Focal Epileptiform Discharges Research Articles

Idiopathic generalized epilepsies in the epilepsy monitoring unit: Systematic quantification of focal EEG and semiological signs

ObjectiveFocal seizure symptoms (FSS) and focal interictal epileptiform discharges (IEDs) are common in patients with idiopathic generalized epilepsies (IGEs), but dedicated studies systematically quantifying them both are lacking. We used automatic IED detection and localization algorithms and correlated these EEG findings with clinical FSS for the first time in IGE patients. Methods32 patients with IGEs undergoing long-term video EEG monitoring were systematically analyzed regarding focal vs. generalized IEDs using automatic IED detection and localization algorithms. Quantitative EEG findings were correlated with FSS. ResultsWe observed FSS in 75% of patients, without significant differences between IGE subgroups. Mostly varying/shifting lateralizations of FSS across successive recorded seizures were seen. We detected a total of 81,949 IEDs, whereof 19,513 IEDs were focal (23.8%). Focal IEDs occurred in all patients (median 13% focal IEDs per patient, range 1.1 – 51.1%). Focal IED lateralization and localization predominance had no significant effect on FSS. ConclusionsAll included patients with IGE showed focal IEDs and three-quarter had focal seizure symptoms irrespective of the specific IGE subgroup. Focal IED localization had no significant effect on lateralization and localization of FSS. SignificanceOur findings may facilitate diagnostic and treatment decisions in patients with suspected IGE and focal signs.

Focal electroclinical features in generalized tonic-clonic seizures: Decision flowchart for a diagnostic challenge.

Bilateral tonic-clonic seizures with focal semiology or focal interictal electroencephalography (EEG) can occur in both focal and generalized epilepsy types, leading to diagnostic errors and inappropriate therapy. We investigated the prevalence and prognostic values of focal features in patients with idiopathic generalized epilepsy (IGE), and we propose a decision flowchart to distinguish between focal and generalized epilepsy in patients with bilateral tonic-clonic seizures and focal EEG or semiology. We retrospectively analyzed video-EEG recordings of 101 bilateral tonic-clonic seizures from 60 patients (18 with IGE, 42 with focal epilepsy). Diagnosis and therapeutic response were extracted after ≥1-year follow-up. The decision flowchart was based on previous observations and assessed concordance between interictal and ictal EEG. Focal semiology in IGE was observed in 75% of seizures and 77.8% of patients, most often corresponding to forced head version (66.7%). In patients with multiple seizures, direction of head version was consistent across seizures. Focal interictal epileptiform discharges (IEDs) were observed in 61.1% of patients with IGE, whereas focal ictal EEG onset only occurred in 13% of seizures and 16.7% of patients. However, later during the seizures, a reproducible pattern of 7-Hz lateralized ictal rhythm was observed in 56% of seizures, associated with contralateral head version. We did not find correlation between presence of focal features and therapeutic response in IGE patients. Our decision flowchart distinguished between focal and generalized epilepsy in patients with bilateral tonic-clonic seizures and focal features with an accuracy of 96.6%. Focal semiology associated with bilateral tonic-clonic seizures and focal IEDs are common features in patients with IGE, but focal ictal EEG onset is rare. None of these focal findings appears to influence therapeutic response. By assessing the concordance between interictal and ictal EEG findings, one can accurately distinguish between focal and generalized epilepsies.

Association of Epileptiform Discharge and Autism Spectrum Disorder Severity in Children Attending the Outpatient Clinics, Child Welfare Teaching Hospital, Baghdad

Background: Subjects with Autism Spectrum Disorder (ASD) have a higher prevalence of seizures than the general population, according to a significant body of research. Also, seizure-free patients with ASD have been found to have a higher prevalence of epileptiform discharge abnormalities compared to healthy controls across investigations. Changes in the electroencephalogram (EEG) can manifest as sharp waves or spikes, sharp and slow waves, generally distributed or general area, or focused, and can manifest in various brain regions. There is a necessity to search for a distinctive EEG characteristic in ASD patients. Objectives: This study used electroencephalography to investigate the relationship between interictal epileptiform discharges and the severity of ASD in children. Patient and methods: The study involved a total of 65 children. The first group consisted of 30 children (seven females and 23 males, 2-12 years of age) recruited from the autism center and the pediatric neurology consultancy clinic in the Child Welfare Teaching Hospital / Medical City. The second group consisted of 35 age- and gender-matched normally-developed children (10 females 25 males, 2-12 years of age) recruited from the Pediatrics Consultation Clinics in the Child Welfare Teaching Hospital. The ASD children met the DSM-5 criteria for autism and the Childhood Autism Rating Scale was utilized to determine the severity of autism. The electroencephalography signals were recorded to detect epileptiform discharge. The data was collected during the period from 5th October 2022 to 1st April 2023. Result: A statistically significant association was found between the epileptiform discharges and the study group (ASD Vs normally developed children). The EEG records were normal in 20 (66.7%), abnormal in the form of focal epileptiform discharge in 5 (16.7%), and in the form of generalized epileptiform discharge in 5 (16.7%) of ASD children. The EEG findings and the CARS-measured autism severity showed a statistically significant association (P=0.05), as the EEG abnormalities increased with the severity of autism. Conclusion: The degree of autism was found to be associated with the abnormalities of the electroencephalogram and the degree of autism. Received: May,, 2023 Accepted: Sept, 2023 Published: Jan. 2024

Index of benign focal epileptiform discharges of childhood and specificity of cognitive functions development in children: А retrospective study

Index of benign focal epileptiform discharges of childhood and specificity of cognitive functions development in children: А retrospective study

Enhanced sensitivity of electrocorticography during awake craniotomy using a novel circular grid electrode.

Awake craniotomy with intraoperative functional brain mapping (FBM) bedside neurological testing is an important technique used to optimize resective brain surgeries near eloquent cortex. Awake craniotomy performed with electrocorticography (ECoG) and direct electrical stimulation (DES) for FBM can delineate eloquent cortex from lesions and epileptogenic regions. However, current electrode technology demonstrates spatial limitations. Our group has developed a novel circular grid with the goal of improving spatial recording of ECoG to enhance detection of ictal and interictal activity. This retrospective study was approved by the institutional review board at Mayo Clinic Florida. We analyzed patients undergoing awake craniotomy with ECoG and DES and compared ECoG data obtained using the 22 contact circular grid to standard 6 contact strip electrode. We included 144 cases of awake craniotomy with ECoG, 73 using circular grid and 71 with strip electrode. No significant differences were seen regarding preoperative clinical and demographic data, duration of ECoG recording (p = 0.676) and use of DES (p = 0.926). Circular grid was more sensitive in detecting periodic focal epileptiform discharges (PFEDs) (p = 0.004), PFEDs plus (p = 0.032), afterdischarges (ADs) per case (p = 0.022) at lower minimum (p = 0.012) and maximum (p < 0.0012) intensity stimulation, and seizures (p = 0.048). PFEDs (p < 0.001), PFEDs plus (p < 0.001), and HFOs (p < 0.001) but not ADs (p = 0.255) predicted electrographic seizures. We demonstrate higher sensitivity in detecting ictal and interictal activity on ECoG during awake craniotomy with a novel circular grid compared to strip electrode, likely due to better spatial sampling during ECoG. We also found association between PFEDs and intraoperative seizures.

Tuberozinės sklerozės kompleksas ir epilepsija. Literatūros apžvalga

Tuberous sclerosis complex (TSC) is a rare genetic disorder characterized by the presence of benign tumors in many organs. The pathogenic mutation is found in either the TSC1 or TSC2 tumor suppressor genes. The presence of cortical or subcortical tubers is associated with focal epileptiform discharges on the electroencephalogram and subclinical seizures prior to the onset of clinical seizures. It is known that epileptic seizures in tuberous sclerosis are very resistant to the treatment, therefore, developmental delay usually occurs. In the last decade, more attention has been paid to early recognition and control of seizures (with vigabatrin or everolimus) in tuberous sclerosis complex, as this is highly correlated with improved developmental and neurological outcomes.The article reviews epilepsy and preventive antiepileptic treatment for tuberous sclerosis complex.

The differing effects of sleep on ictal and interictal network dynamics in drug-resistant epilepsy.

Sleep has important influences on focal interictal epileptiform discharges (IEDs), and the rates and spatial extent of IEDs are increased in non-rapid eye movement (NREM) sleep. In contrast, the influence of sleep on seizures is less clear and its effects on seizure topography are poorly documented. We evaluated the influences of NREM sleep on ictal spatiotemporal dynamics and contrasted these with interictal network dynamics. We included patients with drug-resistant focal epilepsy who underwent continuous intracranial EEG with depth electrodes. Patients were selected if they had 1-3 seizures from each vigilance state, wakefulness and NREM sleep, within a 48-hour window and under the same anti-seizure medication. A 10-min epoch of the interictal iEEG was selected per state, and IEDs were detected automatically. Twenty-five patients (13 females; 32.5±7.1 years) were included. The seizure onset pattern, duration, spatiotemporal propagation and latency of ictal high-frequency activity did not differ significantly between wakefulness and NREM sleep (all p>0.05). In contrast, IED rates and spatial distribution were increased in NREM compared to wakefulness (p<0.001, Cliff's d=0.48 and 0.49). The spatial overlap between vigilance states was higher for seizures (57.1±40.1%) than IEDs (41.7±46.2%) (p=0.001, Cliff's d=0.51). In contrast to its effects on IEDs, NREM sleep does not affect ictal spatiotemporal dynamics. This suggests that once the brain surpasses the seizure threshold, it will follow the underlying epileptic network irrespective of the vigilance state. These findings offer valuable insights into neural network dynamics in epilepsy and have important clinical implications for localizing seizure foci. This article is protected by copyright. All rights reserved.

Heterogeneity of clinical features, EEG and brain imaging findings in anti-leucine-rich glioma-inactivated protein 1 autoimmune encephalitis: a retrospective case series study and review of the literature

BackgroundAnti-leucine-rich glioma-inactivated 1 (LGI-1) autoimmune encephalitis (AE), characterized by rapid decline of memory, seizures, and neuropsychiatric abnormalities, is a rare but devastating disorder. Early diagnosis and treatment are essential to prevent long-term sequelae. In this report, we provide a detailed description of clinical characteristics, laboratory test results, imaging, and electroencephalography (EEG) findings, as well as treatment responses of eight patients with anti-LGI-1 AE treated at our center.Case presentationAt the onset, all eight patients presented with confusion/memory deterioration, seizures (including faciobrachial dystonic seizures or other types of seizure), and behavioral changes such as hallucination, paranoia, and anxiety. Four patients were found with severe hyponatremia. Anti-LGI1 antibodies were detected in the cerebrospinal fluid and/or serum of all patients. For patients with faciobrachial dystonic seizures, no discernible scalp EEG change was detected, while EEG recording of patients experiencing other types of seizure showed focal slowing, focal epileptiform discharges, and focal onset seizures. All patients showed abnormal brain magnetic resonance imaging signals, mainly involving the mesial temporal lobe and the hippocampus. In addition, one patient also experienced fulminant cerebral edema during the acute phase of the illness. All patients received immunotherapy and anti-seizure medications and achieved good seizure control. Nevertheless, these patients continued to experience cognitive impairment during their long-term follow-ups.ConclusionsThe care of anti-LGI1 AE patients requires rapid evaluation, prompt initiation of immunotherapy, and long-term follow-up. The long-term presence of neurocognitive complications observed in these patients underline the importance of developing reliable biomarkers that can distinguish between different subtypes of this disease with heterogeneous clinico-electrographico-radiological features. Further research is needed to understand the molecular mechanisms underlying the heterogeneity, in order to facilitate development of more effective treatments for anti-LGI1 AE.

Peri-ictal EEG in infants with PRRT2-related self-limited infantile epilepsy.

Pathogenic PRRT2 variants cause self-limited (familial) infantile epilepsy (SeLIE), which is responsive to sodium channel blocking antiseizure medications. The interictal EEG is typically normal. We describe a cohort of infants with PRRT2-related SeLIE with striking peri-ictal EEG abnormalities. We included all infants diagnosed with PRRT2-related SeLIE during July 2020 to November 2021 at the Royal Children's Hospital, Melbourne. Clinical features and results of aetiologic investigations were collected from electronic medical records. All EEGs were reviewed independently by two epileptologists. Ten infants presented with focal seizures at a median age of 5 months (range: 3-6 months). Eight had a family history of epilepsy, paroxysmal kinesigenic dyskinesia (PKD) or hemiplegic migraine. Seven of the eight infants with an EEG performed within 24 h of the most recent seizure had epileptiform discharges. Their EEGs showed focal sharp waves, spikes, polyspikes or fast activity independently over the left and right temporo-occipital regions. Conversely, the two infants with last known seizure greater than 24 h prior to their EEG had no epileptiform discharges. Oxcarbazepine was commenced in two infants and was effective. Eight infants were initially treated with levetiracetam, and all were subsequently switched to oxcarbazepine due to ongoing seizures or side effects. Posterior polymorphic focal epileptiform discharges on a peri-ictal EEG recording are a feature of PRRT2-related SeLIE. This finding, particularly in the presence of a family history of infantile epilepsy, PKD or hemiplegic migraine, suggests a diagnosis of PRRT2-related SeLIE and has important treatment implications.

Recognition and epileptology of protracted CLN3 disease.

This study was undertaken to analyze phenotypic features of a cohort of patients with protracted CLN3 disease to improve recognition of the disorder. We analyzed phenotypic data of 10 patients from six families with protracted CLN3 disease. Haplotype analysis was performed in three reportedly unrelated families. Visual impairment was the initial symptom, with onset at 5-9 years, similar to classic CLN3 disease. Mean time from onset of visual impairment to seizures was 12 years (range = 6-41 years). Various seizure types were reported, most commonly generalized tonic-clonic seizures; focal seizures were present in four patients. Progressive myoclonus epilepsy was not seen. Interictal electroencephalogram revealed mild background slowing and 2.5-3.5-Hz spontaneous generalized spike-wave discharges. Additional interictal focal epileptiform discharges were noted in some patients. Age at death for the three deceased patients was 31, 31, and 52 years. Molecular testing revealed five individuals were homozygous for c.461-280_677 + 382del966, the "common 1-kb" CLN3 deletion. The remaining individuals were compound heterozygous for various combinations of recurrent pathogenic CLN3 variants. Haplotype analysis demonstrated evidence of a common founder for the common 1-kb deletion. Dating analysis suggested the deletion arose approximately 1500 years ago and thus did not represent cryptic familial relationship in this Australian cohort. We highlight the protracted phenotype of a disease generally associated with death in adolescence, which is a combined focal and generalized epilepsy syndrome with progressive neurological deterioration. The disorder should be suspected in an adolescent or adult patient presenting with generalized or focal seizures preceded by progressive visual loss. The common 1-kb deletion has been typically associated with classic CLN3 disease, and the protracted phenotype has not previously been reported with this genotype. This suggests that modifying genetic factors may be important in determining this somewhat milder phenotype and identification of these factors should be the subject of future research.

Seizures in Neurosarcoidosis (P9-5.011)

<h3>Objective:</h3> To determine how seizures impact the management of neurosarcoidosis and affect long-term outcomes. <h3>Background:</h3> Though neurosarcoidosis can injure the cerebral cortex via several mechanisms, seizures are uncommonly reported as a clinical manifestation of the disease (4–15%) and have been previously associated with a more severe course. <h3>Design/Methods:</h3> Patients with a diagnosis of neurosarcoidosis were included in this retrospective cohort analysis if seizures were a clinical manifestation of their disease. <h3>Results:</h3> Seizures were present in 26/216 (12.0%) patients and were an initial manifestation of neurosarcoidosis in 11/26 (42.3%). None had a pre-existing seizure disorder. Semiologies were reported in 23: generalized in 12/23 (52.2%), focal in 9/23 (39.1%), and both in 2/23 (8.7%). Status epilepticus occurred in 6/26 (23.1%); 2 (7.7%) were intubated. MRIs were obtained in 25 with cerebral parenchymal lesions (18/25, 72.0%) being the most common radiographic accompaniment, followed by leptomeningitis (13/25, 52.0%) and pachymeningitis (10/25, 40.0%). EEGs showed focal slowing in 12/19 (63.1%), focal epileptiform discharges in 5/19 (26.3%), no abnormalities in 4/19 (21.1%), generalized slowing in 2/19 (10.5%), and epileptiform discharges of unclear distribution in 1/19 (5.3%). No patients had generalized epileptiform discharges. Seizures were controlled in 22/26 (84.6%) compliant with antiseizure medicines (ASMs). Most (18/26, 69.2%) required only 1 medicine for control with levetiracetam being beneficial in 22/22 (100%) trialed. 17/25 (68.0%) had 6 or fewer lifetime seizures. 2/26 (7.7%) were ultimately weaned off ASMs. 13/26 (50.0%) required two or more lines of immunosuppression, all of whom received biologic treatments. The average last mRS was 2.0. No patients died as a result of seizures. Median follow-up of 68.4 months. <h3>Conclusions:</h3> Seizures in neurosarcoidosis occur most commonly with cerebral parenchymal lesions and are relatively easy to control with ASMs, but the accompanying neuroinflammation is often challenging to treat with a high reliance on biologic therapies for management. <b>Disclosure:</b> Dr. Ngo has nothing to disclose. Dr. Hutto has nothing to disclose.

EEG Findings in a Pediatric Patient with 3q29 Microdeletion Syndrome (P13-1.005)

<h3>Objective:</h3> 3q29 microdeletion syndrome is a rare genetic disorder which results from interstitial microdeletion of a segment on the long arm of chromosome 3. The syndrome is characterized by neurodevelopmental and psychiatric manifestations including intellectual disability, autism spectrum disorder, anxiety, executive function deficits, and psychosis/schizophrenia. Systemic manifestations include ocular issues, gastrointestinal disorders, dental anomalies, and congenital heart defects. <h3>Background:</h3> We present a 7-year-old boy with a history of intellectual disability including delayed speech and fine motor abilities, and autism spectrum disorder, who presented with frequent and new onset of complete behavioral arrest, staring, grunting and pulling movements lasting several minutes that were described by his teachers. Spells did not progress to tonic-clonic activity and were not associated with urine loss. His physical examination revealed down slanted eyes, epicanthal folds, wide mouth, long and thin philtrum, thin upper lip and axial and appendulicar tone were decreased. EEG while off ASM revealed excessive beta activity of the background, frontally dominant generalized spike/polyspike and wave discharges, and focal spike/polyspike and wave activity seen independently over the left and right frontocentral regions. MRI showed reduced cerebral white matter hemispheric volume involving the frontoparietal lobes with no obvious seizure focus. He was subsequently started on levetiracetam, which resulted in a cessation of staring spells. <h3>Design/Methods:</h3> NA <h3>Results:</h3> NA <h3>Conclusions:</h3> Seizures have been reported in 13% of patients with 3q29 microdeletion syndrome and are generally mild and responsive to ASM. Previously reported EEG abnormalities in patients with 3q29 microdeletion syndrome include focal epileptiform discharges in the left occipital region and slow waves in the frontotemporal regions. To our knowledge, generalized spike/polyspike wave activity has not previously been reported in this syndrome. Whether the independent focal frontocentral epileptiform discharges represent a forme fruste of the generalized discharges, or the latter represent a rapid secondary bisynchrony phenomenon, remains to be determined. <b>Disclosure:</b> Dr. Sheikh has nothing to disclose. Dr. Nascimento has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Zogenix. The institution of Dr. Nascimento has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biocodex. Dr. Nascimento has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for AAN. The institution of Dr. Nascimento has received research support from Zogenix. The institution of Dr. Nascimento has received research support from Biocodex. The institution of Dr. Nascimento has received research support from Greenwich. Dr. Nascimento has received publishing royalties from a publication relating to health care. Dr. Nascimento has a non-compensated relationship as a Editorial Team Member with Neurology RFS that is relevant to AAN interests or activities. Dr. Nascimento has a non-compensated relationship as a Production Team with Neurology Podcast that is relevant to AAN interests or activities. Dr. Waite has nothing to disclose. Dr. Lam has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sage Therapeutics. Dr. Lam has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Neurona Therapeutics. Dr. Lam has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Cognito Therapeutics. The institution of Dr. Lam has received research support from Sage Therapeutics.

Deep learning-based automated detection and multiclass classification of focal interictal epileptiform discharges in scalp electroencephalograms

Detection and spatial distribution analyses of interictal epileptiform discharges (IEDs) are important for diagnosing, classifying, and treating focal epilepsy. This study proposes deep learning-based models to detect focal IEDs in electroencephalography (EEG) recordings of the frontal, temporal, and occipital scalp regions. This study included 38 patients with frontal (n = 15), temporal (n = 13), and occipital (n = 10) IEDs and 232 controls without IEDs from a single tertiary center. All the EEG recordings were segmented into 1.5-s epochs and fed into 1- or 2-dimensional convolutional neural networks to construct binary classification models to detect IEDs in each focal region and multiclass classification models to categorize IEDs into frontal, temporal, and occipital regions. The binary classification models exhibited accuracies of 79.3–86.4%, 93.3–94.2%, and 95.5–97.2% for frontal, temporal, and occipital IEDs, respectively. The three- and four-class models exhibited accuracies of 87.0–88.7% and 74.6–74.9%, respectively, with temporal, occipital, and non-IEDs F1-scores of 89.9–92.3%, 84.9–90.6%, and 84.3–86.0%; and 86.6–86.7%, 86.8–87.2%, and 67.8–69.2% for the three- and four-class (frontal, 50.3–58.2%) models, respectively. The deep learning-based models could help enhance EEG interpretation. Although they performed well, the resolution of region-specific focal IED misinterpretations and further model improvement are needed.

The diagnostic value of electroencephalography in pediatric patients presenting with syncope Running title: The yield of electroencephalography in pediatric syncope

Aim: In the investigation of the diagnosis of pediatric syncope, it was aimed to evaluate the rate of abnormal EEG findings and the diagnostic yield of the EEG in the electroencephalography (EEG) taken following their neurological examination. Materials and Methods: EEG records of 332 patients younger than 18 years of age who presented to the pediatric neurology outpatient clinic with syncope were retrospectively analyzed. The EEG results were classified as normal and abnormal. Based on the abnormal EEG results, four subgroups were formed as focal epileptiform discharge, generalized epileptiform discharge, focal slowing and generalized slowing. Abnormal EEG results were categorized according to age and gender. Results: Of the cases included in the study, 195 (58.7%) were female and 137 (41.3%) were male. The mean age of the patients was calculated as 12.67±3.21 years. Analysis of the EEG results revealed that 92.5% were normal and 7.53% were abnormal. The most common abnormal EEG finding was focal slowing, which was detected in 12 (3.6%) patients, followed by focal epileptiform discharge which was detected in eight (2.4%) and generalized epileptiform discharge which was detected in five (1.5%) patients. Conclusion: EEG should not be routinely performed to evaluate the diagnosis of pediatric syncope. Therefore, EEG should be performed only on patients to be selected based on their medical history and the results of their neurological examination. In this way, it will be possible to derive more benefits out of EEG and to reduce the associated medical costs.

Electrical Status Epilepticus during Sleep in a Male Filipino with Rare Nonsense Mutation Variant of Sotos Syndrome on Carbamazepine Monotherapy

Electrical status epilepticus during sleep (ESES) is an electrographic pattern associated with specific genetic disorders, brain malformations, and use of some antiseizure medications. This case report aims to present the management of ESES in Sotos syndrome (SoS) on carbamazepine.A nine-year-old Filipino male with clinical features suggestive of overgrowth syndrome presented with febrile seizure at one year old. Cranial imaging showed cavum septum pellucidum, corpus callosal dysgenesis, and ventriculomegaly. He was on carbamazepine monotherapy starting at three years old. A near continuous diffuse spike–wave discharges in slow wave sleep was recorded at nine years old hence shifted to valproic acid. Follow-up study showed focal epileptiform discharges during sleep with disappearance of ESES. Next generation sequencing tested positive for rare nonsense mutation of nuclear receptor binding set-domain protein 1 confirming the diagnosis of SoS.Advanced molecular genetics contributed to determination of ESES etiologies. To date, this is the first documented case of SoS developing ESES. Whether an inherent genetic predisposition or drug-induced, we recommend the avoidance of carbamazepine and use of valproic acid as first-line therapy. &nbsp; &nbsp

Risk of Developing Seizures in Children With Abnormal EEG Findings During Polysomnography

BackgroundPolysomnography (PSG) utilizes abbreviated electroencephalogram (EEG) to stage sleep. The aim of this study was to determine whether epileptiform abnormalities on this limited EEG coverage correlated with abnormalities on routine EEG (rEEG) and an increased risk for seizures in children without a prior diagnosis of epilepsy. MethodsA six-year retrospective chart review was performed assessing children with abnormalities on EEG during PSG. Children who underwent subsequent rEEG were included; children with a prior diagnosis of seizures were excluded. The main outcome measures were rEEG results and subsequent diagnosis of epilepsy. ResultsA total of 67 children met inclusion criteria. Average age was six years, and 43 (64%) were male. rEEG was normal in 16 (24%). Epileptiform abnormalities were focal in 36 (54%), generalized in eight (12%), and mixed in five (8%). An additional two (3%) had slow background rhythm without epileptiform discharges. Thirty-one patients had neurology clinic follow-up with an average duration of 31 months (range 4 to 65 months). Of these, nine (29%) developed seizures, including all three with generalized epileptiform discharges, four of 19 (21%) with focal epileptiform discharges, and two of five (40%) with mixed epileptiform discharges or background slowing. None of the four patients with a normal rEEG had seizures. Eight of the nine patients with seizures were treated with antiepileptic drugs. ConclusionsChildren with no history of seizures found to have abnormal EEG during PSG are likely to have an abnormal rEEG. Additionally, they have an increased risk for developing seizures.

Epileptiform abnormalities in the disconnected hemisphere are common in seizure-free patients after hemispherectomy

The spectrum of EEG abnormalities in the disconnected hemisphere in seizure-free patients after hemispherectomy has not been well characterized. Fifty consecutive patients who were seizure-free following hemispheric disconnection were identified. Data on preoperative clinical, EEG and neuroimaging findings and postoperative EEG findings and antiseizure medication status were collected. Forty-seven patients (94%) had functional hemispherectomy, and three (6%) had more extensive tissue resection of the posterior quadrant or frontal region along with hemispheric disconnection. Etiologies included: residual effects from vascular lesions including perinatal stroke in 35 patients, Rasmussen encephalitis in six, malformation of cortical development in seven, and Sturge-Weber syndrome in two. Pre-operative EEG showed focal epileptiform discharges in the affected hemisphere in 26 patients and in both hemispheres in 19. Eleven patients had diffuse bisynchronous epileptiform discharges. Postoperative EEGs at six to 12 months after surgery showed slowing and attenuation of physiological rhythms on the operated side in all patients. Thirty-four patients (68%) had epileptiform discharges exclusively from the operated hemisphere, six (12%) had bilateral independent epileptiform discharges, nine (18%) had no epileptiform discharges on either side, and one (2%) had epileptiform discharges from the contralateral hemisphere only. Lateralized periodic discharges from the operated hemisphere were noted in three patients (6%). EEG seizures from the operated hemisphere without clinical signs were noted in four patients (8%). After a median follow-up of three years, 30 patients (60%) were off all antiseizure medications, including 8/9 (89%) patients with no epileptiform discharges, 20/34 (59%) patients with postoperative epileptiform discharges from the operated hemisphere, and 2/7 (28%) patients with contralateral discharges. The majority of patients who are seizure-free after disconnective hemispherectomy will continue to show epileptiform discharges in the operated hemisphere. The presence of such discharges should not preclude tapering, nor prompt restarting of antiseizure medication in seizure-free patients.

Involvement of the Thalamus, Hippocampus, and Brainstem in Hypsarrhythmia of West Syndrome: Simultaneous Recordings of Electroencephalography and fMRI Study.

West syndrome is a developmental and epileptic encephalopathy characterized by epileptic spasms, neurodevelopmental regression, and a specific EEG pattern called hypsarrhythmia. Our aim was to investigate the brain activities related to hypsarrhythmia at onset and focal epileptiform discharges in the remote period in children with West syndrome using simultaneous electroencephalography and fMRI recordings. Fourteen children with West syndrome underwent simultaneous electroencephalography and fMRI at the onset of West syndrome. Statistically significant blood oxygen level-dependent responses related to hypsarrhythmia were analyzed using an event-related design of 4 hemodynamic response functions with peaks at 3, 5, 7, and 9 seconds after the onset of each event. Six of 14 children had focal epileptiform discharges after treatment and underwent simultaneous electroencephalography and fMRI from 12 to 25 months of age. At onset, positive blood oxygen level-dependent responses were seen in the brainstem (14/14 patients), thalami (13/14), basal ganglia (13/14), and hippocampi (13/14), in addition to multiple cerebral cortices. Group analysis using hemodynamic response functions with peaks at 3, 5, and 7 seconds showed positive blood oxygen level-dependent responses in the brainstem, thalamus, and hippocampus, while positive blood oxygen level-dependent responses in multiple cerebral cortices were seen using hemodynamic response functions with peaks at 5 and 7 seconds. In the remote period, 3 of 6 children had focal epileptiform discharge-related positive blood oxygen level-dependent responses in the thalamus, hippocampus, and brainstem. Positive blood oxygen level-dependent responses with hypsarrhythmia appeared in the brainstem, thalamus, and hippocampus on earlier hemodynamic response functions than the cerebral cortices, suggesting the propagation of epileptogenic activities from the deep brain structures to the neocortices. Activation of the hippocampus, thalamus, and brainstem was still seen in half of the patients with focal epileptiform discharges after adrenocorticotropic hormone therapy.

Clinical phenotype and genetic features of 16p11.2 microdeletion-related epilepsy in children

To study the clinical phenotype and genetic features of 16p11.2 microdeletion-related epilepsy in children. The medical data of 200 children with epilepsy who underwent a genetic analysis of epilepsy by the whole exon sequencing technology were collected retrospectively, of whom 9 children with epilepsy had 16p11.2 microdeletion. The clinical phenotype and genetic features of the 9 children with 16p11.2 microdeletion were analyzed. The detection rate of 16p11.2 microdeletion was 4.5% (9/200). The 9 children with 16p11.2 microdeletion were 3-10 months old. They experienced focal motor seizures with consciousness disturbance, and some of the seizures developed into generalized tonic-clonic seizures. The interictal electroencephalogram showed focal or multifocal epileptiform discharge, and all 9 children responded well to antiepileptic drugs. The 9 children had a 16p11.2 deletion fragment size of 398-906 kb, and the number of deleted genes was 23-33 which were all pathogenic mutations. The mutation was of maternal origin in 2 children, of paternal origin in 1 child, and de novo in the other children. 16p11.2 microdeletion can be detected in some children with epilepsy. Most of the 16p11.2 microdeletion is de novo mutation and large gene fragment deletion. The onset of 16p11.2 microdeletion-related epilepsy in children is mostly within 1 year of life, and the epilepsy is drug-responsive.

On-Scalp Optically Pumped Magnetometers versus Cryogenic Magnetoencephalography for Diagnostic Evaluation of Epilepsy in School-aged Children.

Background Magnetoencephalography (MEG) is an established method used to detect and localize focal interictal epileptiform discharges (IEDs). Current MEG systems house hundreds of cryogenic sensors in a rigid, one-size-fits-all helmet, which results in several limitations, particularly in children. Purpose To determine if on-scalp MEG based on optically pumped magnetometers (OPMs) alleviates the main limitations of cryogenic MEG. Materials and Methods In this prospective single-center study conducted in a tertiary university teaching hospital, participants underwent cryogenic (102 magnetometers, 204 planar gradiometers) and on-scalp (32 OPMs) MEG. The two modalities for the detection and localization of IEDs were compared. The t test was used to compare IED amplitude and signal-to-noise ratio (SNR). Distributed source modeling was performed on OPM-based and cryogenic MEG data. Results Five children (median age, 9.4 years [range, 5-11 years]; four girls) with self-limited idiopathic (n = 3) or refractory (n = 2) focal epilepsy were included. IEDs were identified in all five children with comparable sensor topographies for both MEG devices. IED amplitudes were 2.3 (7.2 of 3.1) to 4.6 (3.2 of 0.7) times higher (P < .001) with on-scalp MEG, and the SNR was 27% (16.7 of 13.2) to 60% (12.8 of 8.0) higher (P value range: .001-.009) with on-scalp MEG in all but one participant (P = .93), whose head movements created pronounced motion artifacts. The neural source of averaged IEDs was located at approximately 5 mm (n = 3) or higher (8.3 mm, n = 1; 15.6 mm, n = 1) between on-scalp and cryogenic MEG. Conclusion Despite the limited number of sensors and scalp coverage, on-scalp magnetoencephalography (MEG) based on optically pumped magnetometers helped detect interictal epileptiform discharges in school-aged children with epilepsy with a higher amplitude, higher signal-to-noise ratio, and similar localization value compared with conventional cryogenic MEG. Online supplemental material is available for this article. © RSNA, 2022 See also the editorial by Widjaja in this issue.