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STUDY DESIGN: Development of a clinical practice guideline following the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) process. OBJECTIVE: The objectives of this study were to develop guidelines that outline the utility of intraoperative neuromonitoring (IONM) to detect intraoperative spinal cord injury (ISCI) among patients undergoing spine surgery, to define a subset of patients undergoing spine surgery at higher risk for ISCI and to develop protocols to prevent, diagnose, and manage ISCI. METHODS: All systematic reviews were performed according to PRISMA standards and registered on PROSPERO. A multidisciplinary, international Guidelines Development Group (GDG) reviewed and discussed the evidence using GRADE protocols. Consensus was defined by 80% agreement among GDG members. A systematic review and diagnostic test accuracy (DTA) meta-analysis was performed to synthesize pooled evidence on the diagnostic accuracy of IONM to detect ISCI among patients undergoing spinal surgery. The IONM modalities evaluated included somatosensory evoked potentials (SSEPs), motor evoked potentials (MEPs), electromyography (EMG), and multimodal neuromonitoring. Utilizing this knowledge and their clinical experience, the multidisciplinary GDG created recommendations for the use of IONM to identify ISCI in patients undergoing spine surgery. The evidence related to existing care pathways to manage ISCI was summarized and based on this a novel AO Spine-PRAXIS care pathway was created. RESULTS: Our recommendations are as follows: (1) We recommend that intraoperative neurophysiological monitoring be employed for high risk patients undergoing spine surgery, and (2) We suggest that patients at high risk for ISCI during spine surgery be proactively identified, that after identification of such patients, multi-disciplinary team discussions be undertaken to manage patients, and that an intraoperative protocol including the use of IONM be implemented. A care pathway for the prevention, diagnosis, and management of ISCI has been developed by the GDG. CONCLUSION: We anticipate that these guidelines will promote the use of IONM to detect and manage ISCI, and promote the use of preoperative and intraoperative checklists by surgeons and other team members for high risk patients undergoing spine surgery. We welcome teams to implement and evaluate the care pathway created by our GDG.

Spinal cord ischemic-reperfusion injury (SCIRI) could occurs during surgical procedures without detection, presenting a complex course and an unfavorable prognosis. This may lead to postoperative sensory or motor dysfunction in areas innervated by the spinal cord, and in some cases, permanent paralysis. Timely detection of SCIRI and immediate waring can help surgeons implement remedial intervention to prevent irreversible spinal cord injury. Therefore, it is crucial to develop a precise and effective method for early detection of SCIRI. This study utilized rat models to simulate intraoperative SCIRI and employed somatosensory evoked potentials (SEP) for continuous monitoring during surgery. In this study, SEP signal changes were examined in six groups with varying severities of SCIRI and one normal control group. SEP signal changes were examined during operations in different groups and correlated with postoperative behavioral and histopathological data. The result demonstrated specific changes in SEP signals during SCIRI, termed as time-varying characteristics, which are associated with the duration of ischemia and subsequent reperfusion. Timevarying characteristics in SEP could potentially serve as a new biomarker for the intraoperative detection of SCIRI. This finding is significant for clinical surgeons to identify and guide early intervention of SCIRI timely. Additionally, this measurement is easily translatable to clinical application. [ABSTRACT FROM AUTHOR]

Objective To investigate the efficacy of combined intraoperative neurophysiological monitoring (IONM) in predicting nerve function injury during anterior cervical discectomy and fusion (ACDF) surgery in patients with cervical spondylotic myelopathy (CSM) and analyze related influencing factors. Methods Clinical data from 45 CSM patients treated with ACDF surgery were collected. The relationship between the combined IONM (SEP + MEP) monitoring results and postoperative nerve function changes was analyzed. Multivariate logistic regression analysis was used to explore the effects of age, disease duration, preoperative nerve function (mJOA score), high signal on MRI T2 images, number of compression segments, maximum canal compression (MCC), spinal cord compression ratio (SCCR), and spinal cord cross-sectional area (SCCA) on predictive efficacy. Results Intraoperative alarms were noted in 5 cases, and no alarms in 40 cases. Postoperative mJOA scores improved in 42 cases and worsened in 3 cases, showing significant improvement in nerve function after surgery (P<0.05). True positive cases: 2; false positive cases: 3; true negative cases: 39; false negative cases: 1. Sensitivity: 66.67%; specificity: 92. 85%; positive predictive value: 40%; negative predictive value: 97.50%. The association between intraoperative monitoring results and postoperative nerve function changes was statistically significant (P<0.05). Multivariate logistic regression analysis showed no statistically significant differences in age, disease duration, preoperative mJOA score, high signal on MRI T2 images, number of compression segments, MCC, SCCR, and SCCA (P>0.05). Conclusion Combined IONM can predict nerve function injury during ACDF surgery in CSM patients. Although preoperative factors do not significantly affect predictive efficacy, attention should be paid to differentiating surgical operations, blood pressure fluctuations, and hypothermia during surgery. [ABSTRACT FROM AUTHOR]

The primary treatment method for intramedullary spinal cord tumor (IMSCT) is surgical resection, but this procedure carries a significant risk of neurological damage. Intraoperative neurophysiological monitoring (IONM) has become a necessary adjunctive tool for IMSCT resection. The current study aimed to explore the application value of D-wave monitoring in IMSCT surgery, and tried to investigate a tailored criterion for its early warning. A retrospective clinical study. A retrospective analysis was conducted based on the data of patients who underwent IMSCT surgeries performed by the same neurosurgical team at our hospital. IONM was applied in all surgeries. According to inclusion and exclusion criteria, ultimately 90 patients were enrolled in the study. The McCormick Scale (MMS) was applied to assess the functional outcome through outpatient visits or telephone follow-up at one month and six months postoperatively. Patients with an MMS grade over II one month after surgery were considered to have newly developed postoperative motor dysfunction (PMD). If the MMS grade could be restored to I or II six months after surgery, it was defined as a short-term PMD. Otherwise, it was defined as a long-term PMD. The predictive value of different IONM modalities, including somatosensory evoked potential (SEP), muscle motor evoked potential (MEP), and D-wave for PMD, was assessed with sensitivity, specificity, positive predictive value, negative predictive value, and subsequent logistic regression analysis. At last, the cut-off value of the D-wave amplitude reduction ratio for predicting PMD was obtained through the receiver operating characteristic (ROC) curve analysis. SEP showed the worst performance in predicting short-term and long-term PMD. Significant MEP changes were indicated as an independent predictive factor for short-term PMD (OR 5.062, 95% CI 1.947–13.166, p =.001), while D-wave changes were demonstrated as an independent predictor for long-term PMD (OR 339.433, 95% CI 11.337–10770.311, p =.001). The optimum cut-off value of the D-wave amplitude reduction ratio for predicting long-term PMD was 42.18%, with a sensitivity of 100% and a specificity of 93.8% (AUC=0.981, p <.001). D-wave monitoring showed extremely high specificity in predicting PMD compared to SEP and MEP monitoring. Moreover, the authors suggested that a D-wave amplitude reduction of over 40% during IMSCT surgery generally indicates long-term PMD for patients. [ABSTRACT FROM AUTHOR]

• In the time–frequency analysis, P25 and N35 showed power increases of high-frequency activities in comparison to baseline activities, while P50 showed a power decrease. • Short-latency of giant SEPs (P25 and N35) reflect evoked paroxysmal depolarization shifts. • Middle latency of giant SEPs (P50) reflects the inhibitory component. Giant somatosensory evoked potentials (SEPs) are observed in patients with cortical myoclonus. Short-latency components (SLC), are regarded as evoked epileptic activities or paroxysmal depolarization shifts (PDSs). This study aimed to reveal the electrophysiological significance of the middle-latency component (MLC) P50 of the SEPs. Twenty-two patients with cortical myoclonus having giant SEPs (patient group) and 15 healthy controls were included in this study. Waveform changes in SEPs before and after perampanel (PER) treatment were evaluated in the patient group. The wide range, time–frequency properties underlying the waveforms were compared between the groups. After PER treatment, SLC was prolonged and positively correlated with PER concentration, whereas MLC showed no correlation with PER concentration. Time–frequency analysis showed a power increase (156 Hz in all patients, 624 Hz in benign adult familial myoclonus epilepsy patients) underlying SLC and a power decrease (156 Hz, 624 Hz) underlying MLC in the patient group. The high-frequency power increase in SLCs and decrease in MLCs clearly reflected PDS and subsequent hyperpolarization, respectively. This relationship was similar to that of interictal epileptiform discharges, suggesting that giant SEPs evoke epileptic complexes of excitatory and inhibitory components. MLCs of giant SEPs reflected inhibitory components. [ABSTRACT FROM AUTHOR]

• Performance of temporally extended signal space separation (tSSS) was investigated in terms of the choice of the origin of the sphere model. • Individual sphere model resulted in better goodness of fit and confidence volume. • Interictal epileptiform discharges (IEDs) were more influenced by this choice than somatosensory evoked fields was. Temporally extended signal space separation (tSSS) is a powerful method for artifact suppression in magnetoencephalography (MEG). Because tSSS first separates MEG signals coming from inside and outside a certain sphere, definition of the sphere origin is important. For this study, we explored the influence of origin choice on tSSS performance in spontaneous and evoked activity from epilepsy patients. Interictal epileptiform discharges (IEDs) and somatosensory evoked fields (SEFs) were processed with two tSSSs: one with the default origin of (0, 0, 40 mm) in the head coordinate, and the other with an individual origin estimated using each patient's anatomical magnetic resonance imaging (MRI). Equivalent current dipoles (ECDs) were calculated for the data. The ECD location and quality of estimation were compared across conditions. MEG data from 21 patients revealed marginal differences in ECD location, but the estimation quality inferred from goodness of fit (GOF) and confidence volume (CV) was better for the tSSS with individual origins. This choice affected IEDs more than it affected SEFs. Individual sphere model resulted in better GOF and CV. Application of tSSS using an individual origin would be more desirable when available. This parameter might influence spontaneous activity more strongly. [ABSTRACT FROM AUTHOR]

Objective Intraoperative neuromonitoring (IONM) is an acknowledged tool for real-time neuraxis assessment during surgery. Somatosensory evoked potential (SSEP) and transcranial motor evoked potential (MEP) are commonest deployed modalities of IONM. Role of SSEP and MEP in intradural extramedullary spinal cord tumor (IDEMSCT) surgery is not well established. The aim of this study was to evaluate sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and transcranial MEP, in detection of intraoperative neurological injury in IDEMSCT patients as well as their postoperative limb-specific neurological improvement assessment at fixed intervals till 30 days. Materials and Methods Symptomatic patients with IDEMSCTs were selected according to the inclusion criteria of study protocol. On modified McCormick (mMC) scale, their sensory-motor deficit was assessed both preoperatively and postoperatively. Surgery was done under SSEP and MEP (transcranial) monitoring using appropriate anesthetic agents. Gross total/subtotal resection of tumor was achieved as per IONM warning alarms. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and MEP were calculated considering postoperative neurological changes as "reference standard." Patients were followed up at postoperative day (POD) 0, 1, 7, and 30 for convalescence. Statistical Analysis With appropriate tests of significance, statistical analysis was carried out. Receiver-operating characteristic curve was used to find cutoff point of mMC for SSEP being recordable in patients with higher neurological deficit along with calculation of sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and MEP for prediction of intraoperative neurological injury. Results Study included 32 patients. Baseline mean mMC value was 2.59. Under neuromonitoring, gross total resection of IDEMSCT was achieved in 87.5% patients. SSEP was recordable in subset of patients with mMC value less than or equal to 2 with diagnostic accuracy of 100%. MEP was recordable in all patients and it had 96.88% diagnostic accuracy. Statistically significant neurological improvement was noted at POD-7 and POD-30 follow-up. Conclusion SSEP and MEP individually carry high diagnostic accuracy in detection of intraoperative neurological injuries in patients undergoing IDEMSCT surgery. MEP continues to monitor the neuraxis, even in those subsets of patients where SSEP fails to record. [ABSTRACT FROM AUTHOR]

Understanding how inhibitory pathways influence motor cortical activity during fatiguing contractions may provide valuable insight into mechanisms associated with multiple sclerosis (MS) muscle activation. Short‐latency afferent inhibition (SAI) reflects inhibitory interactions between the somatosensory cortex and the motor cortex, and although SAI is typically reduced with MS, it is unknown how SAI is regulated during exercise‐induced fatigue. The current study examined how SAI modulates motor evoked potentials (MEPs) during fatiguing contractions. Fourteen people with relapsing–remitting MS (39 ± 6 years, nine female) and 10 healthy individuals (36 ± 6 years, six female) participated. SAI was induced by stimulation of the median nerve that was paired with TMS over the motor representation of the abductor pollicis brevis. A contraction protocol was employed that depressed force generating capacity using a sustained 3‐min 15% MVC, immediately followed by a low‐intensity (15% MVC) intermittent contraction protocol so that MEP and SAI could be measured during the rest phases of each duty cycle. Similar force, electromyography and MEP responses were observed between groups. However, the MS group had significantly reduced SAI during the contraction protocol compared to the healthy control group (p <.001). Despite the MS group reporting greater scores on the Fatigue Severity Scale and Modified Fatigue Impact Scale, these scales did not correlate with inhibitory measures. As there were no between‐group differences in SSEPs, MS‐related SAI differences during the fatiguing contractions were most likely associated with disease‐related changes in central integration. [ABSTRACT FROM AUTHOR]

Predicting gait recovery after a spinal cord injury (SCI) during an acute rehabilitation phase is important for planning rehabilitation strategies. However, few studies have been conducted on this topic to date. In this study, we developed a deep learning-based prediction model for gait recovery after SCI upon discharge from an acute rehabilitation facility. Data were collected from 405 patients with acute SCI admitted to the acute rehabilitation facility of Korea University Anam Hospital between June 2008 and December 2022. The dependent variable was Functional Ambulation Category at the time of discharge (FAC-DC). Seventy-one independent variables were selected from the existing literature: basic information, International Standards for Neurological Classification of SCI scores, neurogenic bladders, initial FAC, and somatosensory-evoked potentials of the lower extremity. Recurrent neural network (RNN), linear regression (LR), Ridge, and Lasso methods were compared for FAC-DC prediction in terms of the root-mean-squared error (RMSE). RNN variable importance, which is the RMSE gap between a complete RNN model and an RNN model excluding a certain variable, was used to evaluate the contribution of this variable. Based on the results of this study, the performance of the RNN was far better than that of LR, Ridge, and Lasso. The respective RMSEs were 0.3738, 2.2831, 1.3161, and 1.0246 for all the participants; 0.3727, 1.7176, 1.3914, and 1.3524 for those with trauma; and 0.3728, 1.7516, 1.1012, and 0.8889 for those without trauma. In terms of RNN variable importance, lower-extremity motor strength (right and left ankle dorsiflexors, right knee extensors, and left long toe extensors) and the neurological level of injury were ranked among the top five across the boards. Therefore, initial FAC was the seventh, third, and ninth most important predictor for all participants, those with trauma, and those without trauma, respectively. In conclusion, this study developed a deep learning-based prediction model with excellent performance for gait recovery after SCI at the time of discharge from an acute rehabilitation facility. This study also demonstrated the strength of deep learning as an explainable artificial intelligence method for identifying the most important predictors. [ABSTRACT FROM AUTHOR]

Abstract Background The application of evoked potentials (EPs) to the diagnosis of acute disseminated encephalomyelitis (ADEM ) has not been investigated in detail. The aim of this study, therefore, was to analyze the value of multimodal EPs in the early diagnosis of pediatric ADEM. Methods This was a retrospective study in which we enrolled pediatric ADEM patients and controls (Cs) from neurology units between 2017 and 2021. We measured indices in patients using brainstem auditory evoked potentials (BAEPs), visual evoked potentials (VEPs) and somatosensory evoked potentials (SEPs), and then we analyzed their early diagnostic value in ADEM patients. Results The mean age of the ADEM group was 6.15 ± 3.28 years (range,1–12 years) and the male/female ratio was 2.1:1 The mean age of the Cs was 5.97 ± 3.40 years (range,1–12 years) and the male/female ratio was 1.3:1. As we used magnetic resonance imaging (MRI) as the diagnostic criterion, the sensitivity, specificity, and accuracy (κ was 0.88) of multimodal EPs were highly consistent with those of MRI; and the validity could be ranked in the following order with respect to the diagnosis of ADEM: multimodal Eps > single SEP > single VEP > single BAEP. Of 34 patients with ADEM, abnormalities in multimodal EPs were 94.12%, while abnormalities in single VEPs, BAEPs and SEPs were 70.59%,64.71%and 85.3%, respectively. We noted significant differences between single VEP/BAEPs and multimodal EPs (χ2 = 6.476/8.995,P = 0.011/0.003). Conclusions The combined application of multimodal EPs was superior to BAEPs, VEPs, or SEPs alone in detecting the existence of central nerve demyelination, and we hypothesize that these modalities will be applicable in the early diagnosis of ADEM.

• The temporal features of somatosensory processing can be assessed using EEG. • Mismatch negativity was not elicited between vibrations of 100 ms and 115 ms. • Mismatch negativity was elicited between vibrations of 100 ms and 130, 145 or 160 ms. Duration is an amodal feature common to all sensory experiences, but low-level processing of the temporal qualities of somatosensation remains poorly understood. The goal of the present study was to evaluate electrophysiological discrimination of parametric somatosensory stimuli to better understand how the brain processes the duration of tactile information. This research used a somatosensory mismatch negativity (sMMN) paradigm to evaluate electrophysiological sensitivity to differences in the duration of vibrotactile stimuli in healthy young adults. Specifically, a 100 ms standard vibration was presented 80% of the time while the remaining 20% of presentations were made up of deviant stimuli with one of the following durations: 115, 130, 145, or 160 ms. When a deviation from the anticipated tactile input is detected, the distinct electrophysiological signature of the sMMN is present. A companion behavioral task assessed individual thresholds for cognizant awareness of the standard and deviant vibrotactile stimuli. The results of the present study demonstrated a sMMN response when deviant stimuli were 130, 145, and 160 ms, but not when they were 115 ms. This suggests that on average the participants did not electrophysiologically discriminate between the 100 and 115 ms. Future work may apply this paradigm to better understand atypical tactile sensitivity in various clinical conditions. [ABSTRACT FROM AUTHOR]

Stroke patients experience impaired sensory and motor functions, which impact their activities of daily living (ADL). The current study was designed to determine the best neurorehabilitation method to improve clinical outcomes, including the trunk-impairment scale (TIS), Berg balance scale (BBS), Fugl-Meyer assessment (FMA), and modified Barthel index (MBI), in stroke patients with impaired sensory function. Forty-four stroke survivors consistently underwent proprioceptive body vibration rehabilitation training (PBVT) or conventional physical therapy (CPT) for 30 min/session, 5 days a week for 8 weeks. Four clinical outcome variables–the FMA, TIS, BBS, and MBI–were examined pre- and post-intervention. We observed significant differences in the FMA, BBS, and MBI scores between the PBVT and CPT groups. PBVT and CPT showed significant improvements in FMA, BBS, TIS, and MBI scores. However, PVBT elicited more favorable results than CPT in patients with stroke and impaired sensory function. Collectively, this study provides the first clinical evidence of optimal neurorehabilitation in stroke patients with impaired sensory function. [ABSTRACT FROM AUTHOR]

• N20 and N13 in the median nerve SEP were severely involved in sporadic and familial ALS in a completely locked-in state (CLIS). • Two patients with a Cu/Zn superoxide-dismutase 1 gene variants showed peripheral sensory nerve abnormalities. • Median nerve SEP cannot be utilized for communication in patients with ALS in a CLIS. To investigate somatosensory pathway function in patients with amyotrophic lateral sclerosis (ALS) dependent on invasive ventilation and in a completely locked-in state (CLIS). We examined median nerve somatosensory evoked potentials (SEPs) in 17 ALS patients in a CLIS, including 11 patients with sporadic ALS, one with familial ALS with genes not examined, four with a Cu/Zn superoxide-dismutase-1 (SOD1) gene variant (Val118Leu, Gly93Ser, Cys146Arg), and one with a fused-in-sarcoma gene variant (P525L). We evaluated N9, N13, N20 and P25, and central conduction time (CCT); the data were compared with those of 73 healthy controls. N20 and N13 were abolished in 12 and 10 patients, and their latencies was prolonged in four and three patients, respectively. The CCT was prolonged in five patients with measurable N13 and N20. Two patients with SOD1 gene mutations had absent or slightly visible N9. Compared to the CCT and latencies and amplitudes of N13 and N20 in the controls, those in the patient cohort were significantly abnormal. The central somatosensory pathway is severely involved in patients with ALS in a CLIS. Our findings suggest that median nerve SEP cannot be utilized for communication in patients with ALS in a CLIS. [ABSTRACT FROM AUTHOR]

Multisensory human–machine interfaces for virtual- or augmented-reality systems are lacking wearable actuated devices that can provide users with tactile feedback on the softness of virtual objects. They are needed for a variety of uses, such as medical simulators, tele-operation systems and tele-presence environments. Such interfaces require actuators that can generate proper tactile feedback, by stimulating the fingertips via quasi-static (non-vibratory) forces, delivered through a deformable surface, so as to control both the contact area and the indentation depth. The actuators should combine a compact and lightweight structure with ease and safety of use, as well as low costs. Among the few actuation technologies that can comply with such requirements, pneumatic driving appears to be one of the most promising. Here, we present an investigation on a new type of pneumatic wearable tactile displays of softness, recently described by our group, which consist of small inflatable chambers arranged at the fingertips. In order to objectively assess the perceptual response that they can elicit, a systematic electroencephalographic study was conducted on ten healthy subjects. Somatosensory evoked potentials (SEPs) were recorded from eight sites above the somatosensory cortex (Fc2, Fc4, C2 and C4, and Fc1, Fc3, C1 and C3), in response to nine conditions of tactile stimulation delivered by the displays: stimulation of either only the thumb, the thumb and index finger simultaneously, or the thumb, index and middle finger simultaneously, each repeated at tactile pressures of 10, 20 and 30 kPa. An analysis of the latency and amplitude of the six components of SEP signals that typically characterise tactile sensing (P50, N100, P200, N300, P300 and N450) showed that this wearable pneumatic device is able to elicit predictable perceptual responses, consistent with the stimulation conditions. This proved that the device is capable of adequate actuation performance, which enables adequate tactile perceptual performance. Moreover, this shows that SEPs may effectively be used with this technology in the future, to assess variable perceptual experiences (especially with combinations of visual and tactile stimuli), in objective terms, complementing subjective information gathered from psychophysical tests. [ABSTRACT FROM AUTHOR]

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• Increased somatosensory cortical excitability (increased SEP S2/S1 amplitude ratio) is associated with reduced pulmonary function. • Somatosensory cortical excitability is inversely correlated with motor clinical and electrophysiological parameters. • New studies are needed to investigate the relationship between motor and somatosensory cortical excitability changes in ALS. Neuronal loss in the somatosensory, as well as the motor cortex in amyotrophic lateral sclerosis (ALS), indicative of a structural abnormality has been reported. Previously we have shown that afferent inhibition was impaired in ALS, suggestive of sensory involvement. In this study, we aimed to evaluate excitability changes in the somatosensory cortex of ALS patients. ALS patients underwent a paired pulse somatosensory evoked potential (SEP) paradigm at various interstimulus intervals (ISI). The amplitude ratio obtained by dividing the amplitude of paired pulse SEP stimulation S2 (paired pulse stimulation) to S1 (the single pulse stimulation) was considered the somatosensory cortex excitability parameter. Findings were compared to the results obtained from healthy controls. Resting motor threshold (RMT) was also assessed in the ALS group. An increased S2/S1 ratio was found in the ALS group in every ISI examined. Additionally, the reduced inhibition correlated negatively with forced vital capacity, Medical Research Council sum score, median nerve compound muscle action potential amplitude, while there was a positive association with Penn upper motor neuron score and sural nerve conduction velocity. No correlation existed with RMT. Our findings demonstrated increased somatosensory cortical excitability in ALS, which was associated with clinical parameters such as reduced pulmonary function and motor strength. Somatosensory cortical excitability is impaired in ALS. Whether this is associated with increased motor cortical excitability requires further studies. [ABSTRACT FROM AUTHOR]

In this study, a small sample of patients' neuromonitoring data was analyzed using machine learning (ML) tools to provide proof of concept for quantifying complex signals. Intraoperative neurophysiological monitoring (IONM) is a valuable asset for monitoring the neurological status of a patient during spine surgery. Notably, this technology, when operated by neurophysiologists and surgeons familiar with proper alarm criteria, is capable of detecting neurological deficits. However, non-surgical factors, such as volatile anesthetics like sevoflurane, can negatively influence robust IONM signal generation. While sevoflurane has been shown to affect the latency and amplitude of somatosensory evoked potential (SSEP), a more complex and nuanced analysis of the SSEP waveform has not been performed. In this study, signal processing and machine learning techniques were used to more intricately characterize and predict SSEP waveform changes as a function of varying end-tidal sevoflurane concentration. With data from ten patients who underwent spinal procedures, features describing the SSEP waveforms were generated using principal component analysis (PCA), phase space curves (PSC), and time-frequency analysis (TFA). A minimum redundancy maximum relevance (MRMR) feature selection technique was then used to identify the most important SSEP features associated with changing sevoflurane concentrations. Once the features carrying the maximum amount of information about the majority of signal waveform variability were identified, ML models were used to predict future changes in SSEP waveforms. Linear regression, regression trees, support vector machines, and neural network ML models were then selected for testing. Using SSEP data from eight patients, the models were trained using a range of features selected during MRMR calculations. During the training phase of model development, the highest performing models were identified as support vector machines and regression trees. After identifying the highest performing models for each nerve group, we tested these models using the remaining two patients' data. We compared the models' performance metrics using the root mean square error values (RMSEs). The feasibility of the methodology described provides a general framework for the applications of machine learning strategies to further delineate the effects of surgical and non-surgical factors affecting IONM signals. [ABSTRACT FROM AUTHOR]

Cortical responses in somatosensory evoked potentials (SEP) are enhanced in patients with amyotrophic lateral sclerosis (ALS). This study investigated whether sensory gating is involved in the pathophysiology of sensory cortical hyperactivity in ALS patients. The median nerve SEP was recorded at rest and during voluntary finger movements in 14 ALS patients and 13 healthy control subjects. The parietal N20, P25, and frontal N30 were analyzed, and sensory gating was assessed by measuring the amplitude of each component during finger movement. The amplitudes of the N20 onset–peak, N20 peak–P25 peak, and N30 onset–peak were higher in ALS patients than in controls. Nonetheless, there were no significant differences in the amplitude reduction ratio of SEPs between patients and controls. There was a significant correlation between the baseline amplitudes of the N20 onset–peak or N20 peak–P25 peak and their gating ratios in patients with ALS. Our findings indicate that the excitability of the primary sensory cortex and secondary motor cortex is enhanced in ALS, while sensory gating is preserved in the early stages of ALS. This result suggests that enhanced SEP is caused by the hyperexcitability of the primary sensory and secondary motor cortices but not by the dysfunction of inhibitory mechanisms during voluntary movements. [ABSTRACT FROM AUTHOR]

• P25/30 demonstrated higher Positive Predictive Value than the used in clinical practice N20. • Analysis of Peak To Trough amplitude of 20–30 ms complex achieved the highest prognostic efficacy and interpreters agreement. • Using amplitude size in analysis, standardised waveform interpretation and improved the predictive value of 20–30 ms complex. This study attempted to test the effectiveness of an enhanced analysis of the 20–30 ms complex of somatosensory evoked potentials, in predicting the short-term outcome of comatose survivors of out of hospital cardiac arrest and compare it with the current clinical practice. Single-centre, prospective, observational study. Median nerve SSEP recording performed at 24–36 h post-return of spontaneous circulation. Recording was analysed using amplitude measurements of P25/30 and Peak-To-Trough of 20–30 ms complex and thresholds to decide P25/30 presence. Neurological outcome was dichotomised into favourable and unfavourable. 89 participants were analysed. 43.8% had favourable and 56.2% unfavourable outcome. The sensitivity, specificity, positive and negative predictive values of the present SSEP and favourable outcome were calculated. P25/30 presence and size of PTT improved positive predictive value and specificity, while maintained similar negative predictive value and sensitivity, compared to the current practice. Inter-interpreter agreement was also improved. Enhanced analysis of the SSEP at 20–30 ms complex could improve the short-term prognostic accuracy for short-term neurological outcome in comatose survivors of cardiac arrest. Peak-To-Trough analysis of the 20–30 ms SSEP waveform appears to be the best predictor of neurological outcome following out of hospital cardiac arrest. It is also the easiest and most reliable to analyse. [ABSTRACT FROM AUTHOR]

目的 分析卒中后患者上肢体感诱发电位（somatosensory evoked potentials，SEP）、周围神经电生理特征与运动功能的相关性。 方法 此前瞻性研究连续纳入2018年6月—2022年3月康复科收治的亚急性期卒中患者，采用自身健患侧进行对比，进行双侧上肢SEP和周围神经电生理检查并对患侧上肢运动功能进行评分。分析患侧SEP P15、N20、P25、N13及N9潜伏期、感觉神经传导参数、运动神经传导参数与上肢运动功能等指标的相关性。 结果 本研究共纳入卒中后亚急性期偏瘫患者102例，平均（68.76±11.33）岁，男性78例。患者偏瘫侧上肢SEP P15[（16.90±1.67）ms vs.（16.27±1.50）ms，P＜0.001]、N20[（20.13±1.49）ms vs.（19.42±1.60）ms，P＜0.001]、P25[（24.39±1.75）ms vs.（23.70±1.50）ms，P＜0.001]、N13[（14.05±1.25）ms vs.（13.42±1.26）ms，P＜0.001]及N9[（9.25±0.96）ms vs.（8.80±1.40）ms， P＜0.001]的潜伏期均大于健侧；偏瘫侧上肢正中神经（指1-腕）感觉神经传导速度（sensory nerve conduction velocity，SCV）[（48.93±6.82）m/s vs.（51.26±6.40）m/s，P＜0.001]、波幅[（22.54±9.91）μv vs.（32.71±17.68）μv，P＜0.001]小于健侧；正中神经（指3-腕）SCV[（49.26±7.31）m/s vs.（52.98±5.99）m/s，P＜0.001]、波幅[（24.71±11.39）μv vs.（38.57±20.21）μv，P＜0.001]小于健侧；尺神经（指5-腕）SCV[（48.72±7.46）m/s vs.（52.01±6.82）m/s，P＜0.001]、波幅[（19.51±11.35）μv vs.（25.74±13.44）μv，P＜0.001]小于健侧；尺神经（腕-肘上）SCV[（54.53±6.06）m/s vs. （56.99±4.84）m/s，P＜0.001]、波幅[（11.37±6.04）μv vs.（14.53±7.89）μv，P＜0.001]小于健侧。偏瘫侧上肢正中神经（肘-腕）运动神经传导速度（motor nerve conduction velocity，MCV）[（54.79±4.89）m/s vs.（57.10±5.07）m/s，P＜0.001]、波幅[（8.42±3.85）μv vs.（10.00±3.72）μv，P＜0.001]小于健侧；尺神经（腕-肘上）MCV[（53.12±6.81）m/s vs.（55.01±6.35）m/s，P＜0.001]、波幅[（6.89±2.56）μv vs.（8.78±2.26）μv，P＜0.001]小于健侧。P15（r=-0.358，P＜0.001）、N20（r=-0.674，P＜0.001）、P25（r=-0.465，P＜0.001）潜伏期与Fugl-Meyer上肢运动功能评定量表（Fugl-Meyer assessment upper extremity scale，FMA-UE）评分均呈负相关；正中神经电极位置为指3-腕的波幅与FMA-UE评分呈正相关（r=0.231，P=0.026），尺神经电极位置为指5-腕（r=0.292，P=0.006），腕-肘上（r=0.391，P＜0.001）的SCV与FMA-UE评分呈正相关，电极位置为指5-腕的波幅与FMA-UE评分呈正相关（r=0.263，P=0.012），正中神经电极位置为肘-腕的MCV（r=0.220，P=0.037）、波幅（r=0.223，P=0.034）与FMA-UE评分均呈正相关，尺神经电极位置为腕-肘上的MCV（r=0.231，P=0.027）与FMA-UE评分呈正相关。 结论 卒中偏瘫患者常伴有感觉传导通路受损及偏瘫侧上肢周围神经的改变，且与患侧上肢运动功能存在一定的相关性。 Abstract: Objective To analyze the correlation between upper limb somatosensory evoked potential (SEP), peripheral nerve electrophysiological characteristics and motor function in patients with stroke. Methods Patients with subacute stroke admitted to the Department of Rehabilitation from June 2018 to March 2022 were consecutively included in this prospective study. SEP and peripheral nerve electrophysiological examination were performed on both upper limbs, which of the healthy and affected sides were compared, and motor function of the affected side was scored. The correlation of latent period of SEP P15, N20, P25, N13 and N9, sensory nerve conduction parameters, motor nerve conduction parameters of the hemiplegic upper limb and its motor function was analyzed. Results A total of 102 patients were included in this study, with an average age of (68.76±11.33) years and 78 males. The latent period of SEP P15[(16.90±1.67) ms vs.(16.27±1.50) ms, P

Purpose: The aim of this study was to explore the relationship between intraoperative somatosensory evoked potential (SEP) amplitude changes and clinical outcomes of OLIF indirect decompression for degenerative lumbar spinal stenosis (DLSS). Methods: A prospective study was performed on 201 patients who received oblique lumbar interbody fusion (OLIF) in our hospital from July 2017 to May 2021 due to single segmental DLSS. The patients were divided into three groups: group A (mild DLSS), group B (moderate DLSS), and group C (severe DLSS). The P40 amplitude during operation were recorded, and the clinical efficacy was evaluated by JOA score 1 year postoperative. ROC curves for satisfactory efficacy of P40 amplitude improvement rate and CSA improvement rate were established. Pearson correlation was used to analyze the relationship between P40 improvement rate and JOA improvement rate. Results: In group A and group B, the improvement rate of JOA in P40 significantly improved group was significantly greater that in improved group and unimproved group (Pa = 0.009; Pb < 0.000). No significant among-subgroup differences in group C (all P > 0.05). In both groups A and B, there was a significant difference in the improvement rate of P40 amplitude between the satisfactory group and the ineffective group (Pa = 0.013; Pb = 0.001), while in group C, there was no statistical significance (Pc = 0.107). By variable Person correlation analysis, a significant positive correlation was obtained between JOA improvement rate and P40 amplitude improvement rate in groups A and B (r1 = 0.27, P1 = 0.02; r2 = 0.508, P2 = 0.001), no correlation between the two in group C (r3 = 0.243, P3 = 0.056). The area under the ROC for assessing surgical efficacy in terms of CSA improvement rate was 0.813 (95% CI: 0.737–0.889, P < 0.001) and 0.767 (95% CI: 0.677–0.856, P < 0.001) in group A and group B, respectively, with satisfactory efficacy cutoff points of 50.18% and 67.89%. Conclusion: For mild and moderate DLSS, the intraoperative P40 amplitude improvement rate can predict the improvement of clinical symptoms after surgery and can be used as a reference index to assess the effect of indirect decompression. For severe DLSS, the P40 amplitude improvement rate has limited significance in guiding indirect decompression, and OLIF indirect decompression is not the right treatment for this type of patients. [ABSTRACT FROM AUTHOR]

The spinal cord is at risk of injury during spinal surgery. If intraoperative spinal cord injury is identified early, irreversible impairment or loss of neurological function can be prevented. Different types of spinal cord injury result in damage to different spinal cord regions, which may cause different somatosensory and motor evoked potential signal responses. In this study, we examined electrophysiological and histopathological changes between contusion, distraction, and dislocation spinal cord injuries in a rat model. We found that contusion led to the most severe dorsal white matter injury and caused considerable attenuation of both somatosensory and motor evoked potentials. Dislocation resulted in loss of myelinated axons in the lateral region of the injured spinal cord along the rostrocaudal axis. The amplitude of attenuation in motor evoked potential responses caused by dislocation was greater than that caused by contusion. After distraction injury, extracellular spaces were slightly but not significantly enlarged; somatosensory evoked potential responses slightly decreased and motor evoked potential responses were lost. Correlation analysis showed that histological and electrophysiological findings were significantly correlated and related to injury type. Intraoperative monitoring of both somatosensory and motor evoked potentials has the potential to identify iatrogenic spinal cord injury type during surgery.

The current investigation used somatosensory evoked potentials (SEPs) to assess differences in sensorimotor integration and somatosensory processing variables between asymptomatic individuals with and without forward head posture (FHP). We assessed different neural regions of the somatosensory pathway, including the amplitudes of the peripheral N9, spinal N13, brainstem P14, peak-to-peak amplitudes of parietal N20 and P27, and frontal N30 potentials. Central conduction time (N13–N20) was measured as the difference in peak latencies of N13 and N20. We measured these variables in 60 participants with FHP defined as a craniovertebral angle (CVA) < 50° and 60 control participants matched for age, gender, and body mass index (BMI) with normal FHP defined as CVA > 55°. Differences in variable measures were examined using the parametric t-test. Pearson's correlation was used to evaluate the relationship between the CVA and sensorimotor integration and SEP measurements. A generalized linear model (GLM) was used to compare the SEP measures between groups, with adjustment for educational level, marital status, BMI, and working hours per week. There were statistically significant differences between the FHP group and control group for all sensorimotor integration and SEP processing variables, including the amplitudes of spinal N13 (p < 0.005), brainstem P14 (p < 0.005), peak-to-peak amplitudes of parietal N20 and P27 (p < 0.005), frontal N30 potentials (p < 0.005), and the conduction time N13–N20 (p = 0.004). The CVA significantly correlated with all measured neurophysiological variables indicating that as FHP increased, sensorimotor integration and SEP processing became less efficient. FHP group correlations were: N9 (r = −0.44, p < 0.001); N13 (r = −0.67, p < 0.001); P14 (r = −0.58, p < 0.001); N20 (r = −0.49, p = 0.001); P27 (r = −0.58, p < 0.001); N30 potentials (r = −0.64, p < 0.001); and N13–N20 (r = −0.61, p < 0.001). GLM identified that increased working hours adversely affected the SEP measures (p < 0.005), while each 1° increase in the CVA was associated with improved SEP amplitudes and more efficient central conduction time (N13–N20; p < 0.005). Less efficient sensorimotor integration and SEP processing may be related to previous scientific reports of altered sensorimotor control and athletic skill measures in populations with FHP. Future investigations should seek to replicate our findings in different spine disorders and symptomatic populations in an effort to understand how improving forward head posture might benefit functional outcomes of patient care. [ABSTRACT FROM AUTHOR]

Introduction: Detection of neurological complications during extracorporeal membrane oxygenation (ECMO) may be enhanced with non-invasive neuro-monitoring. We investigated the feasibility of non-invasive neuro-monitoring in a paediatric intensive care (PIC) setting. Methods: In a single centre, prospective cohort study we assessed feasibility of recruitment, and neuro-monitoring via somatosensory evoked potentials (SSEP), electroencephalography (EEG) and near infrared spectroscopy (NIRS) during venoarterial (VA) ECMO in paediatric patients (0–15 years). Measures were obtained within 24h of cannulation, during an intermediate period, and finally at decannulation or echo stress testing. SSEP/EEG/NIRS measures were correlated with neuro-radiology findings, and clinical outcome assessed via the Pediatric cerebral performance category (PCPC) scale 30 days post ECMO cannulation. Results: We recruited 14/20 (70%) eligible patients (median age: 9 months; IQR:4–54, 57% male) over an 18-month period, resulting in a total of 42 possible SSEP/EEG/NIRS measurements. Of these, 32/42 (76%) were completed. Missed recordings were due to lack of access/consent within 24 h of cannulation (5/42, 12%) or PIC death/discharge (5/42, 12%). In each patient, the majority of SSEP (8/14, 57%), EEG (8/14, 57%) and NIRS (11/14, 79%) test results were within normal limits. All patients with abnormal neuroradiology (4/10, 40%), and 6/7 (86%) with poor outcome (PCPC ≥4) developed indirect SSEP, EEG or NIRS measures of neurological complications prior to decannulation. No study-related adverse events or neuro-monitoring data interpreting issues were experienced. Conclusion: Non-invasive neuro-monitoring (SSEP/EEG/NIRS) during ECMO is feasible and may provide early indication of neurological complications in this high-risk population. [ABSTRACT FROM AUTHOR]

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Objective: Intraoperative neurophysiological monitoring in intramedullary spinal cord tumor removal surgery helps surgeons detect early warning signs of postoperative nerve damage, in order to reduce or prevent permanent neuron injury. We performed a study to evaluate the value of intraoperative neurophysiological monitoring techniques in intramedullary spinal cord tumor resection surgery. Methods: We performed a retrospective study of 29 patients undergoing surgery for intramedullary spinal cord tumors and intraoperative neurophysiological monitoring from 2017 to 2021 at the University Medical Center, Ho Chi Minh City. Clinical assessment before and after surgery, intraoperative neurophysiological monitoring to find out the sensitivity, specificity, positive predictive value, and negative predictive value of intraoperative neurophysiological monitoring techniques were performed. Results: Of the 29 patients, 4 patients had worse postoperative neurological symptoms (13.8%) at 1 day after surgery. The rate of postoperative worsening neurological symptoms decreased to 10.3% at the 1-month follow-up. SSEP (somatosensory evoked potential) had 75% sensitivity and 72% specificity in detecting postoperative nerve damage, while the sensitivity and specificity of MEP (motor evoked potential) were 100% and 80%, respectively. Conclusion: Both SSEP and MEP have a high sensitivity in detecting postoperative nerve damage, meanwhile, MEP is more sensitive than SSEP. These techniques help predict and possibly prevent timely neurological damage during intramedullary spinal cord resection surgery.

Stroke patients experience impaired sensory and motor functions, which impact their activities of daily living (ADL). The current study was designed to determine the best neurorehabilitation method to improve clinical outcomes, including the trunk-impairment scale (TIS), Berg balance scale (BBS), Fugl-Meyer assessment (FMA), and modified Barthel index (MBI), in stroke patients with impaired sensory function. Forty-four stroke survivors consistently underwent proprioceptive body vibration rehabilitation training (PBVT) or conventional physical therapy (CPT) for 30 min/session, 5 days a week for 8 weeks. Four clinical outcome variables–the FMA, TIS, BBS, and MBI–were examined pre- and post-intervention. We observed significant differences in the FMA, BBS, and MBI scores between the PBVT and CPT groups. PBVT and CPT showed significant improvements in FMA, BBS, TIS, and MBI scores. However, PVBT elicited more favorable results than CPT in patients with stroke and impaired sensory function. Collectively, this study provides the first clinical evidence of optimal neurorehabilitation in stroke patients with impaired sensory function.

Patients undergoing cerebral aneurysm clipping are at risk for cerebral ischemia. Ischemic tolerance varies among individuals. Hence, multimodal intraoperative neuromonitoring (IONM) is essential. IONM is not available in many centers. This case report highlights the utilization of processed electroencephalography (EEG) as a cerebral ischemia monitor during temporary clip application. Our patient underwent clipping of a ruptured anterior-communicating artery aneurysm. After the temporary clip applications on the right and left, A1 arterial segments led to a transient drop of somatosensory evoked potentials (SSEPs). At the same time, the frontal four-channel processed EEG showed a burst suppression (BS) pattern. Blood pressure augmentation and the removal of temporary clips helped restore the SSEP back to baseline and the disappearance of the BS pattern in processed EEG. During the steady state of anesthesia, the sudden appearance of the BS pattern in processed EEG can be attributed to clip-induced cerebral ischemia after ruling out other potential causes for BS.

Objective: To study the benefits of intraoperative neurophysiological monitoring during the resection of posterior fossa lesions. Study Design: Cross-sectional study. Place and Duration of Study: Department of Neurosurgery, Combined Military Hospital (CMH), Rawalpindi Pakistan, from Apr 2020 to Mar 2022. Methodology: One hundred and sixty-nine diagnosed posterior fossa lesions, including cerebellopontine angle tumours, were included. The chi-square test was used to test the association of new neurological deficits among different pathologies. In addition, the sensitivity and specificity of IONM were also calculated for risk identification of new neurological deficits. Results: The mean age of the patients was 35.75±9.31 years. No clinical signs and symptoms were associated with the new neurological deficit (p-value> 0.05). The majority (72.8%) of the surgeries were declared successful, as only 46(27.2%) surgery outcome was “Poor”. The sensitivity of the IONM monitoring was 51.61%, specificity 68.42%, positive predictive value 66.67% and negative predictive value 53.61%. Conclusion: Intraoperative neuro-monitoring plays a vital role in obtaining successful results in posterior fossa surgeries because the prevalence of neurological deficits in the posterior fossa lesions was very high compared to the other surgeries. Keywords: Electroencephalogram (EEG), Electromyography (EMG), Intraoperative neuro-monitoring (IONM), Posterior fossa lesion surgeries, Somatosensory evoked potential, Transcranial motor evoked potentials (tcMEPs).

Background: The ability to produce coordinated movement is dependent on dynamic interactions through transcallosal fibers between the two cerebral hemispheres of the brain. Although typically unilateral, stroke induces changes in functional and effective connectivity across hemispheres, which are related to sensorimotor impairment and stroke recovery. Previous studies have focused almost exclusively on interhemispheric interactions in the primary motor cortex (M1). Objective: To identify the presence of interhemispheric asymmetry (ASY) of somatosensory cortex (S1) excitability and to investigate whether S1 repetitive transcranial magnetic stimulation (rTMS) combined with sensory stimulation (SS) changes excitability in S1 and M1, as well as S1 ASY, in individuals with subacute stroke. Methods: A randomized clinical trial. Participants with a single episode of stroke, in the subacute phase, between 35 and 75 years old, were allocated, randomly and equally balanced, to four groups: rTMS/sham SS, sham rTMS/SS, rTMS/SS, and sham rTMS/Sham SS. Participants underwent 10 sessions of S1 rTMS of the lesioned hemisphere (10 Hz, 1,500 pulses) followed by SS. SS was applied to the paretic upper limb (UL) (active SS) or non-paretic UL (sham SS). TMS-induced motor evoked potentials (MEPs) of the paretic UL and somatosensory evoked potential (SSEP) of both ULs assessed M1 and S1 cortical excitability, respectively. The S1 ASY index was measured before and after intervention. Evaluator, participants and the statistician were blinded. Results: Thirty-six participants divided equally into groups (nine participants per group). Seven patients were excluded from MEP analysis because of failure to produce consistent MEP. One participant was excluded in the SSEP analysis because no SSEP was detected. All somatosensory stimulation groups had decreased S1 ASY except for the sham rTMS/Sham SS group. When compared with baseline, M1 excitability increased only in the rTMS/SS group. Conclusion: S1 rTMS and SS alone or in combination changed S1 excitability and decreased ASY, but it was only their combination that increased M1 excitability. [ABSTRACT FROM AUTHOR]

During Integrated Multiparametric Neurophysiological Monitoring (IMNA), a newborn with suspected hypoxia at birth and microhaemorrhagic and ischaemic lesions presented some clonic-tonic episodes with specific EEG patterns characterized by rolandic and temporal spikes and the appearance of a unilateral enhanced Somatosensory Evoked Potential (SEP) (10.45 µv). Since the literature does not seem to describe cases of giant SEP in newborns, in this case report, we will discuss the hypotheses underlying this potential. It could be assumed that the ischaemic and haemorrhagic lesions presented by the newborn may have developed as a result of neurotransmitter balance failure. This may be the origin of the EEG picture, which, consequently, could have triggered a potential with high amplitude.

Abstract Background Cervical extension and flexion are presumably harmful to patients with degenerative cervical myelopathy (DCM) because they worsen medullary compression visible on dynamic magnetic resonance imaging (MRI). Dynamic somatosensory evoked potentials (SSEPs) are an objective tool to measure the electrophysiological function of the spinal cord at different neck positions. In contrast to previous hypotheses, a considerable proportion of patients with DCM present improved SSEPs upon extension and flexion compared to a neutral position. Methods Patients with DCM who underwent preoperative dynamic SSEP examinations and subsequent decompression surgeries between 2015 and 2019 were retrospectively evaluated. We compared extension and flexion SSEPs with neutral SSEPs in each patient and classified them into extension-improved (EI) or extension-nonimproved (EN) and flexion-improved (FI) or flexion-nonimproved (FN) groups. Preoperative clinical evaluations, decompression surgical methods and one-year follow-up clinical data were recorded. Cervical spondylolisthesis and cervical alignment types were evaluated on plain cervical lateral radiographs. The number of stenotic segments, Mühle stenosis grade and disc degeneration stage of the most severe segment, and presence of ligamentum flavum hypertrophy and intramedullary T2 weighted imaging (T2WI) hyperintensity were evaluated on lateral and axial MRI. Data were compared between the EN and EN groups or FI and FN groups with T-tests, chi-square tests or Kruskal-Wallis tests. Prediction criteria were determined with logistic regression analyses. Results Forty-nine patients were included, and 9 (18.4%) and 11 (22.4%) showed improved extension and flexion SSEPs compared to their own neutral SSEPs, respectively. Interestingly, EI or FI patients had significantly better one-year postoperative mJOA recoveries than EN or FN patients (T-test, P

[Display omitted] • Focal cortical cooling altered somatosensory evoked potentials (SEPs). • SEP amplitude was negatively correlated with cortical temperatures of 27.5−38.0 °C. • GABA A R but not AMPAR nor NMDAR antagonists eliminated the negative correlation. • GABAergic signaling is involved in the temperature dependency of SEPs. Although the focal brain cooling technique is widely used to examine brain function, the effects of cortical temperature at various levels on sensory information processing and neural mechanisms remain underexplored. To elucidate the mechanisms of temperature modulation in somatosensory processing, this study aimed to examine how P1 and N1 deflections of somatosensory evoked potentials (SEPs) depend on cortical temperature and how excitatory and inhibitory inputs contribute to this temperature dependency. SEPs were generated through electrical stimulation of the contralateral forepaw in anesthetized rats. The SEPs were recorded while cortical temperatures were altered between 17–38 °C either without any antagonists, with a gamma-aminobutyric acid type A (GABA A) receptor antagonist (gabazine), with an aminomethylphosphonic acid (AMPA) receptor antagonist (NBQX), or with an N -Methyl-D-aspartic acid (NMDA) receptor antagonist ([R]-CPP). The effects of different gabazine concentrations (0, 1, and 10 µM) were examined in the 35–38 °C range. The P1/N1 amplitudes and their peak-to-peak differences plotted against cortical temperature showed an inverted U relationship with a maximum at approximately 27.5 °C when no antagonists were administered. The negative correlation between these amplitudes and temperatures of ≥ 27.5 °C plateaued after gabazine administration, which occurred progressively as the gabazine concentration increased. In contrast, the correlation remained negative after the administration of NBQX and (R)-CPP. These results suggest that GABAergic inhibitory inputs contribute to the negative correlation between SEP amplitude and cortical temperature around the physiological cortical temperature. [ABSTRACT FROM AUTHOR]

Multisensory human–machine interfaces for virtual- or augmented-reality systems are lacking wearable actuated devices that can provide users with tactile feedback on the softness of virtual objects. They are needed for a variety of uses, such as medical simulators, tele-operation systems and tele-presence environments. Such interfaces require actuators that can generate proper tactile feedback, by stimulating the fingertips via quasi-static (non-vibratory) forces, delivered through a deformable surface, so as to control both the contact area and the indentation depth. The actuators should combine a compact and lightweight structure with ease and safety of use, as well as low costs. Among the few actuation technologies that can comply with such requirements, pneumatic driving appears to be one of the most promising. Here, we present an investigation on a new type of pneumatic wearable tactile displays of softness, recently described by our group, which consist of small inflatable chambers arranged at the fingertips. In order to objectively assess the perceptual response that they can elicit, a systematic electroencephalographic study was conducted on ten healthy subjects. Somatosensory evoked potentials (SEPs) were recorded from eight sites above the somatosensory cortex (Fc2, Fc4, C2 and C4, and Fc1, Fc3, C1 and C3), in response to nine conditions of tactile stimulation delivered by the displays: stimulation of either only the thumb, the thumb and index finger simultaneously, or the thumb, index and middle finger simultaneously, each repeated at tactile pressures of 10, 20 and 30 kPa. An analysis of the latency and amplitude of the six components of SEP signals that typically characterise tactile sensing (P50, N100, P200, N300, P300 and N450) showed that this wearable pneumatic device is able to elicit predictable perceptual responses, consistent with the stimulation conditions. This proved that the device is capable of adequate actuation performance, which enables adequate tactile perceptual performance. Moreover, this shows that SEPs may effectively be used with this technology in the future, to assess variable perceptual experiences (especially with combinations of visual and tactile stimuli), in objective terms, complementing subjective information gathered from psychophysical tests.

Cortical responses in somatosensory evoked potentials (SEP) are enhanced in patients with amyotrophic lateral sclerosis (ALS). This study investigated whether sensory gating is involved in the pathophysiology of sensory cortical hyperactivity in ALS patients. The median nerve SEP was recorded at rest and during voluntary finger movements in 14 ALS patients and 13 healthy control subjects. The parietal N20, P25, and frontal N30 were analyzed, and sensory gating was assessed by measuring the amplitude of each component during finger movement. The amplitudes of the N20 onset–peak, N20 peak–P25 peak, and N30 onset–peak were higher in ALS patients than in controls. Nonetheless, there were no significant differences in the amplitude reduction ratio of SEPs between patients and controls. There was a significant correlation between the baseline amplitudes of the N20 onset–peak or N20 peak–P25 peak and their gating ratios in patients with ALS. Our findings indicate that the excitability of the primary sensory cortex and secondary motor cortex is enhanced in ALS, while sensory gating is preserved in the early stages of ALS. This result suggests that enhanced SEP is caused by the hyperexcitability of the primary sensory and secondary motor cortices but not by the dysfunction of inhibitory mechanisms during voluntary movements.

Objective: To determine the utility of widely used intraoperative neuromonitoring (IONM) alert criteria and intervention for predicting postoperative outcome following paediatric spinal surgery. Methods: Retrospective analysis of somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) in consecutive cervical spine fixations. An intervention protocol followed amplitude-reductions in SSEPs (≥50 %) and/or MEPs (≥80 %). Alert breaches were reversed when SSEP/MEP amplitude was restored to > 50 %/20 % of baseline. Sensorimotor function was assessed preoperatively and 3-months postoperatively via the Modified McCormick Scale score (MMS). We explored associations between postoperative outcome, demographic/surgical and IONM variables. Results: Forty-five procedures in 38 children (mean age:9 ± 4 years;55 % female) were monitored, 42 %of which breached alert criteria. Instrumentation (6/19,32 %) and hypotension (5/19,26 %) were common causes for alert and the majority (13/19,68 %) were reversed following intervention. There was an association between pre- and post-MMS and the type of breach (p = 0.002). All children with worse postoperative MMS (3/38,8%) had irreversible breaches. Conclusions: IONM in this small sample accurately detected neurological injury. The majority of breaches reversed following an intervention protocol. Irreversible breaches frequently led to worse postoperative sensorimotor function. Significance: An intervention protocol which reversed IONM alerts never resulted in postoperative worsening of sensorimotor function.

ObjectiveThis study aimed to evaluate the diagnostic effect of intraoperative neurophysiological monitoring in identifying intraoperative ischemic events and predicting postoperative neurological dysfunction during PCoA aneurysm clipping, as well as to explore the safe duration of intraoperative temporary clipping of the parent artery.MethodsAll 71 patients with PCoA aneurysm underwent craniotomy and aneurysm clipping. MEP and SSEP were used for monitoring during operation to evaluate the influence of MEP/SSEP changes on postoperative neurological function. Receiver operating characteristic (ROC) curve analysis was used to calculate optimal duration of intraoperative temporary clipping.ResultsPatients with intraoperative MEP/SSEP changes were more likely to develop short-term and long-term neurological deficits than those without MEP/SSEP changes (P 4.5 min was significantly higher than that in patients with temporary clipping ≤4.5 min (P = 0.015, P = 0.018).ConclusionIntraoperative MEP/SSEP changes are significantly associated with postoperative neurological dysfunction in patients with PCoA aneurysms. The optimal duration of temporary clipping of the parent artery during posterior communicating aneurysm clipping was 4.5 min under neurophysiological monitoring.

Calpain activation has been implicated in various pathologies, including neurodegeneration. Thus, calpain inhibition could effectively prevent spinal cord injury (SCI) associated with neurodegeneration. In the current study, a dog SCI model was used to evaluate the therapeutic potential of a selective calpain inhibitor (PD150606) in combination with methylprednisolone sodium succinate (MPSS) as an anti-inflammatory drug. SCI was experimentally induced in sixteen mongrel dogs through an epidural balloon compression technique. The dogs were allocated randomly into four groups: control, MPSS, PD150606, and MPSS+PD150606. Clinical evaluation, serum biochemical, somatosensory evoked potentials, histopathological, and immunoblotting analyses were performed to assess treated dogs during the study. The current findings revealed that the combined administration of MPSS+PD150606 demonstrated considerably lower neuronal loss and microglial cell infiltration than the other groups, with a significant improvement in the locomotor score. The increased levels of inflammatory markers (GFAP and CD11) and calcium-binding proteins (Iba1 and S100) were significantly reduced in the combination group and to a lesser extent in MPSS or PD150606 treatment alone. Interestingly, the combined treatment effectively inhibited the calpain-induced cleavage of p35, limited cdk5 activation, and inhibited tau phosphorylation. These results suggest that early MPSS+PD150606 therapy after acute SCI may prevent subsequent neurodegeneration via calpain inhibition. [ABSTRACT FROM AUTHOR]

Objective To explore the value of somatosensory evoked potential (SSEP) during operations in children with fatty filum (FT). Methods From January 2016 to December 2021, clinical data were retrospectively reviewed for 48 FT children operated at Shanghai Children's Hospital. There were 29 boys and 19 girls with an age range from 2 months to 12 years old. The major symptoms included lower urinary tract/bladder symptoms (n=25), low back pain (n=3) and other cases were screened because of dermal sinus, anal/urinary system malformations & low conus (detected by obstetric ultrasound, n=20). The values of P37-N45 amplitude before and after surgery were compared and the correlations between age/radiological features and SSEP parameters examined. Results Among 25 children with an onset of urinary/bowel dysfunctions, 24 patients had improved symptoms and 1 case showed no change during the last follow-up. The symptoms of 3 children with preoperative low back pain relieved postoperatively. The median amplitude of P37-N45 was lower in 25 children with low conus position (0. 3 μV vs. 0. 7 μV at left side with P < 0. 01, 0. 5 μV vs. 0. 8 μV at right side with P < 0. 05). Among all cases, the median amplitude of P37-N45 post-operation was higher than that pre-operation (P < 0. 0 001). The postoperative change of P37-N45 amplitude was negatively correlated with age (r=-0. 45 at left side while r=-0. 44 at right side, both P < 0. 01) and the trend was more obvious in FT with low conus (r=-0. 51 at left side with P < 0. 05 while r=-0. 57 at right side with P < 0. 01). Conclusion Loosening operation relieves the clinical symptoms of FT patients. P37-N45 amplitude hints at potential neurological impairment. Surgery at an earlier age may accelerate the recovery of impaired neurological function. [ABSTRACT FROM AUTHOR]

Study Design: Systematic review and meta-analysis Objectives: The present review aimed to summarize the evidence regarding differences in proprioception between children with and without adolescent idiopathic scoliosis (AIS). Methods: Seven electronic databases were searched from their inception to April 10, 2021. Articles were included if they involved: (1) AIS patients aged between 10 and 18 years, (2) measurements of proprioceptive abilities, and (3) comparisons with non-AIS controls. Animal studies, case reports, commentaries, conference proceedings, research protocols, and reviews were excluded. Two reviewers independently conducted literature screening, data extraction, risks of bias assessments, and quality of evidence evaluations. Relevant information was pooled for meta-analyses. Results: From 432 identified citations, 11 case-control studies comprising 1121 participants were included. The meta-analyses showed that AIS participants displayed proprioceptive deficits as compared to non-AIS controls. Moderate evidence supported that AIS participants showed significantly larger repositioning errors than healthy controls (pooled mean difference = 1.27 degrees, P <.01). Low evidence substantiated that AIS participants had significantly greater motion detection threshold (pooled mean difference = 1.60 degrees, P <.01) and abnormal somatosensory evoked potentials (pooled mean difference =.36 milliseconds, P =.01) than non-AIS counterparts. Conclusions: Consistent findings revealed that proprioceptive deficits occurred in AIS patients. Further investigations on the causal relationship between AIS and proprioception, and the identification of the subgroup of AIS patients with proprioceptive deficit are needed. [ABSTRACT FROM AUTHOR]

Introduction: It is widely known that motor learning changes the excitability of the primary motor cortex. More recently, it has been shown that the primary somatosensory cortex (S1) also plays an important role in motor learning, but the details have not been fully examined. Therefore, we investigated how motor skill training affects somatosensory evoked potential (SEP) in 30 neurologically healthy subjects. Methods: SEP N20/P25_component and N20/P25 SEP paired-pulse depression (SEP-PPD) were assessed before and immediately after complex or simple visuomotor tasks. Results: Motor learning was induced more efficiently by the complex visuomotor task than by the simple visuomotor task. Both the N20/P25 SEP amplitude and N20/P25 SEP-PPD increased significantly immediately after the complex visuomotor task, but not after the simple visuomotor task. Furthermore, the altered N20/P25 SEP amplitude was associated with an increase in motor learning efficiency. Conclusion: These results suggest that motor learning modulated primary somatosensory cortex excitability. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of transcutaneous spinal direct current stimulation (tsDCS) on spinal cord excitability using neurophysiological methods., Methods: Spinal cord motoneuron excitability was assessed using various neurophysiological techniques in a sham-controlled randomized experiment, which involved delivering 2 mA tsDCS and testing four different montages. Transcranial magnetic stimulation (TMS), F-waves to supramaximal ulnar nerve stimulation and somatosensory evoked potentials to upper limb nerves stimulation were measured in the participants with the electrode configuration that yielded the greatest effect, for a total of about 18 min. 18 young volunteers were recruited., Results: Among the tested ones, the most promising tsDCS montage was the one with the anode placed on the 7th cervical spinous process and the cathode on the glottis. With this configuration, a significant enhancement of motor responses in the hand muscles to TMS of the contralateral hand motor area was observed during tsDCS (p<0.00001), reaching a plateau after 6 min. This facilitation rapidly declined within a few minutes after the tsDCS was stopped., Conclusion: Results of the different techniques suggest a possible contribution to facilitatory neuromodulation of the motoneurons at the cervical spine level., Significance: The occurrence of enhanced excitability after tsDCS suggests potential application in individuals with partial corticospinal fiber impairment affecting hand motor function., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)