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Objective: Despite increasing amounts of research on periodic discharges (PDs), large clinical studies regarding their prognostic value are lacking. The aim of the current study was to evaluate the clinical implications and prognostic value of PDs., Methods: In this single-center retrospective cohort study, we included patients who underwent electroencephalographic recording either during hospitalization or from our outpatient clinics. Demographic data, associated seizure events, use of antiepileptic drugs, and outcomes at discharge were analyzed. Multivariate logistic regression analysis was used to evaluate associations between clinical factors and functional outcomes., Results: Four hundred and twenty patients were enrolled during a 17-year period, with a mean age of 66 years. The main etiologies included systemic infection (24%), anoxia (15%), and ischemic stroke (12%). Recent seizures were identified in 283 patients (67%), of whom 84 (30%) had status epilepticus. One hundred and fifty-four patients (37%) did not survive to hospital discharge. In multivariate analysis, old age (>65years; OR=2.55; 95% CI=1.57-4.16; P<0.001) was the strongest predictor of mortality, followed by systemic infection, anoxic encephalopathy, cefepime encephalopathy, and the occurrence of status epilepticus. Conversely, the use of antiepileptic drugs was negatively associated with mortality (OR=0.50; 95% CI=0.28-0.87; P=0.02)., Conclusions: PDs were associated with high rates of comorbidities and recent seizures, while the use of antiepileptic drugs was associated with a lower rate of mortality., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: Previous studies have demonstrated different diagnostic yields with electroencephalography (EEG). Due to the small sample sizes or different patient populations (outpatients or inpatients only) in these previous studies, the clinical use of routine EEG and outpatient/inpatient video-EEG monitoring (VEM) needs further clarification. In this study, we investigated EEGs obtained from patients referred by epileptologists; by comparing the results of different EEG methods, we sought to determine the optimal durations and specific types of EEG recordings for different clinical situations., Methods: The data from 335 routine EEGs, 281 3 h outpatient VEMs, and 247 inpatient VEMs (>48 h) were reviewed. We analyzed the latency to the first epileptiform discharge or clinical event., Results: In patients undergoing outpatient VEMs, 48% of the first epileptiform discharges appeared within 20 min, and 64% appeared within 30 min. In patients undergoing inpatient VEMs, 21.2% had their first attack within 3h. The second peak of event occurrence was during the 33rd-36th h. Only 3.5% of the seizures were recorded after 57 h. The detection rate of epileptiform discharges was higher for 3h outpatient VEM than for routine EEG (54.1% versus 16.4%, p<0.01). Epileptic and/or nonepileptic events were recorded in 45.8% of the inpatient VEMs, the diagnostic yield of which was higher than for outpatient VEMs (p<0.01). Since the patients in this study had been selected to limit the bias between each group, the diagnostic yield of EEGs in this study are likely to have been higher than those found in routine practice. Patients with generalized epilepsy had a shorter latency to the first epileptiform discharge compared to patients with localization-related epilepsy (mean, 22.1 min versus 33.9 min, p<0.05)., Conclusions: Two-thirds of epileptiform discharges were detected within 30 min of VEM. A 30-min recording is recommended for routine EEG examinations that aim to detect epileptiform discharges. A 3h outpatient VEM is a reasonable option when a routine EEG fails to detect epileptiform discharges. The latency to the first epileptiform discharge was shorter in patients with generalized epilepsy than in patients with localization-related epilepsy. 48 h of inpatient VEM might be adequate for detecting the target events., (Copyright © 2013 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Intracranial electroencephalograms (EEG) provide a direct observation of neural activity by placing an electrode array on the cortical surface near the suspected epileptic foci. The neural spikes appeared during inter-ictal stages are mainly produced by abnormal neural discharges from epileptic foci. The topological mapping of spikes' potentials is commonly used to identify the epileptogenic zone. However, the propagations among multi-channel spikes are also important to identify the epileptic source activity. In addition, the changes of source activities in a series of consecutive spikes reveal the time-varying neural activations during discharge process, which provide alternative information for interpreting epileptic source activity. This paper proposes a spike classification based on the similarity of phase-space features to select candidate spikes from the intracranial EEGs recorded from an 8×8 electrocorticogram grid. Then, the partial directed coherence (PDC), which can provide the flow of source activity, at each spiking time point is computed. The outflow PDCs of all electrodes are therefore displayed on the grid. Our result showed that the derived source activities in the preceding spikes had high concentrated distributions but decreased in latter spikes. This implied the epileptic discharges were initially induced by a small-area cortex neurons and then spread out.

The electrophysiological studies of thalamocortical oscillations were mostly done in animal models. Placement of stimulation electrodes at the anterior nucleus of the thalamus (ANT) for seizure reduction enables the study of the thalamocortical interplay in human subjects. Nocturnal sleep electroencephalograms (EEGs) and local field potentials (LFPs) of the left and right thalamus (LT, RT) were recorded in three subjects receiving ANT stimulation. Sleep stages were scored according to American Academy of Sleep Medicine criteria. The whole-night time-frequency coherence maps between EEG (C3, C4) and LFP (LT, RT) showed specific coherence patterns during non-rapid eye movement (NREM) sleep. Pooled coherence in the NREM stage was significant in slow, delta, theta and spindle frequency ranges. The spindle oscillations had the highest coherence (0.17-0.58) in the homolateral hemisphere. Together, these observations indicate that the oscillations were related to thalamocortical circuitry., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Ocular artifacts are the most important form of interference in electroencephalogram (EEG) signals. An adaptive filter based on reference signals from an electrooculogram (EOG) can reduce ocular interference, but collecting EOG signals during a long-term EEG recording is inconvenient and uncomfortable for the patient. In contrast, blind source separation (BSS) is a method of decomposing multiple EEG channels into an equal number of source components (SCs) by independent component analysis. The ocular artifacts significantly contribute to some SCs but not others, so uncontaminated EEG signals can be obtained by discarding some or all of the affected SCs and re-mixing the remaining components. BSS can be performed without EOG data. This study presents a novel ocular-artifact removal method based on adaptive filtering using reference signals from the ocular SCs, which avoids the need for parallel EOG recordings. Based on the simulated EEG data derived from eight subjects, the new method achieved lower spectral errors and higher correlations between original uncorrupted samples and corrected samples than the adaptive filter using EOG signals and the standard BSS method, which demonstrated a better ocular-artifact reduction by the proposed method.

Background: To analyze the surgical outcomes of patients with temporal lobe epilepsy with bilateral foci after one-week bilateral subdural strip electrocorticographic (ECoG) recording., Methods: We retrospectively evaluated 12 patients with bilateral epileptic foci after scalp electroencephalography examination who underwent ECoG between May 1995 and July 2000. Subdural strips were implanted in the bilateral subtemporal regions for a one-week ECoG recording., Results: All but one of the patients exhibited unilateral dominance of epileptogenic discharges (> 65%) and, following an anterior temporal lobectomy, the majority of patients (8 of 11) enjoyed a seizure-free life during the ensuing 3 years. No mortality or morbidity such as intracranial hemorrhage or wound infection was noted., Conclusions: The dominance of an epileptic focus in patients with bitemporal epileptogenic discharges can thus be successfully recorded by electrocorticographic monitoring prior to anterior temporal lobectomy.

Background: Long term video-electroencephalography monitoring (VEM) has been widely used for the diagnosis, classification, and management of seizures. Few studies have systemically examined its safety issues and clinical utility. This prospective study investigates the general clinical application of long term VEM in the management of paroxysmal events., Methods: This study cohort consisted of patients admitted to the inpatient VEM unit at Chang Gung Memorial Hospital (Lin-Kou). Standard 19 channel scalp electroencephalography (EEG), electrocardiography (ECG), and simultaneous video images were recorded continuously for 2 full days. Patient characteristics, and clinical, video-EEG and safety data were obtained and analyzed. The diagnosis and management of paroxysmal events before VEM were compared with those after VEM., Results: Habitual events were recorded in 54.3% of the 129 patients, and VEM had a yield rate of 76% (events recorded or newly recorded interictal discharges) indetermining the nature of the events. Eleven patients had seizure clusters, but there was no status epilepticus or electrode-related injury. After VEM, the diagnostic categories were changed in 41.1% of the patients, and 40.3% had revisions in management., Conclusions: Long term VEM is a safe diagnostic tool providing a high diagnostic yield rate and directing adjustment of management for patients with paroxysmal events.

Patients with juvenile myoclonic epilepsy (JME) may not achieve seizure freedom despite optimal treatment with antiseizure medications (ASMs). The aim of this study was to investigate the clinical and social features of patients with JME, and to determine the factors associated with outcomes. We retrospectively identified 49 patients with JME (25 females, mean age 27.6 ± 8.9 years) who were assessed at the Epilepsy Centre of Linkou Chang Gung Memorial Hospital in Taiwan. The patients were divided into two groups, those who were seizure-free and those with ongoing seizures according to their seizure outcome at the last follow-up for one year. Clinical features and social status were compared between these two groups. Twenty-four (49%) of the JME patients were seizure-free for at least one year, while 51% continued to experience seizures despite being treated with multiple ASMs. The presence of epileptiform discharges in the last electroencephalogram and seizures during sleep were significantly associated with worse seizure outcomes (p < 0.05). The patients who were seizure-free had a higher employment rate compared to those who continued to experience seizures (75% vs. 32%, p = 0.004). Despite receiving ASM treatment, a considerable proportion of the patients with JME continued to have seizures. Moreover, poor seizure control was associated with a lower employment rate, which may lead to negative socioeconomic consequences related to JME. [ABSTRACT FROM AUTHOR]

• Deep neural networks to detect Interictal epileptiform discharges (IEDs) in temporal lobe epilepsy. • Detection models on the basis of convolutional neural network and long short-term memory network. • IED detection across electroencephalograms of interest. Although interictal epileptiform discharges (IEDs) are a biomarker of epilepsy on electroencephalograms (EEGs), the manual annotation of IEDs is laborious. Thus, several IED detection methods have been proposed. However, the majority of these methods focus on single or whole cerebral channels. In this study, we examined the effect of channel selection and epoch length on the IED detection of temporal-lobe epilepsy (TLE). We identified two types of deep neural networks for IED detection: convolutional neural networks (CNNs) and long short-term memory (LSTM) networks. We evaluated their performance using the F1-score, a global index of the sensitivity of IED detection, and the proportion of correctly detected IEDs based on scalp EEGs collected from 20 individuals with TLE. We then discovered that selecting EEGs from the affected temporal lobe or hemisphere was associated with a higher F1-score compared with selecting whole cerebral EEGs. In addition, we discovered that selecting a long EEG epoch (3 s) in the CNN model and selecting a short epoch (1.5 s) in the CNN + LSTM model resulted in the highest F1-score. In conclusion, deep neural networks are effective in detecting the TLE IEDs underlying an adequate epoch length when applied to EEGs of interest. [ABSTRACT FROM AUTHOR]

Background Refractory status epilepticus (RSE) is considered a medical emergency in neurology and is related to high mortality. We report a successfully treated case of RSE using deep brain stimulation (DBS) at the anterior thalamic nuclei (ATN) in a 17-year-old woman. Results This patient developed RSE as a result of progressive seizure activity. RSE with generalized tonic-clonic seizures was noted 2 weeks before admission. Video electroencephalography monitoring showed continuous 3-Hz generalized spike-and-wave complexes with higher amplitude over bilateral frontal. Four weeks after RSE onset, bilateral DBS of the ATN was started. This treatment was immediately followed by the disappearance of tonic-clonic seizures and spike-and-wave complexes, suggesting resolution of the RSE. Significant clinical improvement was noted 1 week after DBS implantation. Conclusions DBS at the ATN significantly improved both the electroencephalography and clinical presentation in the patient with RSE. DBS at the ATN should be considered as a possible treatment choice once a patient develops RSE. [ABSTRACT FROM AUTHOR]

Summary: Purpose: Epileptic seizures in Chinese patients with multiple sclerosis (MS) have not been studied extensively. We investigated the clinical, laboratory, and imaging findings for Chinese patients with MS who had experienced seizures. Methods: A total of 93 (57.4%) patients were diagnosed as having conventional MS and 69 (42.6%) patients as having neuromyelitis optica (NMO) over 20years. Data on clinical symptoms, related examinations, and treatment were analyzed retrospectively. Results: Eight patients (8.6%), all of whom were female, had seizures during the course of relapsing–remitting MS. One had seizures as the presenting symptom of MS. The seizure type was focal onset in all the 8 patients, 6 of whom had secondarily generalized seizures. Only 1 patient was recorded as having focal epileptiform discharges by electroencephalography. The frequency of seizures was significantly higher in patients with recurrent seizures than in those with acute-MS-related seizures. Diffuse or extensive lesions were observed in acute-MS-related seizures; focal persistent lesions were related to recurrent seizures or even status epilepticus, both of which need long-term antiepileptic medication. Conclusion: The seizure courses (acute or recurrent) and distribution of lesions (diffuse or localized) might provide information on seizure recurrence and decide antiepileptic treatment strategies. [Copyright &y& Elsevier]

Background Surgical interventions are often used for freedom from seizure in patients with drug-resistant mesial temporal lobe epilepsy. A patient with seizure foci in the left mesiotemporal region underwent limited-size stereotactic radiofrequency thermocoagulation (RF-TC) over the left hippocampus. Case Description A 37-year-old woman with febrile convulsion in her childhood was admitted to our neurologic department with complex partial seizure with secondary generalization. Electroencephalography showed epileptogenic focus mainly from the left mesiotemporal region, and magnetic resonance imaging confirmed a left hippocampal atrophy. Because of failure to control seizure after use of several antiepileptic drugs, drug-resistant mesial temporal lobe epilepsy was diagnosed. RF-TC was done in the left hippocampus. Unique features of our technique include intraoperative electroencephalography recordings directly from electrodes on the left hippocampus, an aura sensation provoked during the low-temperature test thermocoagulation, and therapeutic thermocoagulation performed via a Radionics radiofrequency lead. In the 16-week period following the surgery, the patient experienced no seizure attacks and no significant postoperative adverse effects or memory impairments. Compared with other reports using RF-TC, our case demonstrates a 1-step minimally invasive surgery that reduces hippocampal volume loss, shortens the length of hospital stay, decreases the occurrence of postoperative infection, and achieves good outcomes for epilepsy control. Conclusions Favorable seizure control was achieved with minimally invasive RF-TC. Further use of this technique is warranted in cases of drug-resistant mesial temporal lobe epilepsy. [ABSTRACT FROM AUTHOR]