Search Results (145)

Objectives: The primary objective was to investigate and compare the effects of three paired-pulse repetitive trans-spinal magnetic stimulation (PP-rTSMS) protocols on balance control and corticospinal network function. Methods: PP-rTSMS (800 pulses, frequency 100 Hz, intensity 70% of the resting motor threshold) was applied over the eighth thoracic vertebra (Th8) in twenty-seven young healthy individuals. Each proband received three verum sessions (using a verum coil with handle oriented (i) cranially, (ii) caudally, and (iii) laterally) and (iv) one sham session (using a sham coil) in a randomised order. Balance ability (Y Balance Test) and corticospinal network functions (motor evoked potentials (MEPs), cortical silent periods (SCPs)) were tested immediately (i) prior to and (ii) after each interventional session. Results: Each verum session induced a significant improvement in balance ability (cranially (F_1,26 = 8.009; p = 0.009; η² = 0.236), caudally (F_1,26 = 4.846; p = 0.037; η² = 0.157), and laterally (F_1,26 = 23,804; p ≤ 0.001; η² = 0.478) oriented grip) as compared to the sham session. In addition, the laterally oriented coil grip was associated with significantly greater balance benefits than both the cranial (F_1,26 = 10.173; p = 0.004; η² = 0.281) and caudal (F_1,26 = 14.058; p ≤ 0.001; η² = 0.351) grip orientations. No significant intervention-induced effects were detected on corticospinal network functions. Conclusions: Our data show that PP-rTSMS effectively supports balance control and that coil orientation significantly influences these effects. Further studies should test variations of this promising approach on healthy and disabled cohorts. Full article

Background/Objectives: Total intravenous anesthesia (TIVA) typically combines propofol and remifentanil. Remifentanil exerts minimal influence on motor evoked potential (MEP), whereas propofol partially reduces MEP amplitude. Remimazolam, a novel agent, is a component of TIVA. However, evidence of remimazolam on MEP is limited. We aimed to compare the effects of propofol and remimazolam, combined with remifentanil, on relative MEP depression. Methods: Using a crossover design, 18 patients undergoing spine surgery were randomly assigned to receive either propofol or remimazolam as the first agent. In the propofol first sequence, anesthesia was induced and maintained with propofol, which was then switched to remimazolam 60 min after surgery. In the remimazolam first sequence, remimazolam was used first and then switched to propofol. The primary outcomes measured were the MEP amplitude and latency. Results: MEP amplitude and latency during propofol and remimazolam infusions were as follows: amplitude (mean (SD); 635.3 (399.1) vs. 738.4 (480.4) μV, p = 0.047) and latency (median [IQR]; 22.4 [20.3–24.6] vs. 21.4 [19.6–23.5] ms, p = 0.070), indicating propofol caused greater depression in amplitude than remimazolam. However, an incident of severe body movement disrupting surgery occurred under remimazolam anesthesia in a young, healthy male patient, although bispectral index remained below 60. This suggests that remimazolam, at hypnotic levels similar to propofol, may result in reduced akinesia in major surgeries, such as spinal surgery, when neuromuscular blockade is not employed. Conclusions: Remimazolam demonstrated comparable or superior effects to propofol on MEP latency and amplitude when combined with remifentanil during spinal surgery, rendering it a potential alternative to propofol for MEP monitoring. Full article

Background/Objectives: We showed that a tailored strengthening intervention based on the size of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) in the affected hemisphere resulted in an improved affected arm function, regardless of stroke severity. Also, adding anodal transcranial direct stimulation (atDCS) during training did not alter the results as participants receiving real or sham stimulation showed similar gains. The goal of this study was to report on the changes in basic measures of corticomotor excitability in response to the intervention and to determine whether these changes were influenced by tDCS and correlated with those measured in arm function. Methods: The TMS measures consisted of the resting motor threshold (rMT), MEP amplitude at rest, and the silent period (SP) duration. Clinical outcomes included the Box and Block test (BBT) and grip strength (GS). Results: Post-intervention, regardless of atDCS (p > 0.62), no significant change in corticomotor excitability was noted (p > 0.15), as well as no association between the changes in TMS measures and arm function gains (p > 0.06). Conclusions: As observed for clinical measures, atDCS did not influence corticomotor excitability. The absence of an increase in the excitability of the affected hemisphere and important associations between changes in corticomotor excitability and clinical gains suggest that factors other than brain plasticity could mediate gains in arm function. Further investigations are required regarding the role of tDCS in stroke rehabilitation. Full article

Introduction: Intradural extramedullary and intramedullary spinal tumors are rare, complex to treat, and require advanced surgical techniques. Ultrasonic aspirators, commonly used for tumor removal, can cause sensory and motor deficits, including loss of motor evoked potentials (MEPs). This study aims to evaluate the safety and efficacy of ultrasonic aspirators in intramedullary tumor surgery using a swine model, comparing different systems and techniques. Methods: Ten pigs underwent D1-D3 laminectomy and myelotomy, with adipose tissue simulating a tumor. The ultrasonic aspirators were tested under varying conditions (fragmentation power, suction, application time, and vibration mode). The primary endpoint is to evaluate the impact of the chosen variables on motor function damage. The secondary endpoints are histological evaluation of the type of damage caused by ultrasound aspirators and the effect of steroid drugs on MEPs’ impairment recovery. Results: Ultrasound aspirators can cause a significant MEP signal reduction when used in continuous mode, with fragmentation power >30 for more than 2 min (p < 0.001). Suction does not affect MEPs. When used in alternating/pulsatile mode, fragmentation power and application time do not affect MEPs. The two-way ANOVA analysis on the interaction between fragmentation power and application time in continuous mode did not demonstrate a significant interaction (p = 0.155). Time alone does not affect motor damage (p = 0.873). Betamethasone can restore MEPs’ signal after damage if administered immediately. Conclusions: Using ultrasonic aspirators in an animal model of intramedullary tumor surgery is safe. The main factor that resulted in the responsibility of motor function impairment is the fragmentation power. Full article

Evoked potentials (EPs), including somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs), are used to assess neural conduction in spinal cord injury (SCI) and multiple sclerosis (MS), conditions marked by demyelination, inflammation, and axonal damage. Machine learning (ML), using data-driven algorithms, enhances EPs’ prognostic utility, but evidence synthesis is limited. This meta-analysis evaluated the predictive performance of EP-based ML models for SCI recovery (ASIA scale) and MS progression (EDSS) using a random-effects model. Five studies (n = 583) were included, extracting accuracy and area under the curve (AUC). Pooled results showed high predictive accuracy of 77.7% (95% CI, 75.1–80.3%; I² = 57%) and AUC 0.82 (95% CI, 0.79–0.85; I² = 55%). Stratified analyses by disease type (SCI vs. MS) or injury severity were not feasible due to the limited number of studies (n = 5). Sensitivity analysis excluding a rat model (N = 551) showed stable results (accuracy 76.9%; AUC 0.81). SSEP latency and MEP time series were key predictors, with amplitude critical in SCI and multimodal approaches enhancing performance. Moderate heterogeneity (I² = 55–57%) and limited studies constrain generalizability. This meta-analysis highlights EPs’ prognostic potential in ML-driven precision neurology, advocating for further human studies to validate multimodal approaches. Full article

Background: Vaccine hesitancy (VH) is a significant public health challenge, especially during the COVID-19 pandemic. Despite extensive research on the psychological and socio-political determinants of VH, its psychophysiological mechanisms remain unexplored. Grounded in the Somatic Marker Hypothesis, this study aims to investigate the neurophysiological and affective processes underlying VH. Methods: Two experiments will assess sensorimotor resonance and affective processes in VH. In the first experiment, motor-evoked potentials (MEPs) will be recorded from the deltoid and extensor carpi radialis muscles while participants view images of people receiving COVID-19 and influenza vaccines, as well as blood injections (Block 1), and images of vial containing the same substances (Block 2). Facial electromyographic (EMG) activity will measure disgust and fear responses. In the second experiment, skin conductance response (SCR) will be recorded during a virtual reality-based fear conditioning and extinction paradigm. Expected Outcomes: We hypothesize that vaccine-hesitant individuals will exhibit altered sensorimotor resonance, higher affective responses to vaccination stimuli, and impaired fear extinction learning. Psychological traits such as disgust sensitivity, paranoia, anxiety, and dogmatism are expected to be associated with VH. Conclusions: By identifying the psychophysiological mechanisms of VH, this study will contribute to developing effective vaccine promotion strategies to address future public health emergencies. Full article

Objectives: Transcranial alternating current stimulation (tACS) can enhance primary motor cortex (M1) excitability and improve motor skill when delivered unilaterally to the dominant hemisphere. However, the impact of tACS on contralateral M1 excitability both during and after application has not been studied. The purpose of this study was to examine the effects of tACS delivered to the dominant left M1 on the excitability of the unstimulated contralateral non-dominant right M1. Methods: This study implemented a double-blind, randomized, SHAM-controlled, within-subjects, crossover experimental design. Eighteen young adults completed a tACS condition and a SHAM condition on two different days in counterbalanced order with a week washout period between days. Transcranial magnetic stimulation (TMS) was utilized to assess excitability of the contralateral right M1 while tACS was delivered to the left M1. TMS was administered in five test blocks (termed Pre, D5, D10, D15, and Post) relative to a 20 min application of tACS (70 Hz, 1 mA current strength). The Pre and Post TMS test blocks were conducted before and immediately after tACS was applied to the left M1, whereas the TMS test blocks performed during tACS were completed at time points starting at the 5, 10, and 15 min marks of the 20 min stimulation period. The primary dependent variable was the 1 mV motor evoked potential (MEP) amplitude. MEP data were analyzed with a 2 condition (tACS, SHAM) × 5 test (Pre, D5, D10, D15, Post) within-subjects ANOVA. Results: The main effect for condition (p = 0.704) and condition × test interaction (p = 0.349) were both non-statistically significant. There was a significant main effect for test (p = 0.003); however, post hoc analysis indicated that none of the pairwise comparisons were statistically significant. Conclusions: Overall, the findings indicate that tACS applied to the left M1 does not significantly modulate contralateral right M1 excitability during or immediately after stimulation, at least when utilizing the present tACS parameters. Full article

This study aims to apply standard statistics and InterCriteria analysis (ICrA) for assessing the effects of different transcranial magnetic stimulation (TMS) intensities and three muscle conditions on the evoked responses of the first dorsal interosseous muscle (FDIM). Surface electromyograms from the right FDIM of ten right-handed healthy volunteers were recorded, and amplitudes of motor evoked potentials (MEPs), latencies of MEPs, and silent periods were obtained. ICrA was used for the first time as a supplementary tool along with the applied statistical methods. Three case studies were processed by the ICrA approach for a wide examination of neuromuscular excitability in humans. As a result, the relations between increasing TMS intensities, MEP amplitudes, MEP latencies, and silent periods were established at relaxed muscle condition, isometric index finger abduction condition, and co-contraction of antagonist muscles condition. Also, the dependencies between MEP amplitudes, MEP latencies, and silent periods themselves, and for different TMS intensities, were outlined. The results confirmed relations known from the literature and showed new ones. Full article

Background/Objectives: Lower-limb amputation (LLA) leads to disability, impaired mobility, and reduced quality of life, affecting 1.6 million people in the USA. Post-amputation, motor cortex reorganization occurs, contributing to phantom limb pain (PLP). Transcranial magnetic stimulation (TMS) assesses changes in cortical excitability, helping to identify compensatory mechanisms. This study investigated the association between TMS metrics and clinical and neurophysiological outcomes in LLA patients. Methods: A cross-sectional analysis of the DEFINE cohort, with 59 participants, was carried out. TMS metrics included resting motor threshold (rMT), motor-evoked potential (MEP) amplitude, short intracortical inhibition (SICI), and intracortical facilitation (ICF). Results: Multivariate analysis revealed increased ICF and rMT in the affected hemisphere of PLP patients, while SICI was reduced with the presence of PLP. A positive correlation between SICI and EEG theta oscillations in the frontal, central, and parietal regions suggested compensatory mechanisms in the unaffected hemisphere. Increased MEP was associated with reduced functional independence. Conclusions: SICI appears to be a key factor linked to the presence of PLP, but not its intensity. Reduced SICI may indicate impaired cortical compensation, contributing to PLP. Other neural mechanisms, including central sensitization and altered thalamocortical connectivity, may influence PLP’s severity. Our findings align with those of prior studies, reinforcing low SICI as a marker of maladaptive neuroplasticity in amputation-related pain. Additionally, longer amputation duration was associated with disrupted SICI, suggesting an impact of long-term plasticity changes. Full article

The strong correlation between evoked potentials (EPs) and American Spinal Injury Association (ASIA) scores in individuals with spinal cord injury (SCI) suggests that EPs may serve as reliable predictive markers for rehabilitation progress. Numerous studies have confirmed a relationship between variations in somatosensory evoked potentials (SSEPs) and ASIA scores, especially in the early stages of SCI. Machine learning’s (ML’s) increasing importance in medicine is driven by the growing availability of health data and improved algorithms. It enables the creation of predictive models for disease diagnosis, progression prediction, personalized treatment, and improved healthcare efficiency. Data-driven approaches can significantly improve patient care, reduce costs, and facilitate personalized medicine. The meticulous analysis of medical data is crucial for timely disease identification, leading to effective symptom management and appropriate treatment. This study applies artificial intelligence to identify predictors of SCI progression, as measured by the disability index, ASIA impairment scale (AIS), and final motor recovery. We aim to clarify the prognostic role of electrophysiological testing (SSEPs, MEPs, and nerve conduction studies (NCSs)) in SCI. We analyzed data from a medical database of 123 records. We developed an ML-based intelligent system, utilizing ensemble algorithms combining decision trees and neural network approaches, to predict SCI recovery. Our evaluation showed SEP accuracies of 90% for motor recovery prediction and 80% for AIS scale determination, comparable to full electrophysiology evaluation accuracies of 93% and 89%, respectively, and generally superior results compared to MEP and NCS results. EPs emerged as the best predictors, comparable to a comprehensive electrophysiology assessment, significantly improving accuracy compared to clinical findings alone. An electrophysiological assessment, when available, increased overall accuracy for final motor recovery prediction to 93% (from a maximum of 75%) and, for ASIA score determination, to 89% (from a maximum of 66%). Further validation is needed with a larger dataset. Future research should validate that sensory electrophysiology assessment is a less expensive, portable, and simpler alternative to other prognostic tests and more effective than clinical assessments, like the AIS, biomarker for SCI, and personalized rehabilitation planning. Full article

Background: Resection or damage of the supplementary motor area (SMA) is associated with the development of a transient negative motor response defined as SMA syndrome. The risk of neurological deficits after resection in the SMA has been reported to vary widely from 23% to 100%. Various influencing factors can be involved. However, since tumors in the SMA are relatively infrequent, most of the evidence for surgical treatment of these lesions is based on small, retrospective, single-center case series. Furthermore, previous studies focused only on a few variables, and our knowledge regarding the outcome of these patients is still limited. Objective: To better define the risk of neurological deficits after brain tumor resection in the SMA. Methods: We retrospectively reviewed 66 surgeries that involved the SMA for gliomas and metastasis in 53 patients from two separate centers. Out of those, 13 cases were recurrence of the disease. We carefully evaluated various clinical factors, preoperative neuroimaging, intraoperative neurophysiology monitoring, and anatomical factors. By using Fisher’s exact probability test, we examined the relationship between these factors and the occurrence of postoperative neurological deficits. Statistical significance was considered at a p-value of less than 0.05. Results: In 28 cases, patients experienced neurological deficits after surgery. Among those cases, 26 experienced partial SMA syndrome, one experienced complete SMA syndrome, and one experienced a permanent neurological deficit. The research found that the patient’s past medical history (p = 0.005), lack of intraoperative language mapping (p = 0.044), and extent of resection (p = 0.040) significantly influenced the occurrence of language deficits. Additionally, the proximity between the corticospinal tract and the tumor (p = 0.005) and fMRI activation of the SMA in response to motor tasks (p = 0.044) were found to correlate with the development of motor deficits. However, there was no correlation found between the lack of intraoperative monitoring of motor-evoked potentials (MEPs) and the development of motor deficits (p > 0.05). Conclusions: Certain pre-existing medical conditions may increase the risk of postoperative language deficits. Intraoperative language mapping can help prevent these deficits. The extent of resection, along with the anatomical characteristics of the resection cavity, correlates with postoperative outcomes. Tractography and fMRI can assist in predicting the risk of motor deficits. Although intraoperative MEP monitoring can help prevent permanent motor deficits, it does not appear to prevent the transient deficits characteristic of SMA syndrome. Further intraoperative studies are needed to refine mapping and monitoring strategies for tumors involving the SMA and pre-SMA. Full article

Background: In this study, we used intraoperative neurophysiological monitoring (IONM) during anterior cervical discectomy and fusion (ACDF). Rather than emphasizing its use for safety purposes, our goal was to evaluate how neurophysiological parameters change during surgery and their correlation with clinical findings. Methods: This study included 30 patients who underwent ACDF. Detailed neurological examination was performed together with manual muscle testing (MMT), the Numeric Pain Rating Scale (NPRS), and the Neck Disability Index (NDI) questionnaire. During surgery, somatosensory-evoked potentials (SSEPs), motor-evoked potentials (MEPs), and spontaneous electromyography were registered. Results: There were statistically significant difference in the latency and amplitude of SSEPs of the right median nerve. Regarding the left median nerve, there was a statistically significant difference in amplitude, but not in latency. Differences were also observed in the amplitudes of right and left tibial nerve SSEPs, though no significant differences were found in their latencies. No statistically significant difference was found in the threshold values required to elicit MEPs between the beginning and end of the surgery. Additionally, we found a statistically significant positive correlation between the latency of the left and right median nerve and the left tibial nerve with somatosensory impairment. There was also a significant negative correlation between the amplitude of both tibial nerves and somatosensory impairment, and their latency showed a significant negative correlation with pain level before surgery. We found statistically significant decreases in NDI and pain level values one month after surgery. Conclusions: The results show significant changes in SSEPs and a correlation between clinical and neurophysiological findings and emphasize the importance of using MEPs to assess the condition of the motor system. Additionally, there was a general improvement in the patients’ condition, as assessed by NDI and pain scores. This study identifies critical surgical phases to consider in the absence of real-time neuromonitoring feedback and emphasizes that clinical observations may not fully reflect the condition of neurological structures in patients with myelopathy, which is crucial when deciding on timely surgery. Full article

Background/Objectives: Unilateral hand movements alter the excitability of the ipsilateral primary motor cortex (ipsi-M1) and contralateral spinal motoneurons. Although this excitability increases during complex, high muscle-activity movements, few studies have examined the excitability of ipsi-M1 and contralateral spinal motoneurons during complex movements while accounting for muscle activity. This study investigated the excitability of ipsi-M1 and contralateral spinal motoneurons during complex and simple movement tasks with comparable muscle activity between the two tasks. Methods: Nineteen healthy adult volunteers participated in this study. The ball rotation task was set as the complex movement task (BR condition), and the grasping task was set as the simple movement task (grasp condition), with peak muscle activity values comparable between the tasks. Motor-evoked potentials (MEPs) and F-waves were recorded from the abductor pollicis brevis muscle contralateral to the movement during task execution. The excitability parameters of ipsi-M1 and contralateral spinal motoneurons were calculated by dividing the MEP, F-wave persistence, and F/M amplitude values recorded in each condition by the corresponding values recorded at rest. These parameters were compared across the rest, BR, and grasp conditions. Results: All the excitability parameters of ipsi-M1 and contralateral spinal motoneurons increased during both the BR and grasp conditions compared with the rest condition but did not differ significantly between the BR and grasp conditions. Conclusions: The excitability of ipsi-M1 and contralateral spinal motoneurons was strongly influenced by the amount of muscle activity but not by the complexity of the movement. Full article

Background: Intraoperative neuromonitoring (IONM) is crucial for the safety of scoliosis surgery, providing real-time feedback on the spinal cord and nerve function, primarily through motor-evoked potentials (MEPs). The choice of anesthesia plays a crucial role in influencing the quality and reliability of these neuromonitoring signals. This systematic review evaluates how different anesthetic techniques—total intravenous anesthesia (TIVA), volatile anesthetics, and regional anesthesia approaches such as Erector Spinae Plane Block (ESPB), spinal, and epidural anesthesia—affect IONM during scoliosis surgery. Methods: A systematic review was conducted following PRISMA guidelines. PubMed, MEDLINE, EMBASE, and Cochrane databases were searched for studies published between 2017 and 2024 that examined the impact of anesthetic techniques on neuromonitoring during scoliosis surgery. The focus was on studies reporting MEP outcomes, anesthetic protocols, and postoperative neurological and analgesic effects. Results: The search initially identified 998 articles. After applying inclusion criteria based on relevance, recency, methodological quality, and citation frequency, 45 studies were selected for detailed review. Conclusion: The erector Spinae Plane Block (ESPB) provides distinct benefits over spinal and epidural anesthesia in scoliosis surgery, particularly in maintaining neuromonitoring accuracy, reducing hemodynamic instability, and minimizing complications. The ESPB’s ability to deliver effective segmental analgesia without compromising motor function makes it a safer and more efficient option for postoperative pain management, enhancing patient outcomes. Full article

Objective: This study aimed to explore longitudinal relationships between neurophysiological biomarkers and upper limb motor function recovery in stroke patients, focusing on electroencephalography (EEG) and transcranial magnetic stimulation (TMS) metrics. Methods: This longitudinal cohort study analyzed neurophysiological, clinical, and demographic data from 102 stroke patients enrolled in the DEFINE cohort. We investigated the associations between baseline and post-intervention changes in the EEG theta/alpha ratio (TAR) and TMS metrics with upper limb motor functionality, assessed using the outcomes of five tests: the Fugl-Meyer Assessment (FMA), Handgrip Strength Test (HST), Pinch Strength Test (PST), Finger Tapping Test (FTT), and Nine-Hole Peg Test (9HPT). Results: Our multivariate models identified that a higher baseline TAR in the lesioned hemisphere was consistently associated with poorer motor outcomes across all five assessments. Conversely, a higher improvement in the TAR was positively associated with improvements in FMA and 9HPT. Additionally, an increased TMS motor-evoked potential (MEP) amplitude in the non-lesioned hemisphere correlated with greater FMA-diff, while a lower TMS Short Intracortical Inhibition (SICI) in the non-lesioned hemisphere was linked to better PST improvements. These findings suggest the potential of the TAR and TMS metrics as biomarkers for predicting motor recovery in stroke patients. Conclusion: Our findings highlight the significance of the TAR in the lesioned hemisphere as a predictor of motor function recovery post-stroke and also a potential signature for compensatory oscillations. The observed relationships between the TAR and motor improvements, as well as the associations with TMS metrics, underscore the potential of these neurophysiological measures in guiding personalized rehabilitation strategies for stroke patients. Full article