ± 12.9) were included. Mean disease duration was 14 months ±14.1. Patients were evaluated with revised ALS functional rating score (ALSFRS-R), Penn upper motor neuron score (UMNS), muscle strength using the Medical Research Council (MRC) score and examined with T-SICI, quantitative electromyography (EMG), and NfL measured in spinal fluid. RESULTS NfL increased with increasing UMNS (rho = 0.45, p = 8.2 × 10-6) whereas T-SICI at 2.5 ms paradoxically increased toward normal values (rho = 0.53, p = 1.9 × 10-7). However, these two measures were uncorrelated. Discrimination between ALS patients and mimics was best for NfL (area under ROC curve 0.842, sensitivity 84.9%, specificity 83.5%), compared with T-SICI (0.675, 39.6%, 91.8%). For the patients with no UMN signs, NfL also discriminated best (0.884, 89.3%, 82.6%), compared with T-SICI (0.811, 71.4%, 82.6%). However, when combining NfL and T-SICI, higher AUCs of 0.854 and 0.922 and specificities of 93.8 and 100 were found when considering all patients and patients with no UMN signs, respectively. INTERPRETATION Both T-SICI and NfL correlated with UMN involvement and combined, they provided a strong discrimination between ALS patients and ALS mimics.
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Affiliation(s)
- Anna B. Jacobsen
- Department of Clinical NeurophysiologyAarhus University HospitalAarhus N8200Denmark
| | - Hugh Bostock
- UCL Queen SquareInstitute of NeurologyQueen SquareLondonWC1N 3BGUK
| | - James Howells
- Central Clinical School, Faculty of Medicine and HealthUniversity of SydneySydneyNSW2006Australia
| | - Bülent Cengiz
- Department of NeurologyGazi University Faculty of MedicineBeşevler06570AnkaraTurkey
| | - Gintaute Samusyte
- Department of Neurology, Medical AcademyLithuanian University of Health SciencesKaunas44307Lithuania
- Department of NeurologyLithuanian University of Health Sciences Hospital Kauno KlinikosKaunas50161Lithuania
| | - Martin Koltzenburg
- UCL Queen SquareInstitute of NeurologyQueen SquareLondonWC1N 3BGUK
- Department of Clinical NeurophysiologyNational Hospital for Neurology and NeurosurgeryQueen SquareLondonWC1N 3BGUK
| | - Hossein Pia
- Department of Clinical NeurophysiologyAarhus University HospitalAarhus N8200Denmark
| | | | - Jakob Blicher
- Department of NeurologyAalborg University HospitalAalborg9000Denmark
| | - Izabella Obál
- Department of NeurologyAalborg University HospitalAalborg9000Denmark
| | - Henning Andersen
- Department of NeurologyAarhus University HospitalAarhus N8200Denmark
| | - Hatice Tankisi
- Department of Clinical NeurophysiologyAarhus University HospitalAarhus N8200Denmark
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McMackin R, Tadjine Y, Fasano A, Mitchell M, Heverin M, Awiszus F, Nasseroleslami B, Carson RG, Hardiman O. Examining short interval intracortical inhibition with different transcranial magnetic stimulation-induced current directions in ALS. Clin Neurophysiol Pract 2024; 9:120-129. [PMID: 38595691 PMCID: PMC11002888 DOI: 10.1016/j.cnp.2024.03.001] [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: 12/13/2023] [Revised: 02/21/2024] [Accepted: 03/03/2024] [Indexed: 04/11/2024] Open
Abstract
Objective To establish if induced current direction across the motor cortex alters the sensitivity of transcranial magnetic stimulation (TMS)-evoked short-interval intracortical inhibition (SICI) as an ALS biomarker. Methods Threshold tracking-TMS was undertaken in 35 people with ALS and 39 controls. Using a coil orientation which induces posterior-anterior (PA)-directed current across the motor cortex, SICI (1 ms and 3 ms interstimulus intervals) and intracortical facilitation (ICF, 10 ms interstimulus interval) were recorded. SICI3ms was also recorded using a coil orientation which induces anterior-posterior (AP)-directed current across the motor cortex. Results At group level, SICI3ms-PA (AUROC = 0.7), SICI3ms-AP (AUROC = 0.8) and SICI1ms (AUROC = 0.66) were substantially lower in those with ALS, although there was considerable interindividual heterogeneity. Averaging across interstimulus intervals (ISIs) marginally improved SICIPA sensitivity (AUROC = 0.76). Averaging SICI values across ISIs and orientations into a single SICI measure did not substantially improve sensitivity (AUROC = 0.81) compared to SICI3ms-AP alone. SICI3ms-AP and SICI3ms-PA did not significantly correlate (rho = 0.19, p = 0.313), while SICI1ms-PA and SICI3ms-PA did (rho = 0.37, p = 0.006). Further, those with ALS with the lowest SICI3ms-PA were not those with the lowest SICI3ms-AP. ICF was similar between groups (AUROC = 0.50). Conclusions SICIPA and SICIAP are uncorrelated measures of motor cortical inhibitory functions which are useful as distinct, unequally affected, measures of disinhibition in ALS. Significance Examining both SICIPA and SICIAP may facilitate more comprehensive characterisation of motor cortical disinhibition in ALS.
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Affiliation(s)
- Roisin McMackin
- Discipline of Physiology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
| | - Yasmine Tadjine
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
| | - Antonio Fasano
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
| | - Matthew Mitchell
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
| | - Mark Heverin
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
| | - Friedemann Awiszus
- Department of Orthopaedic Surgery, Otto-von-Guericke University, Magdeburg, Germany
| | - Bahman Nasseroleslami
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
| | - Richard G Carson
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College Dublin, University of Dublin, Ireland
- School of Psychology, Queen's University Belfast
| | - Orla Hardiman
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Ireland
- Beaumont Hospital, Dublin, Ireland
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Jagaraj CJ, Shadfar S, Kashani SA, Saravanabavan S, Farzana F, Atkin JD. Molecular hallmarks of ageing in amyotrophic lateral sclerosis. Cell Mol Life Sci 2024; 81:111. [PMID: 38430277 PMCID: PMC10908642 DOI: 10.1007/s00018-024-05164-9] [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: 12/05/2023] [Revised: 01/21/2024] [Accepted: 02/06/2024] [Indexed: 03/03/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, severely debilitating and rapidly progressing disorder affecting motor neurons in the brain, brainstem, and spinal cord. Unfortunately, there are few effective treatments, thus there remains a critical need to find novel interventions that can mitigate against its effects. Whilst the aetiology of ALS remains unclear, ageing is the major risk factor. Ageing is a slowly progressive process marked by functional decline of an organism over its lifespan. However, it remains unclear how ageing promotes the risk of ALS. At the molecular and cellular level there are specific hallmarks characteristic of normal ageing. These hallmarks are highly inter-related and overlap significantly with each other. Moreover, whilst ageing is a normal process, there are striking similarities at the molecular level between these factors and neurodegeneration in ALS. Nine ageing hallmarks were originally proposed: genomic instability, loss of telomeres, senescence, epigenetic modifications, dysregulated nutrient sensing, loss of proteostasis, mitochondrial dysfunction, stem cell exhaustion, and altered inter-cellular communication. However, these were recently (2023) expanded to include dysregulation of autophagy, inflammation and dysbiosis. Hence, given the latest updates to these hallmarks, and their close association to disease processes in ALS, a new examination of their relationship to pathophysiology is warranted. In this review, we describe possible mechanisms by which normal ageing impacts on neurodegenerative mechanisms implicated in ALS, and new therapeutic interventions that may arise from this.
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Affiliation(s)
- Cyril Jones Jagaraj
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sina Shadfar
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sara Assar Kashani
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sayanthooran Saravanabavan
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Fabiha Farzana
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Julie D Atkin
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia.
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC, 3086, Australia.
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Strunge K, Bostock H, Howells J, Cengiz B, Samusyte G, Koltzenburg M, Tankisi H. Caffeine and cortical excitability, as measured with paired-pulse transcranial magnetic stimulation. Muscle Nerve 2024; 69:206-212. [PMID: 38124685 DOI: 10.1002/mus.28027] [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: 12/08/2022] [Revised: 11/27/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
INTRODUCTION/AIMS The transcranial magnetic stimulation tests of short-interval intracortical inhibition (SICI) by both conventional amplitude measurements (A-SICI) and threshold-tracking (T-SICI) are important methods to investigate intracortical inhibitory circuits, and T-SICI has been proposed to aid the diagnosis of amyotrophic lateral sclerosis. Beverages containing caffeine are widely consumed, and caffeine has been reported to affect cortical excitability. The aim of this study was to determine whether these SICI tests are affected by caffeine. METHODS Twenty-four healthy subjects (13 females, 11 males, aged from 19 to 31, mean: 26.2 ± 2.4 years) were studied in a single fixed-dose randomized double-blind placebo-controlled cross-over trial of 200 mg caffeine or placebo ingested as chewing gum. A-SICI and T-SICI, using parallel tracking (T-SICIp), were performed before and after chewing gum. RESULTS There was no significant change in SICI parameters after placebo in A-SICI (p > .10) or T-SICIp (p > .30), and no significant effect of caffeine was found on A-SICI (p > .10) or T-SICIp (p > .50) for any of the interstimulus intervals. DISCUSSION There is no need for caffeine abstention before measurements of SICI by either the T-SICI or A-SICI measurements.
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Affiliation(s)
- Kristine Strunge
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Bülent Cengiz
- Department of Neurology, Gazi University Faculty of Medicine, Ankara, Turkey
| | - Gintaute Samusyte
- Department of Neurology, Hospital of Lithuanian University of Health Sciences Kauno Klinikos, Kaunas, Lithuania
- Department of Neurology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Martin Koltzenburg
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, UK
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Di Lazzaro V, Ranieri F, Bączyk M, de Carvalho M, Dileone M, Dubbioso R, Fernandes S, Kozak G, Motolese F, Ziemann U. Novel approaches to motoneuron disease/ALS treatment using non-invasive brain and spinal stimulation: IFCN handbook chapter. Clin Neurophysiol 2024; 158:114-136. [PMID: 38218077 DOI: 10.1016/j.clinph.2023.12.012] [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: 10/13/2023] [Revised: 11/28/2023] [Accepted: 12/17/2023] [Indexed: 01/15/2024]
Abstract
Non-invasive brain stimulation techniques have been exploited in motor neuron disease (MND) with multifold objectives: to support the diagnosis, to get insights in the pathophysiology of these disorders and, more recently, to slow down disease progression. In this review, we consider how neuromodulation can now be employed to treat MND, with specific attention to amyotrophic lateral sclerosis (ALS), the most common form with upper motoneuron (UMN) involvement, taking into account electrophysiological abnormalities revealed by human and animal studies that can be targeted by neuromodulation techniques. This review article encompasses repetitive transcranial magnetic stimulation methods (including low-frequency, high-frequency, and pattern stimulation paradigms), transcranial direct current stimulation as well as experimental findings with the newer approach of trans-spinal direct current stimulation. We also survey and discuss the trials that have been performed, and future perspectives.
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Affiliation(s)
- Vincenzo Di Lazzaro
- Department of Medicine and Surgery, Unit of Neurology, Neurophysiology, Neurobiology and Psychiatry, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy; Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy.
| | - Federico Ranieri
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, P.Le L.A. Scuro 10, 37134 Verona, Italy
| | - Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Królowej Jadwigi Street 27/39, 61-871 Poznań, Poland
| | - Mamede de Carvalho
- Institute of Physiology, Institute of Molecular Medicine-JLA, Egas Moniz Study Centre, Faculty of Medicine, University of Lisbon, Lisbon 1649-028, Portugal; Department of Neurosciences and Mental Health, CHULN, Lisbon, Portugal
| | - Michele Dileone
- Faculty of Health Sciences, UCLM Talavera de la Reina, Toledo, Spain; Neurology Department, Hospital Nuestra Señora del Prado, Talavera de la Reina, Toledo, Spain
| | - Raffaele Dubbioso
- Neurophysiology Unit, Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Napoli, Italy
| | - Sofia Fernandes
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016-Lisboa, Portugal
| | - Gabor Kozak
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany; Hertie-Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Francesco Motolese
- Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy
| | - Ulf Ziemann
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany; Hertie-Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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9
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Mroczek M, de Grado A, Pia H, Nochi Z, Tankisi H. Effects of sleep deprivation on cortical excitability: A threshold-tracking TMS study and review of the literature. Clin Neurophysiol Pract 2023; 9:13-20. [PMID: 38223850 PMCID: PMC10787222 DOI: 10.1016/j.cnp.2023.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 11/09/2023] [Accepted: 12/01/2023] [Indexed: 01/16/2024] Open
Abstract
Objective Insufficient sleep is linked to several health problems. Previous studies on the effects of sleep deprivation on cortical excitability using conventional transcranial magnetic stimulation (TMS) included a limited number of modalities, and few inter-stimulus intervals (ISIs) and showed conflicting results. This study aimed to investigate the effects of sleep deprivation on cortical excitability through threshold-tracking TMS, using a wide range of protocols at multiple ISIs. Methods Fifteen healthy subjects (mean age ± SD: 36 ± 3.34 years) were included. The following tests were performed before and after 24 h of sleep deprivation using semi-automated threshold-tacking TMS protocols: short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) at 11 ISIs between 1 and 30 ms, short interval intracortical facilitation (SICF) at 14 ISIs between 1 and 4.9 ms, long interval intracortical inhibition (LICI) at 6 ISIs between 50 and 300 ms, and short-latency afferent inhibition (SAI) at 12 ISIs between 16 and 30 ms. Results No significant differences were observed between pre- and post-sleep deprivation measurements for SICI, ICF, SICF, or LICI at any ISIs (p < 0.05). As for SAI, we found a difference at 28 ms (p = 0.007) and 30 ms (p = 0.04) but not at other ISIs. Conclusions Sleep deprivation does not affect cortical excitability except for SAI. Significance This study confirms some of the previous studies while contradicting others.
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Affiliation(s)
- Magdalena Mroczek
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Amedeo de Grado
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
- Neurophysiology Unit, IRCCS Fondazione Istituto Neurologico “Carlo Besta”, Università degli Studi di Milano, Milano, Italy
| | - Hossain Pia
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Zahra Nochi
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
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10
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McMackin R, Bede P, Ingre C, Malaspina A, Hardiman O. Biomarkers in amyotrophic lateral sclerosis: current status and future prospects. Nat Rev Neurol 2023; 19:754-768. [PMID: 37949994 DOI: 10.1038/s41582-023-00891-2] [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] [Accepted: 10/09/2023] [Indexed: 11/12/2023]
Abstract
Disease heterogeneity in amyotrophic lateral sclerosis poses a substantial challenge in drug development. Categorization based on clinical features alone can help us predict the disease course and survival, but quantitative measures are also needed that can enhance the sensitivity of the clinical categorization. In this Review, we describe the emerging landscape of diagnostic, categorical and pharmacodynamic biomarkers in amyotrophic lateral sclerosis and their place in the rapidly evolving landscape of new therapeutics. Fluid-based markers from cerebrospinal fluid, blood and urine are emerging as useful diagnostic, pharmacodynamic and predictive biomarkers. Combinations of imaging measures have the potential to provide important diagnostic and prognostic information, and neurophysiological methods, including various electromyography-based measures and quantitative EEG-magnetoencephalography-evoked responses and corticomuscular coherence, are generating useful diagnostic, categorical and prognostic markers. Although none of these biomarker technologies has been fully incorporated into clinical practice or clinical trials as a primary outcome measure, strong evidence is accumulating to support their clinical utility.
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Affiliation(s)
- Roisin McMackin
- Discipline of Physiology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Peter Bede
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- Computational Neuroimaging Group, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland
- Department of Neurology, St James's Hospital, Dublin, Ireland
| | - Caroline Ingre
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden
| | - Andrea Malaspina
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Orla Hardiman
- Academic Unit of Neurology, School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, Dublin, Ireland.
- Department of Neurology, Beaumont Hospital, Dublin, Ireland.
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11
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Xie M, Pallegar PN, Parusel S, Nguyen AT, Wu LJ. Regulation of cortical hyperexcitability in amyotrophic lateral sclerosis: focusing on glial mechanisms. Mol Neurodegener 2023; 18:75. [PMID: 37858176 PMCID: PMC10585818 DOI: 10.1186/s13024-023-00665-w] [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: 04/01/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the loss of both upper and lower motor neurons, resulting in muscle weakness, atrophy, paralysis, and eventually death. Motor cortical hyperexcitability is a common phenomenon observed at the presymptomatic stage of ALS. Both cell-autonomous (the intrinsic properties of motor neurons) and non-cell-autonomous mechanisms (cells other than motor neurons) are believed to contribute to cortical hyperexcitability. Decoding the pathological relevance of these dynamic changes in motor neurons and glial cells has remained a major challenge. This review summarizes the evidence of cortical hyperexcitability from both clinical and preclinical research, as well as the underlying mechanisms. We discuss the potential role of glial cells, particularly microglia, in regulating abnormal neuronal activity during the disease progression. Identifying early changes such as neuronal hyperexcitability in the motor system may provide new insights for earlier diagnosis of ALS and reveal novel targets to halt the disease progression.
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Affiliation(s)
- Manling Xie
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Praveen N Pallegar
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | - Sebastian Parusel
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Aivi T Nguyen
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
- Department of Immunology, Mayo Clinic, Rochester, MN, USA.
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12
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Tankisi H, Pia H, Strunge K, Howells J, Cengiz B, Samusyte G, Koltzenburg M, Fuglsang-Frederiksen A, Bostock H. Three different short-interval intracortical inhibition methods in early diagnosis of amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2023; 24:139-147. [PMID: 35899374 DOI: 10.1080/21678421.2022.2101926] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Objectives: To compare the utility of conventional amplitude measurements of short-interval intracortical inhibition (A-SICI) with two threshold-tracking (T-SICI) methods, as aids to early diagnosis of amyotrophic lateral sclerosis (ALS). The new parallel threshold-tracking method (T-SICIp) was compared with the previously used serial tracking method (T-SICIs). Methods: 112 consecutive patients referred with the suspicion of ALS and 40 healthy controls were prospectively included. Based on clinical follow-up, patients were divided into 67 patients with motor neuron disease (MND) comprising progressive muscular atrophy (PMA) as well as ALS, and 45 patient controls. SICI was recorded from first dorsal interosseus muscle using the three different protocols. Results: MND patients had significantly reduced T-SICIp, T-SICIs and A-SICI, compared with healthy controls and patient controls, while healthy and patient controls were similar. Paradoxically, T-SICIp was least affected in MND patients with the most upper motor neuron (UMN) signs (Spearman ρ = 0.537, P < 0.0001) whereas there was no correlation for T-SICIs or A-SICI. T-SICIp also provided the best discrimination between patient controls and MND as determined by the receiver operating characteristic (ROC) curves. For patients with no UMN signs, area under ROC curve for 2-3ms inter-stimulus intervals was 0.931 for T-SICIp, 0.771 for T-SICIs and 0.786 for A-SICI. Conclusions: SICI is a sensitive measure for detection of cortical involvement in ALS patients. T-SICIp has higher sensitivity and specificity than T-SICIs and A-SICI, particularly in patients without any upper motor neuron signs.
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Affiliation(s)
- Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Hossein Pia
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Kristine Strunge
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Bülent Cengiz
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, Ankara, Turkey
| | - Gintaute Samusyte
- Department of Neurology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Martin Koltzenburg
- Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom, and
| | - Anders Fuglsang-Frederiksen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
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13
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De Carvalho M, Swash M. Transcranial magnetic stimulation to monitor disease progression in ALS: a review. Amyotroph Lateral Scler Frontotemporal Degener 2022. [DOI: 10.1080/21678421.2022.2160649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Mamede De Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Centro de Estudos Egas Moniz, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Department of Neurosciences and Mental Health, Centro Hospitalar Universitário Lisboa Norte, Lisboa, Portugal, and
| | - Michael Swash
- Instituto de Fisiologia, Instituto de Medicina Molecular, Centro de Estudos Egas Moniz, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Barts and the London School of Medicine, Queen Mary University of London, UK
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14
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Imaging Neurodegenerative Metabolism in Amyotrophic Lateral Sclerosis with Hyperpolarized [1-13C]pyruvate MRI. Tomography 2022; 8:1570-1577. [PMID: 35736877 PMCID: PMC9231312 DOI: 10.3390/tomography8030129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/08/2022] [Accepted: 06/11/2022] [Indexed: 11/16/2022] Open
Abstract
The cause of amyotrophic lateral sclerosis (ALS) is still unknown, and consequently, early diagnosis of the disease can be difficult and effective treatment is lacking. The pathology of ALS seems to involve specific disturbances in carbohydrate metabolism, which may be diagnostic and therapeutic targets. Magnetic resonance imaging (MRI) with hyperpolarized [1-13C]pyruvate is emerging as a technology for the evaluation of pathway-specific changes in the brain’s metabolism. By imaging pyruvate and the lactate and bicarbonate it is metabolized into, the technology is sensitive to the metabolic changes of inflammation and mitochondrial dysfunction. In this study, we performed hyperpolarized MRI of a patient with newly diagnosed ALS. We found a lateralized difference in [1-13C]pyruvate-to-[1-13C]lactate exchange with no changes in exchange from [1-13C]pyruvate to 13C-bicarbonate. The 40% increase in [1-13C]pyruvate-to-[1-13C]lactate exchange corresponded with the patient’s symptoms and presentation with upper-motor neuron affection and cortical hyperexcitability. The data presented here demonstrate the feasibility of performing hyperpolarized MRI in ALS. They indicate potential in pathway-specific imaging of dysfunctional carbohydrate metabolism in ALS, an enigmatic neurodegenerative disease.
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15
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Shibuya K, Otani R, Suzuki YI, Kuwabara S, Kiernan MC. Neuronal Hyperexcitability and Free Radical Toxicity in Amyotrophic Lateral Sclerosis: Established and Future Targets. Pharmaceuticals (Basel) 2022; 15:ph15040433. [PMID: 35455429 PMCID: PMC9025031 DOI: 10.3390/ph15040433] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/24/2022] [Accepted: 03/29/2022] [Indexed: 02/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating disease with evidence of degeneration involving upper and lower motor neuron compartments of the nervous system. Presently, two drugs, riluzole and edaravone, have been established as being useful in slowing disease progression in ALS. Riluzole possesses anti-glutamatergic properties, while edaravone eliminates free radicals (FRs). Glutamate is the excitatory neurotransmitter in the brain and spinal cord and binds to several inotropic receptors. Excessive activation of these receptors generates FRs, inducing neurodegeneration via damage to intracellular organelles and upregulation of proinflammatory mediators. FRs bind to intracellular structures, leading to cellular impairment that contributes to neurodegeneration. As such, excitotoxicity and FR toxicities have been considered as key pathophysiological mechanisms that contribute to the cascade of degeneration that envelopes neurons in ALS. Recent advanced technologies, including neurophysiological, imaging, pathological and biochemical techniques, have concurrently identified evidence of increased excitability in ALS. This review focuses on the relationship between FRs and excitotoxicity in motor neuronal degeneration in ALS and introduces concepts linked to increased excitability across both compartments of the human nervous system. Within this cellular framework, future strategies to promote therapeutic development in ALS, from the perspective of neuronal excitability and function, will be critically appraised.
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Affiliation(s)
- Kazumoto Shibuya
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba 260-8677, Japan; (K.S.); (R.O.); (Y.-i.S.); (S.K.)
| | - Ryo Otani
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba 260-8677, Japan; (K.S.); (R.O.); (Y.-i.S.); (S.K.)
| | - Yo-ichi Suzuki
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba 260-8677, Japan; (K.S.); (R.O.); (Y.-i.S.); (S.K.)
| | - Satoshi Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba 260-8677, Japan; (K.S.); (R.O.); (Y.-i.S.); (S.K.)
| | - Matthew C. Kiernan
- Brain and Mind Centre, Department of Neurology, University of Sydney, Royal Prince Alfred Hospital, Sydney 2050, Australia
- Correspondence:
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16
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Cengiz B, Boran HE, Alaydın HC, Tankisi H, Samusyte G, Howells J, Koltzenburg M, Bostock H. Short latency afferent inhibition: comparison between threshold-tracking and conventional amplitude recording methods. Exp Brain Res 2022; 240:1241-1247. [PMID: 35192042 DOI: 10.1007/s00221-022-06327-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 02/05/2022] [Indexed: 11/04/2022]
Abstract
Short-latency afferent inhibition (SAI), which is conventionally measured as a reduction in motor evoked potential amplitude (A-SAI), is of clinical interest as a potential biomarker for cognitive impairment. Since threshold-tracking has some advantages for clinical studies of short-interval cortical inhibition, we have compared A-SAI with a threshold-tracking alternative method (T-SAI). In the T-SAI method, inhibition was calculated by tracking the required TMS intensity for the targeted MEP amplitude (200 uV) both for the test (TMS only) and paired (TMS and peripheral stimulation) stimuli. A-SAI and T-SAI were recorded from 31 healthy subjects using ten stimuli at each of 12 inter-stimulus intervals, once in the morning and again in the afternoon. There were no differences between morning and afternoon recordings. When A-SAI was normalized by log conversion it was closely related to T-SAI. Between subjects, variability was similar for the two techniques, but within-subject variability was significantly smaller for normalized A-SAI. Conventional amplitude measurements appear more sensitive for detecting changes within-subjects, such as in interventional studies, but threshold-tracking may be as sensitive as detecting abnormal SAI in a patient.
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Affiliation(s)
- Bülent Cengiz
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500, Ankara, Turkey.
| | - H Evren Boran
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500, Ankara, Turkey
| | - Halil Can Alaydın
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500, Ankara, Turkey
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Gintaute Samusyte
- Department of Neurology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Martin Koltzenburg
- Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK.,Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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17
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Cortical Hyperexcitability in the Driver’s Seat in ALS. CLINICAL AND TRANSLATIONAL NEUROSCIENCE 2022. [DOI: 10.3390/ctn6010005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by the degeneration of cortical and spinal motor neurons. With no effective treatment available to date, patients face progressive paralysis and eventually succumb to the disease due to respiratory failure within only a few years. Recent research has revealed the multifaceted nature of the mechanisms and cell types involved in motor neuron degeneration, thereby opening up new therapeutic avenues. Intriguingly, two key features present in both ALS patients and rodent models of the disease are cortical hyperexcitability and hyperconnectivity, the mechanisms of which are still not fully understood. We here recapitulate current findings arguing for cell autonomous and non-cell autonomous mechanisms causing cortical excitation and inhibition imbalance, which is involved in the degeneration of motor neurons in ALS. Moreover, we will highlight recent evidence that strongly indicates a cardinal role for the motor cortex as a main driver and source of the disease, thus arguing for a corticofugal trajectory of the pathology.
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18
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Tankisi H, Cengiz B, Samusyte G, Howells J, Koltzenburg M, Bostock H. Short interval intracortical inhibition: Variability of amplitude and threshold-tracking measurements with 6 or 10 stimuli per point. Neurophysiol Clin 2022; 52:170-173. [PMID: 35000804 DOI: 10.1016/j.neucli.2021.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/18/2021] [Accepted: 11/16/2021] [Indexed: 10/19/2022] Open
Abstract
Reduced short-interval intracortical inhibition (SICI) in motor neuron disease has been demonstrated by amplitude changes (A-SICI) and threshold-tracking (T-SICI) using 10 stimuli per inter-stimulus interval (ISI). To test whether fewer stimuli would suffice, A-SICI and T-SICI were recorded twice from 30 healthy subjects using 6 and 10 stimuli per ISI. Using fewer stimuli increased mean A-SICI variances by 23.8% but the 7.3% increase in T-SICI variance was not significant. We conclude that our new parallel threshold-tracking SICI protocol, with 6 stimuli per ISI, can reduce time and stimulus numbers by 40% without appreciable loss of accuracy.
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Affiliation(s)
- Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Bülent Cengiz
- Department of Neurology, Gazi University Faculty of Medicine, Beşevler, 06500 Ankara, Turkey
| | - Gintaute Samusyte
- Department of Neurology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Martin Koltzenburg
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG London, United Kingdom; Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, Queen Square, WC1N 3BG London, United Kingdom
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG London, United Kingdom.
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19
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Test-Retest Reliability of Short-Interval Intracortical Inhibition Assessed by Threshold-Tracking and Automated Conventional Techniques. eNeuro 2021; 8:ENEURO.0103-21.2021. [PMID: 34561238 PMCID: PMC8528507 DOI: 10.1523/eneuro.0103-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 08/09/2021] [Accepted: 08/20/2021] [Indexed: 11/21/2022] Open
Abstract
Two novel short-interval intracortical inhibition (SICI) protocols, assessing SICI across a range of interstimulus intervals (ISIs) using either parallel threshold-tracking transcranial magnetic stimulation (TT-TMS) or automated conventional TMS (cTMS), were recently introduced. However, the test-retest reliability of these protocols has not been investigated, which is important if they are to be introduced in the clinic. SICI was recorded in 18 healthy subjects using TT-TMS (T-SICI) and cTMS (A-SICI). All subjects were examined at four identical sessions, i.e., morning and afternoon sessions on 2 d, 5-7 d apart. Both SICI protocols were performed twice at each session by the same observer. In one of the sessions, another observer performed additional examinations. Neither intraobserver nor interobserver measures of SICI differed significantly between examinations, except for T-SICI at ISI 3 ms (p = 0.00035) and A-SICI at ISI 2.5 ms (p = 0.0103). Intraday reliability was poor-to-good for A-SICI and moderate-to-good for T-SICI. Interday and interobserver reliabilities of T-SICI and A-SICI were moderate-to-good. Although between-subject variation constituted most of the total variation, SICI repeatability in an individual subject was poor. The two SICI protocols showed no considerable systematic bias across sessions and had a comparable test-retest reliability profile. Findings from the present study suggest that both SICI protocols may be reliably and reproducibly employed in research studies, but should be used with caution for individual decision-making in clinical settings. Studies exploring reliability in patient cohorts are warranted to investigate the clinical utility of these two SICI protocols.
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