Rhythmic Delta Activity Research Articles

Electroencephalogram (EEG) in COVID-19: A systematic retrospective study

SummaryObjectivesAlthough rare, neurological manifestations in SARS-CoV-2 infection are increasingly being reported. We conducted a retrospective systematic study to describe the electroencephalography (EEG) characteristics in this disease, looking for specific patterns.MethodsEEGs performed in patients with positive PCR for SARS-CoV-2 between 25/03/2020 and 06/05/2020 in the University Hospital of Bicêtre were independently reviewed by two experienced neurologists. We used the American Clinical Neurophysiology Society's terminology for the description of abnormal patterns. EEGs were classified into five categories, from normal to critically altered. Interobserver reliability was calculated using Cohen's kappa coefficient. Medical records were reviewed to extract demographics, clinical, imaging and biological data.ResultsForty EEGs were reviewed in 36 COVID-19 patients, 18 in intensive care units (ICU) and 22 in medicine units. The main indications were confusion or fluctuating alertness for 23 (57.5%) and delayed awakening after stopping sedation in ICU in six (15%). EEGs were normal to mildly altered in 23 (57.5%) contrary to the 42.5% where EEG alterations were moderate in four (10%), severe in eight (20%) and critical in five (12.5%). Generalized periodic discharges (GPDs), multifocal periodic discharges (MPDs) or rhythmic delta activity (RDA) were found in 13 recordings (32.5%). EEG alterations were not stereotyped or specific. They could be related to an underlying morbid status, except for three ICU patients with unexplained encephalopathic features.ConclusionIn this first systematic analysis of COVID-19 patients who underwent EEG, over half of them presented a normal recording pattern. EEG alterations were not different from those encountered in other pathological conditions.

Acute and Long-Term Outcomes of Lateralized Rhythmic Delta Activity (LRDA) Versus Lateralized Periodic Discharges (LPDs) in Critically Ill Patients.

To assess the acute and long-term outcomes for patients with lateralized rhythmic delta activity (LRDA) compared to patients with lateralized periodic discharges (LPDs). A single-center retrospective study examining consecutive patients older than 10years who had LRDA, LPDs, or both on continuous electroencephalographic (cEEG) between 12/01/2015 and 12/31/2017. Outcomes included inpatient mortality, functional outcome at follow-up, inpatient electrographic seizures, and the presence of new epilepsy at follow-up. Patients were classified into 4 groups: LRDA-only (without LPDs), LPDs-only (without LRDA), LRDA/LPDs, and control (without LRDA or LPDs). Twenty-nine patients (2.7%) were in the LRDA-only group, 76 (7%) patients were in the LPDs-only group, and 25 (2.3%) patients had both patterns (LRDA/LPDs group). 68 patients were identified as a control group. Only one patient (3%) in the LRDA-only group died during their hospitalization, compared to 21 patients (28%) in the LPDs-only group, 2 (8%) LRDA/LPDs group and 7 (10%) in the control group (p 0.003). Patients in the LPDs-only group had three times higher odds of adjusted mortality compared to the control group (p 0.05), while there was no difference in the mortality odds between the LRDA-only and control groups. Patients with LRDA-only had higher odds of good functional outcome at clinic follow-up (p 0.04). When compared to control, patients with both IIC patterns (LRDA/LPDs group) had 24.3 higher odds of acute electrographic seizures (p < 0.001), followed by patients in LPDs-only (OR 12.6, p < 0.001) and then LRDA-only (OR 9.4, p = 0.002). The odds of developing epilepsy following discharge were not increased in patients with either LRDA or LPDs (p = 0.9). Patients with LRDA had superior functional outcome compared to a higher mortality for patients with LPDs. Patients with both patterns had the highest odds of acute seizures, followed by those with only LPDs and then patients with only LRDA. There was no difference in the odds of developing new epilepsy compared to control with any IIC pattern. We hypothesize different underlying mechanisms of injury leading to the observed electrographic patterns.

Clinical Correlates of Frontal Intermittent Rhythmic Delta Activity Without Structural Brain Lesion.

Frontal intermittent rhythmic delta activity (FIRDA), rhythmic slow wave pattern lasting several seconds over the anterior leads of electroencephalography (EEG), has been reported in a wide variety of clinical conditions. We investigated the clinical significance of FIRDA without structural brain lesions. We reviewed 7689 EEGs between October 2017 and September 2019 at a university hospital. Patients (age >18 years) who were confirmed to have "nonsignificant neuroimaging" were examined. Clinical data were retrospectively collected, and the estimated cause was carefully decided. We found 83 FIRDA among 7689 EEGs (1.08%). After patients with any structural lesion identified on neuroimaging were excluded, 37 FIRDAs were reviewed. There were 20 (51.35%) patients of metabolic encephalopathy. Six patients showed FIRDA due to neurodegenerative disease (16.21%). In addition, we found 6 (16.21%) of neurodegenerative disease and 5 (13.51%) of hypoxic encephalopathy (cardiac arrest). Four (16.21%) patients were related to systemic infection (10.81%), whereas 2 were related to encephalitis (5.40%). We demonstrated several potential etiologies, including metabolic encephalopathy, neurodegenerative disease, hypoxic encephalopathy, and infections, which should be considered in the case of FIRDA without structural brain lesions.

Deep Versus Lobar Intraparenchymal Hemorrhage: Seizures, Hyperexcitable Patterns, and Clinical Outcomes.

To compare electrographic seizures, hyperexcitable patterns, and clinical outcomes in lobar and deep intraparenchymal hemorrhage. Additionally, to characterize electrographic seizure and hyperexcitable pattern predictors in each group and determine seizure risk with thalamic involvement. Retrospective cohort study. Tertiary academic medical center. Consecutive adult patients with nontraumatic intraparenchymal hemorrhage undergoing continuous electroencephalography at our center between January 2013 and December 2016. Not applicable. Based on head CT closest to the initial continuous electroencephalography session, we classified intraparenchymal hemorrhage as isolated deep (no insular, subarachnoid, subdural extension) or lobar. Hyperexcitable patterns included the following: periodic discharges, spike-wave complexes, any rhythmic delta other than generalized. We used Fisher exact test for categorical and Mann-Whitney U test for continuous variables. Multivariable regression identified predictors of electrographic seizures, hyperexcitable patterns, and poor outcomes (score of 1-2 on Glasgow Outcome Scale) in lobar intraparenchymal hemorrhage. The cohort comprised of 128 patients, 88 lobar, and 40 deep intraparenchymal hemorrhage. Electrographic seizures occurred in 17% of lobar and 5% of deep intraparenchymal hemorrhage (p = 0.09). Hyperexcitable patterns were more frequent in the lobar group (44.3% vs 17.5%; p = 0.005). In multivariable analyses in the lobar group, lateralized rhythmic delta activity predicted electrographic seizures (odds ratio, 6.24; CI, 1.49-26.08; p = 0.012); insular involvement predicted hyperexcitable patterns (odds ratio, 4.88; CI, 1.36-17.57; p = 0.015); coma, temporal lobe involvement, intraparenchymal hemorrhage volume, and electrographic seizures predicted poor outcome. Thalamic involvement did not affect electrographic seizures or hyperexcitable patterns in either group. Electrographic seizures are frequent in lobar intraparenchymal hemorrhage, occurring in one in six monitored patients, as opposed to only 5% in isolated deep intraparenchymal hemorrhage not extending to cortex/insula, subarachnoid, or subdural spaces. Patients with lobar intraparenchymal hemorrhage and lateralized rhythmic delta activity were six times as likely to have electrographic seizures, which were associated with 5.47 higher odds of a poor outcome. Coma, temporal lobe involvement, hematoma volume, and electrographic seizures predicted poor outcome in lobar intraparenchymal hemorrhage.

Electroencephalography in Predicting Short-Term Clinical Outcomes after Cardiac Arrest.

Early consciousness recovery after cardiac arrest (CA) is one of the most explicit and self-evident prognostic factors for clinical outcomes. We aimed to evaluate the prognostic value of electroencephalography (EEG) phenotypes according to the American Clinical Neurophysiology Society's Critical Care EEG classification for predicting early recovery after CA. Consecutive patients admitted to the ICU after CA were enrolled. We analyzed Glasgow Coma Scale (GCS) score within 10 days after CA and evaluated mortality within 28 days according to EEG pattern subtype. Among the total of 71 patients, 9 had periodic discharges (PDs) EEG pattern, 4 had rhythmic delta activity (RDA), 8 had spike-and-wave (SW), 22 had low voltage, 5 had burst suppression, and 23 had other EEG patterns. Initial GCS scores, GCS scores 3 days after CA (or 3 days after targeted temperature management [TTM]), and 10 days after CA (or 10 days after TTM) were significantly different among EEG subtypes (p < 0.001, respectively) (Table2). GCS scores were significantly higher in RDA and the other EEG group compared to the PDs, SW, low voltage, and burst suppression groups (p < 0.001). Significant group × time interactions were observed for the follow-up period between EEG phenotypes (p < 0.001) demonstrating the most increase in the other EEG pattern group. Consciousness states were significantly worse in the PDs, SW, burst suppression, and low-voltage groups compared to the RDA and the other EEG pattern within 10 days after CA. The degree of consciousness recovery differed significantly by EEG pattern subtype within 10 days.

Predictors of Nonconvulsive Seizure and Their Effect on Short-term Outcome.

Nonconvulsive seizures (NCSs) are common in critically ill adult patients with acute neurologic conditions. However, the effect of NCSs on patient outcome remains unclear. In this study, we aimed to determine the effect of NCSs on short-term outcome and to assess the clinical and EEG factors associated with NCSs. We retrospectively identified 219 adult patients from the EEG reporting system who underwent continuous EEG (cEEG) monitoring between January 2018 and June 2018. Patients with anoxic brain injury were excluded from the study. Clinical, laboratory, and EEG data were reviewed to determine potentially predictive factors of NCSs. The impact of NCSs on in-hospital mortality, length of stay, and disability on discharge was measured; an modified Rankin scale of three or greater was considered disabled. Of the 219 patients included in our study, a total of 14% (n = 31) had NCSs on continuous EEG, of which 42% (n = 13) had their first seizure discharge recorded during the first hour of continuous EEG monitoring. The presence of clinical seizures before continuous EEG (odds ratio = 1.787; 95% confidence interval = 1.197-2.667, P = 0.0045), history of epilepsy (odds ratio = 1.508; 95% confidence interval = 1.027-2.215, P = 0.035), and comatose state (29 vs. 16%; P = 0.0006) were associated with NCSs. Among EEG characteristics, the presence of interictal epileptiform discharges (P < 0.0001), lateralized rhythmic delta activity (P = 0.02), and lateralized periodic discharges (P < 0.0001) were associated with NCSs. Nonconvulsive seizures were significantly associated with longer in-hospital stay (23.68 ± 24.84 vs. 17.14 ± 20.52; P = 0.036) and disability on discharge (87% [n = 27] vs. 13% [n = 4], P = 0.02). However, there was no significant association between NCS and in-hospital mortality (9.6% [n = 3] vs. 10.6% [n = 20]; P = 0.1). Nonconvulsive seizures are associated with longer in-hospital stay and disability on discharge but not with in-hospital mortality in adult patients.

Abstract TMP22: Dynamic Worsening of Epileptiform Abnormalities Following Subarachnoid Hemorrhage is Associated With Poor 3-Month Outcomes

Objective: Worsening epileptiform abnormalities (EAs) and deteriorating background activity are common continuous electroencephalography (cEEG) patterns that predict subsequent clinical deterioration following subarachnoid hemorrhage (SAH). While worsening EAs and background deterioration both imply cortical dysfunction, we sought to clarify if these patterns have a different association with clinical outcomes. Methods: We enrolled patients with SAH undergoing &gt; 3 days of cEEG monitoring enrolled in a prospective outcome study with a modified Rankin Scale (mRS) assessment at 3 months. Worsening EAs included new or increasing burden of sporadic epileptiform discharges, lateralized rhythmic delta activity (LRDA), lateralized periodic discharges (LPD), or generalized periodic discharges (GPD). Background deterioration was defined as decreasing Alpha Delta Ratio (ADR), Relative Alpha Variability (RAV) or worsening focal slowing. We evaluated the association between these cEEG patterns and 3-month mRS &gt;3 and examined whether the influence on outcome was independent of delayed cerebral ischemia (DCI). Results: Of 59 patients meeting inclusion criteria (3-month mRS median 3 [IQR 1-5]), worsening EAs developed in 23 (39%) and new background deterioration in 24 (41%), whereas 24 patients (41%) developed neither finding and 12 (20%) developed both. Patients with worsening EAs were more likely to have a poor 3-month mRS compared to those without worsening EAs (OR 6.44; 95%CI 1.99-20.9; p=0.001). Developing new background deterioration was not significantly associated with poor 3-month outcome (OR 1.56, 95%CI 0.53-4.59; p=0.42). There was no additive effect on poor outcome of developing both findings. In a multivariate logistic regression, the effect of worsening EAs on 3-month mRS was independent of DCI. Interpretation: While both worsening EAs and new background deterioration have previously been associated with DCI, only worsening EAs influences poor long-term outcome. Further investigation may clarify if distinct mechanisms underlie these differences.

Continuous EEG Findings in Autoimmune Encephalitis.

Autoimmune encephalitis (AE) is a cause of new-onset seizures, including new-onset refractory status epilepticus, yet there have been few studies assessing the EEG signature of AE. Multicenter retrospective review of patients diagnosed with AE who underwent continuous EEG monitoring. We identified 64 patients (male, 39%; white, 49%; median age, 44 years); of whom, 43 (67%) were antibody-proven AE patients. Of the patients with confirmed antibody AE, the following were identified: N-methyl-D-aspartate receptor (n = 17, 27%), voltage-gated potassium channel (n = 16, 25%), glutamic acid decarboxylase (n = 6, 9%), and other (n = 4, 6%). The remaining patients were classified as probable antibody-negative AE (n = 11, 17%), definite limbic encephalitis (antibody-negative) (n = 2, 3%), and Hashimoto encephalopathy (n = 8, 13%). Fifty-three percent exhibited electrographic seizures. New-onset refractory status epilepticus was identified in 19% of patients. Sixty-three percent had periodic or rhythmic patterns; of which, 38% had plus modifiers. Generalized rhythmic delta activity was identified in 33% of patients. Generalized rhythmic delta activity and generalized rhythmic delta activity plus fast activity were more common in anti-N-methyl-D-aspartate AE (P = 0.0001 and 0.0003, respectively). No other periodic or rhythmic patterns exhibited AE subtype association. Forty-two percent had good outcome on discharge. Periodic or rhythmic patterns, seizures, and new-onset refractory status epilepticus conferred an increased risk of poor outcome (OR, 6.4; P = 0.0012; OR, 3; P = 0.0372; OR, 12.3; P = 0.02, respectively). Our study confirms a signature EEG pattern in anti-N-methyl-D-aspartate AE, termed extreme delta brush, identified as generalized rhythmic delta activity plus fast activity in our study. We found no other pattern association with other AE subtypes. We also found a high incidence of seizures among patients with AE. Finally, periodic or rhythmic patterns, seizures, and new-onset refractory status epilepticus conferred an increased risk of poor outcome regardless of AE subtype.

Abstract 287: Bimodal Brain Monitoring Using Portable EEG and Cerebral Oximetry During Cardiopulmonary Resuscitation (CPR): A Pilot Study

Background: There is a need to monitor brain resuscitation during CPR. Furthermore, 10% of CA survivors report cognitive activity and 2-3% report consciousness during CPR. Methods: Using data from a prospective study (AWARE-II) with bimodal brain monitoring during CPR (EEG, [Massimo] and regional cerebral oxygenation [rSO2 normal 60-80%]) using cerebral oximetry [Nonin]), we sought to identify EEG rhythms, their progression over time, and underlying rSO2 thresholds. Inclusion criteria: In hospital CA, ≥ 18 years. Raw EEG data were captured as images (1/second) during CPR pauses, while rSO2 was captured continuously. Results: 38 patients were recruited; mean age 69±16 with duration of CPR (10-60 mins). We captured 362 EEG images. 91 (25%) were artifacts. Among the 271 interpretable images, there were 13 EEG rhythms placed into 6 groups based on their association with normal/near normal, seizures, coma, absence of cortical activity as follows: Group 1 (Non-epileptogenic): Theta, Delta, Alpha, Group 2 (Epileptogenic/Spike and Wave): Generalized Rhythmic Delta Activity (GRDA) + Spike (S), Delta + S, Theta + S, Burst Suppression with GRDA + S, Group 3 (Flat-line): Marked Voltage Attenuation (MVA), Group 4 (Coma State): Burst Suppression (w/ GRDA, Delta, and/or Theta), Group 5: GRDA, Group 6: Generalized Periodic Discharges (GPD). MVA/absence of activity was observed throughout CPR time and across all rSO2 ranges. Normal/near normal (non-epileptogenic) including alpha rhythms (which to our knowledge is described for the first time), and epileptogenic rhythms were observed with rSO2&gt;30% Conclusions: While unclear whether non-epileptogenic rhythms are associated with transient periods of ROSC, however real-time bimodal brain monitoring provides insights regarding brain resuscitation and its dynamic interaction with patient factors. While ischemia may cause epileptogenic activity, there are periods of normal/near-normal cortical activity despite prolonged CPR &gt;45-60 mins. A minimal threshold of brain oxygen delivery (rSO2&gt;30%) may be required for cortical activity. These data raise questions regarding assumptions of irreversible brain damage with prolonged CPR, as well as the possibility of consciousness and cognitive activity during CPR.

NCMP-08. CLINICAL FEATURES OF CAR T-CELL THERAPY NEUROTOXICITY AS POTENTIAL SURROGATE MARKERS FOR PROGRESSION AND OUTCOME

Abstract CAR T-cell therapy related neurotoxicity (NT) is common and can lead to fatalities. Early recognition may improve its management and treatment. METHODS Twenty-six patients with relapsed/refractory diffuse large B cell lymphoma who received commercial CAR T-cell therapy (25 axicabtagene ciloleucel [Yescarta®], 1 tisagenlecleucel [Kymriah®]) between December 2017 and September 2018 were assessed for NT based on CARTOX-10 score and Common Terminology Criteria for Adverse Events (CTCAE) version 4. RESULTS Twenty-three of 26 (88%) of patients developed NT, which was severe (Grade III-IV) in 8/26 (31%). Severe NT was associated with complete remission compared to progressive disease by both CTCAE (2.4 ±1.1 vs. 1.4 ± 1.3, p = 0.050) and CARTOX-10 score (8.3 ± 1.6 vs. 9.4 ± 1.5, p = 0.040). CARTOX-10 scores were lower for those transferred to the ICU compared to those transferred, respectively, on Days 8 (2.71 ± 4.78 vs. 9.28 ± 2.31, p = 0.010), 9 (2.71 ± 3.96 vs. 9.06 ± 2.50, p = 0.003) and 10 (2.86 ± 4.27 vs. 8.83 ± 3.37, p = 0.002). Depression was associated with poor overall survival (deceased 67% vs. alive 20%, p = 0.00004) and severe NT (severe NT 63% vs. non-severe NT 20%, p = 0.040). EEG findings of frontal intermittent rhythmic delta activity (FIRDA) in 22% (2/9) and triphasic waves in 33% (3/9) were exclusive found in severe NT. Tremulousness was present in 100% of severe NT compared to 67% of non-severe NT patients (p = 0.060). Delirium occurred in 2 patients, both of whom expired with severe NT. CONCLUSION Depression, tremor, delirium, encephalopathy, and EEG features of FIRDA and triphasic waves may represent early clinical signs that predict the development of severe NT in off-protocol CAR T-cell therapy. Paradoxically, severe NT is positively correlated with progression free survival and may indicate effective therapeutic response.

Diagnostic Reliability of Headset-Type Continuous Video EEG Monitoring for Detection of ICU Patterns and NCSE in Patients with Altered Mental Status with Unknown Etiology.

Simplified continuous electroencephalogram (cEEG) monitoring has shown improvement in detecting seizures; however, it is insufficient in detecting abnormal EEG patterns, such as periodic discharges (PDs), rhythmic delta activity (RDA), spikes and waves (SW), and continuous slow wave (CS), as well as nonconvulsive status epilepticus (NCSE). Headset-type continuous video EEG monitoring (HS-cv EEG monitoring; AE-120A EEG Headset™, Nihon Kohden, Tokyo, Japan) is a recently developed easy-to-use technology with eight channels. However, its ability to detect abnormal EEG patterns with raw EEG data has not been comprehensively evaluated. We aimed to examine the diagnostic accuracy of HS-cv EEG monitoring in detecting abnormal EEG patterns and NCSE in patients with altered mental status (AMS) with unknown etiology. We also evaluated the time required to initiate HS-cv EEG monitoring in these patients. We prospectively observed and retrospectively examined patients who were admitted with AMS between January and December 2017 at the neurointensive care unit at Asakadai Central General Hospital, Saitama, Japan. We excluded patients whose data were missing for various reasons, such as difficulties in recording, and those whose consciousness had recovered between HS-cv EEG and conventional cEEG (C-cEEG) monitoring. For the included patients, we performed HS-cv EEG monitoring followed by C-cEEG monitoring. Definitive diagnosis was confirmed by C-cEEG monitoring with the international 10-20 system. As the primary outcome, we verified the sensitivity and specificity of HS-cv EEG monitoring in detecting abnormal EEG patterns including PDs, RDA, SW, and CS, in detecting the presence of PDs, and in detecting NCSE. As the secondary outcome, we calculated the time to initiate HS-cv EEG monitoring after making the decision. Fifty patients (76.9%) were included in the final analyses. The median age was 72years, and 66% of the patients were male. The sensitivity and specificity of HS-cv EEG monitoring for detecting abnormal EEG patterns were 0.974 (0.865-0.999) and 0.909 (0.587-0.998), respectively, and for detecting PDs were 0.824 (0.566-0.926) and 0.970 (0.842-0.999), respectively. We diagnosed 13 (26%) patients with NCSE using HS-cv EEG monitoring and could detect NCSE with a sensitivity and specificity of 0.706 (0.440-0.897) and 0.970 (0.842-0.999), respectively. The median time needed to initiate HS-cv EEG was 57min (5-142). HS-cv EEG monitoring is highly reliable in detecting abnormal EEG patterns, with moderate reliability for PDs and NCSE, and rapidly initiates cEEG monitoring in patients with AMS with unknown etiology.

Clinical correlates and electroencephalographic features of FIRDA in a tertiary center.

We aimed to explore the diagnostic value, clinical correlates and electroencephalographic features of FIRDA (Frontal intermittent rhythmic delta activity). We retrospectively reviewed reports from EEG studies done in adults at our tertiary center between January 2015 and May 2018. For cases demonstrating FIRDA, medical files were reviewed and each case was given a diagnostic category. EEG recordings were reviewed and electrophysiologic data were extracted including FIRDA characteristics (frequency, location, duration, and symmetry). Then, a statistical analysis was done to evaluate the relationship between the diagnostic categories and EEG variables. Ninety-four cases of FIRDA were found, with a frequency of 1.6% among inpatients. EEG recordings were available for review in 84 cases. FIRDA was asymmetric in 43 of these cases (49%), usually more prominent on the left (36/43, 84%). The diagnostic category groups included epilepsy (n=39, 41%), other central nervous system (CNS) disease (n=33, 35%), and systemic illness (n=22, 23%). A significant difference in FIRDA location was found, as patients with epilepsy or other CNS disease, had a significantly higher probability for the delta activity to involve the temporal areas (frontotemporal location in 27/64 in these groups compared with 3/20 in the systemic illness group, P-value=.033). This study provides insights to the diagnosis underlying FIRDA, especially the high rate of epilepsy patients, and calls for further neurologic investigation of cases in which FIRDA involves the temporal areas since most of these cases were due to epilepsy or other CNS disease and not a systemic illness.

Phenotypic characterization of individuals with SYNGAP1 pathogenic variants reveals a potential correlation between posterior dominant rhythm and developmental progression

BackgroundThe SYNGAP1 gene encodes for a small GTPase-regulating protein critical to dendritic spine maturation and synaptic plasticity. Mutations have recently been identified to cause a breadth of neurodevelopmental disorders including autism, intellectual disability, and epilepsy. The purpose of this work is to define the phenotypic spectrum of SYNGAP1 gene mutations and identify potential biomarkers of clinical severity and developmental progression.MethodsA retrospective clinical data analysis of individuals with SYNGAP1 mutations was conducted. Data included genetic diagnosis, clinical history and examinations, neurophysiologic data, neuroimaging, and serial neurodevelopmental/behavioral assessments. All patients were seen longitudinally within a 6-year period; data analysis was completed on June 30, 2018. Records for all individuals diagnosed with deleterious SYNGAP1 variants (by clinical sequencing or exome sequencing panels) were reviewed.ResultsFifteen individuals (53% male) with seventeen unique SYNGAP1 mutations are reported. Mean age at genetic diagnosis was 65.9 months (28–174 months). All individuals had epilepsy, with atypical absence seizures being the most common semiology (60%). EEG abnormalities included intermittent rhythmic delta activity (60%), slow or absent posterior dominant rhythm (87%), and epileptiform activity (93%), with generalized discharges being more common than focal. Neuroimaging revealed nonspecific abnormalities (53%). Neurodevelopmental evaluation revealed impairment in all individuals, with gross motor function being the least affected. Autism spectrum disorder was diagnosed in 73% and aggression in 60% of cases. Analysis of biomarkers revealed a trend toward a moderate positive correlation between visual-perceptual/fine motor/adaptive skills and language development, with posterior dominant rhythm on electroencephalogram (EEG), independent of age. No other neurophysiology-development associations or correlations were identified.ConclusionsA broad spectrum of neurologic and neurodevelopmental features are found with pathogenic variants of SYNGAP1. An abnormal posterior dominant rhythm on EEG correlated with abnormal developmental progression, providing a possible prognostic biomarker.

A Case of Subcortical Band Heterotopia Presented with Epilepsy and Speech Regression

Subcortical Heterotopia is a rare developmental disorder of human brain due to mutation in the DCX or LIS1gene.It is predominantly a disease of female. It usually present with refractory seizure and varying degree of mental retardation. Here a case of 22 years lady who presented with refractory seizure is reported. Her MRI revealed Double cortex and her EEG revealed Frontal intermittent rhythmic delta activity (FIRDA).&#x0D; Bangladesh Journal of Neuroscience 2019; Vol. 35 (2): 115-118

EEG Findings in Posterior Reversible Encephalopathy Syndrome.

Introduction. Posterior reversible encephalopathy syndrome (PRES) is a relatively common cause of encephalopathy in the hospital setting, and the EEG findings have not been well described. The purpose of this study was to review the EEG findings in a series of patients with PRES. Methods. We retrospectively reviewed our electronic medical record database to identify patients who received a diagnosis of PRES at Tampa General Hospital from January 2016 to October 2017. The diagnosis of PRES was suspected on clinical presentation and confirmed by magnetic resonance imaging. We selected patients with PRES who had received at least 1 EEG. EEGs were interpreted by 2 board-certified electroencephalographers. Results. From January 2016 to October 2017, 19 patients were diagnosed with PRES at Tampa General Hospital. Of those, 10 received at least 1 EEG. Four patients were male, 6 were female. The ages ranged from 21 to 87 (mean was 47). The patients had the following clinical presentations: 5 with encephalopathy, 8 with seizures, 2 with vision changes, and 3 with headache (some patients had more than 1 symptom). EEGs findings were as follows: 3 were normal; 3 showed intermittent generalized slowing; 2 showed continuous generalized slowing; 3 showed background slowing; 1 showed background suppression; 1 showed generalized rhythmic delta activity (GRDA); 1 showed GRDA, plus spike/sharp-wave discharges; 1 showed generalized periodic discharges. The etiologies were as follows: 9 from hypertension, 1 secondary to eclampsia, 3 due to posttransplant immunosuppression, and 1 patient was undergoing chemotherapy (some were multifactorial). Conclusion. EEG findings in PRES are diverse, with no specific or even predominant pattern, based on this small sample size.

The EEG Ictal-Interictal Continuum-A Metabolic Roar But a Whimper of a Functional Outcome.

To investigate the correlation between characteristics of lateralized periodic discharges (LPDs) and glucose metabolism measured by (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET). We retrospectively reviewed medical records to identify patients who underwent FDG-PET during electroencephalography (EEG) monitoring with LPDs present during the FDG uptake period. Two blinded board-certified neurophysiologists independently interpreted EEGs. (18)F-fluorodeoxyglucose uptake was measured using standardized uptake value (SUV). Structural images were fused with PET images to aid with localization of SUV. Two PET readers independently measured maximum SUV. Relative SUV values were obtained by normalization of the maximum SUV to the SUV of pons (SUVRpons). Lateralized periodic discharge frequency was analyzed both as a categorical variable and as a continuous measure. Other secondary variables included duration, amplitude, presence of structural lesion, and "plus" EEG features such as rhythmic or fast sharp activity. Nine patients were identified and 7 had a structural etiology for LPDs. Analysis using frequency as a categorical variable and continuous variable showed an association between increased LPD frequency and increased ipsilateral SUVRpons (P = .02). Metabolism associated with LPDs (0.5 Hz as a baseline) increased by a median of 100% at 1 Hz and for frequencies >1 Hz increased by a median of 309%. There were no statistically significant differences in SUVRpons for other factors including duration (P = .10), amplitude (P = .80), structural etiology (P = .55), or "plus" features such as rhythmic or fast sharp activity (P = .84). Metabolic activity increases monotonically with LPD frequency. Lateralized periodic discharge frequency should be a measure of interest when developing neuroprotection strategies in critical neurologic illness. Continuous Electroencephalography After Moderate to Severe Traumatic Brain Injury Lee H, Mizrahi MA, Hartings JA, Sharma S, Pahren L, Ngwenya LB, Moseley BD, Privitera M, Tortella FC, Foreman B. Crit Care Med. 2019;47(4):574-582. After traumatic brain injury, continuous electroencephalography is widely used to detect electrographic seizures. With the development of standardized continuous electroencephalography terminology, we aimed to describe the prevalence and burden of ictal-interictal patterns, including electrographic seizures after moderate to severe traumatic brain injury, and to correlate continuous electroencephalography features with functional outcome. Post hoc analysis of the prospective, randomized controlled phase 2 multicenter INTREPID study ( ClinicalTrials.gov : NCT00805818). Continuous electroencephalography was initiated upon admission to the intensive care unit. The primary outcome was the 3-month Glasgow Outcome Scale-Extended. Consensus electroencephalography reviews were performed by raters certified in standardized continuous electroencephalography terminology blinded to clinical data. Rhythmic, periodic, or ictal patterns were referred to as "ictal-interictal continuum"; severe ictal-interictal continuum was defined as greater than or equal to 1.5 Hz lateralized rhythmic delta activity or generalized periodic discharges and any lateralized periodic discharges or electrographic seizures. Twenty US level I trauma centers. Patients with nonpenetrating traumatic brain injury and postresuscitation Glasgow Coma Scale score of 4 to 12 were included. None. Among 152 patients with continuous electroencephalography (age = 34 ± 14 years; 88% male), 22 (14%) had severe ictal-interictal continuum including electrographic seizures in 4 (2.6%). Severe ictal-interictal continuum burden correlated with initial prognostic scores, including the International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (r = 0.51; P = .01) and Injury Severity Score (r = 0.49; P = .01), but not with functional outcome. After controlling clinical covariates, unfavorable outcome was independently associated with absence of posterior dominant rhythm (common odds ratio, 3.38; 95% confidence interval, 1.30-9.09), absence of N2 sleep transients (3.69; 1.69-8.20), predominant delta activity (2.82; 1.32-6.10), and discontinuous background (5.33; 2.28-12.96) within the first 72 hours of monitoring. Severe ictal-interictal continuum patterns, including electrographic seizures, were associated with clinical markers of injury severity but not functional outcome in this prospective cohort of patients with moderate to severe traumatic brain injury. Importantly, continuous electroencephalography background features were independently associated with functional outcome and improved the area under the curve of existing, validated predictive models.

Continuous Electroencephalography After Moderate to Severe Traumatic Brain Injury.

After traumatic brain injury, continuous electroencephalography is widely used to detect electrographic seizures. With the development of standardized continuous electroencephalography terminology, we aimed to describe the prevalence and burden of ictal-interictal patterns, including electrographic seizures after moderate-to-severe traumatic brain injury and to correlate continuous electroencephalography features with functional outcome. Post hoc analysis of the prospective, randomized controlled phase 2 multicenter INTREPID study (ClinicalTrials.gov: NCT00805818). Continuous electroencephalography was initiated upon admission to the ICU. The primary outcome was the 3-month Glasgow Outcome Scale-Extended. Consensus electroencephalography reviews were performed by raters certified in standardized continuous electroencephalography terminology blinded to clinical data. Rhythmic, periodic, or ictal patterns were referred to as "ictal-interictal continuum"; severe ictal-interictal continuum was defined as greater than or equal to 1.5 Hz lateralized rhythmic delta activity or generalized periodic discharges and any lateralized periodic discharges or electrographic seizures. Twenty U.S. level I trauma centers. Patients with nonpenetrating traumatic brain injury and postresuscitation Glasgow Coma Scale score of 4-12 were included. None. Among 152 patients with continuous electroencephalography (age 34 ± 14 yr; 88% male), 22 (14%) had severe ictal-interictal continuum including electrographic seizures in four (2.6%). Severe ictal-interictal continuum burden correlated with initial prognostic scores, including the International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (r = 0.51; p = 0.01) and Injury Severity Score (r = 0.49; p = 0.01), but not with functional outcome. After controlling clinical covariates, unfavorable outcome was independently associated with absence of posterior dominant rhythm (common odds ratio, 3.38; 95% CI, 1.30-9.09), absence of N2 sleep transients (3.69; 1.69-8.20), predominant delta activity (2.82; 1.32-6.10), and discontinuous background (5.33; 2.28-12.96) within the first 72 hours of monitoring. Severe ictal-interictal continuum patterns, including electrographic seizures, were associated with clinical markers of injury severity but not functional outcome in this prospective cohort of patients with moderate-to-severe traumatic brain injury. Importantly, continuous electroencephalography background features were independently associated with functional outcome and improved the area under the curve of existing, validated predictive models.

EEG in WNV Neuroinvasive Disease.

Neuroinvasive West Nile virus (WNV) is rare, occurring in less than 1% of those infected, and may manifest as meningitis, encephalitis, and/or acute flaccid paralysis. Patients may present initially with nonspecific symptoms including fevers. Although rare, neuroinvasive WNV is associated with significant morbidity and mortality. The mainstay of treatment is supportive care. Electroencephalography (EEG) allows for identification of nonconvulsive status epilepticus and other epileptiform and nonepileptiform patterns suggestive of underlying cognitive dysfunction. Our aim was to describe specific EEG patterns observed in WNV neuroinvasive disease. A retrospective chart review was conducted. West Nile virus was confirmed with serum and/or cerebrospinal fluid markers. Patients with a history of abnormal EEG were excluded. Electroencephalography reports were classified into categories based on the presence of epileptiform activity, focal slowing, generalized periodic discharges with triphasic morphology, and frontally predominant generalized rhythmic delta activity. In our cohort of 34 patients, 60% of focal EEG abnormalities were anterior-predominant, seen as epileptiform discharges, focal slowing, or frontally predominant generalized rhythmic delta activity. Nonepileptiform EEG patterns included nonspecific slowing and generalized periodic discharges with triphasic morphology. Two patients had electrographic seizures, one arising from the frontocentral head region. EEGs are important in the evaluation of WNV infection to rule out seizures or alternative causes of encephalopathy, and because of the risk of nonconvulsive seizures or status epilepticus in encephalitis. Although an anterior predominance of EEG abnormalities was seen in our cohort, this most likely is more correlative to encephalopathy than WNV itself. Although a specific correlative EEG pattern may not accompany all cases of WNV neuroinvasive disease, WNV should be considered as a possible etiology in patients presenting with an encephalitic or meningitic syndrome in the presence of abnormal EEG findings including encephalopathic patterns, particularly those with anterior predominant EEG changes.

Clinical and EEG Characteristics of Ifosfamide-Related Encephalopathy.

Ifosfamide can lead to a syndrome of central nervous system toxicity. Here, we investigate the clinical and EEG characteristics of patients with ifosfamide-related encephalopathy. Retrospective data were collected on patients from Memorial Sloan Kettering Cancer Center, who developed encephalopathy associated with ifosfamide between 2007 and 2017. Patients who had an EEG performed were included. Clinical and laboratory data were retrospectively collected. Each EEG recording was reviewed and compared with the originally documented EEG report. Sixteen patients with ifosfamide-related encephalopathy were included, with primary tumors consisting of lymphoma (N = 9), sarcoma (N = 4), poorly differentiated ovarian cancer (N = 1), neuroblastoma (N = 1), and papillary serous adenocarcinoma (N = 1). Laboratory results ruled out other etiologies of encephalopathy. Generalized periodic discharges with or without triphasic morphology were seen most commonly (N = 9), with a distinct pattern of interspersed intermittent background attenuation seen in five patients. Background slowing and intermittent rhythmic delta activity (N = 4), bursts of bilateral synchronized delta activity (N = 2), and frontal predominant intermittent delta activity (N = 1) were also seen. One patient demonstrated a pattern consistent with nonconvulsive status epilepticus. Although most patients experienced resolution of symptoms, those who died demonstrated a variety of EEG abnormalities. Abnormal movements were common, with six patients demonstrating characteristic orofacial myoclonus. Ifosfamide-related encephalopathy commonly results in a distinct pattern of generalized periodic discharges admixed with intermittent background attenuation on EEG. Abnormal movements, in particular orofacial myoclonus, are also common. Recognizing these clinical and EEG features might lead to early detection of ifosfamide-related encephalopathy.

Acute Non-Convulsive Status Epilepticus after Experimental Traumatic Brain Injury in Rats.

Severe traumatic brain injury (TBI) induces seizures or status epilepticus (SE) in 20-30% of patients during the acute phase. We hypothesized that severe TBI induced with lateral fluid-percussion injury (FPI) triggers post-impact SE. Adult Sprague-Dawley male rats were anesthetized with isoflurane and randomized into the sham-operated experimental control or lateral FPI-induced severe TBI groups. Electrodes were implanted right after impact or sham-operation, then video-electroencephalogram (EEG) monitoring was started. In addition, video-EEG was recorded from naïve rats. During the first 72 h post-TBI, injured rats had seizures that were intermingled with other epileptiform EEG patterns typical to non-convulsive SE, including occipital intermittent rhythmic delta activity, lateralized or generalized periodic discharges, spike-and-wave complexes, poly-spikes, poly-spike-and-wave complexes, generalized continuous spiking, burst suppression, or suppression. Almost all (98%) of the electrographic seizures were recorded during 0-72 h post-TBI (23.2 ± 17.4 seizures/rat). Mean latency from the impact to the first electrographic seizure was 18.4 ± 15.1 h. Mean seizure duration was 86 ± 57 sec. Analysis of high-resolution videos indicated that only 41% of electrographic seizures associated with behavioral abnormalities, which were typically subtle (Racine scale 1-2). Fifty-nine percent of electrographic seizures did not show any behavioral manifestations. In most of the rats, epileptiform EEG patterns began to decay spontaneously on Days 5-6 after TBI. Interestingly, also a few sham-operated and naïve rats had post-operation seizures, which were not associated with EEG background patterns typical to non-convulsive SE seen in TBI rats. To summarize, our data show that lateral FPI-induced TBI results in non-convulsive SE with subtle behavioral manifestations; this explains why it has remained undiagnosed until now. The lateral FPI model provides a novel platform for assessing the mechanisms of acute symptomatic non-convulsive SE and for testing treatments to prevent post-injury SE in a clinically relevant context.