Epileptiform Discharges In Patients Research Articles

Subclinical epileptiform discharges in Alzheimer’s disease are associated with increased hippocampal blood flow

BackgroundIn epilepsy, the ictal phase leads to cerebral hyperperfusion while hypoperfusion is present in the interictal phases. Patients with Alzheimer’s disease (AD) have an increased prevalence of epileptiform discharges and a study using intracranial electrodes have shown that these are very frequent in the hippocampus. However, it is not known whether there is an association between hippocampal hyperexcitability and regional cerebral blood flow (rCBF). The objective of the study was to investigate the association between rCBF in hippocampus and epileptiform discharges as measured with ear-EEG in patients with Alzheimer’s disease. Our hypothesis was that increased spike frequency may be associated with increased rCBF in hippocampus.MethodsA total of 24 patients with AD, and 15 HC were included in the analysis. Using linear regression, we investigated the association between rCBF as measured with arterial spin-labelling MRI (ASL-MRI) in the hippocampus and the number of spikes/sharp waves per 24 h as assessed by ear-EEG.ResultsNo significant difference in hippocampal rCBF was found between AD and HC (p-value = 0.367). A significant linear association between spike frequency and normalized rCBF in the hippocampus was found for patients with AD (estimate: 0.109, t-value = 4.03, p-value < 0.001). Changes in areas that typically show group differences (temporal-parietal cortex) were found in patients with AD, compared to HC.ConclusionsIncreased spike frequency was accompanied by a hemodynamic response of increased blood flow in the hippocampus in patients with AD. This phenomenon has also been shown in patients with epilepsy and supports the hypothesis of hyperexcitability in patients with AD. The lack of a significant difference in hippocampal rCBF may be due to an increased frequency of epileptiform discharges in patients with AD.Trial registrationThe study is registered at clinicaltrials.gov (NCT04436341).

Termination of convulsion seizures by destabilizing and perturbing seizure memory engrams.

Epileptogenesis, arising from alterations in synaptic strength, shares mechanistic and phenotypic parallels with memory formation. However, direct evidence supporting the existence of seizure memory remains scarce. Leveraging a conditioned seizure memory (CSM) paradigm, we found that CSM enabled the environmental cue to trigger seizure repetitively, and activating cue-responding engram cells could generate CSM artificially. Moreover, cue exposure initiated an analogous process of memory reconsolidation driven by mammalian target of rapamycin-brain-derived neurotrophic factor signaling. Pharmacological targeting of the mammalian target of rapamycin pathway within a limited time window reduced seizures in animals and interictal epileptiform discharges in patients with refractory seizures. Our findings reveal a causal link between seizure memory engrams and seizures, which leads us to a deeper understanding of epileptogenesis and points to a promising direction for epilepsy treatment.

Mandibular and chin electrodes as a supplemental recording for detection of epileptiform discharges in mesial temporal lobe epilepsy.

We previously demonstrated the usefulness of periorbital electrodes in supplemental recording to detect epileptiform discharges in patients with mesial temporal lobe epilepsy (MTLE). However, eye movement may disturb periorbital electrode recording. To overcome this, we developed mandibular (MA) and chin (CH) electrodes and examined whether these electrodes could detect hippocampal epileptiform discharges. This study included a patient with MTLE, who underwent insertion of bilateral hippocampal depth electrodes and video-electroencephalographic (EEG) monitoring with simultaneous recordings of extra- and intracranial EEG as part of a presurgical evaluation. We examined 100 consecutive interictal epileptiform discharges (IEDs) recorded from the hippocampus and two ictal discharges. We compared these IEDs from intracranial electrodes with those from extracranial electrodes such as MA and CH electrodes in addition to F7/8 and A1/2 of international EEG 10-20 system, T1/2 of Silverman, and periorbital electrodes. We analyzed the number, rate of laterality concordance, and mean amplitude of IEDs detected in extracranial EEG monitoring and characteristics of IEDs on the MA and CH electrodes. The MA and CH electrodes had nearly the same detection rate of hippocampal IEDs from other extracranial electrodes without contamination by eye movement. Three IEDs, not detected by A1/2 and T1/2, could be detected using the MA and CH electrodes. In two ictal events, the MA and CH electrodes detected the ictal discharges from the hippocampal onset as well as other extracranial electrodes. The MA and CH electrodes could detect hippocampal epileptiform discharges as well as A1/A2, T1/T2, and peri-orbital electrodes. These electrodes could serve as supplementary recording tools for detecting epileptiform discharges in MTLE.

Epileptiform Discharges in Patients with Psychogenic Non-Epileptic Attacks: A Case Series (P1-1.009)

<h3>Objective:</h3> We present a small case series of patients with psychogenic non-epileptic attacks (PNEA), who were misdiagnosed with “refractory epilepsy” based on the presence of epileptiform discharges (EDs), particularly generalized spike-and-wave, on their EEG. This diagnosis was reversed after admission to the epilepsy monitoring unit for spell characterization, where all stereotypical events of interest were captured and were deemed non-epileptic. <h3>Background:</h3> Over the past decade, there was an increased emphasis on the need to correctly diagnose patients with PNEA to avoid unnecessary treatment with anti-seizure drugs and initiate psychotherapy to attain good clinical outcome. Misdiagnosing PNEA with “refractory epilepsy” could be due to misinterpreted EEG as “abnormal with epileptiform discharges” or co-existence of PNEA with EDs in the absence of clinical seizures. Although, PNEA is seen in up to 12% of epilepsy patients, there are rare cases where PNEA only occurs without confirmed epilepsy despite the presence of EDs. <h3>Design/Methods:</h3> We identified seven patients with only PNEA and EDs admitted to Epilepsy Monitoring Unit for “refractory epilepsy” and retrospectively reviewed their records including their EEG. <h3>Results:</h3> None of the stereotypical events captured on video-EEG was associated with ictal EEG correlates. Six had generalized spike-and-wave discharges (GSW) without clinical accompaniments. Of patients who initiated psychotherapy, 60% had ≥ 50% reduction in frequency of PNEA. <h3>Conclusions:</h3> EDs can occur in “PNEA-only” patients and shouldn’t delay PNEA diagnosis or effective psychotherapeutic treatment. <b>Disclosure:</b> Dr. Afify has nothing to disclose. The institution of Dr. Tolchin has received research support from C.G. Swebilius Trust. The institution of Dr. Altalib has received research support from UCB. The institution of Dr. Altalib has received research support from Eisai. The institution of Dr. Altalib has received research support from Sunovian. The institution of Dr. Altalib has received research support from DEPARTMENT OF DEFENSE - CONGRESSIONALLY DIRECTED MEDICAL RESEARCH PROGRAMS. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Aquestive. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ceribell. Dr. Hirsch has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for marinus. Dr. Hirsch has received personal compensation in the range of $0-$499 for serving as a Consultant for Medtronic. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. Hirsch has received personal compensation in the range of $0-$499 for serving as a Consultant for Accure. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Neuropace. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Neurelis. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Eisai. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Rafa Laboratories, Ltd. Dr. Hirsch has received publishing royalties from a publication relating to health care. Dr. Hirsch has received publishing royalties from a publication relating to health care. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Speaker with Neuropace. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a Speaker with Natus. Dr. Hirsch has received personal compensation in the range of $500-$4,999 for serving as a speaker with UCB. Dr. Herlopian has nothing to disclose.

Additional overnight video EEG for the diagnosis of epilepsy: Experiences from Western Kenya

ObjectiveThe prolonged video EEG monitoring is widely used for the diagnosis and management of epilepsy, especially during the presurgical evaluation. The routine practice in neurology is to order a prolonged recording like an overnight EEG when the initial routine EEG is normal or unrevealing. Only few studies have evaluated this sequential approach and we aimed in this study to evaluate the added diagnostic value of a relatively brief video EEG monitoring especially in developing nations where the history of seizure semiology may be harder to obtain, and the video EEG monitoring technology is scarce. MethodsThis study analyzed retrospectively 167 overnight video EEG records in one of the secondary healthcare facilities in Western Kenya between March 2018 and March 2021. The indications were mainly further diagnosis and seizure classification. All the patients had an unrevealing routine EEG and 162 of them were normal. ResultsAdditional epileptiform discharges were recorded in 91 of those 162 with initial normal routine EEG. Further classification of seizure was achieved in 67 patients among 112 with initially unclassified seizure before the overnight recording. The improvement of 68% (97 out of 143 patients without a prior epilepsy diagnosis) for the diagnosis of epilepsy in those patients without initial final diagnosis is comparable to other similar studies but mostly with a longer duration of recording. The diagnosis was changed or at least improved in 142 (85%) patients out of the 167 patients who underwent the overnight video EEG. The treatment modification was immediately considered in 116 after the prolonged recording. ConclusionsAdding an overnight video EEG to an unrevealing routine EEG can significantly increase the likelihood of detecting additional epileptiform discharges in patients with epilepsy, thereby improving diagnostic yield and aiding in treatment adjustment for all patients suspected of having epilepsy. SignificanceThe sequential approach of adding a prolonged video EEG monitoring even as brief as an overnight video EEG to an unrevealing routine EEG has a very significant impact in further classification of seizure and diagnosis of epilepsy especially in a resource limited set up.

Effect of current conduction for local epileptiform discharges in patients with temporal lobe epilepsy.

The effects of current conduction were researched to confirm that it can decrease focal epileptogenicity in patients with temporal lobe epilepsy (TLE). Data from 13 patients with mesial TLE were collected. After no less than two habitual seizures were captured during stereo-electroencephalogram monitoring, current conduction was measured in the hippocampus to a homemade, zero potential circuit board. The interictal spike, ripple, fast ripple, and ictal epileptogenicity index (EI) changes were analyzed in the hippocampus, amygdala, and anterior and middle temporal neocortex regions. Significant differences were found in the percentage of patients without spikes in the temporal neocortex between pre- and post-current conduction. Significant decreases in average ripple rates were found in the hippocampus and amygdala after current conduction. The percentage of fast ripple rate decrease in the hippocampus and amygdala was significantly higher than that in the temporal neocortex, and significant decreases were found in the fast ripple rate in the hippocampus from post- to pre-current conduction. Significant decreases were found in the EI values after current conduction in the amygdala and middle temporal lobe compared to the EI values before current conduction. After current conduction in patients with TLE, the spike rate decreases in the hippocampus, amygdala, and anterior and middle temporal neocortex, the ripple rate decreases in the hippocampus and amygdala, the fast ripple decreases in the hippocampus, and the EI decreases in the amygdala and middle temporal neocortex. Current conduction can reduce epileptogenicity in the hippocampus in mesial TLE.

Omitting Hyperventilation in Electroencephalogram during the COVID-19 Pandemic May Reduce Interictal Epileptiform Discharges in Patients with Juvenile Myoclonic Epilepsy.

Background: To prevent the spread of coronavirus disease 2019 (COVID-19), hyperventilation (HV) activation has been avoided in electroencephalograms (EEGs) since April 2020. The influence of omitting HV in EEG on epilepsy diagnosis remains uncertain for patients with epilepsies other than child absence epilepsy. We hypothesized that EEGs with HV would show more interictal epileptiform discharges (IEDs) than EEGs without HV in patients with juvenile myoclonic epilepsy (JME). Methods: We reviewed the EEGs of seizure-free patients with JME who underwent EEG, both with and without HV, from January 2019 to October 2021, in our institution, and compared IEDs between EEG with and without HV. Results: This study analyzed 23 JME patients. The IED-positive rate was significantly higher in EEG with HV (65.2%) than in EEG without HV (34.8%, p = 0.016). The mean ± standard deviation number of IEDs per minute was significantly larger during HV (1.61 ± 2.25 × 10−1) than during non-activation of both first EEG (0.57 ± 0.93 × 10−1, p = 0.039) and second EEG (0.39 ± 0.76 × 10−1, p = 0.009). Conclusions: In JME patients, performing HV during EEG may increase IEDs and appears to facilitate the accurate diagnosis of epilepsy.

Let there be light: Inhibitory effect of photic stimulation on spike frequency in patients with mesial temporal lobe epilepsy with hippocampal sclerosis

Inhibition of epileptic discharges and seizures by sensory stimuli is an interesting phenomenon, but highly understudied. Here, we aimed to investigate the modulation of epileptiform discharges in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) via photic stimulation (PS), based on a hypothesis that light stimulation may activate thalamocortical networks limiting the propagation of interictal epileptiform discharges. In order to do so, all EEGs performed in patients diagnosed with MTLE-HS were reviewed to include available recordings with definite epileptiform abnormalities. These were reevaluated by two clinical neurophysiologists independently, and spikes were counted in a blinded manner to calculate spike index (SI) (spikes per minute-pm) for baseline EEG, hyperventilation (HV), and PS periods. Our final study group consisted of 30 MTLE-HS patients with a mean age of 34.5 (±12.5) years. Mean seizure frequency was 38.1 per year (±46.6), and the mean disease duration was 16.2 years (±12.1). Mean SI during baseline was calculated as 1.17 pm (±1.4), during HV 2.1 pm (±2.8) and during PS 0.8 pm (±2.5). As a result, SI was significantly lower during PS compared to baseline (p = 0.001). Our findings suggest that PS has a remarkable inhibitory effect on epileptiform discharges in MTLE-HS patients, indicating the need for further prospective investigations for clinical translation.

Electro-clinical analysis of epilepsy patients with generalized seizures on adjunctive perampanel treatment

Quantifying epileptiform discharges before and after the initiation of treatment can be useful for evaluating the efficacy of antiepileptic drugs in generalized epilepsy. The aim of this study was to determine if the selective α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor antagonist perampanel alters the electroencephalographic signals in patients with drug resistant generalized seizures (primary or secondary). We also assessed the clinical efficacy, safety and tolerability of perampanel as an adjunctive treatment for patients with refractory generalized seizures after 3, 6 and 12 months of treatment to determine if there is an electro-clinical correlation. We carried out a 1-year retrospective, unicentric, observational, descriptive and non-interventional study to analyze changes in epileptiform discharges, seizure frequency and adverse effects in patients with generalized seizures taking perampanel as an add-on treatment. Perampanel significantly reduced the total number, total duration, maximal duration and average duration of epileptiform discharges in patients with primary generalized epilepsy (n = 44). In patients with focal onset epilepsy and secondary generalized seizures (n = 8) significant decreases in the maximal duration and average duration of epileptiform discharges were found. These findings correlate with the significant decrease in seizure frequency and clinical improvement observed after taking perampanel as an adjunctive therapy for 3, 6 and 12 months. To our knowledge, this is the first study to show that perampanel reduces epileptiform activity, and that this effect correlates with patients’ clinical improvement. Analysing patients’ electroencephalographic activity in response to perampanel could be useful for assessing the drug’s efficacy and optimising adjunctive treatments.

The association between duration of video-electroencephalogram (VIDEO-EEG) recording and detecting epileptiform discharges in patients with psychogenic non epileptic seizures (PNES) and epilepsy

The association between duration of video-electroencephalogram (VIDEO-EEG) recording and detecting epileptiform discharges in patients with psychogenic non epileptic seizures (PNES) and epilepsy

P01-F Let there be light: Inhibition of spikes by photic stimulation in mesial temporal lobe epilepsy

Background Inhibition of epileptic discharges and seizures by sensory stimuli is an interesting field of study with possible clinical translations. We aimed to investigate modulation of epileptiform discharges in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) via photic stimulation. Material and methods All EEGs recorded in 2018 have been screened for MTLE-HS patients retrospectively. Those EEGs with epileptiform abnormalities have been re-evaluated by two clinical neurophysiologists independently and all spikes were counted in a blinded manner. Spike indices (SI) (spikes per minute) have been calculated for baseline EEG, hyperventilation and photic stimulation periods after a consensus training, based on two different counts. Clinical findings like age, side of HS, hand dominance, antiepileptic drug regimen, disease duration have been noted from their files. Results There were 76 MTLE-HS patients, 33 of them had at least one available EEG with epileptiform abnormalities; clinical data was available for 30 patients. Mean age of these included 30 patients was 34.5 (SD: 12.5), male to female ratio was 8:7, 33.3% had right (n = 10), 26.7% had left (n = 8) and 40% had bilateral MTLE-HS (n = 12). Mean SI during the baseline was 1.17 (SD: 1.4), hyperventilation 2.1 (SD: 2.8) and photic stimulation 0.8 (SD: 2.5). SI was significantly lower during photic stimulation compared to baseline EEG (p = 0.001). Hyperventilation gave rise to an increase in SI (p Conclusions Our findings suggest that photic stimulation have a remarkable inhibitory effect on epileptiform discharges in MTLE-HS patients.

Diagnostic Yield of 2-Hour EEG Is Similar With 30-Minute EEG in Patients With a Normal 30-Minute EEG.

Current literature suggests that longer duration of EEG recording increases the yield of detecting interictal epileptiform discharges. However, optimal duration for a repeat study in patients with initially normal 30-minute EEG is not clear. Thus, the purpose of this study is to determine whether a 2-hour EEG has a diagnostic advantage over a routine 30-minute EEG in detecting epileptiform abnormalities in patients who had a first normal 30-minute EEG. This is a single-center, retrospective study done at UT Southwestern Medical Center at Dallas and Parkland Memorial Hospital. The data from 1997 to 2015 were extracted from the existing EEG report database for patients who had a first normal 30-minute EEG recording. EEG was interpreted by board-certified clinical neurophysiologists, who classified each EEG as normal or abnormal, with relevant subsequent subclassification. Over 18 years, a total of 12,425 individual 30-minute EEGs were performed. Of these, 1,023 patients had at least one repeated EEG after the first normal EEG. Among these patients, 763 had a 30-minute EEG as the second study and 260 had a 2-hour EEG as the second study. The yield of epileptiform discharges was 3.3% in the 30-minute EEG group and 4.2% in the 2-hour EEG group (P = 0.5) in the repeating studies. Two-hour EEG has a similar yield as 30-minute EEG to detect epileptiform discharges in patients with a normal 30-minute EEG.

Source analysis of epileptiform discharges in absence epilepsy using Magnetoencephalography (MEG)

PurposeMagnetoencephalography (MEG) was used to record and localize the sources of the epileptiform discharges, in absence epilepsy, at three different time intervals to infer the sources of involvement during generation and propagation. MethodsTwenty patients with absence epilepsy (M:F=1:1; age: 10.2±3.4years), which included 12 patients with childhood absence epilepsy (CAE) and 8 patients with juvenile absence epilepsy (JAE), were recruited in this prospective MEG based study. MEG epileptiform discharges were divided into three sub-groups based on the duration viz., 1s (very short),>1–9.9s (short) and ≥10s (long) and the discharges of each group were averaged independently in each patient. MEG source analysis was performed on these averaged discharges, of each of the subgroups, at the onset, during middle and offset. ResultsThe source locations obtained, in lobar and gyri levels, were compared across these three groups of varying duration of discharges and in the CAE and JAE subjects. It was observed that the most frequent location of sources from the sublobar, limbic and frontal lobes in all the discharge groups at different time intervals. Also, it was noted that there were only subtle and variable degree of the differences of source localization of epileptic discharges among CAE and JAE subgroups. ConclusionThe study provided novel findings regarding origin and propagation of sources of epileptiform discharges in patients with childhood and juvenile absence epilepsies. Such analysis further improves the understanding of network involvement of subcortical and cortical regions in these patients.

Seizures and Epileptiform Discharges in Patients With Acute Subdural Hematoma.

Subdural hematomas (SDH) are associated with seizures and epileptiform discharges, but little is known about the prevalence and impact of seizures, status epilepticus (SE), and epileptiform discharges on outcomes in patients with isolated acute SDH (aSDH). Continuous EEG reports from 76 adult patients admitted to Rush University Medical Center with aSDH between January 2009 and March 2012 were reviewed. Clinical and radiographic findings, comorbidities, treatment, and outcome parameters, such as mortality, discharge destination, need for tracheostomy/percutaneous endoscopic gastrostomy placement, and length of stay (LOS), were assessed. Univariate and multivariate analyses were performed to assess the impact of clinical seizures, SE, and epileptiform EEG on outcomes. Of 76 patients with aSDH who underwent EEG monitoring, 74 (97.4%) received antiseizure prophylaxis. Thirty-two (41.1%) patients had seizures, most of which were clinical seizures. Twenty-four (32%) patients had epileptiform EEG findings. Clinical or nonconvulsive SE was diagnosed in 12 (16%) patients. Clinical seizures were not associated with outcome parameters. Epileptiform EEG findings were independently associated with longer hospital LOS (13 vs. 8 days, P = 0.04) and intensive care unit LOS (10 vs. 4 days, P = 0.002). The SE also predicted longer intensive care unit LOS (10 vs. 4 days, P = 0.002). Neither epileptiform EEG nor SE was significantly related to mortality, discharge destination, or need for tracheostomy/percutaneous endoscopic gastrostomy placement. Seizures and epileptiform EEG findings are very common in patients with aSDH despite antiseizure prophylaxis. While clinical seizures did not affect outcomes, the presence of epileptiform EEG findings and SE was independently associated with longer intensive care unit LOS and hospital LOS.

Impaired Executive Function by Interictal Epileptiform Discharges in Patients with Idiopathic Generalized Epilepsy

Objective: Many patients with Idiopathic Generalized Epilepsy (IGE) exhibit cognitive deficits. Interictal Epileptiform Discharges (IEDs) may contribute to cognitive impairment in epilepsy; however, the relationship between IEDs and cognitive impairment is unclear. Methods: In this study, we analysed executive function in three groups: IGE patients with IEDs, IGE patients without IEDs and healthy controls. Executive function was assessed using the Stroop Test, the Verbal Fluency Test, the Digit Span Test and Wisconsin Card-Sorting Test. Results: The IGE patients with IEDs performed worse on executive function tests compared with patients without IEDs. Furthermore, the IGE patients without IEDs performed worse compared with healthy controls. There were significant differences between the three groups in performance on the Stroop Test, the Digit Span Test (forward and backward), Verbal Fluency Test (animals, fruits) and the subscales of WCST (Categories Completed, Correct Response, Total Errors and Preservative Errors). Conclusion: These results suggest that executive function in patients with IGE is impaired and is further impaired by IEDs. Future studies should determine whether well-controlled patients with IGE could benefit from antiepileptic treatment.

Clinical Impact of Epileptiform Discharge in Children With Attention-Deficit/Hyperactivity Disorder (ADHD)

The aim of this study was to investigate the prevalence and clinical significance of epileptiform discharges in patients with attention-deficit/hyperactivity disorder (ADHD). The authors retrospectively reviewed 180 children who were diagnosed with ADHD and had an electroencephalography (EEG) recording. Epileptiform discharges were found in 29 (16.1%) of 180 patients with ADHD. Of these, 15 (8.3%) had generalized epileptiform discharges and 14 (7.7%) had focal epileptiform discharges. The focal epileptiform discharges were most prevalent from the frontal (5/14) and rolandic area (5/14). Among the 29 patients with epileptiform discharges and ADHD, 5 patients had previous history of epilepsy and 4 patients developed epilepsy later, whereas none of the normal EEG group developed epilepsy. The authors suggest that interictal epileptiform discharges appear to be associated with seizure occurrence in children with ADHD and might reflect maturational pathophysiology overlapping with epilepsy.

A study on circadian rhythm of interictal epileptiform discharges in patients with localization related epilepsy

Objective To investigate the effects of circadian rhythm on interictal epileptiform discharges in patients with localization-related epilepsy. Methods Patients diagnosed with epilepsy in Sanbo Brain Hospital from January 2011 to January 2012 participated in this study.All patients were subjected to comprehensive evaluation, which included prolonged video-electroencephalogram (EEG), magnetic resonance imaging. Intracranial electrodes, PET, SPECT were also adopted if necessary. Circadian rhythm was divided into four stages: REM, NREM I-II, NREM III-IV, and waking.The amount and distribution of IID were compared by ANOVA. Results Significant differences in the amount and distribution of IID were found among NREM I-II, NREM III-IV, REM, and waking. However, no differences in the amount and distribution of IID were noted between NREM I-II and NREM III-IV as well as between REM and waking. Conclusion The amount of IID is higher in NREM than in REM and waking; thus, NREM is more sensitive to diagnose epilepsy.The distribution of IID in REM and waking is more restricted than that in NREM. Key words: 【Key word】 Interictal epileptiform discharges; Epilepsy; Sleep; Circadian rhythm

Higher mortality rate is associated with advanced age and periodic lateralized epileptiform discharges in patients with refractory status epilepticus

To evaluate clinical data, electroencephalogram, etiology, classification, treatment, morbidity, and mortality in acute refractory status epilepticus. Fifteen patients, mean age of 41.3 years-old, six males, with refractory status epilepticus, were retrospectively studied. All of them were followed by serial electroencephalogram or continuous electroencephalographic monitoring. The most common comorbidity was hypertension. Seven (46.7%) patients were diagnosed with previous symptomatic focal epilepsy. More than one etiology was identified in 40.0% of the cases. Status epilepticus partial complex was the most common (n=14, 93.3%), and discrete seizures were the most observed initial ictal pattern. Continuous intravenous midazolam was used in nine (60.0%) patients and continuous thiopental in three (20.0%). Nine (60.0%) participants died, one (6.6%) had neurological sequelae, and five (33.3%) presented no neurological sequelae. Higher mortality rate was associated with advanced age and periodic lateralized epileptiform discharges. Midazolam proved to be a safe drug. The refractory status epilepticus is related to high mortality.

Continuous Epileptiform Discharges in Patients Treated With Cefepime or Meropenem

To test the hypothesis that treatment with cefepime hydrochloride leads to higher incidence of periodic epileptiform discharges compared with treatment with other β-lactams. Data from hospital pharmacy databases of patients treated with cefepime or meropenem during a 42-month period (from January 1, 2007, through June 30, 2010) were retrospectively crossed with data from the electroencephalography database for the same period. Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium. Patients who underwent electroencephalographic testing while taking cefepime or meropenem were selected. Only electroencephalographic tests performed during the antibiotic treatment period were considered. Matches were compared with nurses' medication records to ensure that the antibiotic considered was effectively given. Proportions of patients with continuous epileptiform discharges in the 2 groups were compared using the Fisher exact test. A total of 1120 patients were treated with cefepime and 1572 patients with meropenem. Electroencephalographic testing was performed during treatment in 59 patients treated with cefepime and 80 treated with meropenem (5.26% vs 5.08%, P = .85). Continuous epileptiform discharges were present in 14 patients in the cefepime group and 3 in the meropenem group (1.25% vs 0.19%, P < .001). Blood creatinine concentration was elevated in 5 of the 17 patients (range, 1.5-4.2 mg/dL; reference range, 0.7-1.2 mg/dL), and liver enzyme levels were elevated in 5 patients. No patient had major electrolyte disturbances. Our study showed a prevalence of electroencephalographic test results with continuous epileptiform discharges in 14 of 1120 patients receiving cefepime (1.25%) but only 3 of 1572 patients receiving meropenem (0.19%). Contrary to the results of previous case series, these electroencephalographic patterns occurred, in most cases, in patients with normal renal function. These results suggest that cefepime may be an independent risk factor for periodic epileptiform discharges, which are associated with worse outcomes. This finding could provide a partial explanation for the higher mortality rates reported in patients treated with cefepime compared with other β-lactams.

EEG‐fMRI reveals activation of brainstem and thalamus in patients with Lennox‐Gastaut syndrome

Even if etiologies of Lennox-Gastaut syndrome (LGS) are diverse, the multiple causes converge into a final common pathway that results in this specific epilepsy phenotype. There is little knowledge, however, about neuronal networks that may be a part of this pathway. To investigate these networks, 11 children with LGS and 9 control children with multifocal epileptic activity were investigated using simultaneous recordings of EEG and functional MRI (EEG-fMRI) in a 3 Tesla scanner. Individual and group analyses revealed significant activation of brainstem and thalamus (especially centromedian and anterior thalamus) associated with epileptiform discharges in patients with LGS. None of the patients with multifocal epileptic activity presented with the same hemodynamic activation pattern. Because brainstem activation has been associated with infantile spasms, which often evolve into LGS, and thalamus activation has been observed in patients with primary (idiopathic generalized syndromes) and secondary (focal epilepsies) bilateral synchrony, the described network in LGS may represent the common pathogenetic pathway of these different conditions.