•In children >5 years, language mapping led to improved neuropsychological outcomes.•This effect was more prominent in language non-dominant hemisphere surgeries.•Seizure outcomes, age, and semiology ...also determine neuropsychological outcomes.•Pre-surgical electrical stimulation language mapping should be performed more widely.
We studied the association between electrical stimulation mapping (ESM) with a visual naming task and post-operative neuropsychological outcomes after pediatric epilepsy surgery.
Children who underwent epilepsy surgery, having pre- and 1-year post-surgery neuropsychological evaluation (NPE) available, were included. NPE scores were transformed using principal components (PC) analysis. The relationship between post-surgical PC scores, adjusted for pre-surgery PC scores, and ESM was analyzed. Clinical variables influencing this relationship were also sought.
One hundred and four children (89 patients >5 years-old, and 15 patients 3−5 years-old) were included. Among children >5 years-of-age, a significant effect of language ESM was observed on all 3 post-surgery PC scores adjusted for respective pre-surgery PC scores. Specifically, only 30 % patients who underwent language ESM had a decrease in PC1 scores ≥1-year after epilepsy surgery, compared to 68 % those who did not undergo language ESM (p = 0.001). Seizure outcomes, age at the time of surgery, predominant seizure type, and family history of epilepsy were other significant determinants of post-surgical PC scores including a change in PC scores from pre-surgery baseline. Combinations of pre-surgical variables were able to predict post-surgical PC scores with high specificity. In children aged 3−5 years, no significant effect of language ESM was seen on post-surgery PC scores adjusted for respective pre-surgery PC scores.
Speech/language ESM should be performed more widely in patients >5 years-of-age undergoing epilepsy surgery. Also, more efficient brain mapping techniques and language paradigms are needed for younger children.
Summary Purpose Magnetoencephalography (MEG) has been shown a useful diagnostic tool for presurgical evaluation of pediatric medically intractable partial epilepsy as MEG source localization has been ...shown to improve the likelihood of seizure onset zone (SOZ) sampling during subsequent evaluation with intracranial EEG (ICEEG). We investigated whether ictal MEG onset source localization further improves results of interictal MEG in defining the SOZ. Methods We identified 20 pediatric patients with one habitual seizure during MEG recordings between October 2007 and April 2011. MEG was recorded with sampling rates of 600 Hz and 4000 Hz for 10 and 2 min respectively. Continuous head localization (CHL) was applied. Source localization analyses were applied using multiple algorithms, both at the beginning of ictal onset and for interictal MEG discharges. Ictal MEG onsets were identified by visual inspection and power spectrum using short-time Fourier transform (STFT). Source localizations were compared with ICEEG, surgical procedure and outcome. Key findings Eight patients met all inclusion criteria. Five of the 8 patients (63%) had concordant ictal MEG onset source localization and interictal MEG discharge source localizations in the same lobe, but the source of ictal MEG onset was closer to the SOZ defined by ICEEG. Significance Although the capture of seizures during MEG recording is challenging, the source localization for ictal MEG onset proved to be a useful tool for presurgical evaluation in our pediatric population with medically intractable epilepsy.
Patients with tuberous sclerosis complex (TSC) epilepsy present with unique clinical challenges such as early seizure onset and high rates of intractability and multifocality. Although there are ...numerous studies about the safety and efficacy of stereoelectroencephalography (SEEG), this topic has not been studied in TSC patients who have distinct epilepsy profiles. The authors investigated subdural grid (SDG) and SEEG monitoring to determine whether these procedures lead to similar seizure and safety outcomes and to identify features unique to this pediatric population.
TSC patients who underwent SDG or SEEG placement and a second epilepsy surgery during the period from 2007 to 2021 were included in this single-center retrospective cohort analysis. Various patient, hospitalization, and epilepsy characteristics were collected.
A total of 50 TSC patients were included in this study: 30 were included in the SDG cohort and 20 in the SEEG cohort. Baseline weekly seizure count did not significantly differ between the 2 groups (p = 0.412). The SEEG group had a greater mean baseline number of antiepileptic drugs (AEDs) (3.0 vs 2.0, p = 0.003), higher rate of previous surgical interventions (25% vs 0%, p = 0.007), and larger proportion of patients who underwent bilateral monitoring (50% vs 13.3%, p = 0.005). Despite this, there was no significant difference in seizure freedom between the SDG and SEEG cohorts. The mean reduction in seizure count was 84.9% and 47.8% of patients were seizure free at last follow-up (mean 79.4 months). SEEG trended toward being a safer procedure than SDG monitoring, with a shorter mean ICU stay (0.7 days vs 3.9 days, p < 0.001), lower blood transfusion rate (0% vs 13.3%, p = 0.140), and lower surgical complication rate (0% vs 10%, p = 0.265).
In the comparison of the SDG and SEEG cohorts, the SEEG group included patients who appeared to receive more aggressive management and have a higher rate of multifocality, more prior surgical interventions, more AEDs at baseline, and a higher rate of bilateral invasive monitoring. Despite this, the SEEG cohort had similar seizure outcomes and a trend toward increased safety. Based on these findings, SEEG appears to allow for monitoring of a wider breadth of TSC patients given its minimally invasive nature and its relative simplicity for monitoring numerous regions of the brain.
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.
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.
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.
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.
•fMRI needs improved validation for pre-surgical language localization.•fMRI has moderate specificity (0.74, 95% CI 0.58–0.85) compared to electrical stimulation mapping (ESM).•fMRI is moderately sensitive (0.71, 95% CI 0.54–0.83) compared to ESM but CI are close to line of no-effect.•fMRI has higher sensitivity in studies using higher maximal ESM currents.
Summary
Objective
This prospective study compared presurgical language localization with visual naming–associated high‐γ modulation (HGM) and conventional electrical cortical stimulation (ECS) in ...children with intracranial electrodes.
Methods
Patients with drug‐resistant epilepsy who were undergoing intracranial monitoring were included if able to name pictures. Electrocorticography (ECoG) signals were recorded during picture naming (overt and covert) and quiet baseline. For each electrode the likelihood of high‐γ (70–116 Hz) power modulation during naming task relative to the baseline was estimated. Electrodes with significant HGM were plotted on a three‐dimensional (3D) cortical surface model. Sensitivity, specificity, and accuracy were calculated compared to clinical ECS.
Results
Seventeen patients with mean age of 11.3 years (range 4–19) were included. In patients with left hemisphere electrodes (n = 10), HGM during overt naming showed high specificity (0.81, 95% confidence interval CI 0.78–0.85), and accuracy (0.71, 95% CI 0.66–0.75, p < 0.001), but modest sensitivity (0.47) when ECS interference with naming (aphasia or paraphasic errors) and/or oral motor function was regarded as the gold standard. Similar results were reproduced by comparing covert naming‐associated HGM with ECS naming sites. With right hemisphere electrodes (n = 7), no ECS‐naming deficits were seen without interference with oral‐motor function. HGM mapping showed a high specificity (0.81, 95% CI 0.78–0.84), and accuracy (0.76, 95% CI 0.71–0.81, p = 0.006), but modest sensitivity (0.44) compared to ECS interference with oral‐motor function. Naming‐associated ECoG HGM was consistently observed over Broca's area (left posterior inferior‐frontal gyrus), bilateral oral/facial motor cortex, and sometimes over the temporal pole.
Significance
This study supports the use of ECoG HGM mapping in children in whom adverse events preclude ECS, or as a screening method to prioritize electrodes for ECS testing.
•High Frequency Oscillation were observed in epileptogenic zone in all patient with TSC.•Complete resection of high frequency oscillations (HFOs) led to the better surgical outcome.•Tuber types were ...not associated with either type of HFOs (fast ripple or ripple) or surgical outcome.
Resective epilepsy surgery can improve seizures when the epileptogenic zone (EZ) is limited to a well-defined region. High frequency oscillations (HFO) have been recognized as having a high association with the seizure onset zone. Therefore, we retrospectively identified ictal HFOs and determined their relationship to specific intracranial features of cortical tubers in children with TSC who underwent resective surgery. We identified 14 patients with drug resistant epilepsy secondary to TSC who underwent subdural grid and strip implantation for presurgical evaluation and subsequent resection with adequate post-surgical follow-up. We aimed to determine the relationship between ictal HFOs, post-resection outcome and neuroimaging features in this population.
The largest tuber was identified in all 14 patients (100%). Four patients (29%) had unusual tubers. HFOs were observed at ictal onset in all 14 patients. Seven of 10 patients with complete resection of HFOs were seizure free. The better seizure outcome (ILAE=1–3) was achieved with complete HFO resection regardless of the unique TSC structural features (p=0.0140).
Our study demonstrates the presence of ripple and fast ripple range HFOs at ictal onset in children with TSC. Our study showed that complete HFO resection led to the better surgical outcome, independent of MR imaging findings.
Summary
Objective
We studied age‐related dynamics of information sharing among cortical language regions with electrocorticographic high‐gamma modulation during picture‐naming and story‐listening ...tasks.
Methods
Seventeen epilepsy patients aged 4‐19 years, undergoing extraoperative monitoring with left‐hemispheric subdural electrodes, were included. Mutual information (MI), a nondirectional measure of shared information, between 16 pairs of cortical regions of interest, was computed from trial‐averaged 70–150 Hz power modulations during language tasks. Impact of age on pairwise MI between language regions and their determinants were ascertained with regression analysis.
Results
During picture naming, significant increase in MI with age was seen between pairwise combinations of Broca's area, inferior precentral gyrus (iPreC), and frontal association cortex (FAC); Wernicke's area and posterior association cortex (PAC); and Broca's and Wernicke's areas. During story listening, significant age‐related increase in MI was seen between Wernicke's area and either Broca's area, FAC, or PAC; and between Broca's area and FAC. Significant impact of baseline intelligence quotient was seen on the relationship between age and MI for all pairs, except between Broca's area and iPreC. The mean MI was higher during naming compared to listening for pairs including iPreC with Broca's area, FAC, or PAC and was lower for pairs of Wernicke's area or PAC with anterior language regions.
Significance
Information sharing matures with age “within” frontal and temporoparietal language cortices, and “between” Broca's and Wernicke's areas. This study provides evidence for distinct patterns of developmental plasticity within perisylvian language cortex and has implications for planning epilepsy surgery.
Highlights • Acute postoperative seizures (APOS) predict 1-year seizure outcomes after epilepsy surgery. • APOS were reported in 22.58% of epilepsy surgery patients. • Patients without APOS are 4.2 ...times more likely to be seizure free after ≥1-year
Functional magnetic resonance imaging has become a critical research tool for evaluating brain function during active tasks and resting states. This has improved our understanding of developmental ...trajectories in children as well as the plasticity of neural networks in disease states. In the clinical setting, functional maps of eloquent cortex in patients with brain lesions and/or epilepsy provides crucial information for presurgical planning. Although children are inherently challenging to scan in this setting, preparing them appropriately and providing adequate resources can help achieve useful clinical data. This article will review the basic underlying physiologic aspects of functional magnetic resonance imaging, review clinically relevant research applications, describe known validation data compared to gold standard techniques and detail future directions of this technology.
•Three SISCOM patterns were seen in pediatric temporal lobe epilepsy and unilateral anterior hyperperfusion is most identified.•Type of focal cortical dysplasia and presence of hippocampal sclerosis ...were significant determinants of SISCOM patterns.•Lobar concordance of SISCOM and ictal and interictal scalp EEG significantly correlated with postoperative outcomes.•There was no significant correlation between SISCOM patterns and one-year postoperative outcomes.
We evaluated SISCOM patterns and their relationship with surgical outcome in children with temporal lobe epilepsy (TLE) who had undergone a temporal lobe surgery.
This was an observational study evaluating SISCOM patterns in 40 children with TLE. We classified SISCOM patterns into 4 categories; (i) unilateral anteromesial and/or anterolateral temporal pattern; (ii) unilateral anteromesial and/or anterolateral temporal plus posterior extension pattern; (iii) bilateral anteromesial and/or anterolateral temporal pattern; and (iv) atypical pattern. Determinants of SISCOM pattern and correlation between postoperative outcomes and SISCOM patterns were evaluated.
Pattern (i), (ii), (iii), and (iv) were identified in 10 (25%), 14 (35%), 0 (0%), and 16 (40%) patients, respectively. There was no significant correlation between patterns and postoperative outcomes. SISCOM patterns significantly associated with the presence of hippocampal sclerosis and type of focal cortical dysplasia (p-value = 0.048 and 0.036, respectively). Patients with HS had 5 times the odds of having unilateral temporal pattern, compared to patients with other neuropathology (OR = 5, 95% CI 0.92 to 27.08). Patients with FCD type 2 had 9.71 times the odds of having atypical pattern, compared to patients with other types of FCD (OR = 9.71, 95% CI 0.92 to 103.04). Lobar concordance of SISCOM and ictal and interictal scalp EEG significantly correlated with postoperative outcomes (p-value = 0.018 and 0.013, respectively).
Three SISCOM patterns were seen. Patients with HS had increased odds of having unilateral temporal pattern while patients with FCD type 2 had increased odds of having atypical pattern. However, there was no significant correlation between SISCOM patterns and postoperative outcomes. Lobar concordance of SISCOM and ictal and interictal scalp EEG significantly correlated with postoperative outcome.
This study shows that the distribution of SISCOM patterns and their relationship with postoperative outcomes in children with TLE are different from adult population. Besides, SISCOM may add only limited diagnostic and prognostic information in children with drug-resistant TLE undergoing epilepsy surgery. Further evaluation to identify patient populations that may benefit from SISCOM is desirable.
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