Bilateral Spikes Research Articles

An attention-based deep learning method for the detection of electrical status epilepticus during sleep from electroencephalogram waveform analysis in children

Electrical status epilepticus during sleep (ESES) is a special interictal electroencephalographic phenomenon observed in children with epilepsy. ESES refers to continuous or nearly continuous epileptiform discharges of bilateral (or unilateral) spikes and waves induced during non-rapid eye movement (NREM) sleep. It mainly manifests in a series of childhood epileptic syndromes characterized by seizures, ESES, and cognitive impairment, which seriously affect the health of children. Typically, the spike-wave index (SWI), which is the percentage of spikes and waves duration in the total NREM time, is an important criterion for diagnosing ESES. The SWI measures the proportion of the total duration of spikes and waves to the NREM sleep time within several hours. Currently, SWI is obtained primarily by manual measurement and calculation, which has a certain subjective bias, low accuracy, time and labor consumption, and is a waste of medical resources. Therefore, we designed a novel data segmentation model based on a multiresolution convolutional neural network and a self-attention mechanism to calculate the SWI quickly and accurately. This can assist clinicians in making more accurate judgments and providing a better guide for the treatment of children with epilepsy. A large amount of clinical patient data was used to test the proposed model. The results confirmed that this model has an acceptable generalization ability for data from different patients and the same patient at different times. Each performance index of the model was superior to that of current common models, thus fulfilling the requirements for clinical testing.

Bilateral and synchronous “dents de scie” spikes: A highly specific EEG pattern of young adult Dravet syndrome

BackgroundIn Dravet syndrome (DS), EEGs evolve over time. ObjectiveTo describe a peculiar EEG pattern in two adults with a de novo SCN1A gene mutation, in exon 5 (case 1) and 9 (case 2). MethodsTwo female patients underwent a prolonged video EEG (24 h) as part of their epilepsy assessment. ResultsIn both cases, the EEG showed a very peculiar and stereotypical pattern of bilateral synchronous spikes at about 5–6 Hz. This activity was present during wakefulness and highly activated at sleep onset and in NREM sleep, which could show nearly continuous spike activity. This activity dramatically decreased in REM sleep and after awakening. This pattern of “dents de scie” (sawtooth) spikes maintained the same morphology throughout the entire EEG recording. In both patients, the spikes were favored by passive eye closure. During wakefulness, the spikes could evolve into atypical absences while keeping the same “dents de scie” pattern. Neither patient had tonic or myoclonic seizures at the time of the EEG assessment. Both were moderately retarded, and neither one had a typical DS gait disorder. Previous EEG recordings of case 1 performed at 9.5 and 18.5 years showed spike-waves, but the morphology did not correspond to the EEG recording observed at 22 years. ConclusionsBoth patients have a similar electro-clinical phenotype. This “dents de scie” pattern appears to be very specific and could be pathognomonic in a subgroup of young adults with DS. Results of sleep EEG recording could be added to the diagnostic criteria for this syndrome.

CLINICAL FEATURES, ELECTROENCEPHALOGRAM FINDINGS AND TREATMENT OF SELF-LIMITED FOCAL EPILEPSIES OF CHILDHOOD

Objectives: The objective is to study the clinical features of self-limited focal epilepsies of childhood and to describe their electroencephalogram (EEG) findings and treatment. Methods: Twenty cases of self-limited focal epilepsies of childhood attending the Department of Neurology Government Medical College, Kozhikode, between August 2019 and July 2020 were included in the study. Details of history, examination, EEG, and treatment were collected. Results: The age at first seizure was 1.5–12 years. Most children were diagnosed with self-limited focal epilepsy of childhood with centrotemporal spikes. One child had Panayiotopoulos syndrome. Most of the seizures occurred during sleep. The majority were generalized tonic–clonic seizures. The majority had bilateral centrotemporal spikes in EEG. The child with Panayiotopoulos had bilateral spikes from the posterior head region. All were treated with antiepileptics. Conclusion: Self-limited focal epilepsy of childhood with centrotemporal spikes was the most common self-limited focal epilepsy of childhood. They had typical centrotemporal epileptiform discharges, seen bilaterally in most. The most commonly used drug was valproate. None had any major adverse effects on therapy.

Role of EEG as a monitoring tool in patients with glucose transporter type I deficiency syndrome (GLUT1-DS) on ketogenic diet.

Glucose transporter type I deficiency syndrome (GLUT1-DS) is the fourth most frequent single-gene epilepsy refractory to standard antiepileptic drugs. Multiple seizure types and variable electrographic findings are reported. Ketogenic diet is expected to result in the complete resolution of the epileptiform activity. A retrospective chart review of patients with GLUT1-DS on ketogenic diet between December 2012 and February 2022 was done. Analysis of the EEGs prior to and during the ketogenic diet was done. 34 patients on ketogenic diet were reviewed. Ten had clinical diagnosis of GLUT1-DS, and seven of them had genetic confirmation. 71% were female. The average age at seizure onset was 13.85 m.o. (range: 3-60, SD ±20.52), at diagnosis was 44.57 m.o (range: 19-79), and at the onset of ketogenic diet was 46.43 m.o. (range: 20-83). 29 months (range: 13-38) delay between symptoms onset until diagnosis was noticed. At the diagnosis 100% reported seizures: 71% myoclonic, 57% generalized motor, 57% absence, 28% atonic, and 14% focal motor. Also, 71% abnormal eye movements, 57% ataxia, and 28% intolerance to fasting. 86% had normal brain MRI. 71% had abnormal EEG. All were on ketogenic diet, and four on classical (1.75:1-2.25:1 ratio). Six were clinically seizure-free after the ketogenic diet. EEG features included notch delta, focal spike and wave, and generalized spike/polyspike and wave. One patient had bilateral independent centrotemporal spikes. Spikes showed high and very high amplitude in all of them (>200 μV). The variation of the spike index decreased in three patients but increased in two. Ketogenic diet is the choice treatment for patients with GLUT1-DS. Electrographic features could show worsening after initiation of the ketogenic diet even with seizure control. EEG did not prove to be a reliable tool for adjusting KD in our cohort. Centrotemporal spikes have not been reported in patients with GLUT-1 DS.

CDKL5 Deficiency Disorder Without Epilepsy

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) has epilepsy as a cardinal feature. Here we report two new female patients and review six previously published patients, one male and five females, with features of CDD but who never developed epilepsy. In contrast with the classical and severe CDD phenotype, they presented with milder gross motor delays, autism spectrum disorder, and no visual cortical impairment. Prolonged video electroencephalography was normal in adult cases but showed interictal frontal-temporal bilateral spikes and sharp waves in sleep in the three-year-old girl. Causative CDKL5 variants included two likely gene damaging (nonsense and frameshift) and six missense variants, being de novo or maternally inherited from asymptomatic females with skewed X-chromosome inactivation (two missense variants). Our data indicate that a milder form of CDD without epilepsy can occur in some cases without clear correlation with specific variants in the CDKL5 gene.

Diagnostic and prognostic value of EEG patterns recorded on foramen ovale and epidural peg electrodes

ObjectiveTo describe and assess the significance of EEG characteristics recorded during presurgical video-EEG monitoring (VEM) utilizing foramen ovale (FO) and epidural peg electrodes. MethodsSeizure onset (SOP) and termination pattern morphology and regions, ipsilateral and contralateral latencies, seizure duration, and interictal spike counts were examined in 106 patients (412 seizures). An EEG feature-based logistic regression model predicting one-year post-surgical seizure freedom was assessed using a 5-fold nested cross-validation approach. ResultsFour SOPs and five termination patterns were identified. Seventy-one percent of patients had a single unique SOP, the most common being sharp activity ≤ 13 Hz (28.9% of seizures). Seizures recorded by FO electrodes were associated with SOPs ≤ 13 Hz (OR 1.9, p = .008). Focal-to-bilateral tonic-clonic seizures were associated with SOPs > 13 Hz (p = .04) and bilateral spike and wave termination (p < .001). In patients with temporal lobe epilepsy, logistic regression based prediction of post-surgical outcome had a mean area under the curve of 0.69, with the most important features being SOP, right sided interictal epileptic activity, and contralateral latency. ConclusionsFO and peg recordings yield characteristic EEG patterns. SignificanceEEG features of FO and peg recordings may have diagnostic and prognostic utility in presurgical VEM.

Development and Validation of the 5-SENSE Score to Predict Focality of the Seizure-Onset Zone as Assessed by Stereoelectroencephalography

Stereoelectroencephalography (SEEG) has become the criterion standard in case of inconclusive noninvasive presurgical epilepsy workup. However, up to 40% of patients are subsequently not offered surgery because the seizure-onset zone is less focal than expected or cannot be identified. To predict focality of the seizure-onset zone in SEEG, the 5-point 5-SENSE score was developed and validated. This was a monocentric cohort study for score development followed by multicenter validation with patient selection intervals between February 2002 to October 2018 and May 2002 to December 2019. The minimum follow-up period was 1 year. Patients with drug-resistant epilepsy undergoing SEEG at the Montreal Neurological Institute were analyzed to identify a focal seizure-onset zone. Selection criteria were 2 or more seizures in electroencephalography and availability of complete neuropsychological and neuroimaging data sets. For validation, patients from 9 epilepsy centers meeting these criteria were included. Analysis took place between May and July 2021. Based on SEEG, patients were grouped as focal and nonfocal seizure-onset zone. Demographic, clinical, electroencephalography, neuroimaging, and neuropsychology data were analyzed, and a multiple logistic regression model for developing a score to predict SEEG focality was created and validated in an independent sample. A total of 128 patients (57 women [44.5%]; median [range] age, 31 [13-58] years) were analyzed for score development and 207 patients (97 women [46.9%]; median [range] age, 32 [16-70] years) were analyzed for validation. The score comprised the following 5 predictive variables: focal lesion on structural magnetic resonance imaging, absence of bilateral independent spikes in scalp electroencephalography, localizing neuropsychological deficit, strongly localizing semiology, and regional ictal scalp electroencephalography onset. The 5-SENSE score had an optimal mean (SD) probability cutoff for identifying a focal seizure-onset zone of 37.6 (3.5). Area under the curve, specificity, and sensitivity were 0.83, 76.3% (95% CI, 66.7-85.8), and 83.3% (95% CI, 72.30-94.1), respectively. Validation showed 76.0% (95% CI, 67.5-84.0) specificity and 52.3% (95% CI, 43.0-61.5) sensitivity. High specificity in score development and validation confirms that the 5-SENSE score predicts patients where SEEG is unlikely to identify a focal seizure-onset zone. It is a simple and useful tool for assisting clinicians to reduce unnecessary invasive diagnostic burden on patients and overutilization of limited health care resources.

Altered functional connectivity in newly diagnosed benign epilepsy with unilateral or bilateral centrotemporal spikes: A multi-frequency MEG study

ObjectiveRolandic epilepsy (RE) is one of the most common forms of epilepsy syndromes in children. The condition is usually accompanied with either unilateral or bilateral centrotemporal epileptic discharge. Despite the term “benign”, many studies have reported that children with benign epilepsy with centrotemporal spikes (BECTS) display a range of pervasive cognitive difficulties. In addition, existing research suggests that unilateral and bilateral centrotemporal spikes may affect cognition through different mechanisms. Consequently, the present study aimed to investigate cognitive impairment and the resting-state network topology of children with benign epilepsy with unilateral centrotemporal spikes (U-BECTS) and with bilateral centrotemporal spikes (B-BECTS). MethodsThis study recruited 14 children with U-BECTS and 14 with B-BECTS. Thereafter, cognition was assessed in 28 children with BECTS and 14 healthy controls, using the fourth edition of the Wechsler Intelligence Scale (WISC-IV). Additionally, the functional network of the brain was constructed through magnetoencephalography (MEG) to record the resting-state brain magnetic signals of the brain and by computing virtual sensor waveforms at the source level. Moreover, graph theory (GT) analysis was used to assess the properties of the brain network. ResultsChildren in the B-BECTS group had an earlier onset of epilepsy compared to those in the U-BECTS category. In addition, both the B-BECTS and U-BECTS groups had lower Full Scale Intelligence Quotient (FSIQ), Verbal Comprehension Index (VCI), and Working Memory Index (WMI) scores, compared to the healthy controls although only children in the B-BECTS category had lower Perceptual Reasoning Index (PRI) scores. The results also showed that both BECTS groups had increased frontal cortex connectivity in specific frequency bands. Notably, children with B-BECTS showed a more disorderly and randomized network in the 1–4-Hz and 80–250-Hz frequency bands. Moreover, GT analysis showed that children with B-BECTS had lower clustering coefficient and characteristic path length in the 80–250-Hz frequency bands and higher connection strength in the 4–8-Hz frequency bands. On the other hand, the U-BECTS group had a higher clustering coefficient in the 8–12-Hz frequency bands, compared to the healthy controls. Correlation analysis revealed that there were negative correlations between network parameters, clinical characteristics, and neuropsychological data in the U-BECTS category. ConclusionThe findings revealed that children with BECTS display a diffuse early cognitive deficit. In addition, resting-state suboptimal network topology may be the mechanism of cognitive impairment in children with BECTS. The study also showed that and children with B-BECTS may be at a higher risk of cognitive impairment.

A Young Child with Subacute Onset of Behavioral Changes.

1. Sarah Pradhan, MD* 2. Jessica Goldstein, MD† 3. Erin Frank, MD* 4. Allayne Stephans, MD* 1. *Department of Pediatric Hospital Medicine, 2. †Department of Pediatric Neurology, Rainbow Babies and Children’s Hospital, Cleveland, OH 1. Address Correspondence to Sarah Pradhan, MD; E-mail: sarah.pradhan6{at}gmail.com A 5-year-old healthy boy presents with a 3-week history of new onset aggression, obsessive-compulsive behavior, and nocturnal enuresis. One month ago he sustained a minor head trauma when he was sliding down the slide at a local playground. He was initially diagnosed with a mild concussion. His symptoms have now progressed and include frequent night waking, hand wringing, and behavioral outbursts. This prompts his pediatrician to refer him to the emergency department for evaluation. He undergoes computed tomography scan of the head, which is unremarkable. Laboratory evaluations include electrolytes, liver enzymes, complete blood cell count, rapid group A streptococcal antigen, thyroids studies, and heterophile antibody test, which are unremarkable. Urine and blood toxicology screens are negative. He is admitted to the inpatient unit. Vital signs are appropriate for age. He has difficulty answering questions and following commands. He is restless and disoriented. He intermittently gets up to run around the room and occasionally bangs his head on the wall. His cranial nerve, motor, reflexes, sensory, coordination, and gait examinations are normal. Brain magnetic resonance imaging is unremarkable. On video electroencephalogram he has bilateral fronto-temporal spikes that correspond with his abnormal movements and subclinical seizures arising from the right and left frontotemporal areas independently (arrows in Fig 1). Fosphenytoin is started, which controls his seizures, but he continues to have abnormal behavioral outbursts. Over the course of the week, he develops dysarthria, oral-facial …

Panayiotopoulos syndrome: A benign childhood epilepsy syndrome masquerading as head injury

Panayiotopoulos syndrome (PS) is a benign childhood epilepsy syndrome characterized by autonomic seizures and electroencephalogram (EEG) showing predominant occipital paroxysms. PS may easily be confused with many non-epileptic conditions such as atypical migraine, gastroenteritis, or syncope. We here present a 5 ½-year-old boy who presented to us with a history of head injury followed by vomiting, seizures, and prolonged unresponsiveness. Neuroimaging was normal, and on detailed history, it was clear that autonomic symptoms preceded the head injury and so an EEG was done. Interictal EEG showed bilateral occipital spikes and wave discharges with characteristic “fixation-off sensitivity.” Hence, the seizure semiology along with the EEG pattern helped to clinch the diagnosis. Parents were counseled about the benign nature of the condition

Benign Rolandic epilepsy: widespread increases in connectivity in a focal epilepsy syndrome.

Benign Rolandic epilepsy (benign epilepsy with centrotemporal spikes; recently renamed self-limited epilepsy with centrotemporal spikes) is associated with widespread deficits in cognition and behavior, suggesting abnormalities in networks that extend beyond the centrotemporal region. To assess functional connectivity in children with benign Rolandic epilepsy, we assessed EEG spectral power and coherence during awake and sleep records in 27 children with centrotemporal spikes. Coherence represents the consistency of the phase difference between two EEG signals when compared over time and serves as a measure of synchronization between two EEG signals based mainly on phase consistency. Epochs of EEG with and without centrotemporal spikes were compared during both waking and sleep. During the spike epochs, there was an increase in spectral power at all frequencies, although statistical significance was seen primarily in the delta, theta and alpha bandwidths. This increase in absolute power was seen at all electrode sites and was similar in left and right-sided electrodes. During centrotemporal spikes, there were significant changes in coherence compared to the EEG segments without spikes. In the theta, alpha and beta bandwidths, there were significant increases in coherence. The increases in coherences were widespread and bilateral, and involved electrode pairs outside the central and temporal regions. To determine if there was a relationship between location of the spikes and coherence values, right-sided, left-sided and bilateral centrotemporal spikes were compared. There was no relationship between location of the centrotemporal spikes and power or coherence values. These findings indicate that benign Rolandic epilepsy results in generalized changes in spectral power and connectivity and raises the suggestion that from a functional standpoint, benign Rolandic epilepsy resembles a generalized rather than focal seizure disorder.

Electroencephalogram findings in chronic kidney disease

Introduction Uremic polyneuropathy is a common complication of chronic renal in sufficiency in the peripheral nervous system (PNS). EEG is useful in assessing patients with uremic encephalopathy and in monitoring their progress. EEG in CKD usually shows irregular low voltage with slowing of the posterior dominant alpha rhythm and occasional theta bursts. Prolonged bursts of bilateral, synchronous slow and sharp waves or spike waves are characteristic. These changes stabilize with dialysis when adequate, efficient of long duration and sufficient for appropriate urea clearance. However many patients as, hypertensive patients, those with associated electrolyte disorders (hypocalcemia, hypo or hypernatremia, hypo or hyperkalemia, intractable acidosis) will not show any improvement. Aim of the study To investigate the Electroencephalogram findings in different stages of chronic kidney disease. Patients and Methods In this prospective observational study, we included 54 children (22 males and 32 females) with different stages of chronic renal diseases (from stage 1 to stage 5, either in pre dialytic or dialytic stage), with mean age of 12.2 years & a ra (4-18). Results Stages (3, 4 & 5) had significantly higher Theta pattern record compared to stages 1 & 2 (33.3% of both stage 3 & 4 and 50% of stage 5 cases have shown theta records. Increased frequency of asymetry and sharp waves with progress of CKD to a maximum in dialytic stage. Conclusions Pediatric patients with chronic kidney diseases have obvious distinct EEG deviations from normality which increase with the progress

The effect of fluoxetine on penicillin-induced epileptiform activity

AimDepression is the most frequent psychiatric comorbidity in patients with epilepsy.Fluoxetine is the most widely used selective serotonin reuptake inhibitor (SSRI) in depression. The aim of the present study was to evaluate the dose-dependent effect of fluoxetine on penicillin-induced seizure by electrocorticogram (ECoG), a model for simple partial epilepsy. MethodThe epileptiform activity was induced by intracortical (i.c.) microinjection of penicillin into the left sensorimotor cortex. Thirty minutes after penicillin injection, 5, 10, or 20 mg/kg doses of fluoxetine were administered intraperitoneally (i.p.). An ECoG recording was performed for 180 min using the data acquisition system. The frequency and the amplitude of the epileptiform activity were analyzed. ResultsPenicillin induced bilateral spikes and spike–wave complexes within 2–5 min. The 5 and 10 mg/kg doses of fluoxetine significantly reduced the frequency (58%, p < 0.05 and 69%, p < 0.01, 40 and 50 min after fluoxetine injection, respectively) and amplitude (60%, p < 0.01 and 73%, p < 0.05, 40 and 120 min after fluoxetine injection, respectively) of epileptiform activity compared with penicillin-induced seizure group (control). Five-milligram fluoxetine (i.p.) was the most effective dose to decrease frequency and amplitude on penicillin-induced epileptiform activity. However, a higher fluoxetine dose (20 mg/kg) significantly increased frequency (147%, p < 0.01) and amplitude (123%, p < 0.05) of epileptiform activity 40 and 120 min after fluoxetine administration compared with control group. Also, bursts of population spikes were seen in 20 mg/kg fluoxetine doses. ConclusionResults of the present study indicate that low and moderate fluoxetine doses have an anticonvulsant effect while high doses have proconvulsant effect on penicillin-induced epileptic activity.

Progressive myoclonus epilepsy caused by a gain-of-function KCNA2 mutation

Progressive myoclonus epilepsy caused by a gain-of-function KCNA2 mutation

Network characteristics in benign epilepsy with centro-temporal spikes patients indicating defective connectivity during spindle sleep: A partial directed coherence study of EEG signals

ObjectiveTo investigate the changes in EEG connectivity in children with the typical presentation of benign epilepsy with centro-temporal spikes (BECTS). MethodsWe compared awake and spindle-sleep EEG recordings obtained by a standard electrode array in patients with lateralised (10 Right, 9 Left-BECTS) or bilateral spikes (10 MF-BECTS) and in 17 age-matched controls. We analysed EEG activity using partial directed coherence, an estimator of connectivity based on the multivariate autoregressive models and calculated in- and out-degrees, strength, clustering coefficient and betweenness centrality. ResultsIn comparison with the controls, the awake EEG recordings of the patients with lateralised BECTS showed a minimal increase in out-degrees on F4 and F3. The greater differences, found during sleep, included significant reductions in both in- and out-degrees and strength in all of the patient groups, but in T4 or T3 showing increased out-degrees and strength in Right and Left-BECTS. Betweenness centrality was significantly reduced on C3 and C4 in the patients with MF-BECTS. ConclusionsOur observations suggest that the main finding in BECTS patients is widely reduced local connectivity. SignificanceThe network changes in BECTS can be interpreted as a permissive condition occurring in a developmental window that predisposes to seizure generation during spindle-sleep.

Unusual ictal propagation patterns suggesting poor prognosis after temporal lobe epilepsy surgery: Switch of lateralization and bilateral asynchrony

ObjectiveThe objective of this study was to investigate unusual ictal propagation patterns in patients with drug-resistant temporal lobe epilepsy (TLE) and reveal their electrophysiological, neuroimaging, and prognostic properties after surgery. MethodsAmong 248 patients with TLE who underwent scalp video-electroencephalographic (EEG) monitoring, 24 patients with ‘switch of lateralization’ or ‘bilateral asynchrony’ in at least one of their seizures (9.3%) were analyzed retrospectively. The postoperative outcome was determined in 16 patients who had undergone epilepsy surgery. ResultsAll but 5 of the included patients had hippocampal sclerosis (HS) as their magnetic resonance imaging (MRI) findings. Twelve out of 16 patients (75%) who had surgery were seizure-free for at least 1 year. Nine out of 12 patients (75%) with good outcome had unilateral interictal EEG discharges in temporal regions whereas 3 out of 4 patients with poor outcome had bilateral temporal interictal spiking (p = 0.018). ConclusionUnusual ictal propagation patterns are not always related to poor prognosis after surgery in patients with TLE. Patients with unilateral interictal spiking in the temporal region tend to have good outcome despite these unusual patterns. These patterns can also be seen in patients with TLE with other etiologies besides the well-known HS in MRI.

Advances in dialysis encephalopathy research: a review.

Dialysis encephalopathy (DE) is a progressive, fatal disease with a high mortality rate. Understanding the causes of this disease and the efforts to prevent and treat it would help improve the prognosis and quality of life of affected patients. This paper reviews the etiology, clinical features, methods of examining accessory features, diagnosis, treatment, and prevention of DE. We found that DE is likely to be related to aluminum poisoning. The clinical manifestations of DE include language disorders, mental and behavioral disorders, cognitive decline, and movement disorders. Electroencephalogram (EEG) findings mainly consist of an abundance of low waves, intermittent bilateral synchronous high-amplitude spikes, and ridge waves. Assessing the clinical features and obtaining an EEG are of great value in diagnosis, and DE is treated by both reducing aluminum intake and increasing aluminum excretion. Deferoxamine (DFO) is an effective treatment for DE.

T160. Magnetoencephalography findings of benign epileptiform transients of sleep on scalp EEG in three patients with temporal lobe epilepsy

Introduction Benign epileptiform transients of sleep (BETS) is a finding on electroencephalography, defined as monophasic or diphasic transients with low amplitude ( μ V) and short duration ( Methods Patient 1, a 37-year-old right-handed male, was diagnosed with left TLE. Complex partial seizures started from age 15 years. Video-EEG (VEEG) showed interictal left anterior and posterior temporal sharp waves, and left temporal seizure onset was suggested. Magnetic resonance (MR) imaging revealed a mass lesion in the left lateral temporal lobe, suspected to be dysembryoplastic neuroepithelial tumor. Patient 2, a 38-year-old right-handed male, was diagnosed with left TLE. Complex partial seizures started from age 20 years. VEEG showed interictal bilateral independent temporal spikes, and left temporal seizure onset was suggested. MR imaging showed no abnormalities. Patient 3, a 33-year-old right-handed female, was diagnosed with right TLE. Complex partial seizures with oral automatism started from age 20 years. VEEG showed interictal right anterior temporal spikes, and right temporal seizure onset was suggested. MR imaging showed no abnormalities. All three patients underwent simultaneous EEG-MEG recording. EEG electrode placement used the 10–10 system with additional anterior temporal electrodes. MEG used a 200 channel whole-head system (MEGvision PQA160C, Ricoh Company, Ltd., Tokyo, Japan). The study investigated MEG activities correlated with EEG findings concordant with BETS. Results In Patient 1, MEG spikes correlated with BETS in the left temporal lobe had epileptic form, with high amplitude spike activity followed by slow wave activity. The source as evaluated with equivalent current dipoles was estimated around the left temporal lesion. In Patient 2, MEG spikes correlated with BETS in the right temporal lobe had epileptic form, with high amplitude spike activity followed by slow wave activity. No activity fulfilling the definition of BETS was detected in the left hemisphere. In Patient 3, no apparent MEG activity correlated with BETS was seen in the right temporal lobe. Conclusion The present study demonstrated variations in MEG findings correlated with EEG BETS in patients with TLE. These results may indicate heterogeneous background of BETS, so that only some BETS have an epileptic mechanism.

S61. Electroencephalography patterns in patients with thymoma and limbic autoimmune encephalitis: Report of three cases

Introduction Although Myasthenia gravis (MG) is the most common autoimmune disease associated with thymoma, a small proportion of thymomatous patients can suffer from limbic autoimmune encephalitis (LE). LE is usually characterized by rapid progressive short-term memory deficits, psychiatric symptoms, and seizures. Patients can present antibodies against cell surface antigens, including contactin-associated protein-like 2 (CASPR2) and a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR). Our aim was to analyze the EEG findings of these patients to find possible EEG homologies among their patterns. Methods Clinical information was obtained from a retrospective review of medical records and EEG recordings of three patients with thymoma and LE: two with seropositivity for AMPAR antibodies and one for CASPR2 antibodies. Results The first case was a 37 years-old man with a subacute onset of memory loss, confusion, anxiety and behavioral disorders in the setting of an invasive thymoma (type B2-B3). Brain MRI and dosage of acetylcholine receptor antibodies (AChR-Abs) were normal. EEG showed bilateral fronto-temporal spikes together with slow theta and delta activity. Clinical suspicion of a paraneoplastic neurological syndrome associated with thymoma was confirmed by the serological presence of AMPAR-Abs. The second case was a 47 years-old female patient with Myasthenia Gravis (MG) and seropositivity for AChR-Abs, treated for recurrent thymoma (type B2). She presented three episodes of generalized seizures, together with mental disorientation, impairment of recent memory and insomnia. Brain MRI was normal. EEG showed a peculiar pattern, comprising lateralized right fronto-temporal spikes and generalized sharp waves. Serological tests detected the presence of antibodies to CASPR2. The third case was a 52 years-old female patient with thymoma (type B2-B3) who developed confusion, short-term memory loss and psychomotor agitation after thymectomy. Cerebrospinal fluid (CSF) examination showed a mild blood-CSF barrier damage and brain MRI revealed increased T2 signal involving mesio-temporal cortical areas. EEG showed electrical abnormalities in the fronto-temporal regions. Antibodies to the glutamate receptor 1 (GluR1) and GluR3 subunits of AMPAR were detected both in serum and CSF. Conclusion Limbic autoimmune encephalitis should be suspected in patients with invasive thymoma and subacute onset of confusion, memory loss and seizures. In all these three cases EEG showed epileptiform activity, especially in the fronto-temporal regions, together with slow theta and delta activity, without a pathognomonic pattern. Our results strongly emphasize the importance of testing biological samples when a possible autoimmune CNS involvement is suspected. Even if antibody testing remains the cornerstone in the diagnostic pathway, EEG is paramount in the differential diagnosis with similar disorders, in orienting toward limbic encephalopathy, especially when MRI is inconclusive.

F122. Non-lesional eating epilepsy with mesial temporal and inferior insular onset: A stereo-EEG study

Introduction Reflex epilepsy is characterized by seizures that are triggered by internal or external stimuli. Based on the complexity of the trigger, the reflex epilepsies can be subdivided into simple and complex. Eating Epilepsy (EE) is a subtype of the complex reflex epilepsies and represents a heterogeneous electro-clinical syndrome. The body of literature on EE consists mostly of a few case series with variable medical and surgical outcomes. We present a case of non-lesional EE with excellent outcome from resective epilepsy surgery after an extensive pre-surgical investigation to identify of the seizure onset zone (SOZ). Methods We retrospectively evaluated a case of drug-resistant eating-induced seizures referred for pre surgical assessment at London Health Sciences Centre Epilepsy Program, London, Canada. Patient’s data was reviewed including clinical history, neurological exam, imaging (Brain MRI and FDG-PET), neuropsychology assessment, scalp video-EEG, Stereoelectroencephalography (SEEG) and the surgical management. Results A 34-year-old gentleman has a 4-year history of seizures characterized by diffuse tingling sensation followed by loss of awareness with staring and right hand automatisms that lasted 1–2 min. 90% of his seizures were observed to be induced by eating at the beginning of a meal. His neuropsychological testing was essentially normal. Scalp video-EEG showed independent bilateral temporal spikes (R > L). Five eating-induced seizures were recorded immediately after initiation of eating with 2–3 Hz rhythmic activity over the right temporal region with perisylvian spreading. Brain MRI and PET studies were normal. Based on the electro-clinical data, the working hypothesis was right perisylvian onset of the seizures. The patient underwent intracranial recordings with stereo-EEG sampling the right temporal pole, amygdala, hippocampus, parietal operculum, temporal operculum and insula. Five seizures were captured induced by eating with stereotypical electrographic onset involving the right amygdala and hippocampus and inferior insula. Extra operative cortical stimulation (1–3.5 mA) elicited many prolonged after discharges in the same regions but they did not provoke clinical seizures. The patient thus underwent a right anterior temporal lobectomy and partial inferior insulectomy with decortication of the posterior short insular gyrus & the anterior and posterior gyri. Pathology revealed transcortical and hippocampal gliosis. He remained seizure-free (Engel 1) at his 8 months post-surgical follow-up. Conclusion This case of a drug-resistant non-lesional EE illustrates the value of stereo-EEG in the presurgical work-up that led to seizure-freedom following combined right anterior temporal lobectomy and right inferior insula resection. In non-lesional cases of drug-resistant EE, the epileptogenic zone is likely wide and it requires stereo-EEG to determine the SOZ.