Neurophysiological evaluation of patients with degenerative diseases of the cervical spine

Bacground/Aim. Diagnostic protocol for patients with degenerative diseases of the cervical spine demands, in parallel with neuroimaging methods, functional evaluation through neurophysiological methods (somatosensitive and motor evoked potentials and electromyoneurography) aiming to evaluate possible subclinical affection of spinal medula resulting in neurological signs of long tract abnormalities. Considering diversities of clinical outcomes for these patients, complex diagnostic evaluation provides a prognosis of the disease progression. Methods. The study included 21 patients (48.24 ? 11.01 years of age) with clinical presentation of cervical spondylarthropathy, without neuroradiological signs of myelopathy. For each patient, in addition to conventional neurophysiological tests (somatisensory evoked potentials - SSEP, motor evoked potentials - MEP, electromyoneurography - EMG, nerve conduction studies), we calculated central motor conduction time (CMCTF), as well the same parameter in relation to a different position of the head (maximal anteflexion and retroflexion), so-called dynamic tests. Results. Abnormalities of the peripheral motor neurone by conventional EMNeG was established in 2/3 of the patients, correponding to the findings of root condution time. Prolonged conventional CVMPF were found in 29% of the patients, comparing to 43% CVMPF abnormalities found with the dynamic tests. In addition, the SSEP findings were abnormal in 38% of the patients with degenerative diseases of the cervical spine. Conclusion. An extended neurophysiological protocol of testing corticospinal functions, including dynamic tests of central and periheral motor neurons are relevant for detection of subclinical forms of cervical spondylothic myelopathy, even at early stages. In addition to the conventional neurophysiological tests, we found usefull to include the dynamic motor tests and root conduction time measurement in diagnostic evaluation.

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The size of motor-evoked potentials: influencing parameters and quantification

10.1093/oxfordhb/9780198568926.013.0009 ◽

2012 ◽

Author(s):

Kai M. Rösler ◽

Michel R. Magistris

Keyword(s):

Evoked Potentials ◽

Motor Neurons ◽

Healthy Subjects ◽

Motor Evoked Potentials ◽

Conduction Block ◽

Phase Cancellation ◽

Pathological Conditions ◽

The Central Nervous System ◽

Stimulation Technique ◽

Triple Stimulation Technique

This article discusses parameters influencing the size of motor-evoked potentials (MEPs) in normal and pathological conditions, and the methods of meaningful quantification of the MEPs. MEPs are widely used to study the physiology of corticospinal conduction in healthy subjects and in patients with diseases of the central nervous system. The characteristics of MEP size are, stimulus intensity, coil positioning, and facilitation. MEPs show variability in size and shape from one stimulus to the next, even if the stimulus parameters are kept constant. This article describes the triple stimulation technique (TST), which was developed to eliminate the effects of phase cancellation from the MEPs, to allow for a better quantification. Pathological conditions may modify the parameters discussed in the article and influence the size of the MEPs by lesions of motor neurons or of their axons, central conduction velocity slowing, or conduction block.

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Motor Evoked Potentials after Supraspinal Stimulation in Pre- and Postoperative Evaluations of Patients with Cervical Radiculopathy

BioMed Research International ◽

10.1155/2019/4576493 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11

Author(s):

Aleksandra Bryndal ◽

Magdalena Wojtysiak ◽

Jakub Moskal ◽

Joanna Lipiec-Kowalska ◽

Martyna Borowczyk ◽

...

Keyword(s):

Clinical Trials ◽

Muscle Strength ◽

Evoked Potentials ◽

Motor Evoked Potentials ◽

Cervical Radiculopathy ◽

Diagnostic Value ◽

Pain Severity ◽

Test And Evaluation ◽

Neurophysiological Tests ◽

F Wave

Objective. Pre- and postoperative comparative evaluation of neurophysiological tests and clinical trials. Analysis of the diagnostic value of motor evoked potentials (MEP) induced by a magnetic field after supraspinal stimulation. Evaluation of the sensitivity and specificity of electromyography (EMG) and MEP is achieved. Methods. EMG, ENG, M-wave, F-wave, and MEP tests were performed on 35 patients with confirmed cervical radiculopathy in pre- and postoperative evaluations. The clinical trial consisted of evaluation of muscle strength, a sensory perception test and evaluation of tendon reflexes and pain severity. Results. The sensitivity of the resting EMG and MEP tests is 24%-67% and 6%-27%, while their specificity is 43%-80% and 86%-100%, respectively. The postoperative evaluation revealed a statistically significant reduction in pain severity (p=0001), an increase in muscle strength in DP (p=0.0431), BB (p=0,0431), and TB (p=0.0272), and improvement of touch sensation in terms of dermatomal innervation in C5 (p=0.0001) and C6 (p=0.0044). Conclusions. Tests comparing MRI sensitivity to neurophysiological tests show that neuroimaging is more sensitive in diagnostics of patients with cervical radiculopathy; however, clinical neurophysiology tests are more specific in reference to clinical trials.

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Motor evoked potentials in clinically isolated syndrome suggestive of multiple sclerosis

Multiple Sclerosis Journal ◽

10.1177/1352458508099612 ◽

2009 ◽

Vol 15 (3) ◽

pp. 355-362 ◽

Cited By ~ 17

Author(s):

A Rico ◽

B Audoin ◽

J Franques ◽

A Eusebio ◽

F Reuter ◽

...

Keyword(s):

Multiple Sclerosis ◽

Evoked Potentials ◽

Amplitude Ratio ◽

Motor Evoked Potentials ◽

Clinically Isolated Syndrome ◽

Conduction Time ◽

Motor Pathway ◽

Clinical Sensitivity ◽

Conduction Failure ◽

Stimulation Technique

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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Determining the Corticospinal and Neuromuscular Responses Following a Warm-Up Protocol

The Journal of Science and Medicine ◽

10.37714/josam.v2i2.45 ◽

2020 ◽

Vol 2 (2) ◽

pp. 1-12

Author(s):

Rhys Painter ◽

Alan Pearce ◽

Mohamad Rostami ◽

Ashlyn Frazer ◽

Dawson Kidgell

Keyword(s):

Heart Rate ◽

Evoked Potentials ◽

Neuromuscular Transmission ◽

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Corticospinal Excitability ◽

Muscle Temperature ◽

Conduction Time ◽

Warm Up ◽

Time To Peak

Background: The effect of warming-up prior to exercise on increased neuromuscular transmission speed remains largely untested. Objective: This study used transcranial magnetic stimulation (TMS) and peripheral nerve stimulation (PNS) to quantify neuromuscular transmission along the corticospinal tract (CST) before and after a warm-up protocol of the elbow flexors. Method: Using a single-group, pre-test-post-test design, 30 participants (20 male; 10 female; mean age 26.3 ± 7.4 years) completed four sets of bicep curls that aimed to increase heart rate (HR) and biceps brachii (BB) muscle temperature by a minimum of 40 beats per minute (bpm) and 1°C, respectively. Single-pulse TMS was applied to the primary motor cortex, and over the cervical and thoracic (C7-T1) areas of the spine to quantify motor evoked potentials (MEPs) and spinal evoked potentials (SEPs), respectively. Central motor conduction time (CMCT) was determined by calculating the difference in latency time of the onset of MEPs and SEPs. Peripheral motor conduction time (PMCT) was calculated following stimuli from Erb’s point to the onset of the maximal compound muscle action potential twitch (MMAX latency). MMAX time to peak twitch was also measured. MMAX amplitude was used to normalize the MEP to quantify corticospinal excitability. Results: Following the warm-up, significant increases in mean heart rate (44.8 ± 11.7 bpm; P < 0.001) and muscle temperature (1.4 ± 0.6°C; P < 0.001) were observed. No changes were seen in corticospinal excitability (P = 0.39), CMCT (P = 0.09), or MMAX latency (P = 0.24). However, MMAX time to peak twitch was significantly reduced (P = 0.003). Conclusion: This study has shown that exercise-based warm-ups improve neuromuscular conduction velocity via thermoregulatory processes that result in the onset of muscle contraction being more rapid, but not as a result of changes in the efficacy of neural transmission along the CST.

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Transcranial stimulation excites virtually all motor neurons supplying the target muscle. A demonstration and a method improving the study of motor evoked potentials

Brain ◽

10.1093/brain/121.3.437 ◽

1998 ◽

Vol 121 (3) ◽

pp. 437-450 ◽

Cited By ~ 190

Author(s):

M. Magistris

Keyword(s):

Evoked Potentials ◽

Motor Neurons ◽

Motor Evoked Potentials ◽

Transcranial Stimulation

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NAIAD-2020: Characteristics of Motor Evoked Potentials After 3-Day Exposure to Dry Immersion in Women

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.753259 ◽

2021 ◽

Vol 15 ◽

Author(s):

Inna Nosikova ◽

Alexandra Riabova ◽

Liubov Amirova ◽

Vladimir Kitov ◽

Elena Tomilovskaya

Keyword(s):

Menstrual Cycle ◽

Evoked Potentials ◽

Motor Evoked Potentials ◽

Recovery Period ◽

Microgravity Environment ◽

Conduction Time ◽

Gravitational Unloading ◽

Dry Immersion ◽

Small Group Size ◽

Underlying Mechanisms

As female astronauts participate in space flight more and more frequently, there is a demand for research on how the female body adapts to the microgravity environment. In particular, there is very little research on how the neuromuscular system reacts to gravitational unloading in women. We aimed to estimate changes in motor evoked potentials (MEPs) in the lower leg muscles in women after 3-day exposure to Dry Immersion (DI), which is one of the most widely used ground models of microgravity. Six healthy female volunteers (mean age 30.17 ± 5.5 years) with a natural menstrual cycle participated in this experiment. MEPs were recorded from the gastrocnemius and soleus muscles twice before DI, on the day of DI completion, and 3 days after DI, during the recovery period. To evoke motor responses, transcranial and trans-spinal magnetic stimulation was applied. We showed that changes in MEP characteristics after DI exposure were different depending on the stimulation site, but were similar for both muscles. For trans-spinal stimulation, MEP thresholds decreased compared to baseline values, and amplitudes, on the contrary, increased, resembling the phenomenon of hypogravitational hyperreflexia. This finding is in line with data observed in other experiments on both male and female participants. MEPs to transcranial stimulation had an opposing dynamic, which may have resulted from the small group size and large inter-subject variability, or from hormonal fluctuations during the menstrual cycle. Central motor conduction time remained unchanged, suggesting that pyramidal tract conductibility was not affected by DI exposure. More research is needed to explore the underlying mechanisms.

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Preventing Position-Related Brachial Plexus Injury with Intraoperative Somatosensory Evoked Potentials and Transcranial Electrical Motor Evoked Potentials during Anterior Cervical Spine Surgery

American Journal of Electroneurodiagnostic Technology ◽

10.1080/1086508x.2011.11079820 ◽

2011 ◽

Vol 51 (3) ◽

pp. 198-205 ◽

Cited By ~ 14

Author(s):

Faisal R. Jahangiri ◽

Andrea Flolmberg ◽

Francisco Vega-Bermudez ◽

Vincent Arlet

Keyword(s):

Cervical Spine ◽

Evoked Potentials ◽

Brachial Plexus ◽

Spine Surgery ◽

Somatosensory Evoked Potentials ◽

Brachial Plexus Injury ◽

Motor Evoked Potentials ◽

Cervical Spine Surgery ◽

Anterior Cervical Spine Surgery

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031 Investigating motor evoked potentials as a biomarker for disease severity in hereditary spastic paraplegia

Journal of Neurology Neurosurgery & Psychiatry ◽

10.1136/jnnp-2018-anzan.30 ◽

2018 ◽

Vol 89 (6) ◽

pp. A13.2-A13

Author(s):

Sue-Faye Siow ◽

Carolyn Sue ◽

Kishore Kumar ◽

Sharon Coward ◽

Amy Lofts ◽

...

Keyword(s):

Evoked Potentials ◽

Disease Severity ◽

Lower Limb ◽

Hereditary Spastic Paraplegia ◽

Disease Duration ◽

Rating Scale ◽

Motor Evoked Potentials ◽

Conduction Time ◽

Spastic Paraplegia ◽

Resting Motor Threshold

IntroductionHereditary spastic paraplegia (HSP) encompasses a diverse group of neurodegenerative disorders that results in significant disability with no curative or disease-modifying treatment. The lack of standardised biomarkers of disease severity has limited the evaluation of potential therapeutic agents. Our aim is to investigate motor evoked potentials (MEPs) as a marker of HSP disease severity.MethodsWe studied 21 subjects (10 male, 11 female; mean age 54.3±13.8 years) with a clinical diagnosis of HSP (10 SPG4, 4 SPG7, 1 SPG3A, 1 SPG 30, 5 genetically undetermined). All patients underwent transcranial magnetic stimulation to measure central motor conduction time (CMCT), resting motor threshold (rMT) and MEP amplitude from the tibialis anterior (TA), abductor hallucis (AH) and abductor digiti minimi (ADM). Clinical disease severity was assessed with the Spastic Paraplegia Rating Scale (SPRS). Pearson correlation coefficient was used to assess correlation between variables, significance was defined as P value<0.05.ResultsTA CMCT was prolonged in 16/21 subjects (76%). AH CMCT was absent in 3/18 subjects (16.7%) and prolonged in 9/18 subjects (50%). ADM CMCT was measured in 19 subjects; all were normal. There was no significant correlation between SPRS scores and MEP amplitude, rMT or CMCT for TA or AH. There was also no significant correlation between these MEP measures and disease duration or patient age. Subgroup analysis of SPG4 HSP (10 subjects) revealed significant correlation between TA and AH CMCT with disease duration (r=0.841, p=0.001; r=0.930, p=0.001) but not SPRS scores.ConclusionLower limb CMCT was absent or prolonged in the majority of subjects. Despite being potentially useful as a diagnostic biomarker for HSP, this study only showed a correlation between lower limb CMCT and disease duration in the SPG4 subgroup. Further genotype-specific studies utilising larger numbers may clarify the relationship between MEP markers and clinical features.

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