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Jacques FH, Apedaile BE, Danis I, Sikati-Foko V, Lecompte M, Fortin J. Motor Evoked Potential-A Pilot Study Looking at Reliability and Clinical Correlations in Multiple Sclerosis. J Clin Neurophysiol 2024; 41:357-364. [PMID: 36943437 PMCID: PMC11060055 DOI: 10.1097/wnp.0000000000001003] [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] [Indexed: 03/23/2023] Open
Abstract
PURPOSE Multiple sclerosis (MS) is a clinically heterogeneous disease. Biomarkers that can assess pathological processes that are unseen with conventional imaging remain an unmet need in MS disease management. Motor evoked potentials (MEPs) could be such a biomarker. To determine and follow longitudinal MEP reliability and correlations with clinical measures in MS patients. METHODS This is a single-center study in alemtuzumab-treated MS patients to evaluate temporal reliability of MEPs, identify MEP minimum detectible differences, and explore correlations with existing clinical scales. Ten MS patients recently treated with alemtuzumab were evaluated every 6 months over 3 years. Clinical evaluations consisted of expanded disability status scale, timed 25-foot walk, 6-minute walk, and nine-hole peg test. MEPs were measured twice, 2 weeks apart, every 6 months. RESULTS Eight patients completed all 3 years of study. The intraclass correlation coefficient for MEP parameters ranged from 0.76 to 0.98. TA latency and amplitude with facilitation significantly and strongly correlated with all clinical measures, whereas the MEP duration modestly correlated. Biceps latency with facilitation significantly and moderately correlated with 9-hole peg test. Longitudinal correlations demonstrated good predictive values for either clinical deterioration or improvement. CONCLUSIONS MEPs have excellent intrapatient and intrarater reliability, and TA MEPs significantly and strongly correlated with expanded disability status scale, 6-minute walk, and timed 25-foot walk, whereas biceps MEPs significantly and moderately correlated with nine-hole peg test. Further studies using larger cohorts of MS patients are indicated. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, Identifier: NCT02623946.
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Affiliation(s)
- F H Jacques
- Clinique Neuro-Outaouais, Gatineau, Quebec, Canada
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Faro Viana F, Cotovio G, da Silva DR, Seybert C, Pereira P, Silva A, Carvalho F, Oliveira-Maia AJ. Reducing motor evoked potential amplitude variability through normalization. Front Psychiatry 2024; 15:1279072. [PMID: 38356910 PMCID: PMC10864444 DOI: 10.3389/fpsyt.2024.1279072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/04/2024] [Indexed: 02/16/2024] Open
Abstract
BackgroundTranscranial Magnetic Stimulation (TMS) is used for in vivo assessment of human motor cortical excitability, with application of TMS pulses over the motor cortex resulting in muscle responses that can be recorded with electromyography (EMG) as Motor Evoked Potentials (MEPs). These have been widely explored as potential biomarkers for neuropsychiatric disorders but methodological heterogeneity in acquisition, and inherent high variability, have led to constraints in reproducibility. Normalization, consisting in scaling the signal of interest to a known and repeatable measurement, reduces variability and is standard practice for between-subject comparisons of EMG. The effect of normalization on variability of MEP amplitude has not yet been explored and was assessed here using several methods.MethodsThree maximal voluntary isometric contractions (MVICs) and 40 MEPs were collected from the right hand in healthy volunteers, with a retest session conducted 4 to 8 weeks later. MEP amplitude was normalized using either external references (MVICs) or internal references (extreme MEPs). Iterative re-sampling of 30 normalized MEPs per subject was repeated 5,000 times to define, for each normalization method, distributions for between-subject coefficients of variation (CV) of the mean MEP amplitude. Intra-class correlation coefficients (ICC) were used to assess the impact of normalization on test–retest stability of MEP amplitude measurements.ResultsIn the absence of normalization, MEPs collected from the right hand of 47 healthy volunteers were within reported values regarding between-subject variability (95% confidence intervals for the CV: [1.0567,1.0577]) and showed good temporal stability (ICC = 0.77). Internal reference normalization substantially reduced between-subject variability, by values of up to 64%, while external reference normalization had no impact or increased between-subject variability. Normalization with the smallest references reduced test–retest stability, with use of the largest references resulting in slight reduction or improvement of ICCs. Internal reference normalization using the largest MEPs was found to be robust to several sensitivity analyses.ConclusionInternal, but not external, reference normalization reduces between-subject variability of MEP amplitude, and has a minimal impact on within-subject variability when conducted with the largest references. Additional research is necessary to further validate these normalization methods toward potential use of MEPs as biomarkers of neuropsychiatric disorders.
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Affiliation(s)
- Francisco Faro Viana
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
| | - Gonçalo Cotovio
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
- NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, Portugal
- Department of Psychiatry and Mental Health, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal
| | - Daniel Rodrigues da Silva
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
| | - Carolina Seybert
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
| | - Patrícia Pereira
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
- Portuguese Red Cross Health School, Lisbon, Portugal
| | - Artur Silva
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Filipe Carvalho
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Albino J. Oliveira-Maia
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
- Champalimaud Clinical Centre, Champalimaud Foundation, Lisbon, Portugal
- NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisbon, Portugal
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Daroszewski P, Kaczmarek K, Huber J. Monitoring of the pharmacological treatment availability in patients with multiple sclerosis in the Greater Poland population. Reumatologia 2024; 61:473-480. [PMID: 38322107 PMCID: PMC10839914 DOI: 10.5114/reum/177143] [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: 09/19/2023] [Accepted: 12/16/2023] [Indexed: 02/08/2024] Open
Abstract
Introduction There is no clear explanation for the availability of multiple sclerosis (MS) pharmacological treatment for patients in Greater Poland and it can be assumed that the same reason is common in most of the developed countries in the United Europe. As an autoimmune disease MS can overlap with other diseases especially rheumatic disease (RD) as well as some feature of RD may mimic MS, such as MS-like syndrome in the course of primary Sjögren's syndrome. Therefore proper diagnosis and sufficient treatment of MS is important not only for neurologists but also for other clinicians including rheumatologists.The study aims to provide insights that could help healthcare managers create more effective logistical guidelines to improve the timely initiation of pharmacological treatment for MS. Materials and methods The analysis of the treatment of MS patients has been conducted on a group of 500 patients who were under the management of one healthcare center in Greater Poland. Results The results point to the different factors influencing the delay in the undertaking the pharmacological treatment, among others the age of the patient, waiting time for clinical evaluation and the final diagnosis from first symptoms to diagnosis, and the patient's waiting time from diagnosis to referral for qualification for treatment. Conclusions The outcomes of this study have the potential to serve as a valuable resource for healthcare managers. The study's findings could be used as a foundation for developing logistical guidelines aimed at enhancing the pharmacological treatment of MS patients.Furthermore, the study suggests that the reasons behind treatment delays in MS patients might be prevalent in many countries across the United Europe region. However, it's important to note that confirming this conclusion requires additional comparative studies.
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Affiliation(s)
- Przemysław Daroszewski
- Department of Organization and Management in Health Care, University of Medical Sciences, Poznan, Poland
| | - Katarzyna Kaczmarek
- Department of Pathophysiology of Locomotor Organs, University of Medical Sciences, Poznan, Poland
| | - Juliusz Huber
- Department of Pathophysiology of Locomotor Organs, University of Medical Sciences, Poznan, Poland
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Swanson CW, Fling BW. Links between Neuroanatomy and Neurophysiology with Turning Performance in People with Multiple Sclerosis. SENSORS (BASEL, SWITZERLAND) 2023; 23:7629. [PMID: 37688084 PMCID: PMC10490793 DOI: 10.3390/s23177629] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/14/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023]
Abstract
Multiple sclerosis is accompanied by decreased mobility and various adaptations affecting neural structure and function. Therefore, the purpose of this project was to understand how motor cortex thickness and corticospinal excitation and inhibition contribute to turning performance in healthy controls and people with multiple sclerosis. In total, 49 participants (23 controls, 26 multiple sclerosis) were included in the final analysis of this study. All participants were instructed to complete a series of turns while wearing wireless inertial sensors. Motor cortex gray matter thickness was measured via magnetic resonance imaging. Corticospinal excitation and inhibition were assessed via transcranial magnetic stimulation and electromyography place on the tibialis anterior muscles bilaterally. People with multiple sclerosis demonstrated reduced turning performance for a variety of turning variables. Further, we observed significant cortical thinning of the motor cortex in the multiple sclerosis group. People with multiple sclerosis demonstrated no significant reductions in excitatory neurotransmission, whereas a reduction in inhibitory activity was observed. Significant correlations were primarily observed in the multiple sclerosis group, demonstrating lateralization to the left hemisphere. The results showed that both cortical thickness and inhibitory activity were associated with turning performance in people with multiple sclerosis and may indicate that people with multiple sclerosis rely on different neural resources to perform dynamic movements typically associated with fall risk.
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Affiliation(s)
- Clayton W. Swanson
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL 32608, USA;
- Department of Neurology, University of Florida, Gainesville, FL 32608, USA
| | - Brett W. Fling
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80521, USA
- Molecular, Cellular, and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80521, USA
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Cantone M, Lanza G, Fisicaro F, Bella R, Ferri R, Pennisi G, Waterstraat G, Pennisi M. Sex-specific reference values for total, central, and peripheral latency of motor evoked potentials from a large cohort. Front Hum Neurosci 2023; 17:1152204. [PMID: 37362949 PMCID: PMC10288153 DOI: 10.3389/fnhum.2023.1152204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/26/2023] [Indexed: 06/28/2023] Open
Abstract
Background Differentiating between physiologic and altered motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) is crucial in clinical practice. Some physical characteristics, such as height and age, introduce sources of variability unrelated to neural dysfunction. We provided new age- and height-adjusted normal values for cortical latency, central motor conduction time (CMCT), and peripheral motor conduction time (PMCT) from a large cohort of healthy subjects. Methods Previously reported data from 587 participants were re-analyzed. Nervous system disorders were ruled out by clinical examination and magnetic resonance imaging. MEP latency was determined as stimulus-to-response latency through stimulation with a circular coil over the "hot spot" of the First Dorsal Interosseous and Tibialis Anterior muscles, during mild tonic contraction. CMCT was estimated as the difference between MEP cortical latency and PMCT by radicular magnetic stimulation. Additionally, right-to-left differences were calculated. For each parameter, multiple linear regression models of increasing complexity were fitted using height, age, and sex as regressors. Results Motor evoked potential cortical latency, PMCT, and CMCT were shown to be age- and height-dependent, although age had only a small effect on CMCT. Relying on Bayesian information criterion for model selection, MEP cortical latency and PMCT were explained best by linear models indicating a positive correlation with both height and age. Also, CMCT to lower limbs positively correlated with height and age. CMCT to upper limbs positively correlated to height, but slightly inversely correlated to age, as supported by non-parametric bootstrap analysis. Males had longer cortical latencies and CMCT to lower limbs, as well as longer PMCT and cortical latencies to upper limbs, even when accounting for differences in body height. Right-to-left-differences were independent of height, age, and sex. Based on the selected regression models, sex-specific reference values were obtained for all TMS-related latencies and inter-side differences, with adjustments for height and age, where warranted. Conclusion A significant relationship was observed between height and age and all MEP latency values, in both upper and lower limbs. These set of reference values facilitate the evaluation of MEPs in clinical studies and research settings. Unlike previous reports, we also highlighted the contribution of sex.
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Affiliation(s)
- Mariagiovanna Cantone
- Neurology Unit, Policlinico University Hospital “G. Rodolico-San Marco”, Catania, Italy
| | - Giuseppe Lanza
- Department of Surgery and Medical-Surgery Specialties, University of Catania, Catania, Italy
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
| | - Francesco Fisicaro
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Rita Bella
- Department of Medical and Surgical Sciences and Advanced Technologies, University of Catania, Catania, Italy
| | - Raffaele Ferri
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
| | - Giovanni Pennisi
- Clinical Neurophysiology Research Unit, Oasi Research Institute-IRCCS, Troina, Italy
| | - Gunnar Waterstraat
- Department of Neurology and Experimental Neurology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Manuela Pennisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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Šoda J, Pavelin S, Vujović I, Rogić Vidaković M. Assessment of Motor Evoked Potentials in Multiple Sclerosis. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23010497. [PMID: 36617096 PMCID: PMC9824873 DOI: 10.3390/s23010497] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 06/01/2023]
Abstract
Transcranial magnetic stimulation (TMS) is a noninvasive technique mainly used for the assessment of corticospinal tract integrity and excitability of the primary motor cortices. Motor evoked potentials (MEPs) play a pivotal role in TMS studies. TMS clinical guidelines, concerning the use and interpretation of MEPs in diagnosing and monitoring corticospinal tract integrity in people with multiple sclerosis (pwMS), were established almost ten years ago and refer mainly to the use of TMS implementation; this comprises the magnetic stimulator connected to a standard EMG unit, with the positioning of the coil performed by using the external landmarks on the head. The aim of the present work was to conduct a narrative literature review on the MEP assessment and outcome measures in clinical and research settings, assessed by TMS Methodological characteristics of different TMS system implementations (TMS without navigation, line-navigated TMS and e-field-navigated TMS); these were discussed in the context of mapping the corticospinal tract integrity in MS. An MEP assessment of two case reports, by using an e-field-navigated TMS, was presented; the results of the correspondence between the e-field-navigated TMS with MRI, and the EDSS classifications were presented. Practical and technical guiding principles for the improvement of TMS studies in MEP assessment for MS are discussed, suggesting the use of e-field TMS assessment in the sense that it can improve the accuracy of corticospinal tract integrity testing by providing a more objective correspondence of the neurophysiological (e-field-navigated TMS) and clinical (Expanded Disability Status Scale-EDSS) classifications.
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Affiliation(s)
- Joško Šoda
- Signal Processing, Analysis, and Advanced Diagnostics Research and Education Laboratory (SPAADREL), Faculty of Maritime Studies, University of Split, 21000 Split, Croatia
| | - Sanda Pavelin
- Department of Neurology, University Hospital of Split, 21000 Split, Croatia
| | - Igor Vujović
- Signal Processing, Analysis, and Advanced Diagnostics Research and Education Laboratory (SPAADREL), Faculty of Maritime Studies, University of Split, 21000 Split, Croatia
| | - Maja Rogić Vidaković
- Laboratory for Human and Experimental Neurophysiology, Department of Neuroscience, School of Medicine, University of Split, 21000 Split, Croatia
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Royer N, Coates K, Aboodarda SJ, Camdessanché JP, Millet GY. How is neuromuscular fatigability affected by perceived fatigue and disability in people with multiple sclerosis? Front Neurol 2022; 13:983643. [DOI: 10.3389/fneur.2022.983643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/23/2022] [Indexed: 11/13/2022] Open
Abstract
Whereas fatigue is recognized to be the main complaint of patients with multiple sclerosis (PwMS), its etiology, and particularly the role of resistance to fatigability and its interplay with disability level, remains unclear. The purposes of this review were to (i) clarify the relationship between fatigue/disability and neuromuscular performance in PwMS and (ii) review the corticospinal and muscular mechanisms of voluntary muscle contraction that are altered by multiple sclerosis, and how they may be influenced by disability level or fatigue. Neuromuscular function at rest and during exercise are more susceptible to impairement, due to deficits in voluntary activation, when the disability is greater. Fatigue level is related to resistance to fatigability but not to neuromuscular function at rest. Neurophysiological parameters related to signal transmission such as central motor conduction time, motor evoked potentials amplitude and latency are affected by disability and fatigue levels but their relative role in the impaired production of torque remain unclear. Nonetheless, cortical reorganization represents the most likely explanation for the heightened fatigability during exercise for highly fatigued and/or disabled PwMS. Further research is needed to decipher how the fatigue and disability could influence fatigability for an ecological task, especially at the corticospinal level.
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Castoldi V, Rossi E, Marenna S, Comi G, Leocani L. Improving reproducibility of motor evoked potentials in mice. J Neurosci Methods 2022; 367:109444. [PMID: 34921842 DOI: 10.1016/j.jneumeth.2021.109444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/13/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND In preclinical research involving murine models of neurological diseases, Motor Evoked Potentials (MEPs) can detect pathological alterations in nerve conduction throughout the cortico-spinal tract. In mice, MEPs elicited by electrical stimulation of the motor cortex can be performed with epicranial or subdermal electrodes such as implanted screws or removable needles, which are associated with invasive surgery and variability in placement of the stimulating electrodes, respectively. METHODS We compared MEPs induced by epicranial or subcutaneous stimulation with a non-invasive surface cup electrode over five recording sessions, in healthy C57BL/6 mice. Additionally, using surface stimulation, we examined the recordings obtained with intramuscular needles or surface electrodes to understand if MEP reproducibility could be improved. RESULTS Resting motor threshold (RMT), MEP latency and amplitude were comparable among the different stimulation methods. Epicranial, subcutaneous and surface stimulation techniques presented good repeatability over time, with surface stimulation showing a significantly reduced inter-session variability. Compared with intramuscular needles, MEPs recorded with surface electrode showed reduced peak-to-peak amplitude at all timepoints. RMT and MEP latency were comparable with both recording methods. On the other hand, amplitudes recorded with the surface electrode presented a significantly lower inter-session variance, resulting in improved repeatability. CONCLUSION Overall, there is evidence for highly reproducible results using different stimulating methods, with indication for reduced inter-session variability for surface stimulation. Moreover, MEP recording with surface electrode provided a decrease in amplitude variability over time, indicating improved measurement stability when considering amplitude as functional outcome in longitudinal studies.
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Affiliation(s)
- Valerio Castoldi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Elena Rossi
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Silvia Marenna
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Giancarlo Comi
- Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milan, Italy; Casa di Cura del Policlinico, via Giuseppe Dezza, 48, 20144 Milan, Italy
| | - Letizia Leocani
- Experimental Neurophysiology Unit, INSPE - Institute of Experimental Neurology, San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy; Vita-Salute San Raffaele University, via Olgettina 58, 20132 Milan, Italy.
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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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Non-invasive brain stimulation to assess neurophysiologic underpinnings of lower limb motor impairment in multiple sclerosis. J Neurosci Methods 2021; 356:109143. [PMID: 33757762 DOI: 10.1016/j.jneumeth.2021.109143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/20/2021] [Accepted: 03/10/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND Multiple sclerosis (MS) is a neuroinflammatory disease resulting in axonal demyelination and an amalgamation of symptoms which commonly result in decreased quality of life due to mobility dysfunction and limited participation in meaningful activities. NEW METHOD The use of non-invasive brain stimulation (NIBS) techniques, specifically transcranial magnetic and transcranial direct current stimulation, have been essential in understanding the pathophysiological decrements related to disease progression, particularly with regard to motor impairments. Although the research in this area has primarily focused on the upper extremities, new interest has arisen in understanding the neurophysiological underpinnings of lower limb impairment. Therefore, the purpose of this review is to: first, provide an overview of common NIBS techniques used to explore sensorimotor neurophysiology; second, summarize lower limb neuromuscular and mobility impairments typically observed in PwMS; third, review the current knowledge regarding interactions between TMS-assessed neurophysiology and lower limb impairments in PwMS; and fourth, provide recommendations for future NIBS studies based on current gaps in the literature. RESULTS PwMS exhibit reduced excitability and increased inhibitory neurophysiologic function which has been related to disease severity and lower limb motor impairments. Comparison with existing methods: Moreover, promising results indicate that the use of repetitive stimulation and transcranial direct current stimulation may prime neural adaptability and prove useful as a therapeutic tool in ameliorating lower limb impairments. CONCLUSIONS While these studies are both informative and promising, additional studies are necessary to be conclusive. As such, studies assessing objective measures of lower limb impairments associated with neurophysiological adaptations need further evaluation.
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Mohy AB, Hatem AK, Kadoori HG, Hamdan FB. Motor disability in patients with multiple sclerosis: transcranial magnetic stimulation study. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2020. [DOI: 10.1186/s41983-020-00255-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Transcranial magnetic stimulation (TMS) is a non-invasive procedure used in a small targeted region of the brain via electromagnetic induction and used diagnostically to measure the connection between the central nervous system (CNS) and skeletal muscle to evaluate the damage that occurs in MS.
Objectives
The study aims to investigate whether single-pulse TMS measures differ between patients with MS and healthy controls and to consider if these measures are associated with clinical disability.
Patients and methods
Single-pulse TMS was performed in 26 patients with MS who hand an Expanded Disability Status Scale (EDSS) score between 0 and 9.5 and in 26 normal subjects. Different TMS parameters from upper and lower limbs were investigated.
Results
TMS disclosed no difference in all MEP parameters between the right and left side of the upper and lower limbs in patients with MS and controls. In all patients, TMS parameters were different from the control group. Upper limb central motor conduction time (CMCT) was prolonged in MS patients with pyramidal signs. Upper and lower limb CMCT and CMCT-f wave (CMCT-f) were prolonged in patients with ataxia. Moreover, CMCT and CMCT-f were prolonged in MS patients with EDSS of 5–9.5 as compared to those with a score of 0–4.5. EDSS correlated with upper and lower limb cortical latency (CL), CMCT, and CMCT-f whereas motor evoked potential (MEP) amplitude not.
Conclusion
TMS yields objective data to evaluate clinical disability and its parameters correlated well with EDSS.
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Craig JJ, Bruetsch AP, Lynch SG, Huisinga JM. Trunk and foot acceleration variability during walking relates to fall history and clinical disability in persons with multiple sclerosis. Clin Biomech (Bristol, Avon) 2020; 80:105100. [PMID: 32798813 PMCID: PMC7983701 DOI: 10.1016/j.clinbiomech.2020.105100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 05/19/2019] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Persons with multiple sclerosis are often at higher risk for falling, but clinical disability scales and fall risk questionnaires are subjective and don't provide specific feedback about why an individual is unstable. The purpose of this study was to determine how relationships between trunk and foot acceleration variability relate to physiological impairments, clinical disability scales, and mobility questionnaires in persons with multiple sclerosis. METHODS 15 fallers and 25 non-fallers with multiple sclerosis walked on a treadmill at normal walking speed while trunk and foot accelerations were recorded with wireless accelerometers and variability measures were extracted and used to calculate the gait stability index metrics as a ratio of trunk acceleration variability divided foot acceleration variability. Subjects' sensorimotor delays and lower extremity vibration sensitivity were tested. Subjects also completed clinical disability scales (Guy's Neurological Disability Scale and Patient Reported Expanded Disability Status Scale) and mobility questionnaires (Falls Efficacy Scale, Activities Balance Confidence Scale, 12 Item Multiple Sclerosis Walk Scale). FINDINGS Multiple gait stability index metrics were significantly correlated with clinical measures of disability and mobility in multiple sclerosis subjects (r = 0.354-0.528), but no correlations were found for sensorimotor delays or lower extremity sensation. Multiple gait stability indices performed at least as well as clinical questionnaires for separating fallers from non-fallers. INTERPRETATION The gait stability indices can potentially be used outside of a laboratory setting to measure walking characteristics related to fall history and disability level in people with multiple sclerosis.
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Affiliation(s)
- Jordan J Craig
- Landon Center on Aging, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 1005, Kansas City, KS 66160, United States; Bioengineering Graduate Program, University of Kansas, 3135A Learned Hall, 1530 W 15(th) St, Lawrence, KS 66045, United States
| | - Adam P Bruetsch
- Landon Center on Aging, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 1005, Kansas City, KS 66160, United States
| | - Sharon G Lynch
- Department of Neurology, 3901 Rainbow Blvd., Kansas City, KS 66160, United States
| | - Jessie M Huisinga
- Department of Physical Therapy and Rehabilitation Science, 3901 Rainbow Blvd., Mail Stop 2002, Kansas City, KS 66160, United States.
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Mamoei S, Hvid LG, Boye Jensen H, Zijdewind I, Stenager E, Dalgas U. Neurophysiological impairments in multiple sclerosis-Central and peripheral motor pathways. Acta Neurol Scand 2020; 142:401-417. [PMID: 32474916 DOI: 10.1111/ane.13289] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/09/2020] [Accepted: 05/24/2020] [Indexed: 12/27/2022]
Abstract
A systematic review of the literature was conducted comparing neurophysiological outcomes in persons with multiple sclerosis (PwMS) to healthy controls (HC), in studies of the central nervous system (CNS) function comprising motor evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) and in studies of the peripheral nervous system (PNS) function comprising electroneuronography (ENG) outcomes elicited by peripheral nerve stimulation. Studies comparing neuromuscular function, assessed during maximal voluntary contraction (MVC) of muscle, were included if they reported muscle strength along with muscle activation by use of electromyography (EMG) and/or interpolated twitch technique (ITT). Studies investigating CNS function showed prolonged central motor conduction times, asymmetry of nerve conduction motor pathways, and prolonged latencies in PwMS when compared to HC. Resting motor threshold, amplitude, and cortical silent periods showed conflicting results. CNS findings generally correlated with disabilities. Studies of PNS function showed near significant prolongation in motor latency of the median nerve, reduced nerve conduction velocities in the tibial and peroneal nerves, and decreased compound muscle action potential amplitudes of the tibial nerve in PwMS. ENG findings did not correlate with clinical severity of disabilities. Studies of neuromuscular function showed lower voluntary muscle activation and increased central fatigue in PwMS, whereas EMG showed divergent muscle activation (ie, EMG amplitude) during MVC. When comparing the existing literature on neurophysiological motor examinations in PwMS and HC, consistent and substantial impairments of CNS function were seen in PwMS, whereas impairments of the PNS were less pronounced and inconsistent. In addition, impairments in muscle activation were observed in PwMS.
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Affiliation(s)
- Sepehr Mamoei
- Department of Regional Health Research University of Southern Denmark Odense Denmark
- Denmark/MS‐Clinic of Southern Jutland (Sønderborg, Kolding, Esbjerg) Department of Neurology University Hospital of Southern Jutland Sønderborg Denmark
| | - Lars G. Hvid
- Exercise Biology Department of Public Health Aarhus University Aarhus C Denmark
| | - Henrik Boye Jensen
- Department of Regional Health Research University of Southern Denmark Odense Denmark
- Department of Neurology Kolding Sygehus Kolding Denmark
| | - Inge Zijdewind
- Department of Biomedical Sciences of Cells and Systems UMCG University of Groningen Groningen The Netherlands
| | - Egon Stenager
- Department of Regional Health Research University of Southern Denmark Odense Denmark
- Denmark/MS‐Clinic of Southern Jutland (Sønderborg, Kolding, Esbjerg) Department of Neurology University Hospital of Southern Jutland Sønderborg Denmark
| | - Ulrik Dalgas
- Exercise Biology Department of Public Health Aarhus University Aarhus C Denmark
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Thompson AK, Sinkjær T. Can Operant Conditioning of EMG-Evoked Responses Help to Target Corticospinal Plasticity for Improving Motor Function in People With Multiple Sclerosis? Front Neurol 2020; 11:552. [PMID: 32765389 PMCID: PMC7381136 DOI: 10.3389/fneur.2020.00552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/15/2020] [Indexed: 11/25/2022] Open
Abstract
Corticospinal pathway and its function are essential in motor control and motor rehabilitation. Multiple sclerosis (MS) causes damage to the brain and descending connections, and often diminishes corticospinal function. In people with MS, neural plasticity is available, although it does not necessarily remain stable over the course of disease progress. Thus, inducing plasticity to the corticospinal pathway so as to improve its function may lead to motor control improvements, which impact one's mobility, health, and wellness. In order to harness plasticity in people with MS, over the past two decades, non-invasive brain stimulation techniques have been examined for addressing common symptoms, such as cognitive deficits, fatigue, and spasticity. While these methods appear promising, when it comes to motor rehabilitation, just inducing plasticity or having a capacity for it does not guarantee generation of better motor functions. Targeting plasticity to a key pathway, such as the corticospinal pathway, could change what limits one's motor control and improve function. One of such neural training methods is operant conditioning of the motor-evoked potential that aims to train the behavior of the corticospinal-motoneuron pathway. Through up-conditioning training, the person learns to produce the rewarded neuronal behavior/state of increased corticospinal excitability, and through iterative training, the rewarded behavior/state becomes one's habitual, daily motor behavior. This minireview introduces operant conditioning approach for people with MS. Guiding beneficial CNS plasticity on top of continuous disease progress may help to prolong the duration of maintained motor function and quality of life in people living with MS.
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Affiliation(s)
- Aiko K Thompson
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Thomas Sinkjær
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.,Lundbeck Foundation, Copenhagen, Denmark
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Giffroy X, Dive D, Kaux JF, Maes N, Albert A, Göbels C, Wang F. Is the triple stimulation technique a better quantification tool of motor dysfunction than motor evoked potentials in multiple sclerosis? Acta Neurol Belg 2019; 119:47-54. [PMID: 30136146 DOI: 10.1007/s13760-018-1001-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/13/2018] [Indexed: 01/07/2023]
Abstract
The triple stimulation technique (TST) was rarely used in multiple sclerosis (MS). This study aimed to compare TST and motor evoked potentials (MEP) for the quantification of motor dysfunction. Central motor conduction based on MEP (four limbs) and TST (upper limbs) was assessed in 28 MS patients with a median Expanded Disability Status Scale (EDSS) of 4. EDSS, timed 25-foot walk (T25FW), grasping strength and motor components of the MS functional composite were evaluated. Regression analysis was used to assess the relationship between MEP, TST and clinical findings. TST was negatively correlated with EDSS (r = - 0.74, p < 0.0001) and to a lesser extent with T25FW (r = - 0.47, p < 0.05), and grasping strength (r = - 0.43, p < 0.05). A multiple regression analysis underlined the better correlation between clinical data and TST (R2 = 0.56, p < 0.0005) than with MEP (0.03 < R2 < 0.22, p > 0.05). This study evidenced the value of TST as a quantification tool of motor dysfunction. TST appeared to reflect a global disability since it was correlated not only to hand function but also to walking capacity.
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Chaves AR, Wallack EM, Kelly LP, Pretty RW, Wiseman HD, Chen A, Moore CS, Stefanelli M, Ploughman M. Asymmetry of Brain Excitability: A New Biomarker that Predicts Objective and Subjective Symptoms in Multiple Sclerosis. Behav Brain Res 2019; 359:281-291. [DOI: 10.1016/j.bbr.2018.11.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/24/2018] [Accepted: 11/05/2018] [Indexed: 12/13/2022]
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Operant Up-Conditioning of the Tibialis Anterior Motor-Evoked Potential in Multiple Sclerosis: Feasibility Case Studies. Neural Plast 2018; 2018:4725393. [PMID: 30123249 PMCID: PMC6079394 DOI: 10.1155/2018/4725393] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 04/12/2018] [Indexed: 11/18/2022] Open
Abstract
Damage to the corticospinal pathway often results in weak dorsiflexion of the ankle, thereby limiting the mobility of people with multiple sclerosis (MS). Thus, strengthening corticospinal connectivity may improve locomotion. Here, we investigated the feasibility of tibialis anterior (TA) motor-evoked potential (MEP) operant conditioning and whether it can enhance corticospinal excitability and alleviate locomotor problems in people with chronic stable MS. The protocol consisted of 6 baseline and 24 up-conditioning sessions over 10 weeks. In all sessions, TA MEPs were elicited at 10% above active threshold while the sitting subject provided 30–35% maximum voluntary contraction (MVC) level of TA background EMG. During baseline sessions, MEPs were simply measured. During conditioning trials of the conditioning sessions, the subject was encouraged to increase MEP and was given immediate feedback indicating whether MEP size was above a criterion. In 3/4 subjects, TA MEP increased 32–75%, MVC increased 28–52%, locomotor EMG modulation improved in multiple leg muscles, and foot drop became less severe. In one of them, MEP and MVC increases were maintained throughout 3 years of extensive follow-up sessions. These initial results support a therapeutic possibility of MEP operant conditioning for improving locomotion in people with MS or other CNS disorders, such as spinal cord injury and stroke.
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Craig JJ, Bruetsch AP, Lynch SG, Huisinga JM. The relationship between trunk and foot acceleration variability during walking shows minor changes in persons with multiple sclerosis. Clin Biomech (Bristol, Avon) 2017; 49:16-21. [PMID: 28826011 PMCID: PMC5681884 DOI: 10.1016/j.clinbiomech.2017.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 07/19/2017] [Accepted: 07/27/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Identifying how relationships between variability of upper and lower body segments during walking are altered in persons with multiple sclerosis may uncover specific strategies for maintaining overall stability. The purpose of this study was to examine relationships between trunk and foot acceleration variability during walking in healthy controls and in persons with multiple sclerosis. METHODS Linear and nonlinear variability measures were calculated for 40 healthy controls and 40 persons with multiple sclerosis from the acceleration time series recorded by inertial sensors attached to the trunk and foot while subjects walked on a treadmill at self-selected preferred pace. FINDINGS No main effect of group was found for any variability measures. Main effect of location was found for all variability measures, with larger magnitudes of variability at the foot compared to the trunk, and more predictable variability patterns at the foot compared to the trunk. Differences in strength of correlations between trunk and foot accelerations were found between persons with multiple sclerosis and healthy controls in the frontal and sagittal plane. Sample entropy of accelerations at the feet and at the trunk correlated significantly higher in healthy controls than in persons with multiple sclerosis. INTERPRETATION Relationships between variability of trunk and foot accelerations, which may provide a valuable comprehensive description of whole body stability during gait, showed minor changes in persons with MS compared to healthy controls.
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Affiliation(s)
- Jordan J. Craig
- Landon Center on Aging, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 1005, Kansas City, KS 66160, United States of America,Bioengineering Graduate Program, University of Kansas, 3135A Learned Hall, 1530 W 15th St, Lawrence, KS 66045, United States of America
| | - Adam P. Bruetsch
- Landon Center on Aging, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 1005, Kansas City, KS 66160, United States of America
| | - Sharon G. Lynch
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 2002, Kansas City, KS 66160, United States of America
| | - Jessie M. Huisinga
- Landon Center on Aging, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 1005, Kansas City, KS 66160, United States of America,Bioengineering Graduate Program, University of Kansas, 3135A Learned Hall, 1530 W 15th St, Lawrence, KS 66045, United States of America,Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 2002, Kansas City, KS 66160, United States of America
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Errors in the ankle plantarflexor force production are related to the gait deficits of individuals with multiple sclerosis. Hum Mov Sci 2016; 51:91-98. [PMID: 27923175 DOI: 10.1016/j.humov.2016.11.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Individuals with multiple sclerosis (MS) often have limited mobility that is thought to be due to the neuromuscular impairments of the ankle. Greater isometric motor control of the ankle has been associated with better standing postural balance but its relationship to mobility is less understood. The objectives of this investigation were to quantify the motor control of the ankle plantarflexors of individuals with MS during a dynamic isometric motor task, and explore the relationship between the ankle force control and gait alterations. METHODS Fifteen individuals with MS and 15 healthy adults participated in both a dynamic isometric ankle plantarflexion force matching task and a biomechanical gait analysis. FINDINGS Our results displayed that the subjects with MS had a greater amount of error in their dynamic isometric force production, were weaker, walked with altered spatiotemporal kinematics, and had reduced maximal ankle moment at toe-off than the control group. The greater amount of error in the dynamic force production was related to the decreases in strength, step length, walking velocity, and maximal ankle moment during walking. INTERPRETATION Altogether these results imply that errors in the ankle plantarflexion force production may be a limiting factor in the mobility of individuals with MS.
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Arpin DJ, Davies BL, Kurz MJ. Multiple sclerosis influences the precision of the ankle plantarflexon muscular force production. Gait Posture 2016; 45:170-4. [PMID: 26979901 DOI: 10.1016/j.gaitpost.2016.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/27/2016] [Accepted: 02/01/2016] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To quantify the precision of the steady-state isometric control of the ankle plantarflexors musculature of individuals with multiple sclerosis (MS), and to evaluate if the precision is related to the mobility impairments. METHODS Individuals with MS and healthy adults performed a submaximal steady-state isometric contraction with the ankle plantarflexors. The coefficient of variation was used to assess the amount of variability or error in the precision of the torques generated by the ankle plantarflexor musculature. The participants also walked across a digital mat at their preferred and fast-as-possible walking speeds, which recorded their spatiotemporal gait kinematics. RESULTS The individuals with MS: (1) had reduced maximal voluntary torques at the ankle, (2) a greater amount of variability in the precision of the isometric ankle torques, (3) altered and more variable spatiotemporal gait kinematics, and (4) a greater amount of variability in the isometric ankle torques were related to a slower walking speed and cadence, shorter step length and a greater amount of gait variability. CONCLUSIONS These results further fuels the impression that a reduction in control of the ankle joint musculature may be a key factor in the mobility and balance impairments seen in individuals with MS.
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Affiliation(s)
- David J Arpin
- Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States
| | - Brenda L Davies
- Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States
| | - Max J Kurz
- Department of Physical Therapy, Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, United States.
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Simpson M, Macdonell R. The use of transcranial magnetic stimulation in diagnosis, prognostication and treatment evaluation in multiple sclerosis. Mult Scler Relat Disord 2015; 4:430-436. [PMID: 26346791 DOI: 10.1016/j.msard.2015.06.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 06/10/2015] [Accepted: 06/22/2015] [Indexed: 11/26/2022]
Abstract
Despite advances in brain imaging which have revolutionised the diagnosis and monitoring of patients with Multiple Sclerosis (MS), current imaging techniques have limitations, including poor correlation with clinical disability and prognosis. There is growing evidence that electrophysiological techniques may provide complementary functional information which can aid in diagnosis, prognostication and perhaps even monitoring of treatment response in patients with MS. Transcranial magnetic stimulation (TMS) is an underutilised technique with potential to assist diagnosis, predict prognosis and provide an objective surrogate marker of clinical progress and treatment response. This review explores the existing body of evidence relating to the use of TMS in patients with MS, outlines the practical aspects and scope of TMS testing and reviews the current evidence relating to the use of TMS in diagnosis, disease classification, prognostication and response to symptomatic and disease-modifying therapies.
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Affiliation(s)
- Marion Simpson
- Department of Neurology, Austin Health and Faculty of Medicine, The University of Melbourne, Melbourne, Vic, Australia.
| | - Richard Macdonell
- Department of Neurology, Austin Health and Faculty of Medicine, The University of Melbourne, Melbourne, Vic, Australia
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22
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A new neurophysiological approach to assess central motor conduction damage to proximal and distal muscles of lower limbs. Clin Neurophysiol 2014; 125:133-41. [PMID: 23867064 DOI: 10.1016/j.clinph.2013.06.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/26/2013] [Accepted: 06/21/2013] [Indexed: 01/28/2023]
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Abstract
The availability of new treatments able to modify the natural course of multiple sclerosis (MS) has generated interest in paraclinical measures to monitor disease evolution. Among these, neurophysiologic measures, mainly evoked potentials (EPs), are used in the functional assessment of central sensorimotor and cognitive networks affected by MS. EP abnormalities may reveal subclinical lesions, objectivate the involvement of sensory and motor pathways in the presence of vague disturbances, and provide indications of the demyelinating nature of the disease process. However, their diagnostic value is much lower than that of magnetic resonance imaging, and is more sensitive to brain and cervical spinal cord lesions. The application of EPs in assessing disease severity and monitoring the evolution of nervous damage is more promising, thanks to their good correlation with disability in cross-sectional and longitudinal studies, and potential use as paraclinical endpoints in clinical trials. Recent evidence indicates that EPs performed early in the disease may help to predict a worse future progression in the long term. If confirmed, these data suggest the possible usefulness of EPs in the early identification of patients who are more likely to develop future disability, thus requiring more frequent monitoring or being potential candidates for more aggressive disease-modifying treatments.
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Affiliation(s)
- Letizia Leocani
- Department of Neurology, Clinical Neurophysiology and Neurorehabilitation, University Hospital San Raffaele, Milan, Italy.
| | - Giancarlo Comi
- Department of Neurology, Clinical Neurophysiology and Neurorehabilitation, University Hospital San Raffaele, Milan, Italy
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Pallix-Guyot M, Guennoc AM, Blasco H, de Toffol B, Corcia P, Praline J. Predictive value of motor evoked potentials in clinically isolated syndrome. Acta Neurol Scand 2011; 124:410-6. [PMID: 21355856 DOI: 10.1111/j.1600-0404.2011.01498.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To assess the predictive role of several measures obtained by transcranial magnetic stimulation (TMS) in patients with clinically isolated syndrome (CIS) for the risk of conversion to multiple sclerosis (MS) during the first 2 years. MATERIALS AND METHODS We investigated 34 patients with CIS. After 2 years of follow-up and classification into two groups according to MS diagnosis, initial TMS measures were compared to determine their predictive values for conversion to MS. RESULTS Sixteen patients developed MS. We observed a significant difference between the two groups for contralateral silent period and no significant difference for the central motor conduction time, amplitude ratio, motor threshold, ipsilateral silent period, and the transcallosal conduction time. CONCLUSIONS Contralateral silent period (SP) seems to be a valuable parameter to early distinguish patients who will develop MS or not. This result about SP during CIS has never been described until now. An increased contralateral silent period would predict a conversion to MS with a positive predictive value of 75%, but this result needs to be confirmed in larger groups.
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Affiliation(s)
- M Pallix-Guyot
- Service de Neurologie et de Neurophysiologie Clinique, Hôpital Bretonneau, CHRU Tours, France.
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25
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Assessment of motor pathways by magnetic stimulation in human and veterinary medicine. Vet J 2011; 187:174-81. [DOI: 10.1016/j.tvjl.2009.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 12/09/2009] [Accepted: 12/11/2009] [Indexed: 11/22/2022]
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26
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Rico A, Zaaraoui W, Franques J, Attarian S, Reuter F, Malikova I, Confort-Gouny S, Soulier E, Pouget J, Cozzone PJ, Pelletier J, Ranjeva JP, Audoin B. Motor cortical reorganization is present after a single attack of multiple sclerosis devoid of cortico-spinal dysfunction. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2010; 24:77-84. [PMID: 21165670 DOI: 10.1007/s10334-010-0232-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 10/21/2010] [Accepted: 10/26/2010] [Indexed: 12/11/2022]
Abstract
OBJECT While occurrence of motor cortical reorganization has been clearly demonstrated in patients with multiple sclerosis (MS), it is not yet clear whether this cortical reorganization constitutes a response to cortico-spinal lesions or to more diffuse damage affecting the neuronal network involved in motor act preparation, or both. We proposed to investigate the changes in the activation pattern during a simple motor task devoid of cortico-spinal dysfunction occurring in patients with clinically isolated syndrome (CIS) suggestive of MS. MATERIALS AND METHODS Among 15 right-handed CIS patients, we selected eight patients with a preserved central motor pathway established by motor evoked potentials. Ten healthy right-handed gender- and age-matched volunteers were also included. After morphological MRI, subjects performed calibrated conjugated finger flexion and extension movements during fMRI acquisition. RESULTS In CIS patients, simple movements of the non-dominant hand induced recruitment of the anterior cingulate cortex (BA32) usually involved in complex motor movements. This reorganization was correlated with the diffuse brain tissue damage (brain T₂ lesion load). CONCLUSION These results suggest that at least part of the cortical reorganization observed during very simple tasks in the earliest stage of MS occurs whether or not the efferent pathways are intact.
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Affiliation(s)
- Audrey Rico
- Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 6612 Facultéde Médecine, Université de la Méditerranée, Marseille, France.
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Iyer S, Maybhate A, Presacco A, All AH. Multi-limb acquisition of motor evoked potentials and its application in spinal cord injury. J Neurosci Methods 2010; 193:210-6. [PMID: 20832429 DOI: 10.1016/j.jneumeth.2010.08.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 08/18/2010] [Accepted: 08/18/2010] [Indexed: 12/21/2022]
Abstract
The motor evoked potential (MEP) is an electrical response of peripheral neuro-muscular pathways to stimulation of the motor cortex. MEPs provide objective assessment of electrical conduction through the associated neural pathways, and therefore detect disruption due to a nervous system injury such as spinal cord injury (SCI). In our studies of SCI, we developed a novel, multi-channel set-up for MEP acquisition in rat models. Unlike existing electrophysiological systems for SCI assessment, the set-up allows for multi-channel MEP acquisition from all limbs of rats and enables longitudinal monitoring of injury and treatment for in vivo models of experimental SCI. The article describes the development of the set-up and discusses its capabilities to acquire MEPs in rat models of SCI. We demonstrate its use for MEP acquisition under two types of anesthesia as well as a range of cortical stimulation parameters, identifying parameters yielding consistent and reliable MEPs. To validate our set-up, MEPs were recorded from a group of 10 rats before and after contusive SCI. Upon contusion with moderate severity (12.5mm impact height), MEP amplitude decreased by 91.36±6.03%. A corresponding decline of 93.8±11.4% was seen in the motor behavioral score (BBB), a gold standard in rodent models of SCI.
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Affiliation(s)
- Shrivats Iyer
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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28
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Rico A, Audoin B, Franques J, Eusebio A, Reuter F, Malikova I, Ali Cherif A, Pouget J, Pelletier J, Attarian S. Motor evoked potentials in clinically isolated syndrome suggestive of multiple sclerosis. Mult Scler 2009; 15:355-62. [DOI: 10.1177/1352458508099612] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of the present study was to determine the sensitivity and the profile of motor evoked potentials (MEP) in patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). We measured the central motor conduction time (CMCT), amplitude ratio (AR), and surface ratio (SR) in tibialis anterior and first dorsal interosseous muscles in 22 patients with CIS. In 12 patients, the triple stimulation technique (TST) was also performed. AR was abnormal in 50% of patients, CMCT in 18% of patients, and TST in 25% of patients. AR had the highest sub-clinical sensitivity and the best positive predictive value. In the absence of clinical pyramidal signs, an early AR decrease seems to result from demyelination inducing excessive temporal dispersion of the MEP, while in territories with clinical pyramidal signs, it seems to result from conduction failure, which suggests that clinical pyramidal signs may be attributable to conduction failure. This study demonstrates that MEP, especially the AR, is sensitive to motor pathway dysfunction right from the early stages of MS.
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Affiliation(s)
- A Rico
- Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France; Pôle de Neurosciences Cliniques, Service de Neurologie, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - B Audoin
- Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France; Pôle de Neurosciences Cliniques, Service de Neurologie, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - J Franques
- Pôle de Neurosciences Cliniques, Service de Neurologie et des pathologies neuromusculaires, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - A Eusebio
- Pôle de Neurosciences Cliniques, Service de Neurologie et des pathologies neuromusculaires, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - F Reuter
- Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France; Pôle de Neurosciences Cliniques, Service de Neurologie, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - I Malikova
- Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France; Pôle de Neurosciences Cliniques, Service de Neurologie, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - A Ali Cherif
- Pôle de Neurosciences Cliniques, Service de Neurologie, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - J Pouget
- Pôle de Neurosciences Cliniques, Service de Neurologie et des pathologies neuromusculaires, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - J Pelletier
- Centre de Résonance Magnétique Biologique et Médicale UMR CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France; Pôle de Neurosciences Cliniques, Service de Neurologie, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
| | - S Attarian
- Pôle de Neurosciences Cliniques, Service de Neurologie et des pathologies neuromusculaires, Faculté de Médecine de Marseille, Université de la Méditerranée, Hôpital de la Timone, Marseille, France
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