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Summary: We present a child with myoclonic seizures, epileptic spasms and generalized epileptiform discharges on scalp EEG. Magnetoencephalography and coherence-phase analysis for scalp EEG suggested focal onset in the left hemisphere. Intracranial video EEG confirmed seizure onset in the left frontal lobe with ictal high-frequency oscillations. Left frontal lobectomy suppressed his seizures. Subsets of myoclonic seizures can be focal in origin despite bilaterally synchronized epileptiform discharges on scalp EEG. [Copyright &y& Elsevier]

Cognitive flexibility encompasses the ability to efficiently shift focus and forms a critical component of goal-directed attention. The neural substrates of this process are incompletely understood in part due to difficulties in sampling the involved circuitry. We leverage stereotactic intracranial recordings to directly resolve local-field potentials from otherwise inaccessible structures to study moment-to-moment attentional activity in children with epilepsy performing a flexible attentional task. On an individual subject level, we employed deep learning to decode neural features predictive of task performance indexed by single-trial reaction time. These models were subsequently aggregated across participants to identify predictive brain regions based on AAL atlas and FIND functional network parcellations. Through this approach, we show that fluctuations in beta (12–30 Hz) and gamma (30–80 Hz) power reflective of increased top-down attentional control and local neuronal processing within relevant large-scale networks can accurately predict single-trial task performance. We next performed connectomic profiling of these highly predictive nodes to examine task-related engagement of distributed functional networks, revealing exclusive recruitment of the dorsal default mode network during shifts in attention. The identification of distinct substreams within the default mode system supports a key role for this network in cognitive flexibility and attention in children. Furthermore, convergence of our results onto consistent functional networks despite significant inter-subject variability in electrode implantations supports a broader role for deep learning applied to intracranial electrodes in the study of human attention. [ABSTRACT FROM AUTHOR]

Purpose: To characterize the spatial and temporal course of ictal high-frequency oscillations (HFOs) recorded by subdural EEG in children with intractable neocortical epilepsy. Methods: We retrospectively studied nine children (four girls, five boys; 4–17 yr) who presented with intractable extrahippocampal localization-related epilepsy and who underwent extraoperative video subdural EEG (1000 Hz sampling rate) and cortical resection. We performed multiple band frequency analysis (MBFA) to evaluate the frequency, time course, and distribution of ictal HFOs. We compared ictal HFO changes before and after clinical onset and postsurgical seizure outcomes. Results: Seventy-eight of 79 seizures showed HFOs. We observed wide-band HFOs (∼250Hz, ∼120 electrodes) in six patients either with partial seizures alone (three patients) or with epileptic spasms (three patients). Three patients with partial seizures that secondarily generalized had wide-band HFOs (∼170 Hz) before clinical onset and sustained narrow-band HFOs (60–164 Hz) with electrodecremental events after clinical onset (∼28 electrodes). In four postoperatively seizure-free patients, more electrodes recorded higher-frequency HFOs inside the resection area than outside before and after clinical seizure onset. In five patients with residual seizures, electrodes recorded more HFOs that were of higher or equal frequency outside the surgical area than inside after clinical onset. Conclusion: For partial seizures alone and epileptic spasms, more electrodes recorded only wide-band HFOs; for partial seizures that secondarily generalized, fewer electrodes recorded wide-band HFOs, but in these seizures electrodes also recorded subsequent sustained narrow-band ictal HFOs. Resection of those brain regions having electrodes with ictal, higher HFOs resulted in postsurgical seizure-free outcomes. [ABSTRACT FROM AUTHOR]

Children and adults with genetic generalized epilepsy may have focal clinical seizure symptoms as well as electroencephalographic (EEG) findings. This may pose a diagnostic challenge to clinicians, especially when concomitant focal neuroimaging findings exist and the epilepsy is medically refractory. We sought to highlight the challenges that clinicians may face through the description of 2 children with suspected genetic generalized epilepsy who had both focal seizure symptoms and EEG/neuroimaging findings and underwent invasive EEG monitoring. Ultimately, invasive monitoring failed to demonstrate a focal origin for the seizures in both cases, and instead confirmed the presence of genetic generalized epilepsy. We demonstrate that ≥3-Hz generalized monomorphic spike and waves are less likely to represent secondary bilateral synchrony, that focal neuroimaging findings may not always be causal and that repeated hyperventilation is an essential activation procedure for genetic generalized epilepsy. [ABSTRACT FROM AUTHOR]

Highlights • Extra-operative mapping (penfield technique) frequently leads to after-discharges and seizures. • Intra-operative motor-mapping (IODCS-SDG) using "train of five" provided more mapping information. • No stimulation-provoked seizures were noted during IODCS-SDG. Abstract Objectives The objective of this study was to review our experience with intra-operative "train of five" stimulation using subdural grid for motor mapping in children undergoing epilepsy surgery evaluation. Methods Twenty consecutive children below 18-years of age with drug-refractory epilepsy who underwent invasive-EEG monitoring using subdural-grid placement and intra-operative motor mapping using direct cortical stimulation by sub-dural grid electrodes (IODCS-SDG) at our institution between January-2016 and June-2017 were reviewed. Stimulation was delivered through the subdural-grid electrodes using a train-of-five pulses and muscle responses were recorded by motor-evoked-potentials (MEPs). Intra-operative direct cortical stimulation delivered through a ball-tipped probe (IODCS-probe) and extra-operative motor-mapping (EODCS-SDG) were also performed. Results IODCS-SDG was completed in 20 patients and subsequent EODCS-SDG was done in 17/20 patients. MEP responses were more commonly obtained in the deltoid (19/20), extensor-digitorum-communis (20/20) and first-dorsal-interosseus (19/20). The median thresholds varied between 40 V and 60 V for the six muscle groups. The respective IODCS-probe thresholds tended to be similar. No stimulation-provoked seizures or anaesthesia-related complications were noted during IODCS-SDG. EODCS-SDG could not be completed in 4/17 children and mapping data obtained was frequently inadequate. Nine patients demonstrated 100% concordance between IODCS-SDG and EODCS-SDG for the common mapped body regions. Stimulation-provoked seizures during EODCS-SDG were seen in 6/17 (35.3%) and after-discharges in 7/17 (41.2%) children. Conclusions IODCS-SDG could be performed safely in children with drug refractory epilepsy undergoing invasive EEG monitoring. Significance IODCS-SDG may be a useful adjunct to EODCS-SDG in motor mapping for children. [ABSTRACT FROM AUTHOR]

Objective: Epileptic spasms (ES) often become drug-resistant. To reveal the electrophysiological difference between children with ES (ES+) and without ES (ES-), we compared the occurrence rate (OR) of high-frequency oscillations (HFOs) and the modulation index (MI) of coupling between slow and fast oscillations. In ES+, we hypothesized that (1) pathological HFOs are more widely distributed and (2) slow oscillations show stronger coupling with pathological HFOs than in ES-. Methods: We retrospectively reviewed 24 children with drug-resistant multilobar onset epilepsy, who underwent intracranial video electroencephalography prior to multilobar resections. We measured the OR of HFOs and determined the electrodes with a high rate of HFOs by cluster analysis. We calculated MI, which reflects the degree of coupling between HFO (ripple/fast ripple [FR]) amplitude and 5 different frequency bands of delta and theta activities (0.5-1 Hz, 1-2 Hz, 2- 3 Hz, 3-4 Hz, 4-8 Hz). Results: In ES+ (n = 10), the OR(FRs), the number of electrodes with high-rate FRs, and the MI(FRs & 3-4 Hz) in all electrodes were significantly higher than in ES- (n = 14). In both the ES+ and ES- groups, MI(ripples/FRs & 3-4 Hz) was the highest among the 5 frequency bands. Within the good seizure outcome group, the OR(FRs) and the MI(FRs & 3-4 Hz) in the resected area in ES+ were significantly higher than in ES (OR[FRs], P = .04; MI[FRs & 3-4 Hz], P = .04). Significance: In ES+, the larger number of high-rate FR electrodes indicates more widespread epileptogenicity than in ES-. High values of OR(FRs) and MI(FRs & 3-4 Hz) in ES+ compared to ES- are a signature of the severity of epileptogenicity. We proved that ES+ children who achieved seizure freedom following multilobar resections exhibited strong coupling between slow oscillations and FRs. [ABSTRACT FROM AUTHOR]

Background: The identification of a biomarker for sudden unexpected death in epilepsy (SUDEP) has the potential to save lives. Generalized convulsive seizures and postictal generalized suppression on electroencephalography (EEG) most often precede sudden unexpected death in epilepsy (SUDEP) and are potential biomarkers. We identify the EEG and seizure characteristics associated with postictal generalized EEG suppression in children with epilepsy.Methods: Video EEGs were reviewed for seizure type, duration and semiology, and electrographic features. To identify predictors of postictal generalized EEG suppression, we identified 40 children with generalized convulsive seizures from a group of 399 patients who experienced an electroclinical seizure during video-EEG. Seventy-seven generalized convulsive seizures with and without postictal generalized EEG suppression were anayzed.Results: Age of seizure onset was older in 19 children with postictal generalized EEG suppression (mean 6.8 years old, 95% CI [4.7-8.9]) than in 21 without postictal generalized EEG suppression (3.0 years old, [1.1-4.1], P = 0.041). Postictal generalized EEG suppression occurred significantly more often from sleep than awake (point of estimate 16.67; 95% CI [0.97-32.36], P < 0.038). Shorter duration of the clonic phase (-0.76; [-1.338, -0.133], P = 0.018) was significantly associated with postictal generalized EEG suppression. Ictal symmetric tonic extension posturing significantly increased the odds of postictal generalized EEG suppression (42.94; [18.77, 67.12], P = 0.001). All 15 generalized convulsive seizures with a terminal burst-suppression pattern were followed by postictal generalized EEG suppression in contrast to 19 of 62 generalized convulsive seizures without burst-suppression (15.32, P < 0.001).Conclusions: Ictal decerebrate-like symmetric tonic extension posturing with shorter clonic phase and a terminal burst-suppression pattern identify malignant generalized convulsive seizures, associated with postictal generalized EEG suppression and a potentially increased risk of sudden unexpected death in epilepsy. [ABSTRACT FROM AUTHOR]

Objective Epilepsy surgery can be successful in children with extensive congenital or early acquired focal or hemispheric brain lesion on magnetic resonance imaging ( MRI) despite generalized interictal epileptiform discharges ( IEDs). The aim of this study was to assess if rapid eye movement ( REM) sleep reduced generalized IEDs and revealed lateralized IEDs to identify the epileptogenic hemisphere in children with generalized IEDs and normal/subtle changes on MRI. Methods We studied 20 children with generalized IEDs on scalp electroencephalography ( EEG) and normal/subtle changes on MRI who underwent intracranial video- EEG for epilepsy surgery. We assessed a minimum of 100 IEDs during REM, non- REM, and wakefulness, and assigned the distribution (generalized, left, or right hemisphere) to each IED. The number of lobes in the resected areas and seizure outcome were compared between 20 children with generalized IEDs and a comparison group of 28 children without generalized IEDs. Results The mean occurrence rate of generalized IEDs during REM (37%) was significantly lower than that during non- REM (67%, p < 0.001) and wakefulness (54%, p = 0.003). The number of children whose largest number of IEDs was lateralized in REM was significantly higher than that in non- REM (15 vs. 3 children, 75% vs. 15%, p < 0.001). The hemisphere with lateralized IEDs among three states corresponded with the surgical side in 16 children with generalized IEDs. Seventeen children (85%) with generalized IEDs and 27 (96%) without generalized IEDs underwent resective surgery. Multilobar resection was required for 16 children (94%) with generalized IEDs more frequently than 7 children (26%) without generalized IEDs (p < 0.001). Thirteen children (77%) with generalized IEDs and 19 (73%) without generalized IEDs were seizure-free with a mean of 3.3 years of follow-up. Significance Our study demonstrates the importance of assessing REM in children with generalized IEDs as it reveals lateralized epileptogenic spikes. Seizure freedom may be achieved with multilobar resection in these children with generalized IEDs and normal/subtle changes on MRI. Generalized IEDs in children with normal/subtle changes on MRI should not preclude surgical resection. [ABSTRACT FROM AUTHOR]

Objective Infantile spasms ( IS) are a severe form of childhood epilepsy associated with autism spectrum disorders ( ASD) in up to 35% of cases. The objective of this post hoc analysis of our randomized control trial was to determine whether rapid diagnosis and treatment of IS could limit the incidence of ASD while identifying risk factors related to ASD outcome. Methods Patients with IS were randomized in a standardized diagnostic and treatment protocol. Clinical and electroencephalogram ( EEG) evaluations were completed at all eight visits over 5 years, while cognitive evaluations were administered at 0, 6, 24 and 60 months, respectively. Autism was initially screened by means of the Checklist for Autism in Toddlers ( CHAT) at 24 months, and formally assessed at the 30-and 60-month follow-ups using the Autism Diagnostic Observation Schedule-Generic ( ADOS-G). Results Of the 69 patients included in the study, 25 could not be assessed due to severe delay or death. Eleven of the 42 patients screened with CHAT, were found to be at risk of an ASD outcome. ADOS was performed in 44 and 10 were diagnosed with ASD. The CHAT proved to correlate highly with the ADOS (80% ppv). Only patients with symptomatic IS developed ASD (p = 0.003). Earlier diagnosis or successful treatment did not correlate with a reduced rate of ASD. Other risk factors were identified such as having chronic epileptic discharges in the frontotemporal areas after disappearance of hypsarrhythmia (p = 0.005 and p = 0.007) and being of nonwhite origin (p = 0.009). Significance ASD was only observed in children with sympyomatic IS. Other clinical risk factors include chronic frontotemporal epileptic activity and being of non-white origin. Early diagnosis and treatment did not prevent ASD as an outcome of IS. However, patients at risk for ASD could be identified early on and should in the future benefit from early intervention to potentially improve their long-term outcome. [ABSTRACT FROM AUTHOR]

Abstract: Pathological high frequency oscillations (pHFOs) have been proposed to be robust markers of epileptic cortex. Oscillatory activity below this frequency range has been shown to be modulated by phase of lower frequency oscillations. Here, we tested the hypothesis that dynamic cross-frequency interactions involving pHFOs are concentrated within the epileptogenic cortex. Intracranial electroencephalographic recordings from 17 children with medically-intractable epilepsy secondary to focal cortical dysplasia were obtained. A time-resolved analysis was performed to determine topographic concentrations and dynamic changes in cross-frequency amplitude-to-phase coupling (CFC). CFC between pHFOs and the phase of theta and alpha rhythms was found to be significantly elevated in the seizure-onset zone compared to non-epileptic regions (p<0.01). Data simulations showed that elevated CFC could not be attributed to the presence of sharp transients or other signal properties. The phase of low frequency oscillations at which pHFO amplitudes were maximal was inconsistent at seizure initiation, yet consistently at the trough of the low frequency rhythm at seizure termination. Amplitudes of pHFOs were most significantly modulated by the phase of alpha-band oscillations (p<0.01). These results suggest that increased CFC between pHFO amplitude and alpha phase may constitute a marker of epileptogenic brain areas and may be relevant for understanding seizure dynamics. [Copyright &y& Elsevier]

Summary: Introduction: To identify the perceived practice among Canadian epileptologists regarding discontinuation of antiepileptic drugs (AEDs) following successful resective surgery for temporal and extratemporal surgery. Methods: We performed a survey of pediatric and adult epileptologists in Canada, using a 77-item questionnaire to explore attitudes, timing, rate of withdrawal, and factors contributing to the decision to withdraw AEDs after successful epilepsy surgery. Surveys were mailed with a postage-paid return envelope. Two subsequent surveys were mailed to non-respondents at 15 days intervals. All procedures received institutional review board approval. Results: Surveys were sent to 82 epileptologists in all the Canadian provinces. Sixty-six physicians answered the survey (80.5%), representing all epilepsy centers across Canada. The minimum seizure free period required after epilepsy surgery before withdrawing AEDs, varied substantially among responders: <6 months in 10%, 6–11 months in 21%, >1 year in 50%, >2 years in 12%, >2 years in 3% after. The most important factors influencing the decision to withdraw AEDs a negative EEG before discontinuation (71%), patients’ preferences (78%) and the presence of unilateral mesial temporal sclerosis (70%). The most important factors against reduction were the following: patients’ wishes to resume driving (67%), focal (65%) or generalized (78%) epileptiform activity on EEG after surgery, persistent isolated auras (78%), any seizures after hospital discharge (81%), and presurgical multifocal/bilateral/diffuse findings (78%). Discussion: Canadian epileptologists indicated that AED levels, EEG and MRI are typically done before discontinuing AEDs. Generally, a good candidate for stopping AEDs has focal pathology, is completely seizure free, had an anterior temporal lobe resection, complete resection of seizure focus, and has no epileptiform discharges on postoperative EEG. The data pertaining to self-reported practice styles, and actual practice may differ. [Copyright &y& Elsevier]

Although children with epilepsy exhibit numerous neurological and cognitive deficits, the mechanisms underlying these impairments remain unclear. Synchronization of oscillatory neural activity in the gamma frequency range (.30 Hz) is purported to be a mechanism mediating functional integration within neuronal networks supporting cognition, perception and action. Here, we tested the hypothesis that seizure-induced alterations in gamma synchronization are associated with functional deficits. By calculating synchrony among electrodes and performing graph theoretical analysis, we assessed functional connectivity and local network structure of the hand motor area of children with focal epilepsy from intracranial electroencephalographic recordings. A local decrease in inter-electrode phase synchrony in the gamma bands during ictal periods, relative to interictal periods, within the motor cortex was strongly associated with clinical motor weakness. Gammaband ictal desychronization was a stronger predictor of deficits than the presence of the seizure-onset zone or lesion within the motor cortex. There was a positive correlation between the magnitude of ictal desychronization and impairment of motor dexterity in the contralateral, but not ipsilateral hand. There was no association between ictal desynchronization within the hand motor area and non-motor deficits. This study uniquely demonstrates that seizure-induced disturbances in cortical functional connectivity are associated with network-specific neurological deficits. [ABSTRACT FROM AUTHOR]

Summary Purpose: High-frequency oscillations (HFOs), termed ripples at 80-200 Hz and fast ripples (FRs) at >200/250 Hz, recorded by intracranial electroencephalography (EEG), may be a valuable surrogate marker for the localization of the epileptogenic zone. We evaluated the relationship of the resection of focal brain regions containing high-rate interictal HFOs and the seizure-onset zone (SOZ) determined by visual EEG analysis with the postsurgical seizure outcome, using extraoperative intracranial EEG monitoring in pediatric patients and automated HFO detection. Methods: We retrospectively analyzed 28 pediatric epilepsy patients who underwent extraoperative intracranial video-EEG monitoring prior to focal resection. Utilizing the automated analysis, we identified interictal HFOs during 20 min of sleep EEG and determined the brain regions containing high-rate HFOs. We investigated spatial relationships between regions with high-rate HFOs and SOZs. We compared the size of these regions, the surgical resection, and the amount of the regions with high-rate HFOs/SOZs within the resection area with seizure outcome. Key Findings: Ten patients were completely seizure-free and 18 were not at 2 years after surgery. The brain regions with high-rate ripples were larger than those with high-rate FRs (p = 0.0011) with partial overlap. More complete resection of the regions with high-rate FRs significantly correlated with a better seizure outcome (p = 0.046). More complete resection of the regions with high-rate ripples tended to improve seizure outcome (p = 0.091); however, the resection of SOZ did not influence seizure outcome (p = 0.18). The size of surgical resection was not associated with seizure outcome (p = 0.22-0.39). Significance: The interictal high-rate FRs are a possible surrogate marker of the epileptogenic zone. Interictal ripples are not as specific a marker of the epileptogenic zone as interictal FRs. Resection of the brain regions with high-rate interictal FRs in addition to the SOZ may achieve a better seizure outcome. [ABSTRACT FROM AUTHOR]

We developed a technique to produce images of dynamic changes in ictal high-frequency oscillations (HFOs) >40 Hz recorded on subdural electroencephalography (EEG) that are time-locked to the ictal EEG and ictal semiology video. We applied this technique to Jacksonian seizures to demonstrate ictal HFO propagation along the homunculus in the primary sensory-motor cortex to visualize the underlying epileptic network. We analyzed intracranial ictal EEGs from two patients with intractable Jacksonian seizures who underwent epilepsy surgery. We calculated the degrees of increase in amplitude within 40-80, 80-200, and 200-300 Hz frequency bands compared to the interictal period and converted them into topographic movies projected onto the brain surface picture. We combined these data with the ictal EEGs and video of the patient demonstrating ictal semiology. The ictal HFOs began in the sensory cortex and appeared concomitantly with the sensory aura. They then propagated to the motor cortex at the same time that focal motor symptoms evolved. As the seizure progressed, the ictal HFOs spread or reverberated in the rolandic region. However, even when the seizure became secondarily generalized, the ictal HFOs were confined to the rolandic region. In both cases, there was increased amplitude of higher frequency bands during seizure initiation compared to seizure progression. This combined movie showed the ictal HFO propagation corresponding to the ictal semiology in Jacksonian seizures and revealed the epileptic network involved in seizure initiation and progression. This method may advance understanding of neural network activities relating to clinical seizure generation and propagation. [ABSTRACT FROM AUTHOR]

Abstract: We compared frequency and power of neonatal EEG delta brush rapid oscillatory activity (ROA) using multiple band frequency analysis (MBFA) in three groups; pre-term (PT, post-conceptional age 33–35.6weeks, n =5); full-term (FT, 39.4–40.6weeks, n =5) and pre-term or full-term with phenobarbital exposure (PB, n =5). Mean number of delta brushes analyzed was 29.4 (range 26–47) in PT, 20.8 (14–33) in FT and 20 (7–37) in PB. Mean frequency±standard deviation (s.d.) was 16.9±2.1Hz (range 15–20Hz) in PT, 17.3±1.9Hz (15–20Hz) in FT and 16.1±1.6Hz (14–19Hz) in PB. Mean power±s.d. was 22.9±6.2μV2 (range 16–39μV2) in PT, 11.9±4.1μV2 (7–19μV2) in FT and 17.1±6.2μV2 (9–26μV2) in PB. Power was significantly higher in PT than FT (p <0.005). Power after merging PB into respective PT (PT′, n =8) and FT (FT′, n =7) groups, remained significantly higher in PT′ (mean±s.d. 21.8±7.4μV2) than FT′ (11.4±3.6μV2) (p <0.05). We characterise ROA in delta brushes in maturing neonates using MBFA, which may provide additional information for assessing future seizure recurrence and epilepsy risk. [Copyright &y& Elsevier]

Abstract: Objective: During seizures, intracranial EEG electrodes can record ictal muscle movements. Our purpose was to differentiate the high-frequency oscillations (HFOs) of extracranial muscle contractions from those of intracranial epileptogenic discharges. Methods: Using intracranial video-EEG (IVEEG), we recorded seizures in a 17-year-old boy with left mesial–temporal lobe epilepsy. We used multiple band frequency analysis (MBFA) to differentiate extracranial HFOs of craniofacial muscle activities from intracranial HFOs recorded ictally and interictally. Results: During 11 seizures, IVEEG showed low-amplitude fast waves (∼60Hz) starting at the left mesial–temporal electrodes. Ictal facial grimacing projected low-amplitude (∼20μV) fast waves (∼160Hz) on inferior lateral–temporal electrodes. Interictal chewing projected medium-amplitude (∼100μV) fast waves (∼140Hz) correlating to mouth movements. MBFA topographic power spectrograms revealed a sustained, consistent ictal fast-frequency band from electrodes in the seizure-onset zone and randomly scattered HFOs without a specific frequency band from ictal and interictal extracranial muscle contractions. Conclusions: MBFA power spectrograms differentiated randomly scattered muscle HFOs without a specific frequency band at electrodes close to temporal muscles from ictal epileptic HFOs with a sustained, fast-frequency band in the seizure-onset zone. Significance: The pattern and distribution of frequency power spectrograms of extracranial HFOs differ from those of intracranial HFOs. [Copyright &y& Elsevier]

To study the role of magnetoencephalography (MEG) in the surgical evaluation of children with recurrent seizures after epilepsy surgery. We studied 17 children with recurrent seizures after epilepsy surgery using interictal and ictal scalp EEG, intracranial video EEG (IVEEG), MRI, and MEG. We analyzed the location and distribution of MEG spike sources (MEGSSs) and the relationship of MEGSSs to the margins of previous resections and surgical outcome. Clustered MEGSSs occurred at the margins of previous resections within two contiguous gyri in 10 patients (group A), extended spatially from a margin by ≤3 cm in three patients (group B), and were remote from a resection margin by >3 cm in six patients (group C). Two patients had concomitant group A and C clusters. Thirteen patients underwent second surgeries. IVEEG was used in four patients. Six of seven patients with group A MEGSS clusters did not require IVEEG for second surgeries. Follow-up periods ranged from 0.6 to 4.3 years (mean: 2.6 years). Eleven children, including eight who became seizure-free, achieved Engel class I or II. Our data demonstrate the utility of MEG for evaluating patients with recurrent seizures after epilepsy surgery. Specific MEGSS cluster patterns delineate epileptogenic zones. Removing cluster regions adjacent to the margins of previous resections, in addition to removing recurrent lesions, achieves favorable surgical outcome. Cluster location and extent identify which patients require IVEEG, potentially eliminating IVEEG for some. Patients with remotely located clusters require IVEEG for accurate assessment and localization of the entire epileptogenic zone. [ABSTRACT FROM AUTHOR]

Abstract: Gelastic seizures are relatively uncommon and rarely observed secondary to frontal lobe lesions. This report presents magnetoencephalography (MEG) and diffusion tensor imaging (DTI) findings in an adolescent with gelastic seizures secondary to a left anterior cingulate gyrus lesion. Ictal scalp video EEG showed bilateral frontal 4Hz theta discharges. Interictal EEG showed left fronto-temporal spikes or sharp waves. Interictal MEG showed spike sources over bilateral temporal regions. DTI and tractography delineated slightly shifted corpus callosum posterior to the lesion, unaffected uncinate and inferior longitudinal fasciculi. The patient became seizure free for 12 months after surgical excision of a pleomorphic xanthoastrocytoma in the left anterior cingulate region. In our patient, MEG and EEG did not localize the deep-seated epileptogenic zone. The combination of DTI and neurophysiologic studies, however, possibly disclosed neuronal connections within the epileptic network and indicated that epileptic discharges propagated via the uncinate fibers from the primary epileptogenic zone in the anterior cingulate region to the mesial temporal region in this case with gelastic seizures secondary to a cingulate lesion. [Copyright &y& Elsevier]

Purpose: To understand the rapid dynamic changes of ictal intracranial high-frequency oscillations (HFOs) in neocortical epilepsy. Methods: We integrated multiple band frequency analysis and brain-surface topographic maps of HFOs from ictal subdural EEG (SDEEG) recordings. We used SDEEG to record partial seizures consisting of right-arm jerks with secondary generalization in a 17-year-old right-handed girl. We selected 20-s EEG sections that included preclinical seizure recordings. We averaged the HFO power between 60 and 120 Hz for 25 selected electrodes, made topographic maps from these averaged powers, and superimposed the maps on the brain-surface image. We filmed consecutive HFO maps at a 10-ms frame rate. Results: Before clinical seizure onset, high-power HFOs emerged at the superior portion of the left precentral gyrus, then appeared in the middle of the left postcentral gyrus, and subsequently reverberated between both regions as well as the posterior portion of the left postcentral gyrus. Right-arm extension and facial grimacing started as the HFO power decreased. As generalized tonic–clonic seizures evolved, HFO power increased but remained within the central region. Conclusions: Topographic movies of intracranial HFOs on the brain surface allow visualization of the dynamic ictal changes in neocortical epilepsy. [ABSTRACT FROM AUTHOR]

Postictal generalized electroencephalographic suppression (PGES) has been associated with sudden unexpected death in epilepsy (SUDEP) in adults. Decreased heart rate variability (HRV) is one clinical marker of SUDEP in adults with epilepsy. The objective of this study was to analyze the characteristics of HRV associated with generalized convulsive seizures (GCS) ± PGES in children. Nine hundred and seventy-seven consecutive children who underwent prolonged scalp video-EEG (vEEG) and 1-lead electrocardiogram (ECG) monitoring at the Hospital for Sick Children, Toronto, Ontario, Canada were reviewed retrospectively from 2009 to 2011. Thirty-five children had GCS captured during their vEEG with or without PGES and met inclusion criteria. Children were subdivided into three age groups and compared with age-matched controls: 3–6 years; 7–12 years; and 13–18 years. Interictal HRV was measured at 5 min during N2 sleep. Preictal HRV was measured at 1 h prior to GCS onset, and postictal HRV was measured at 3 min post-GCS cessation. Low frequency (LF: ms2, 0.04–0.15 Hz) and high frequency (HF: ms2, 0.15–0.4 Hz) bands of heart rate oscillations were analyzed during the interictal and preictal periods. The root mean square of successive differences (RMSSDs) was analyzed during the following time points: interictal; preictal; and postictal. Thirty-five children had GCS: 18 children with PGES [3–6 years (n = 2); 7–12 years (n = 6); 13–18 years (n = 10)] and 17 children without PGES [3–6 years (n = 6); 7–12 years (n = 5); 13–18 years (n = 6)]. Seventeen additional age-matched controls were identified [3–6 years (n = 3); 7–12 years (n = 5); 13–18 years (n = 9)]. Seventy-four GCS were captured consisting of 36 GCS + PGES and 38 GCS − PGES. There was no difference of interictal HRV among children with GCS ± PGES and controls. The preictal LF and HF in 36 GCS + PGES were significantly higher compared with 38 GCS − PGES (p < 0.01). The postictal RMSSD in 36 GCS + PGES was significantly higher compared with 38 GCS − PGES (p < 0.01). The pre- to postictal RMSSD change was significantly lower in children with GCS + PGES than in those with GCS − PGES (p = 0.035). In summary, the preictal HRV in GCS + PGES was significantly higher than in children with GCS − PGES. The higher remaining postictal RMSSD in children with GCS + PGES is a potential indicator of autonomic dysregulation. In certain children with epilepsy, autonomic dysregulation may contribute to poor recovery from a GCS with subsequent PGES, thereby contributing to SUDEP. Heart rate variability and autonomic regulation in children with epilepsy should be further studied prospectively in order to better understand the mechanism by which PGES may lead to SUDEP. • Preictal LF and HF in GCS + PGES were significantly higher than those in GCS − PGES. • Postictal RMSSD in GCS + PGES was significantly higher than that of GCS − PGES. • Pre- to postictal RMSSD change was significantly lower in GCS + PGES than in GCS – PGES. • Patients with GCS + PGES may have potential autonomic dysregulation. • Autonomic dysregulation leading to GCS results in PGES and possible SUDEP. [ABSTRACT FROM AUTHOR]