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Objective: We investigated the role of transverse temporal gyrus and adjacent cortex (TTG+) in facial expressions and perioral movements., Methods: In 31 patients undergoing stereo-electroencephalography monitoring, we describe behavioral responses elicited by electrical stimulation within the TTG+. Task-induced high-gamma modulation (HGM), auditory evoked responses, and resting-state connectivity were used to investigate the cortical sites having different types of responses on electrical stimulation., Results: Changes in facial expressions and perioral movements were elicited on electrical stimulation within TTG+ in 9 (29%) and 10 (32%) patients, respectively, in addition to the more common language responses (naming interruptions, auditory hallucinations, paraphasic errors). All functional sites showed auditory task induced HGM and evoked responses validating their location within the auditory cortex, however, motor sites showed lower peak amplitudes and longer peak latencies compared to language sites. Significant first-degree connections for motor sites included precentral, anterior cingulate, parahippocampal, and anterior insular gyri, whereas those for language sites included posterior superior temporal, posterior middle temporal, inferior frontal, supramarginal, and angular gyri., Conclusions: Multimodal data suggests that TTG+ may participate in auditory-motor integration., Significance: TTG+ likely participates in facial expressions in response to emotional cues during an auditory discourse., (Copyright © 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: This systematic review and meta-analysis evaluated the diagnostic validity of functional magnetic resonance imaging (fMRI) compared to electrical stimulation mapping (ESM) for pre-surgical language mapping., Methods: A structured literature search was performed and studies with electrode-level data comparing fMRI and ESM for language localization were analyzed. Outcome measures included pooled estimates of diagnostic odds ratio (DOR), sensitivity, and specificity. Sources of heterogeneity were explored with a meta-regression framework., Results: Nine studies were included in the analysis having 5-40 patients with mean age 11.3-43.4 years. Verb generation and picture naming were the most common fMRI tasks, while picture naming was the most common ESM task. Sensitivity (0.37-0.95), specificity (0.36-0.97), and DOR (1.9-44.6) for fMRI compared to ESM varied widely across studies with statistically significant heterogeneities. Pooled estimates were: sensitivity 0.71 (95% confidence interval 0.54, 0.83), specificity 0.74 (0.58, 0.85), and DOR 7.0 (3.5, 13.8), from a valid meta-analysis (area under the summary receiver-operating-curve 0.78). fMRI was noted to have higher sensitivity in studies using higher maximal ESM currents. fMRI variables could not be included in the meta-regression because of substantial methodological differences among studies., Conclusions: fMRI is moderately sensitive and moderately specific for language localization compared to ESM in well-designed studies. However, because the confidence limits for sensitivity and DOR are close to the line of no effect, and there is high unmeasured heterogeneity, fMRI cannot perhaps be used as the only modality for language localization to inform neurosurgical decisions at present., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objective: To clinically validate the connectivity-based magnetoencephalography (MEG) analyses to identify seizure onset zone (SOZ) with comparing to equivalent current dipole (ECD)., Methods: The ECD cluster was quantitatively analyzed by calculating the centroid of the cluster and maximum distance (the largest distance between all dipoles). The "primary hub" was determined by the highest eigencentrality. The distribution of nodes in the top 5% of eigenvector centrality values was quantified by generating the convex hull between each node., Results: Thirty-one patients who underwent MEG, stereotactic-EEG, and focal surgery were included. The primary hub was significantly closer to the sEEG-defined SOZ compared to ECD (p = 0.009). The seizure freedom positive and negative predictive values of complete ECD cluster and primary hub resections did not significantly differ, although complete resection of the primary hub showed slightly better negative predictive value (ECD: 50.0% NPV, hub: 64.7% NPV). Both quantitative ECD and functional connectivity analyses suggested that spatially restricted dipole distributions and higher connectivity in a smaller region correlate with better seizure outcomes., Conclusions: Our findings suggest that MEG network analysis could be a valuable complement to the ECD methods., Significance: The results of this study are an important step towards using non-invasive neurophysiologic recordings to accurately define the epileptic network., 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 © 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Children with Benign Epilepsy with Centrotemporal Spikes (BECTS), despite high likelihood for seizure remission, are reported to have subtle difficulties in language and other cognitive skills. We used functional MRI and a story listening task to examine the effect of BECTS on patterns of activation and connectivity. Language and cognitive skills were assessed using standardized measures. Twenty-four children with recently diagnosed BECTS and 40 typically-developing children participated. In a functionally-defined region of interest in right inferior frontal gyrus, BECTS patients showed a lower level of activation. Across both groups combined, increased activation in superior/middle temporal regions of interest was associated with better language scores. Connectivity in the story processing network was similar between groups, but connectivity within left inferior frontal gyrus was decreased in children with BECTS. These results suggest that language networks are largely maintained in new-onset BECTS, but some subtle changes in activation and connectivity can be observed., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: We evaluated the impact of radiotracer injection latency and post-injection seizure duration on subtraction ictal SPECT co-registered to MRI (SISCOM) test performance in identifying the epileptogenic zone (EZ) in children with drug-resistant epilepsy who had undergone a resective epilepsy surgery., Methods: SISCOM concordance with the EZ was retrospectively reviewed to evaluate its performance in 113 children. The impact of radiotracer injection latency and post-injection seizure duration was evaluated for their predictive value of SISCOM localization accuracy., Results: The overall sensitivity and specificity of SISCOM in identifying an EZ was 64.8% (95%CI = 50.6-77.3) and 40.7% (95%CI = 28.1-54.3). The positive likelihood ratio and diagnostic odd ratio was 1.09 (95%CI = 0.80-1.48) and 1.26 (95%CI = 0.59-2.71), respectively. Logistic regression showed that injection latency and post-injection seizure duration did not significantly predict the probability of true positive SISCOM (p-value = 0.45 and 0.29, respectively)., Conclusion: Radiotracer injection latency and post-injection seizure duration were not shown to have a statistical significant impact on SISCOM performance in identifying the EZ., Significance: This study demonstrates that further study of factors contributing to the performance of SISCOM in EZ identification in children is needed., (Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To examine current thresholds and their determinants for language and motor mapping with extra-operative electrical cortical stimulation (ECS)., Methods: ECS electrocorticograph recordings were reviewed to determine functional thresholds. Predictors of functional thresholds were found with multivariable analyses., Results: In 122 patients (age 11.9±5.4years), average minimum, frontal, and temporal language thresholds were 7.4 (± 3.0), 7.8 (± 3.0), and 7.4 (± 3.1) mA respectively. Average minimum, face, upper and lower extremity motor thresholds were 5.4 (± 2.8), 6.1 (± 2.8), 4.9 (± 2.3), and 5.3 (± 3.3) mA respectively. Functional and after-discharge (AD)/seizure thresholds were significantly related. Minimum, frontal, and temporal language thresholds were higher than AD thresholds at all ages. Minimum motor threshold was higher than minimum AD threshold up to 8.0years of age, face motor threshold was higher than frontal AD threshold up to 11.8years age, and lower subsequently. UE motor thresholds remained below frontal AD thresholds throughout the age range., Conclusions: Functional thresholds are frequently above AD thresholds in younger children., Significance: These findings raise concerns about safety and neurophysiologic validity of ECS mapping. Functional and AD/seizure thresholds relationships suggest individual differences in cortical excitability which cannot be explained by clinical variables., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: This study examined the incidence, thresholds, and determinants of electrical cortical stimulation (ECS)-induced after-discharges (ADs) and seizures., Methods: Electrocorticograph recordings were reviewed to determine incidence of ECS-induced ADs and seizures. Multivariable analyses for predictors of AD/seizure occurrence and their thresholds were performed., Results: In 122 patients, the incidence of ADs and seizures was 77% (94/122) and 35% (43/122) respectively. Males (odds ratio [OR] 2.92, 95% CI 1.21-7.38, p=0.02) and MRI-negative patients (OR 3.69, 95% CI 1.24-13.7, p=0.03) were found to have higher odds of ECS-induced ADs. A significant trend for decreasing AD thresholds with age was seen (regression co-efficient -0.151, 95% CI -0.267 to -0.035, p=0.011). ECS-induced seizures were more likely in patients with lateralized functional imaging (OR 6.62, 95% CI 1.36-55.56, p=0.036, for positron emission tomography) and presence of ADs (OR 3.50, 95% CI 1.12-13.36, p=0.043)., Conclusions: ECS is associated with a high incidence of ADs and seizures. With age, current thresholds decrease and the probability for AD/seizure occurrence increases., Significance: ADs and seizures during ECS brain mapping are potentially hazardous and affect its functional validity. Thus, safer method(s) for brain mapping with improved neurophysiologic validity are desirable., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Purpose: Lack of a potentially epileptogenic lesion on brain magnetic resonance imaging (MRI) is a poor prognostic marker for epilepsy surgery. We present a single-center series of childhood-onset MRI-negative drug-resistant epilepsy (DRE) and analyze surgical outcomes and predictors., Methods: Children with MRI-negative DRE who had resective surgery from January 2007 to December 2013 were identified using an institutional database. Relevant clinical, neurophysiological, imaging, and surgical data was extracted. The primary outcome measure was seizure freedom. Predictors of seizure freedom were obtained using multivariate logistic regression., Results: Out of 47 children with MRI-negative DRE, 12 (25.5%) were seizure free (International League Against Epilepsy [ILAE] outcome class I), after mean follow-up of 2.75 (±1.72) years. Seizure-free proportion was significantly higher in patients with single seizure semiology and concordant ictal EEG (50.0% vs. 15.2%, p=0.025). Multivariate analysis using only non-invasive pre-surgical data showed that children with daily seizures (OR 0.02, 95% CI<0.001-0.55), and earlier onset of seizures (OR 0.72, 95% CI 0.52-0.99) were less likely to be seizure-free. Also, each additional anti-epileptic drug (AED) tried before surgery decreased the probability of seizure-free outcome (OR 0.16, 95% CI 0.04-0.63). Repeat multivariate analysis after including surgical variables found no additional significant predictors of seizure-freedom. Cortical dysplasia (ILAE type IB) was the commonest histopathology., Conclusion: Surgical outcomes in children with MRI-negative DRE are determined by clinical factors including seizure frequency, age of onset of seizures, and number of failed AEDs., (Copyright © 2016 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)