scholarly journals Brain Response Induced with Paired Associative Stimulation Is Related to Repetition Suppression of Motor Evoked Potential

2020 ◽  
Vol 10 (10) ◽  
pp. 674
Author(s):  
Shohreh Kariminezhad ◽  
Jari Karhu ◽  
Laura Säisänen ◽  
Jusa Reijonen ◽  
Mervi Könönen ◽  
...  
Keyword(s):  
Motor Evoked Potentials ◽  
Stable State ◽  
Motor Evoked Potential ◽  
Brain Response ◽  
Dynamic Component ◽  
Paired Associative Stimulation ◽  
Stable Component ◽  
Repetition Suppression ◽  
The Mean ◽  
The Brain

Repetition suppression (RS), i.e., the reduction of neuronal activity upon repetition of an external stimulus, can be demonstrated in the motor system using transcranial magnetic stimulation (TMS). We evaluated the RS in relation to the neuroplastic changes induced by paired associative stimulation (PAS). An RS paradigm, consisting of 20 trains of four identical suprathreshold TMS pulses 1 s apart, was assessed for motor-evoked potentials (MEPs) in 16 healthy subjects, before and following (at 0, 10, and 20 min) a common PAS protocol. For analysis, we divided RS into two components: (1) the ratio of the second MEP amplitude to the first one in RS trains, i.e., the “dynamic” component, and (2) the mean of the second to fourth MEP amplitudes, i.e., the “stable” component. Following PAS, five subjects showed change in the dynamic RS component. However, nearly all the individuals (n = 14) exhibited change in the stable component (p < 0.05). The stable component was similar between subjects showing increased MEPs and those showing decreased MEPs at this level (p = 0.254). The results suggest the tendency of the brain towards a stable state, probably free from the ongoing dynamics, following PAS.

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.

Feasibility of intraoperative monitoring of motor evoked potentials obtained through transcranial electrical stimulation in infants younger than 3 months

2019 ◽  
Vol 23 (6) ◽  
pp. 758-766 ◽  
Author(s):  
You Gyoung Yi ◽  
Keewon Kim ◽  
Hyung-Ik Shin ◽  
Moon Suk Bang ◽  
Hee-Soo Kim ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Motor Evoked Potentials ◽  
Young Patients ◽  
Motor Evoked Potential ◽  
The Other ◽  
Neurological Deficits ◽  
Transcranial Electrical Stimulation ◽  
Neurosurgical Procedures ◽  
Limb Weakness ◽  
The Mean

OBJECTIVEThis study aimed to investigate the feasibility and safety of intraoperative motor evoked potential (MEP) monitoring in infants less than 3 months of age.METHODSThe authors investigated 25 cases in which infants younger than 3 months (mean age 72.8 days, range 39–87) underwent neurosurgery between 2014 and 2017. Myogenic MEPs were obtained through transcranial electrical stimulation. In all cases, surgery was performed under total intravenous anesthesia, maintained with remifentanil and propofol.RESULTSMEPs were documented in 24 infants, the sole exception being 1 infant who was lethargic and had 4-limb weakness before surgery. The mean stimulation intensity maintained during monitoring was 596 ± 154 V (range 290–900 V). In 19 of 24 infants MEP signals remained at ≥ 50% of the baseline amplitude throughout the operation. Among 5 cases with a decrease in intraoperative MEP amplitude, the MEP signal was recovered in one during surgery, and in the other case a neurological examination could not be performed after surgery. In the other 3 cases, 2 infants had relevant postoperative weakness and the other did not show postoperative neurological deficits. Postoperative weakness was not observed in any of the 20 infants who had no deterioration (n = 19) or only temporary deterioration (n = 1) in MEP signal during surgery.CONCLUSIONSTranscranial electrical MEPs could be implemented during neurosurgery in infants between 1 and 3 months of age. Intraoperative MEP monitoring may be a safe adjunct for neurosurgical procedures in these very young patients.

Effects of transcranial stimulating electrode montages over the head for lower-extremity transcranial motor evoked potential monitoring

2016 ◽  
Vol 126 (6) ◽  
pp. 1951-1958 ◽  
Author(s):  
Ryosuke Tomio ◽  
Takenori Akiyama ◽  
Takayuki Ohira ◽  
Kazunari Yoshida
Keyword(s):  
Finite Element ◽  
Lower Extremity ◽  
Electric Field ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Threshold Level ◽  
Lower Threshold ◽  
Transcranial Electrical Stimulation ◽  
Head Model ◽  
The Brain

OBJECTIVEThe aim of this study was to determine the most effective electrode montage to elicit lower-extremity transcranial motor evoked potentials (LE-tMEPs) using a minimum stimulation current.METHODSA realistic 3D head model was created from T1-weighted images. Finite element methods were used to visualize the electric field in the brain, which was generated by transcranial electrical stimulation via 4 electrode montage models. The stimulation threshold level of LE-tMEPs in 52 patients was also studied in a practical clinical setting to determine the effects of each electrode montage.RESULTSThe electric field in the brain radially diffused from the brain surface at a maximum just below the electrodes in the finite element models. The Cz-inion electrode montage generated a centrally distributed high electric field with a current direction longitudinal and parallel to most of the pyramidal tract fibers of the lower extremity. These features seemed to be effective in igniting LE-tMEPs.Threshold level recordings of LE-tMEPs revealed that the Cz-inion electrode montage had a lower threshold on average than the C3–C4 montage, 76.5 ± 20.6 mA and 86.2 ± 20.6 mA, respectively (31 patients, t = 4.045, p < 0.001, paired t-test). In 23 (74.2%) of 31 cases, the Cz-inion montage could elicit LE-tMEPs at a lower threshold than C3–C4.CONCLUSIONSThe C3–C4 and C1–C2 electrode montages are the standard for tMEP monitoring in neurosurgery, but the Cz-inion montage showed lower thresholds for the generation of LE-tMEPs. The Cz-inion electrode montage should be a good alternative for LE-tMEP monitoring when the C3–C4 has trouble igniting LE-tMEPs.

Motor Evoked Potential Recordings During Segmented Deep Brain Stimulation—A Feasibility Study

2021 ◽  
Vol 20 (4) ◽  
pp. 419-425
Author(s):  
Jay Shils ◽  
Ryan B Kochanski ◽  
Alireza Borghei ◽  
Alexander Candocia ◽  
Gian D Pal ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
General Anesthesia ◽  
Brain Stimulation ◽  
Pulse Generator ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Therapeutic Window ◽  
The Mean ◽  
Deep Brain ◽  
Stimulation Of

Abstract BACKGROUND Segmented deep brain stimulation (DBS) leads, which are capable of steering current in the direction of any 1 of 3 segments, can result in a wider therapeutic window by directing current away from unintended structures, particularly, the corticospinal tract (CST). It is unclear whether the use of motor evoked potentials (MEPs) is feasible during DBS surgery via stimulation of individual contacts/segments in order to quantify CST activation thresholds and optimal contacts/segments intraoperatively. OBJECTIVE To assess the feasibility of using MEP to identify CST thresholds for ring and individual segments of the DBS lead under general anesthesia. METHODS MEP testing was performed during pulse generator implantation under general anesthesia on subjects who underwent DBS lead implantation into the subthalamic nucleus (STN). Stimulation of each ring and segmented contacts of the directional DBS lead was performed until CST threshold was reached. Stereotactic coordinates and thresholds for each contact/segment were recorded along with the initially activated muscle group. RESULTS A total of 34 hemispheres were included for analysis. MEP thresholds were recorded from 268 total contacts/segments. For segmented contacts (2 and 3, respectively), the mean highest CST thresholds were 2.33 and 2.62 mA, while the mean lowest CST thresholds were 1.7 and 1.89 mA, suggesting differential thresholds in relation to CST. First dorsal interosseous and abductor pollicis brevis (34% each) were the most commonly activated muscle groups. CONCLUSION MEP threshold recording from segmented DBS leads is feasible. MEP recordings can identify segments with highest CST thresholds and may identify segment orientation in relation to CST.

Comparison of Fluorine(18)-fluorodeoxyglucose and Gallium(68)-citrate PET/CT in patients with tuberculosis

2019 ◽  
Vol 58 (05) ◽  
pp. 371-378
Author(s):  
Alfred O. Ankrah ◽  
Ismaheel O. Lawal ◽  
Tebatso M.G. Boshomane ◽  
Hans C. Klein ◽  
Thomas Ebenhan ◽  
...  
Keyword(s):  
Tracer Uptake ◽  
Pet Ct ◽  
The Mean ◽  
18F Fdg ◽  
Definition Of ◽  
Gallium 68 ◽  
Attending Physician ◽  
Pet Scans ◽  
The Brain

Abstract 18F-FDG and 68Ga-citrate PET/CT have both been shown to be useful in the management of tuberculosis (TB). We compared the abnormal PET findings of 18F-FDG- and 68Ga-citrate-PET/CT in patients with TB. Methods Patients with TB on anti-TB therapy were included. Patients had a set of PET scans consisting of both 18F-FDG and 68Ga-citrate. Abnormal lesions were identified, and the two sets of scans were compared. The scan findings were correlated to the clinical data as provided by the attending physician. Results 46 PET/CT scans were performed in 18 patients, 11 (61 %) were female, and the mean age was 35.7 ± 13.5 years. Five patients also had both studies for follow-up reasons during the use of anti-TB therapy. Thirteen patients were co-infected with HIV. 18F-FDG detected more lesions than 68Ga-citrate (261 vs. 166, p < 0.0001). 68Ga-citrate showed a better definition of intracerebral lesions due to the absence of tracer uptake in the brain. The mean SUVmax was higher for 18F-FDG compared to 68Ga-citrate (5.73 vs. 3.01, p < 0.0001). We found a significant correlation between the SUVmax of lesions that were determined by both tracers (r = 0.4968, p < 0.0001). Conclusion Preliminary data shows 18F-FDG-PET detects more abnormal lesions in TB compared to 68Ga-citrate. However, 68Ga-citrate has better lesion definition in the brain and is therefore especially useful when intracranial TB is suspected.

Intraoperative facial motor evoked potential monitoring for pontine cavernous malformation resection

2020 ◽  
Vol 132 (1) ◽  
pp. 265-271
Author(s):  
Ridzky Firmansyah Hardian ◽  
Tetsuya Goto ◽  
Yu Fujii ◽  
Kohei Kanaya ◽  
Tetsuyoshi Horiuchi ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Cavernous Malformation ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Warning Signs ◽  
Constant Current ◽  
Karnofsky Performance Scale ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Cavernous Malformations

OBJECTIVEThe aim of this study was to predict postoperative facial nerve function during pontine cavernous malformation surgery by monitoring facial motor evoked potentials (FMEPs).METHODSFrom 2008 to 2017, 10 patients with pontine cavernous malformations underwent total resection via the trans–fourth ventricle floor approach with FMEP monitoring. House-Brackmann grades and Karnofsky Performance Scale (KPS) scores were obtained pre- and postoperatively. The surgeries were performed using one of 2 safe entry zones into the brainstem: the suprafacial triangle and infrafacial triangle approaches. Six patients underwent the suprafacial triangle approach, and 4 patients underwent the infrafacial triangle approach. A cranial peg screw electrode was used to deliver electrical stimulation for FMEP by a train of 4 or 5 pulse anodal constant current stimulation. FMEP was recorded from needle electrodes on the ipsilateral facial muscles and monitored throughout surgery by using a threshold-level stimulation method.RESULTSFMEPs were recorded and analyzed in 8 patients; they were not recorded in 2 patients who had severe preoperative facial palsy and underwent an infrafacial triangle approach. Warning signs appeared in all patients who underwent the suprafacial triangle approach. However, after temporarily stopping the procedures, FMEP findings during surgery showed recovery of the thresholds. FMEPs in patients who underwent the infrafacial triangle approach were stable during the surgery. House-Brackmann grades were unchanged postoperatively in all patients. Postoperative KPS scores improved in 3 patients, decreased in 1, and remained the same in 6 patients.CONCLUSIONSFMEPs can be used to monitor facial nerve function during surgery for pontine cavernous malformations, especially when the suprafacial triangle approach is performed.

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 Use of an Insulation-Tipped Knife during Rigid Bronchoscopic Treatment of Benign Tracheobronchial Stenosis

Medicina ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 251
Author(s):  
Ji-Won Park ◽  
Yousang Ko ◽  
Changhwan Kim
Keyword(s):  
Tracheal Stenosis ◽  
Treatment Success ◽  
Stable State ◽  
Forced Expiratory Volume ◽  
Rigid Bronchoscopy ◽  
Bronchial Stenosis ◽  
Tracheobronchial Stenosis ◽  
Acute Complications ◽  
The Mean ◽  
Post Intubation

Background and Objectives: Tracheal or bronchial tears are potential complications of rigid bronchoscopy. This study aimed to investigate the acute complications and outcomes of using an insulation-tipped (IT) knife in combination with rigid bronchoscopic dilatation for treating benign tracheobronchial stenosis. Materials and Methods: We conducted a chart review of patients with benign tracheobronchial stenosis who were treated with rigid bronchoscopy and an IT knife at two referral centers. Treatment success was defined as a clinically stable state without worsening symptoms after 3 months of treatment. Results: Of the 23 patients with benign tracheobronchial stenosis, 15 had tracheal stenosis and 6 had main bronchial stenosis. Among them, three cases were of simple stenosis (13%), while the others were of complex stenosis (87%). The overall treatment success rate was 87.0%. Pneumomediastinum and subcutaneous emphysema occurred due to bronchial laceration in two cases of distal left main bronchial stenosis (8.7%), and no other significant acute complications developed. Silicone stents were inserted in 20 patients, and successful stent removal was possible in 11 patients (55.0%). Six of the seven stents inserted in patients with post-intubation tracheal stenosis were removed successfully (85.7%). However, most of the patients with post-tracheostomy tracheal stenosis required persistent stenting (80%). Pulmonary function was significantly increased after treatment, and the mean increase in the forced expiratory volume in 1 s was 391 ± 171 mL (160–700 mL). Conclusion: The use of an IT knife can be suggested as an effective and safe modality for rigid bronchoscopic treatment of benign tracheobronchial stenosis.

scholarly journals Conditional Entropy: A Potential Digital Marker for Stress

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 286
Author(s):  
Soheil Keshmiri
Keyword(s):  
Resting State ◽  
Nearest Neighbor ◽  
Brain Activity ◽  
Solution Concept ◽  
Conditional Entropy ◽  
K Nearest Neighbor ◽  
Brain Response ◽  
Substantial Progress ◽  
Eeg Recordings ◽  
The Brain

Recent decades have witnessed a substantial progress in the utilization of brain activity for the identification of stress digital markers. In particular, the success of entropic measures for this purpose is very appealing, considering (1) their suitability for capturing both linear and non-linear characteristics of brain activity recordings and (2) their direct association with the brain signal variability. These findings rely on external stimuli to induce the brain stress response. On the other hand, research suggests that the use of different types of experimentally induced psychological and physical stressors could potentially yield differential impacts on the brain response to stress and therefore should be dissociated from more general patterns. The present study takes a step toward addressing this issue by introducing conditional entropy (CE) as a potential electroencephalography (EEG)-based resting-state digital marker of stress. For this purpose, we use the resting-state multi-channel EEG recordings of 20 individuals whose responses to stress-related questionnaires show significantly higher and lower level of stress. Through the application of representational similarity analysis (RSA) and K-nearest-neighbor (KNN) classification, we verify the potential that the use of CE can offer to the solution concept of finding an effective digital marker for stress.

scholarly journals Motor Evoked Potential Warning Criteria in Supratentorial Surgery: A Scoping Review

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2803
Author(s):  
Evridiki Asimakidou ◽  
Pablo Alvarez Abut ◽  
Andreas Raabe ◽  
Kathleen Seidel
Keyword(s):  
Scoping Review ◽  
Predictive Value ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Critical Duration ◽  
Motor Deficit ◽  
Warning Sign ◽  
Outcome Reporting ◽  
Scoping Reviews ◽  
Warning Criteria

During intraoperative monitoring of motor evoked potentials (MEP), heterogeneity across studies in terms of study populations, intraoperative settings, applied warning criteria, and outcome reporting exists. A scoping review of MEP warning criteria in supratentorial surgery was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Sixty-eight studies fulfilled the eligibility criteria. The most commonly used alarm criteria were MEP signal loss, which was always a major warning sign, followed by amplitude reduction and threshold elevation. Irreversible MEP alterations were associated with a higher number of transient and persisting motor deficits compared with the reversible changes. In almost all studies, specificity and Negative Predictive Value (NPV) were high, while in most of them, sensitivity and Positive Predictive Value (PPV) were rather low or modest. Thus, the absence of an irreversible alteration may reassure the neurosurgeon that the patient will not suffer a motor deficit in the short-term and long-term follow-up. Further, MEPs perform well as surrogate markers, and reversible MEP deteriorations after successful intervention indicate motor function preservation postoperatively. However, in future studies, a consensus regarding the definitions of MEP alteration, critical duration of alterations, and outcome reporting should be determined.

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