Quantitative assessment of myelopathy patients using motor evoked potentials produced by transcranial magnetic stimulation

Nakamae, Toshio; Tanaka, Nobuhiro; Nakanishi, Kazuyoshi; Fujimoto, Yoshinori; Sasaki, Hirofumi; Kamei, Naosuke; Hamasaki, Takahiko; Yamada, Kiyotaka; Yamamoto, Risako; Izumi, Bunichiro; Ochi, Mitsuo

doi:10.1007/s00586-009-1246-8

Cited by 24 publications

(15 citation statements)

References 24 publications

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“…Motor evoked potential (MEP) is a rapid and feasible method to evaluate the integrity of corticospinal pathways, and can be administered in a noninvasive, and even pain-free, manner [ 1 2 3 4 5 6 7 ]. Previous studies have suggested the usefulness of MEP as a screening and diagnostic tool for myelopathy, and as a prognostic predictor after spinal cord injury (SCI) [ 7 8 9 10 ]. Nakamae et al [ 7 ] reported that MEP latency and central motor conduction time (CMCT) were prolonged (86% and 59%, respectively) among myelopathy patients and a control group.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have suggested the usefulness of MEP as a screening and diagnostic tool for myelopathy, and as a prognostic predictor after spinal cord injury (SCI) [ 7 8 9 10 ]. Nakamae et al [ 7 ] reported that MEP latency and central motor conduction time (CMCT) were prolonged (86% and 59%, respectively) among myelopathy patients and a control group. In patients with acute transverse myelitis CMCT, where MEP amplitudes were different from a control, MEP shapes were abnormal (96% of patients), and MEP thresholds were elevated [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

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Relationship Between Motor Evoked Potential Response and the Severity of Paralysis in Spinal Cord Injury Patients

Kim

et al. 2017

Ann Rehabil Med

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ObjectiveTo investigate the relationship between motor evoked potential (MEP) response and the severity of motor paralysis, evaluated according to the Korean disability evaluation system in patients with spinal cord injury (SCI).MethodsWe analyzed 192 lower limbs of 96 SCI patients. Lower limbs were classified according to their motor scores, as determined by the International Standards for Neurological Classification of Spinal Cord Injury: motor score <10 (group 1); ≥10 and <15 (group 2); ≥15 and <20 (group 3); and ≥20 (group 4). MEP responses were classified as ‘normal’, ‘delayed’ or ‘absent’, based on their onset latency, which was compared between the different motor score groups.ResultsMEP responses and limb motor scores were highly correlated (p<0.001). There was a significant difference of MEP responses between the motor score groups (p<0.001). MEP response was markedly poorer in motor group 1 (limb motor score <10) than in the other three groups (p<0.0001). However, there were no differences between the three groups with motor scores of 10 or above.ConclusionClinical utility of MEP as a complimentary tool to manual muscle tests could be limited to discriminating motor score groups with severe paralysis, i.e., single lower limb motor power grades of 0 or 1, and from grade 2, 3, and 4, or above, in the Korean disability evaluation system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Relationship Between Motor Evoked Potential Response and the Severity of Paralysis in Spinal Cord Injury Patients

Kim

et al. 2017

Ann Rehabil Med

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“…Spontaneous systems are usually focused on generating commands to control a device taking advantage of the users capability to control their EEG signals [5] – [7] . Regarding evoked systems, there are studies focused on generating control commands [8] , [9] and also on the evaluation of the brain response to different external stimulus with diagnosis purposes [10] – [12] . Besides, BMIs (both spontaneous and evoked) are used on other topics in the field of human health, such as the measurement of the mental state of a patient (workload, attention level, emotional state,...) [13] or as support systems on rehabilitation processes [14] .…”

Section: Introductionmentioning

confidence: 99%

A Supplementary System for a Brain-Machine Interface Based on Jaw Artifacts for the Bidimensional Control of a Robotic Arm

et al. 2014

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Non-invasive Brain-Machine Interfaces (BMIs) are being used more and more these days to design systems focused on helping people with motor disabilities. Spontaneous BMIs translate user's brain signals into commands to control devices. On these systems, by and large, 2 different mental tasks can be detected with enough accuracy. However, a large training time is required and the system needs to be adjusted on each session. This paper presents a supplementary system that employs BMI sensors, allowing the use of 2 systems (the BMI system and the supplementary system) with the same data acquisition device. This supplementary system is designed to control a robotic arm in two dimensions using electromyographical (EMG) signals extracted from the electroencephalographical (EEG) recordings. These signals are voluntarily produced by users clenching their jaws. EEG signals (with EMG contributions) were registered and analyzed to obtain the electrodes and the range of frequencies which provide the best classification results for 5 different clenching tasks. A training stage, based on the 2-dimensional control of a cursor, was designed and used by the volunteers to get used to this control. Afterwards, the control was extrapolated to a robotic arm in a 2-dimensional workspace. Although the training performed by volunteers requires 70 minutes, the final results suggest that in a shorter period of time (45 min), users should be able to control the robotic arm in 2 dimensions with their jaws. The designed system is compared with a similar 2-dimensional system based on spontaneous BMIs, and our system shows faster and more accurate performance. This is due to the nature of the control signals. Brain potentials are much more difficult to control than the electromyographical signals produced by jaw clenches. Additionally, the presented system also shows an improvement in the results compared with an electrooculographic system in a similar environment.

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“…The F wave is produced by antidromic activation of motoneurons following distal motor nerve electrical stimulation and provides a means of assessing the excitability of the peripheral nerve between the spinal cord and the target muscle [ 33 ]. The latencies recorded at PRE (50.9 ± 0.2 ms), POST (51.0 ± 0.1 ms) and RET (51.1 ± 0.2 ms) allowed us to subsequently calculate peripheral conduction time (PCT: 0.5*((latency of M max130 + latency of F wave ) – 1) and central motor conduction time (CMCT: latency of MEP 150 - PCT) [ 34 ]. There was no difference between testing periods in CMCT ( p > 0.05); whereas a strong time effect was found in PCT (F = 16.84, p < 0.001; ŋ 2 = 0.68), demonstrating that the WPHF-induced lengthening in MEP 150 latency was due to a disturbance in the transmission of the motor-evoked potential distal to the site of medial plantar nerve stimulation.…”

Section: Discussionmentioning

confidence: 99%

Wide‐pulse, high‐frequency, low‐intensity neuromuscular electrical stimulation has potential for targeted strengthening of an intrinsic foot muscle: a feasibility study

James

Solan

Mileva

2018

Journal of Foot and Ankle Research

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BackgroundStrengthening the intrinsic foot muscles is a poorly understood and largely overlooked area. In this study, we explore the feasibility of strengthening m. abductor hallucis (AH) with a specific paradigm of neuromuscular electrical stimulation; one which is low-intensity in nature and designed to interleave physiologically-relevant low frequency stimulation with high-frequencies to enhance effective current delivery to spinal motoneurones, and enable a proportion of force produced by the target muscle to be generated from a central origin. We use standard neurophysiological measurements to evaluate the acute (~ 30 min) peripheral and central adaptations in healthy individuals.MethodsThe AH in the dominant foot of nine healthy participants was stimulated with 24 × 15 s trains of square wave (1 ms), constant current (150% of motor threshold), alternating (20 Hz–100 Hz) neuromuscular electrical stimulation interspersed with 45 s rest. Prior to the intervention, peripheral variables were evoked from the AH compound muscle action potential (Mwave) and corresponding twitch force in response to supramaximal (130%) medial plantar nerve stimulation. Central variables were evoked from the motor evoked potential (MEP) in response to suprathreshold (150%) transcranial magnetic stimulation of the motor cortex corresponding to the AH pathway. Follow-up testing occurred immediately, and 30 min after the intervention. In addition, the force-time-integrals (FTI) from the 1st and 24th WPHF trains were analysed as an index of muscle fatigue. All variables except FTI (T-test) were entered for statistical analysis using a single factor repeated measures ANOVA with alpha set at 0.05.ResultsFTI was significantly lower at the end of the electrical intervention compared to that evoked by the first train (p < 0.01). Only significant peripheral nervous system adaptations were observed, consistent with the onset of low-frequency fatigue in the muscle. In most of these variables, the effects persisted for 30 min after the intervention.ConclusionsAn acute session of wide-pulse, high-frequency, low-intensity electrical stimulation delivered directly to abductor hallucis in healthy feet induces muscle fatigue via adaptations at the peripheral level of the neuromuscular system. Our findings would appear to represent the first step in muscle adaptation to training; therefore, there is potential for using WPHF for intrinsic foot muscle strengthening.Electronic supplementary materialThe online version of this article (10.1186/s13047-018-0258-1) contains supplementary material, which is available to authorized users.

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Quantitative assessment of myelopathy patients using motor evoked potentials produced by transcranial magnetic stimulation

Cited by 24 publications

References 24 publications

Relationship Between Motor Evoked Potential Response and the Severity of Paralysis in Spinal Cord Injury Patients

Relationship Between Motor Evoked Potential Response and the Severity of Paralysis in Spinal Cord Injury Patients

A Supplementary System for a Brain-Machine Interface Based on Jaw Artifacts for the Bidimensional Control of a Robotic Arm

Wide‐pulse, high‐frequency, low‐intensity neuromuscular electrical stimulation has potential for targeted strengthening of an intrinsic foot muscle: a feasibility study

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