Ictal sensory periodic lateralized epileptiform discharges

We describe the case of a 74-year-old man with left parietal arteriovenous malformation (AVM) and cerebral white matter radiation necrosis who developed persistent subjective right-sided groin pulsations. The EEG revealed left parietal periodic lateralized epileptiform discharges (PLEDs) time-locked to these sensations, confirming that the patient's symptoms represented sensory seizures with ictal PLEDs as the electrographic correlate. To our knowledge, this is the first reported case of ictal PLEDs manifesting as sensory seizures.     

Gaze deviation from contralateral pseudoperiodic lateralized epileptiform discharges (PLEDs)

Pseudoperiodic lateralized epileptiform discharges (PLEDs) usually produce "negative" neurologic findings. This contrasts with seizures which typically induce cortical activation with "positive" clinical manifestations. Gaze preference may arise from ipsilateral frontal eye fields (FEFs) damage because of the unopposed action of an intact contralateral FEF. Epileptic nystagmus (EN) and gaze deviation (GD) can also occur with focal temporo-parieto-occipital or hemispheric seizures in awake or obtunded patients. A patient with old right frontal and parieto-temporal cerebral infarctions manifested leftward gaze preference and deviation (without nystagmus) while alert and talking. Digitized EEG demonstrated PLEDs at approximately 1 Hz over the right fronto-central region, without electrographic seizures. This report illustrates that PLEDs without seizures may excite frontal regions proximate to the FEFs to produce contraversive gaze preference in an awake patient, and discusses putative mechanisms. Gaze deviation, in this case, was the principal clinical feature of PLEDs.     

Benign bilateral independent periodic lateralized epileptiform discharges

Bilateral independent periodic lateralized epileptiform discharges (BIPLEDs) usually appear transiently in patients with severe disturbances of consciousness and are indicative of a poor prognosis. Recurrent BIPLEDs have not previously been reported in the literature. We report a 64-year-old patient with bilateral hippocampal lesions (cerebral infarction) who exhibited persistent periodic lateralized epileptiform discharges (PLEDs) (chronic PLEDs) associated with recurrent BIPLEDs. Electroencephalography was recorded for more than 6 months. Left hemispheric PLEDs appeared first. Next, PLEDs shifted to the right hemisphere and BIPLEDs occasionally developed. Brain magnetic resonance imaging and single-photon emission computed tomography with technetium-99-hexamethyl-propyleneamine oxime was performed before and after the appearance of BIPLEDs. The patient had no remarkable clinical symptoms aside from mild memory impairment for this period of time. This is the first case of recurrent 'benign' BIPLEDs, that is, BIPLEDs with a positive prognosis.     

Periodic lateralized frontal epileptiform discharges with ipsilateral epilepsia partialis continua

PURPOSE: Lateralized clonic jerks of the extremities during epileptic seizures usually arise from the contralateral rolandic cortex. In our exceptional case one-sided extremity twitches related to epileptiform activity in the ipsilateral frontal lobe. METHODS: Case study with clinical-electroencephalographic correlation. RESULTS: A 47-year-old man suffered destruction of most of his right cerebral hemisphere, including the perirolandic region. Epilepsia partialis continua (EPC) ensued, with clonic jerks of the proximal right upper and lower limbs temporally related to periodic lateralized epileptiform discharges (PLEDs) from the parasagittal region of the right frontal lobe with a variable time interval over 100 ms. Sectioning of the subcortical callosal and projection connections of the frontal lobe abolished the clonic jerks. CONCLUSIONS: We propose the ipsilateral EPC arose from projections from the supplementary motor region to the medullary reticular formation to account for the long and variable latency between PLEDs and jerks.     

Periodic focal epileptiform discharges

ObjectiveTo report intraoperative periodic focal epileptiform discharges (PFEDs) during awake craniotomy using high-density electrocorticography (HD-ECoG).MethodsWe retrospectively analyzed 81 patients undergoing awake craniotomy between 9/29/2016 and 7/5/2018. Intraoperative HD-ECoG was performed with direct electrocortical stimulation (DECS) for functional brain mapping. Real-time interpretation was performed and compared to scalp EEG when performed. Perioperative seizures, surgical complications, and characteristics of PFEDs were assessed.Results69/81 patients (mean age 48.5 years) underwent awake surgery; 55 operated for brain tumor, 11 for epilepsy and 3 for cavernomas. A focal abnormality on brain MRI was present in 63/69 (91.3%) patients. 43/69 (62.3%) patients had seizures preoperatively, 4/69 (5.7%) had seizures during DECS. PFEDs were identified in 11 patients (15.9%); 2 on depth recording and 9 during intraoperative HD-ECoG. 32 patients (46.3%) had preoperative EEG. HD-ECoG detected more epileptiform discharges (EDs) than standard EEG (32/43; 74.4% vs 9/32; 28.1%) (p = <0.001). Of 9/43 patients with PFEDs on HD-ECoG, 7 patients also had scalp EEG but only one case had EDs (p = 0.02), and 0/32 had periodic EDs.ConclusionsIntraoperative PFEDs are novel, highly focal EDs approximating a single gyrus. In patients with brain tumors, PFEDs did not demonstrate a relationship to pre-operative seizures though has similarities to other common waveforms in patients with epilepsy.SignificancePFEDs expand our understanding of the interictal-ictal continuum and highlight improved temporo-spatial information obtained from increasing sensor density during intracranial EEG recording.     

Neuroimaging and neurophysiology of periodic lateralized epileptiform discharges: observations and hypotheses

PURPOSE: We assessed neuroimaging lesion type and distribution in patients with periodic lateralized epileptiform discharges (PLEDs), with a view to identifying electrographic differences between PLEDs associated with differing lesion locations. Our observations led us to consider a conceptual synthesis between PLEDs and periodic complexes (PCs). METHODS: Retrospective review of acute neuroimaging results (CT/MRI) on patients identified to have EEG PLEDs, for the period 1999-2003 (n=106). Blinded classification of original EEG recordings. RESULTS: Neuroimaging abnormalities were classified as acute or chronic cortical, or acute or chronic subcortical. Seven out of 106 scans were classified nonlesional. Overall approximately 70% of scans had cortical abnormalities, whether acute or chronic; approximately 23% had subcortical abnormalities. "Cortical" PLEDs were significantly longer in duration (p<0.05) and more variable in morphology (p<0.01) than "subcortical" PLEDs. CONCLUSIONS: Structural brain disease commonly, but not invariably, underlies PLEDs; lesion type is spatiotemporally variable. Cortical and subcortical PLEDs have distinct EEG signatures. There is evidence that these may relate to mechanisms for other pathological large-scale oscillatory brain synchronies (e.g., PCs).     

Effect of vagal nerve stimulation on interictal epileptiform discharges: a scalp EEG study

PURPOSE: To investigate the effects of acute vagal nerve stimulation (VNS) on interictal epileptiform discharges (IEDs). METHODS: Fifteen epilepsy patients, all of whom had been treated with VNS for > or =6 months, entered the study. In each subject, the absolute number of IEDs was counted at the baseline period (BP), the stimulation period (SP), six interstimulation periods (IPs), and the prestimulation period (PP), by using an original paradigm. The number of IEDs at the BP and the PP was compared with the number of IEDs at the SP and IPs. The results were correlated with other variables (the duration of VNS, the value of the output current, the duration of epilepsy, the type of epilepsy, the effect of VNS, and the effect of extrastimulation). RESULTS: We observed a significantly higher reduction in the number of IEDs in the SP and all the IPs as compared with the BP. We noticed a significantly higher reduction in the number of IEDs in the SP and in the first IP as compared with the PP. The reduction of IEDs was greater in patients who responded to VNS (>50% reduction of all seizures) and in patients who responded positively to magnetic extrastimulation. There were no other significant results in the reduction of IEDs when comparing other variables. CONCLUSIONS: Short-term VNS reduces IEDs significantly. The reduction is most prominent during the SP (i.e., when the pulse generator is active). The value of reduction of IEDs is higher in patients who respond to VNS and in patients with positive experiences with magnetic extrastimulation. These results can be useful in predicting the effect of VNS.     

Risk for developing epilepsy and epileptiform discharges on EEG in patients with febrile seizures

Purpose: The aim of the present study was to investigate the correlation between epileptiform discharges on EEGs after febrile seizures and the prognosis of patients in terms of the development of epilepsy and recurrence of febrile seizures. This study also evaluated the characteristics of epileptiform discharges and EEG changes on follow-up examination. Methods: This study consisted of 36 children who presented to our hospital with febrile seizures and whose electroencephalograms (EEG) showed epileptiform discharges. The development of epilepsy and the recurrence of febrile seizures were compared between the study group (n = 36) and the control group (n = 87), which included children with febrile seizure but with normal EEG findings. Results: No significant correlation was detected between the recurrence rate of febrile seizures in patients with normal EEG (23 out of 87, 26.4%) findings and that of patients whose EEGs showed epileptiform discharges (12 out of 36, 33.3%) [adjusted OR 0.67 (0.26–1.68)]. However, 9 (25.0%) out of 36 patients with epileptiform discharges on EEG had epilepsy compared to 2 patients (2.3%) in the control group. The correlation was statistically significant [crude OR 10.88 (2.47–47.88) and adjusted OR 8.75 (1.49–51.6)]. Conclusion: Epileptiform discharges on the EEGs of patients with febrile seizures are important predictive risk factors of the development of epilepsy.     

EEG autoregressive modeling analysis: A diagnostic tool for patients with epilepsy without epileptiform discharges

ObjectiveNumerous types of nonepileptic paroxysmal events, such as syncopes and psychogenic nonepileptic seizures, may imitate epileptic seizures and lead to diagnostic difficulty. Such misdiagnoses may lead to inappropriate treatment in patients that can considerably affect their lives. Electroencephalogram (EEG) is a commonly used tool in assisting diagnosis of epilepsy. Although the appearance of epileptiform discharges (EDs) in EEG recordings is specific for epilepsy diagnosis, only 25%–56% of patients with epilepsy show EDs in their first EEG examination.MethodsIn this study, we developed an autoregressive (AR) model prediction error–based EEG classification method to distinguish EEG signals between controls and patients with epilepsy without EDs. Twenty-three patients with generalized epilepsy without EDs in their EEG recordings and 23 age-matched controls were enrolled. Their EEG recordings were classified using AR model prediction error–based EEG features.ResultsAmong different classification methods, XGBoost achieved the highest performance in terms of accuracy and true positive rate. The results showed that the accuracy, area under the curve, true positive rate, and true negative rate were 85.17%, 87.54%, 89.98%, and 81.81%, respectively.ConclusionsOur proposed method can help neurologists in the early diagnosis of epilepsy in patients without EDs and might help in differentiating between nonepileptic paroxysmal events and epilepsy.SignificanceEEG AR model prediction errors could be used as an alternative diagnostic marker of epilepsy.     

Treatment of interictal epileptiform discharges in cerebral palsy patients without clinical epilepsy: hope for a better outcome in prognosis

Cerebral palsy (CP) is a motor disorder due to cerebral damage. It is commonly associated with neuro-psychological retardation and also with epilepsy; hence, its management warrants a multi-dimensional approach. In a significant number of CP patients, interictal epileptiform discharges (IEDs) are obtained in their EEG even in absence of clinical epilepsy. Epileptiform discharge-firing cortical neurons are found to be associated with elevated intracellular Ca(2+) levels and exhibition of abnormal response on exposure to excitotoxic glutamate; both these features have been found to lead to subsequent death of these neurons. This further damage is likely to aggravate the already existing cortical damage in CP patients thereby worsening their prognosis. IEDs are also known to be associated with other neuro-psychological disorders like cognitive impairment and behavioral problems even in absence of clinical epilepsy. Thus, the IEDs cannot be viewed as benign events and their occurrence even in absence of clinical epilepsy cannot be ignored. A few trials aimed at treating IEDs in autistic patients without epilepsy and in children with behavior problems have yielded favorable results. Based on these studies, the author proposes inclusion of EEG investigation in the management protocol of CP patients and treatment of IEDs (when detected even in absence of clinical epilepsy) for a better outcome in their prognosis.     

An artificial intelligence-based EEG algorithm for detection of epileptiform EEG discharges: Validation against the diagnostic gold standard

ObjectiveTo validate an artificial intelligence-based computer algorithm for detection of epileptiform EEG discharges (EDs) and subsequent identification of patients with epilepsy.MethodsWe developed an algorithm for automatic detection of EDs, based on a novel deep learning method that requires a low amount of labeled EEG data for training. Detected EDs are automatically grouped into clusters, consisting of the same type of EDs, for rapid visual inspection. We validated the algorithm on an independent dataset of 100 patients with sharp transients in their EEG recordings (54 with epilepsy and 46 with non-epileptic paroxysmal events). The diagnostic gold standard was derived from the video-EEG recordings of the patients’ habitual events.ResultsThe algorithm had a sensitivity of 89% for identifying EEGs with EDs recorded from patients with epilepsy, a specificity of 70%, and an overall accuracy of 80%.ConclusionsAutomated detection of EDs using an artificial intelligence-based computer algorithm had a high sensitivity. Human (expert) supervision is still necessary for confirming the clusters of detected EDs and for describing clinical correlations. Further studies on different patient populations will be needed to confirm our results.SignificanceThe automated algorithm we describe here is a useful tool, assisting neurophysiologist in rapid assessment of EEG recordings.     

Benign epileptiform discharges in Rolandic region with mesial temporal lobe epilepsy: MEG, scalp and intracranial EEG features

AIM OF THE STUDY: To report benign epileptiform discharges (BEDs) in the Rolandic region, coexisting in a pediatric patient with intractable localization-related epilepsy, secondary to hippocampal sclerosis. METHODS: We describe the clinical features, MRI, scalp video EEG, magnetoencephalography (MEG) and intracranial video EEG findings, and surgical outcome in a 9-year-old boy with BEDs and intractable complex partial seizures. RESULTS: MRI showed left hippocampal sclerosis. Scalp video EEG interictally demonstrated left temporal spike and sharply contoured slow waves, and right fronto-centro-temporal spike and waves. Ictal scalp video EEG showed left temporal rhythmic sharp waves after the clinical onset of epigastric aura, followed by staring. MEG showed interictal dipoles in the bilateral Rolandic regions with a uniform orientation and right hemispheric predominance. Intracranial video EEG, with bilateral mesial temporal depth and fronto-temporo-parietal strip electrodes, interictally showed polyspikes and slow waves with superimposed low-amplitude fast waves in the left mesial and posterior lateral temporal regions, and spike and waves in the bilateral fronto-parietal regions. Ictal onset was marked by low-amplitude fast waves in the left mesial and posterior lateral temporal regions. He underwent left anterior temporal lobectomy with hippocampectomy. Pathology was hippocampal sclerosis. Predominant right fronto-centro-temporal spike and waves and MEG right Rolandic dipoles persisted after surgery. He was seizure-free 14 months after surgery. CONCLUSION: This is the first report on MEG and intracranial video EEG features of BEDs in the Rolandic region, coexisting with hippocampal sclerosis. Persistence of contralateral benign MEG Rolandic dipoles after surgery indicates that BEDs are coincidental in mesial temporal lobe epilepsy. MEG identified Rolandic dipoles, although was unable to localize the deep and focal epileptogenic dipoles from the hippocampal sclerosis.     

Effect of epilepsy, seizures and epileptiform EEG discharges on cognitive function

Patients with an established diagnosis of epilepsy were included in three groups on the basis of the absence (Group 2) or presence (Group 3) of epileptiform EEG discharges or subtle seizures (Group 4) during the cognitive assessment procedure. A separate age-matched non-epileptic control group (Group 1) was formed. Twenty-five patients were included in each of the four groups. Thus, a total of 100 patients were investigated. The patients were assessed with continuous 21-channel EEG and video-monitoring, combined with cognitive testing. The results show consistently lower performance on cognitive tests for Group 4, the group with subtle seizures. The difference with the control group was significant for the intelligence subtests and for the complex information processing test (p<0.05). No transient cognitive impairment was found. The results are discussed in the light of possible factors that may be responsible for the lower test-scores in the patients of Group 4: both the ictal effects of the seizures themselves, postictal effects and the effects of the epileptiform EEG discharges may have had an impact on cognitive performance. Finally the absence of evidence for transient cognitive impairment in a group with frequent epileptiform EEG discharges is discussed in detail.     

伴全面放电的局灶性癫痫的临床特征及手术治疗

目的 探讨伴有全面性发作间期癫痫样放电（GIEDs）的局灶性癫痫患者的临床特征及手术疗效。方法 回顾性分析2011年1月至2014年6月收治的733例MRI显示有局部异常的癫痫患者的临床资料,发作间期出现全导联同步异常放电（包括同时有局灶性异常放电形式）60例（伴GIEDs组）,673例没有这种表现（不伴GIEDs组）。伴GIEDs组中,19例采用手术治疗。结果 伴GIEDs组起病年龄≤12岁比例（80.0%,48/60）明显高于不伴GIEDs组（46.2%,311/673;PPP<0.05）。19例手术治疗患者术后随访1年以上,无明显永久的神经功能损伤,发作控制效果按engel分级:ⅰ级13例,ⅱ级2例,ⅲ~ⅳ级4例。>结论 局灶性癫痫患者可伴有GIEDs,手术治疗或可为该类患者提供一定的获益。     

Periodic lateralized epileptiform discharges (PLEDs): a possible role for metabolic factors in pathogenesis

Periodic, lateralized, epileptiform discharges (PLEDs) in the electroencephalogram have been reported in association with a variety of structural lesions of the brain. Although a great deal of attention has been directed to the neuropathological basis of PLEDs, little emphasis has been placed on the functional basis of this EEG syndrome. In this paper, we reported a patient with multiple systemic problems whose EEG showed PLEDs. However, radiological and pathological studies revealed no neuropathological basis for the occurrence of this EEG syndrome. Thus, we presented evidence that metabolic factors may play a part in the pathogenesis of PLEDs.     

Periodic lateralized epileptiform discharges (PLEDs) as the sole electrographic correlate of a complex partial seizure.

We describe a patient in whom the only electrographic manifestation of a complex partial seizure recorded by video-EEG telemetry was periodic lateralized epileptiform discharges (PLEDs) with a left anterior temporal emphasis. The abnormality, which persisted throughout the whole recorded seizure, lends support to the claim that PLEDs can be an ictal phenomenon.     

Subacute encephalopathy with seizures in alcoholics (SESA syndrome) revisited

PurposeThe aim of this paper is to describe two additional cases of subacute encephalopathy with seizures in alcoholics (SESA syndrome), and to propose that this entity now should be considered as a subtype of nonconvulsive status epilepticus (NCSE).MethodsWe retrospectively analyzed the clinical characteristics, electroencephalography (EEG), neuroimaging data, and prognosis of these two further cases of SESA syndrome. In addition, we compare our findings with the cases previously described in the English literature in order to propose new diagnostic criteria.ResultsTwo adults with history of chronic alcohol abuse were admitted because of confusion and seizures. A routine EEG showed frequent periodic lateralized epileptiform discharges (PLEDs) localized over the right temporal regions. In one case, we captured two complex partial seizures (CPSs) arising from the right hemisphere. Neuroimaging studies revealed subjacent chronic vascular pathology. Following transfer to the intensive care unit (ICU), both improved to antiepileptic treatment and were discharged with full recovery.ConclusionOn the basis of our findings and a review of the literature, we suggest that SESA syndrome represents a subtype of partial or localization-related NCSE given its particular clinical, electroencephalographic, neuroimaging and prognostic characteristics.