scholarly journals Mechanisms of motor‐evoked potential facilitation following prolonged dual peripheral and central stimulation in humans

2001 ◽  
Vol 537 (2) ◽  
pp. 623-631 ◽  
Author(s):  
M. C. Ridding ◽  
J. L. Taylor
Keyword(s):  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Central Stimulation

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.

Intraoperative motor and somatosensory evoked potential monitoring during surgical clipping of ruptured and unruptured intracranial aneurysms: a comparative study

2021 ◽  
pp. 1-8
Author(s):  
Hao You ◽  
Xing Fan ◽  
Jiajia Liu ◽  
Dongze Guo ◽  
Zhibao Li ◽  
...  
Keyword(s):  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Critical Values ◽  
Somatosensory Evoked Potential ◽  
Short Term ◽  
Surgical Clipping ◽  
Unruptured Aneurysms ◽  
Ruptured Aneurysms ◽  
Unruptured Intracranial Aneurysms

OBJECTIVE The current study investigated the correlation between intraoperative motor evoked potential (MEP) and somatosensory evoked potential (SSEP) monitoring and both short-term and long-term motor outcomes in aneurysm patients treated with surgical clipping. Moreover, the authors provide a relatively optimal neurophysiological predictor of postoperative motor deficits (PMDs) in patients with ruptured and unruptured aneurysms. METHODS A total of 1017 patients (216 with ruptured aneurysms and 801 with unruptured aneurysms) were included. Patient demographic characteristics, clinical features, intraoperative monitoring data, and follow-up data were retrospectively reviewed. The efficacy of using changes in MEP/SSEP to predict PMDs was assessed using binary logistic regression analysis. Subsequently, receiver operating characteristic curve analysis was performed to determine the optimal critical value for duration of MEP/SSEP deterioration. RESULTS Both intraoperative MEP and SSEP monitoring were significantly effective for predicting short-term (p < 0.001 for both) and long-term (p < 0.001 for both) PMDs in aneurysm patients. The critical values for predicting short-term PMDs were amplitude decrease rates of 57.30% for MEP (p < 0.001 and area under the curve [AUC] 0.732) and 64.10% for SSEP (p < 0.001 and AUC 0.653). In patients with an unruptured aneurysm, the optimal critical values for predicting short-term PMDs were durations of deterioration of 17 minutes for MEP (p < 0.001 and AUC 0.768) and 21 minutes for SSEP (p < 0.001 and AUC 0.843). In patients with a ruptured aneurysm, the optimal critical values for predicting short-term PMDs were durations of deterioration of 12.5 minutes for MEP (p = 0.028 and AUC 0.706) and 11 minutes for SSEP (p = 0.043 and AUC 0.813). CONCLUSIONS The authors found that both intraoperative MEP and SSEP monitoring are useful for predicting short-term and long-term PMDs in patients with unruptured and ruptured aneurysms. The optimal intraoperative neuromonitoring method for predicting PMDs varies depending on whether the aneurysm has ruptured or not.

scholarly journals Impact of Motor-Evoked Potential Monitoring on Facial Nerve Outcomes after Vestibular Schwannoma Resection

2018 ◽  
Vol 128 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Kareem O. Tawfik ◽  
Zoe A. Walters ◽  
Gavriel D. Kohlberg ◽  
Noga Lipschitz ◽  
Joseph T. Breen ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Predictive Value ◽  
Evoked Potential ◽  
Amplitude Ratio ◽  
Motor Evoked Potential ◽  
Level Of Evidence ◽  
Facial Function

Objectives: Assess the utility of intraoperative transcranial facial motor-evoked potential (FMEP) monitoring in predicting and improving facial function after vestibular schwannoma (VS) resection. Study Design: Retrospective chart review. Methods: Data were obtained from 82 consecutive VS resections meeting inclusion criteria. Sixty-two cases were performed without FMEP and 20 with FMEP. Degradation of FMEP response was defined as a final-to-baseline amplitude ratio of 0.5 or less. House-Brackmann (HB) grade was assessed preoperatively, postoperatively, at follow-up assessments, and it was compared between pre- and post-FMEP cohorts. Positive predictive value (PPV) and negative predictive value (NPV), sensitivity, and specificity of FMEP degradation in predicting facial weakness were calculated. Results: In the pre-FMEP group, at length of follow-up (LOF) ⩾9 months, 83.9% (52/62) of patients exhibited HB 1-2 outcome. In the post-FMEP cohort, 75.0% (15/20) exhibited HB 1-2 function at LOF ⩾9 months. There was no difference in rates of HB 1-2 outcomes between groups in the immediate postoperative period ( P = .35) or at long-term follow-up ( P = 1.0). With respect to predicting immediate postoperative facial function, FMEP demonstrated high specificity (88.9%) and moderate sensitivity (54.5%). The PPV and NPV for immediate postoperative facial function were 85.7% and 61.5%, respectively. With respect to long-term (⩾9 months LOF) facial function, intraoperative FMEP was moderately sensitive (71.4%) and highly specific (84.6%); PPV was moderate (71.4%), and NPV was high (84.6%). Conclusions: Intraoperative FMEP is highly specific and moderately sensitive in predicting postoperative facial function for patients undergoing VS resection, but its use may not be associated with improved facial nerve outcomes. Level of Evidence: 4

Intraoperative monitoring of motor-evoked potential for parenchymal brain tumor removal: An analysis of false-negative cases

2018 ◽  
Vol 57 ◽  
pp. 105-110
Author(s):  
Takeru Umemura ◽  
Shigeru Nishizawa ◽  
Yoshiteru Nakano ◽  
Takeshi Saito ◽  
Takehiro Kitagawa ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Intraoperative Monitoring ◽  
Evoked Potential ◽  
False Negative ◽  
Motor Evoked Potential ◽  
Tumor Removal

scholarly journals Awareness during anaesthesia for surgery requiring evoked potential monitoring: A pilot study

2017 ◽  
Vol 04 (01) ◽  
pp. 036-041
Author(s):  
Pritish Korula ◽  
Ramamani Mariappan ◽  
Justin James ◽  
Prashant Kumar ◽  
Grace Korula
Keyword(s):  
Pilot Study ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Maintenance Phase ◽  
Primary Objective ◽  
Anaesthetic Technique ◽  
Depth Of Anaesthesia ◽  
Electrophysiological Monitoring ◽  
Evoked Potential Monitoring ◽  
Potential Monitoring

Abstract Background: Evoked potential monitoring such as somatosensory-evoked potential (SSEP) or motor-evoked potential (MEP) monitoring during surgical procedures in proximity to the spinal cord requires minimising the minimum alveolar concentrations (MACs) below the anaesthetic concentrations normally required (1 MAC) to prevent interference in amplitude and latency of evoked potentials. This could result in awareness. Our primary objective was to determine the incidence of awareness while administering low MAC inhalational anaesthetics for these unique procedures. The secondary objective was to assess the adequacy of our anaesthetic technique from neurophysiologist’s perspective. Methods: In this prospective observational pilot study, 61 American Society of Anesthesiologists 1 and 2 patients undergoing spinal surgery for whom intraoperative evoked potential monitoring was performed were included; during the maintenance phase, 0.7–0.8 MAC of isoflurane was targeted. We evaluated the intraoperative depth of anaesthesia using a bispectral (BIS) index monitor as well as the patients response to surgical stimulus (PRST) scoring system. Post-operatively, a modified Bruce questionnaire was used to verify awareness. The adequacy of evoked potential readings was also assessed. Results: Of the 61 patients, no patient had explicit awareness. Intraoperatively, 19 of 61 patients had a BIS value of above sixty at least once, during surgery. There was no correlation with PRST scoring and BIS during surgery. Fifty-four out of 61 patient’s evoked potential readings were deemed ‘good’ or ‘fair’ for the conduct of electrophysiological monitoring. Conclusions: This pilot study demonstrates that administering low MAC inhalational anaesthetics to facilitate evoked potential monitoring does not result in explicit awareness. However, larger studies are needed to verify this. The conduct of SSEP electrophysiological monitoring was satisfactory with the use of this anaesthetic technique. However, the conduct of MEP monitoring was satisfactory, only in patients with Nurick Grade 1 and 2. The MEP response was poor in patients with Nurick Grade 4 and 5.

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