scholarly journals Peculiarities of motor evoked potential in healthy children of different age

2019 ◽  
Vol 19 (4) ◽  
pp. 228-231
Author(s):  
Vladislav B. Voitenkov ◽  
N. V. Skripchenko ◽  
A. V. Klimkin ◽  
A. I. Aksenova
Keyword(s):  
Normative Data ◽  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Pediatric Population ◽  
Motor Evoked Potential ◽  
Conduction Time ◽  
Healthy Children ◽  
Abductor Hallucis ◽  
Abductor Pollicis Brevis ◽  
Pediatric Disorders

Aim of the work The implementation of the database for reference values of motor evoked potentials (MEP) in healthy children of different ages. Methods 95 healthy children were enrolled. Age ranged from 1 to 204 months. Three subgroups were established: children of 1-12 months (n=31, 18 males, 13 females), 12-144 months (n=27, 14 males, 13 females) and 144-204 (n=37, 20 males, 17 females) months. All children were healthy. Diagnostic transcranial magnetic stimulation (TMS) was performed in all patients. MEP shape, threshold, latency and amplitudes were recorded for hands (m. Abductor pollicis brevis) and legs (m. Abductor Hallucis). Central motor conduction time (CMCT) was calculated. Results. Along with age there was observed the elongation of MEP latency, gain in amplitudes and shape normalization. There were significant differences in the elongation of MEP latency between children aged of 1-12 months and children from two other subgroups (12-144 and 144-204 months). Conclusions. Our normative data can be usedfor comparative studies in the broad spectrum of pediatric disorders. Age restrictions have to be taken in a consideration when performing the TMS in pediatric population.

Motor threshold, motor evoked potential, central motor conduction time

2021 ◽  
Author(s):  
Sein H. Schmidt ◽  
Stephan A. Brandt
Keyword(s):  
Magnetic Stimulation ◽  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Conduction Time ◽  
Optical Navigation ◽  
Motor Threshold ◽  
Pathological Conditions ◽  
Latency Variability ◽  
First Time

In this chapter, we survey parameters influencing the assessment of the size and latency of motor evoked potentials (MEP), in normal and pathological conditions, and methods to allow for a meaningful quantification of MEP characteristics. In line with the first edition of this textbook, we extensively discuss three established mechanisms of intrinsic physiological variance and collision techniques that aim to minimize their influence. For the first time, in line with the ever wider use of optical navigation and targeting systems in brain stimulation, we discuss novel methods to capture and minimize the influence of extrinsic biophysical variance. Together, following the rules laid out in this chapter, transcranial magnetic stimulation (TMS) can account for spinal and extrinsic biophysical variance to advance investigations of the central origins of MEP size and latency variability.

scholarly journals Comparison of The Electrophysiological Characteristics of Tight Filum Terminale And Tethered Cord Syndrome

2021 ◽  
Author(s):  
Naosuke Kamei ◽  
Toshio Nakamae ◽  
Kazuyoshi Nakanishi ◽  
Taiki Morisako ◽  
Takahiro Harada ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Motor Evoked Potential ◽  
Tethered Cord ◽  
Compound Action Potential ◽  
Conduction Time ◽  
Filum Terminale ◽  
Abductor Hallucis ◽  
Abductor Pollicis Brevis ◽  
Compound Muscle Action Potentials ◽  
Tight Filum Terminale

Abstract This study aims to characterize tight filum terminale (TFT) in motor evoked potential (MEP) testing by comparing TFT patients with both tether cord syndrome (TCS) patients and healthy subjects. Fifty TFT patients, 18 TCS patients, and 35 healthy volunteers participated in this study. We recorded MEPs following transcranial magnetic stimulation from the bilateral abductor hallucis muscles as well as compound muscle action potentials and F-waves evoked by electrical stimulation of the tibial nerve from the bilateral abductor pollicis brevis muscles. The peripheral conduction time (PCT) was calculated from the latency of the compound action potential and F-wave. Furthermore, the central motor conduction time (CMCT) was calculated by subtracting PCT from MEP latency. TFT and TCS patients had a significantly longer MEP latency than healthy subjects. PCT in TFT patients were significantly longer than those in TCS patients or healthy subjects. Using the cut-off values for PCT, we were able to diagnose patients with TFT patients with a sensitivity of 72.0% and a specificity of 91.4%. Prolonged PCT in the MEP test may be a useful indicator for TFT and suggests that MEP may be used as an adjunct diagnostic tool for TFT.

Comparison of Isoflurane Effects on Motor Evoked Potential and F Wave

2000 ◽  
Vol 93 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Henry H. Zhou ◽  
Ching Zhu
Keyword(s):  
Wave Amplitude ◽  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Wilcoxon Test ◽  
Medial Malleolus ◽  
Abductor Hallucis ◽  
Motor Pathway ◽  
Tibialis Muscle ◽  
F Wave

Background Volatile anesthetics produce surgical immobility by suppressing the motor system. The anesthetic action site in the motor pathway is unclear. Anesthetic effects on the whole and the lower portion of motor pathway can be studied by measuring the motor evoked potentials (MEP) and the F wave. This study measured the effect of isoflurane on the MEP and the F wave. Methods With institutional review board approval, we studied 12 adult patients with American Society of Anesthesiologists physical status I or II. After intubation, anesthesia was maintained with nitrous oxide/oxygen and propofol infusion. MEPs were elicited by transcranial electrical stimuli (train-of-five pulse; stimuli intensity 40-160 mA) through electrodes placed in the scalp at C3/C4 positions and recorded at the anterior tibialis muscle with an Axon Sentinel-4EP monitor. F waves were elicited by an electrode fixed over the posterior tibial nerve at the medial malleolus and recorded at the abductor hallucis muscle. After end-tidal concentration of isoflurane was maintained at 0.5% for 20 min, the MEP and F wave were measured again. MEP and F-wave changes before and after isoflurane were analyzed using paired Wilcoxon test with Bonferroni correction. The difference between the changes in MEP and F wave was analyzed using Friedman's test. Results Motor evoked potential amplitudes (median, 205 microV; 25th-75th percentiles, 120-338 microV), F-wave amplitude (median, 100 microV; 25th-75th percentiles, 64.2-137.5 microV), and F-wave persistence (59 +/- 29%) were decreased to 0 microV (0-15 microV), 49 microV (12.4-99.6 microV), and 30 +/- 31%, respectively, by 0.5% isoflurane. MEP amplitude suppression was different from the changes in F-wave amplitude and persistence (P < 0.02). Conclusions Isoflurane 0.5% suppresses the motor pathway by decreasing both MEP and F wave. The MEP is suppressed more than the F wave.

scholarly journals Long-term motor deficit in brain tumour surgery with preserved intra-operative motor-evoked potentials

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Davide Giampiccolo ◽  
Cristiano Parisi ◽  
Pietro Meneghelli ◽  
Vincenzo Tramontano ◽  
Federica Basaldella ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Brain Tumour ◽  
Evoked Potential ◽  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Motor Deficit ◽  
Motor Deficits ◽  
Brain Tumour Surgery

Abstract Muscle motor-evoked potentials are commonly monitored during brain tumour surgery in motor areas, as these are assumed to reflect the integrity of descending motor pathways, including the corticospinal tract. However, while the loss of muscle motor-evoked potentials at the end of surgery is associated with long-term motor deficits (muscle motor-evoked potential-related deficits), there is increasing evidence that motor deficit can occur despite no change in muscle motor-evoked potentials (muscle motor-evoked potential-unrelated deficits), particularly after surgery of non-primary regions involved in motor control. In this study, we aimed to investigate the incidence of muscle motor-evoked potential-unrelated deficits and to identify the associated brain regions. We retrospectively reviewed 125 consecutive patients who underwent surgery for peri-Rolandic lesions using intra-operative neurophysiological monitoring. Intraoperative changes in muscle motor-evoked potentials were correlated with motor outcome, assessed by the Medical Research Council scale. We performed voxel–lesion–symptom mapping to identify which resected regions were associated with short- and long-term muscle motor-evoked potential-associated motor deficits. Muscle motor-evoked potentials reductions significantly predicted long-term motor deficits. However, in more than half of the patients who experienced long-term deficits (12/22 patients), no muscle motor-evoked potential reduction was reported during surgery. Lesion analysis showed that muscle motor-evoked potential-related long-term motor deficits were associated with direct or ischaemic damage to the corticospinal tract, whereas muscle motor-evoked potential-unrelated deficits occurred when supplementary motor areas were resected in conjunction with dorsal premotor regions and the anterior cingulate. Our results indicate that long-term motor deficits unrelated to the corticospinal tract can occur more often than currently reported. As these deficits cannot be predicted by muscle motor-evoked potentials, a combination of awake and/or novel asleep techniques other than muscle motor-evoked potentials monitoring should be implemented.

scholarly journals Clinical feasibility and safety of transoesophageal motor-evoked potential monitoring

2020 ◽  
Vol 57 (6) ◽  
pp. 1076-1082 ◽  
Author(s):  
Norihiko Shiiya ◽  
Kazumasa Tsuda ◽  
Ken Yamanaka ◽  
Daisuke Takahashi ◽  
Naoki Washiyama ◽  
...  
Keyword(s):  
Evoked Potential ◽  
Spinal Cord Injuries ◽  
Motor Evoked Potentials ◽  
False Positive Rate ◽  
Large Diameter ◽  
Motor Evoked Potential ◽  
Monitoring Methods ◽  
Evoked Potential Monitoring ◽  
Transcranial Motor Evoked Potentials ◽  
Potential Monitoring

Abstract OBJECTIVES Canine experiments have shown that transoesophageal motor-evoked potential monitoring is feasible, safe and stable, with a quicker response to ischaemia and a better prognostic value than transcranial motor-evoked potentials. We aimed to elucidate whether or not these findings were clinically reproducible. METHODS A bipolar oesophageal electrode mounted on a large-diameter silicon tube and a train of 5 biphasic wave stimuli were used for transoesophageal stimulation. Results of 18 patients (median age 74.5 years, 13 males) were analysed. RESULTS There were no mortalities, spinal cord injuries or complications related with transoesophageal stimulation. Transcranial motor-evoked potential could not be monitored up to the end of surgery in 3 patients for unknown reasons, 2 of whom from the beginning. Transoesophageal motor-evoked potential became non-evocable after manipulation of a transoesophageal echo probe in 2 patients. Strenuous movement of the upper limbs during transoesophageal stimulation was observed in 3 patients. In 14 patients who successfully completed both monitoring methods up to the end of surgery (11 thoraco-abdominal and 3 descending aortic repair), the final results were judged as false positives in 6 by transcranial stimulation and in 1 by transoesophageal stimulation. The stimulation intensity was significantly lower and the upper limb amplitude was significantly higher by transoesophageal stimulation, while the lower limb amplitude was comparable. CONCLUSIONS Transoesophageal motor-evoked potential monitoring is clinically feasible and safe with a low false positive rate. A better electrode design is required to avoid its migration by transoesophageal echo manipulation. Further studies may be warranted. Clinical registration number UMIN000022320.

Clinical results of cervical myelopathy in patients older than 80 years of age: evaluation of spinal function with motor evoked potentials

2009 ◽  
Vol 11 (4) ◽  
pp. 421-426 ◽  
Author(s):  
Nobuhiro Tanaka ◽  
Kazuyoshi Nakanishi ◽  
Yoshinori Fujimoto ◽  
Hirofumi Sasaki ◽  
Naosuke Kamei ◽  
...  
Keyword(s):  
Cervical Myelopathy ◽  
Motor Evoked Potentials ◽  
Japanese Orthopaedic Association ◽  
Motor Evoked Potential ◽  
Posterior Longitudinal Ligament ◽  
Clinical Results ◽  
Conduction Time ◽  
Average Recovery Rate ◽  
The Mean ◽  
Spinal Function

Object In this prospective analysis the authors describe the clinical results of surgical treatment in patients > 80 years of age in whom spinal function was evaluated with motor evoked potential (MEPs) monitoring. Methods The authors included 57 patients > 80 years of age who were suspected of having cervical myelopathy. The mean age of the patients was 83.0 years (range 80–90 years). The central motor conduction time (CMCT) was calculated from the latencies of the MEPs following transcranial magnetic stimulation and from M and F waves following peripheral nerve stimulation. Results Preoperative electrophysiological evaluation demonstrated significant elongation of CMCT or abnormalities in MEP waveforms in 37 patients (65%), and 35 patients of these underwent laminoplasty. In 30 patients cervical spondylotic myelopathy was diagnosed and 5 patients ossification of the posterior longitudinal ligament was diagnosed. The preoperative mean Japanese Orthopaedic Association Scale score was 8.6 (range 3–12.5) and the mean postoperative score was 12.6 (range 6–14.5) with an average recovery rate of 45% (range −21 to 100%). There were no major complications in any of the patients during the operative period and there were no cases of death resulting from operative intervention. Conclusions Sufficient clinical results are expected even in patients with myelopathy who are older than 80 years of age, provided the patients are correctly selected by electrophysiological evaluation with MEPs and CMCT.

scholarly journals The influence of depth of anesthesia on motor evoked potential response during awake craniotomy

2017 ◽  
Vol 126 (1) ◽  
pp. 260-265 ◽  
Author(s):  
Shunya Ohtaki ◽  
Yukinori Akiyama ◽  
Aya Kanno ◽  
Shouhei Noshiro ◽  
Tomo Hayase ◽  
...  
Keyword(s):  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Awake Craniotomy ◽  
Awake Surgery ◽  
Precentral Gyrus ◽  
Depth Of Anesthesia ◽  
Potential Response ◽  
Awake State ◽  
Neurological Surgery

OBJECTIVE Motor evoked potentials (MEPs) are a critical indicator for monitoring motor function during neurological surgery. In this study, the influence of depth of anesthesia on MEP response was assessed. METHODS Twenty-eight patients with brain tumors who underwent awake craniotomy were included in this study. From a state of deep anesthesia until the awake state, MEP amplitude and latency were measured using 5-train electrical bipolar stimulations on the same site of the precentral gyrus each minute during the surgery. The depth of anesthesia was evaluated using the bispectral index (BIS). BIS levels were classified into 7 stages: < 40, and from 40 to 100 in groups of 10 each. MEP amplitude and latency of each stage were compared. The deviation of the MEP measurements, which was defined as a fluctuation from the average in every BIS stage, was also considered. RESULTS A total of 865 MEP waves in 28 cases were evaluated in this study. MEP amplitude was increased and latency was decreased in accordance with the increases in BIS level. The average MEP amplitudes in the > 90 BIS level was approximately 10 times higher than those in the < 40 BIS level. Furthermore, the average MEP latencies in the > 90 BIS level were 1.5–3.1 msec shorter than those in the < 60 BIS level. The deviation of measured MEP amplitudes in the > 90 BIS level was significantly stabilized in comparison with that in the < 60 BIS level. CONCLUSIONS MEP amplitude and latency were closely correlated with depth of anesthesia. In addition, the deviation in MEP amplitude was also correlated with depth of anesthesia, which was smaller during awake surgery (high BIS level) than during deep anesthesia. Therefore, MEP measurement would be more reliable in the awake state than under deep anesthesia.

Motor Evoked Potentials from Transcranial Stimulation of the Motor Cortex in Humans

Neurosurgery ◽  
1984 ◽  
Vol 15 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Walter J. Levy ◽  
Donald H. York ◽  
Michael McCaffrey ◽  
Fred Tanzer
Keyword(s):  
Spinal Cord ◽  
Motor Cortex ◽  
Evoked Potentials ◽  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Sensory Modality ◽  
Motor Evoked Potential ◽  
Transcranial Stimulation ◽  
Direct Stimulation ◽  
Stimulation Of

Abstract Electrical monitoring of the motor system offers the potential for the detection of injury, the diagnosis of disease, the evaluation of treatment, and the prediction of recovery from damage. Existing evoked potentials monitor one or another sensory modality, but no generally usable motor monitor exists. We have reported a motor evoked potential using direct stimulation of the spinal cord over the motor tracts in cats and in humans. To achieve a less invasive monitor, we used transcranial stimulation over the motor cortex in the cat, thus stimulating the motor cortex. We report here the initial application of this method to humans. A plate electrode over the motor cortex on the scalp and a second electrode on the palate direct a mild current through the motor cortex which will activate the motor pathways. This signal can be recorded over the spinal cord. It can elicit contralateral peripheral nerve and electromyographic signals in the limbs or movements when the appropriate stimulation parameters are used. In clinical use to date, this has been more reliable than the somatosensory evoked potential in predicting motor function in patients where the two tests differed. It offers a number of possibilities for the development of valuable brain and spinal cord monitoring techinques, but requires further animal studies and clinical experience. Studies to date have not demonstrated adverse effects, but evaluation is continuing.

The Effect of Etomidate on Motor Evoked Potentials Induced by Transcranial Magnetic Stimulation in the Monkey

Neurosurgery ◽  
1990 ◽  
Vol 27 (6) ◽  
pp. 936-942 ◽  
Author(s):  
Ramsis F. Ghaly ◽  
James L. Stone ◽  
Walter J. Levy ◽  
Peter Roccaforte ◽  
Edward B. Brunner
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Evoked Potentials ◽  
Total Dose ◽  
Magnetic Stimulation ◽  
Motor Evoked Potentials ◽  
Mean Amplitude ◽  
Abductor Hallucis ◽  
Abductor Pollicis Brevis ◽  
Hypnotic Agent ◽  
The Mean

Abstract Etomidate (ET) is a known hypnotic agent in neuroanesthesia. This study was designed to examine the reliability of motor evoked potentials (MEPs) after transcranial magnetic stimulation in monkeys anesthetized intravenously with ET. The ET regimen was as follows: an initial dose (0.5 mg/kg) followed by 13 doses (0.2 mg/kg every 6-12 min; mean, 8.0 ± 1.3 min). The total dose administered was 3.1 mg/kg. The magnetic coil was placed over the MEP scalp stimulation region. Evoked electromyographic responses were recorded from the contralateral abductor pollicis brevis (APB) and abductor hallucis (AH) muscles of the fore- and hindlimbs, respectively. Reproducible MEP responses were consistently recorded while the animal was under total ET anesthesia. The coil demography was altered and the MEP scalp topography was moderately reduced by ET injections. Significant threshold elevation was noted after a total dose of 1.7 mg/kg for APB responses and 0.5 mg/kg for AH responses (P &lt; 0.05). Marked prolongation of latency was observed after a dose of 0.5 mg/kg for APB MEPs and 2.5 mg/kg for AH MEPs (P &lt; 0.05). MEP amplitude responses showed marked variability. Repeated doses of ET produced a mean threshold rise of 14 to 28% for the APB and 19 to 29% for the AH. The mean latency delay was 5 to 11% for the APB and 0.5 to 8% for the AH, while the mean amplitude depression was 24 to 59% for the APB and 15 to 50% for the AH. Apparent seizure activity or abnormalities in behavior and feeding were not noted over a 1-year period. We conclude that monitoring of MEPs induced by transcranial magnetic stimulation under ET anesthesia is feasible. Clear MEP responses can be maintained under ET anesthesia. ET caused alterations in MEPs induced by transcranial magnetic stimulation, and awareness of such changes is important. Further investigation in humans is recommended.

scholarly journals Measurement of Motor Evoked Potential in Acute Ischemic Stroke: Based on Latency, Amplitude, Central Motoric Conduction Time and Resting Motor Threshold

2016 ◽  
Vol 8 (3) ◽  
pp. 157 ◽  
Author(s):  
Tugas Ratmono ◽  
Andi Wijaya ◽  
Cahyono Kaelan ◽  
Andi Asadul Islam ◽  
Ferry Sandra
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Conduction Time ◽  
Size Measurement ◽  
Motor Threshold ◽  
Dynamic Changes ◽  
Resting Motor Threshold ◽  
Function Impairment

BACKGROUND: After stroke, there are dynamic changes of motor evoked potential (MEP), including latency, amplitude, central motoric conduction time (CMCT) and resting motor threshold (RMT) in cerebral. However, latency, CMCT, amplitude and RMT have not been clearly shown in acute ischemic stroke patients with motoric function impairment based on Modified Motoric Research Council Scale (MRCs).METHODS: Patients with motoric function impairment after acute ischemic stroke were recruited, scored based on MRCs and grouped. Latency, amplitude, CMCT and RMT (% intensity) was measured using transcranial magnetic stimulation (TMS). Latency, amplitude, CMCT and RMT of subjects based on affected hemisphere (AH) and unaffected hemisphere (UH); stroke onset; and motoric severity; were analyzed and compared statistically.RESULTS: Thirty-seven subjects with complete assessments were selected. Results of MEP size measurement between AH and UH showed that latency, amplitude, CMCT and RMT of AH and UH were significantly different (p<0.05). In accordance to AH and UH results, latency, amplitude, CMCT and RMT of mild, moderate and severe groups based on motoric severity, showed that latency and CMCT were prolonged, RMT was increased, while amplitude was decreased along with severity increment. The amplitude and RMT among the groups were significantly different with p=0.034 and p=0.029, respectively.CONCLUSION: MEP size measurement including latency, amplitude, CMCT and RMT have significant different in AH and UH. In addition, amplitude and RMT were significantly different in MRCs groups, therefore the MEP size measurement could be suggested as prognostic tool.KEYWORDS: MEP, latency, amplitude, CMCT, RMT

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