Nonconvulsive electrographic seizures after traumatic brain injury result in a delayed, prolonged increase in intracranial pressure and metabolic crisis:

Relevance of Continuous EEG versus Routine EEG for Outcome Prediction after Traumatic Brain Injury

INTRODUCTION

In a cohort of adult patients with disturbance of consciousness after TBI, we aimed to explore the relationship of continuous video-EEG (cEEG) versus routine EEG (rEEG) with mortality and functional outcome.

METHODS

This is a post hoc analysis of a randomized controlled trial (CERTA), in which adults with disorder of consciousness and needing EEG (excluding those with proven seizures/SE just before) were randomized 1:1 to cEEG or two rEEG. In TBI patients, correlation between EEG duration, mortality, and modified Rankin score (mRs, good 0-2) at 6 months was assessed.

RESULTS

Among 364 patients, 44 presenting with consciousness impairment after TBI were included; 29 randomized to cEEG and 15 to rEEG. Mortality (p = 0.88) and functional outcome (p = 0.58) at 6 months were similar between groups. There was a nonsignificant tendency toward more seizure/status epilepticus detection with cEEG (p = 0.08). In multivariable regression, cEEG was not related to functional outcome (OR: 0.75 [0.13-4.24], p = 0.745) or mortality (OR: 7.11 [0.51-99.32], p = 0.145).

CONCLUSION

Despite allowing increased seizure detections in TBI patients, cEEG does not seem to be associated with better functional outcome or mortality over rEEG. Pending larger trials, repeated rEEG might be acceptable in post-TBI disorder of consciousness, especially in resource-limited environments.

Status epilepticus: review on diagnosis, monitoring and treatment

Status epilepticus (SE) is a frequent neurological emergency associated with high morbidity and mortality. According to the new ILAE 2015 definition, SE results either from the failure of the mechanisms responsible for seizure termination or initiation, leading to abnormally prolonged seizures. The definition has different time points for convulsive, focal and absence SE. Time is brain. There are changes in synaptic receptors leading to a more proconvulsant state and increased risk of brain lesion and sequelae with long duration. Management of SE must include three pillars: stop seizures, stabilize patients to avoid secondary lesions and treat underlying causes. Convulsive SE is defined after 5 minutes and is a major emergency. Benzodiazepines are the initial treatment, and should be given fast and an adequate dose. Phenytoin/fosphenytoin, levetiracetam and valproic acid are evidence choices for second line treatment. If SE persists, anesthetic drugs are probably the best option for third line treatment, despite lack of evidence. Midazolam is usually the best initial choice and barbiturates should be considered for refractory cases. Nonconvulsive status epilepticus has a similar initial approach, with benzodiazepines and second line intravenous (IV) agents, but after that, aggressiveness should be balanced considering risk of lesion due to seizures and medical complications caused by aggressive treatment. Usually, the best approach is the use of sequential IV antiepileptic drugs (oral/tube are options if IV options are not available). EEG monitoring is crucial for diagnosis of nonconvulsive SE, after initial control of convulsive SE and treatment control. Institutional protocols are advised to improve care.

Risk Factors and Prognosis of Early Posttraumatic Seizures in Moderate to Severe Traumatic Brain Injury

IMPORTANCE

Early posttraumatic seizures (EPS) that may occur following a traumatic brain injury (TBI) are associated with poorer outcomes and development of posttraumatic epilepsy (PTE).

OBJECTIVE

To evaluate risk factors for EPS, associated morbidity and mortality, and contribution to PTE.

DESIGN, SETTING, AND PARTICIPANTS

Data were collected from an Australian registry-based cohort study of adults (age ≥18 years) with moderate to severe TBI from January 2005 to December 2019, with 2-year follow-up. The statewide trauma registry, conducted on an opt-out basis in Victoria (population 6.5 million), had 15 152 patients with moderate to severe TBI identified via Abbreviated Injury Scale (AIS) head severity score, with an opt-out rate less than 0.5% (opt-out n = 136).

MAIN OUTCOMES AND MEASURES

EPS were identified via International Statistical Classification of Diseases, Tenth Revision, Australian Modification (ICD-10-AM) codes recorded after the acute admission. Outcome measures also included in-hospital metrics, 2-year outcomes including PTE, and post-discharge mortality. Adaptive least absolute shrinkage and selection operator (LASSO) regression was used to build a prediction model for risk factors of EPS.

RESULTS

Among the 15 152 participants (10 457 [69%] male; median [IQR] age, 60 [35-79] y), 416 (2.7%) were identified with EPS, including 27 (0.2%) with status epilepticus. Significant risk factors on multivariable analysis for developing EPS were younger age, higher Charlson Comorbidity Index, TBI sustained from a low fall, subdural hemorrhage, subarachnoid hemorrhage, higher Injury Severity Score, and greater head injury severity, measured using the AIS and Glasgow Coma Score. After adjustment for confounders, EPS were associated with increased ICU admission and ICU length of stay, ventilation and duration, hospital length of stay, and discharge to inpatient rehabilitation rather than home, but not in-hospital mortality. Outcomes in TBI admission survivors at 24 months, including mortality (relative risk [RR] = 2.14; 95% CI, 1.32-3.46; P = .002), development of PTE (RR = 2.91; 95% CI, 2.22-3.81; P < .001), and use of antiseizure medications (RR = 2.44; 95% CI, 1.98-3.02; P < .001), were poorer for cases with EPS after adjustment for confounders. The prediction model for EPS had an area under the receiver operating characteristic curve of 0.72 (95% CI, 0.66-0.79), sensitivity of 66%, and specificity of 73% in the validation set.

DISCUSSION

We identified important risk factors for EPS following moderate to severe TBI. Early posttraumatic seizures were associated with longer ICU and hospital admissions, ICU ventilation, and poorer 24-month outcomes including mortality and development of PTE.

First-in-clinical application of a time-gated diffuse correlation spectroscopy system at 1064 nm using superconducting nanowire single photon detectors in a neuro intensive care unit

Recently proposed time-gated diffuse correlation spectroscopy (TG-DCS) has significant advantages compared to conventional continuous wave (CW)-DCS, but it is still in an early stage and clinical capability has yet to be established. The main challenge for TG-DCS is the lower signal-to-noise ratio (SNR) when gating for the deeper traveling late photons. Longer wavelengths, such as 1064 nm have a smaller effective attenuation coefficient and a higher power threshold in humans, which significantly increases the SNR. Here, we demonstrate the clinical utility of TG-DCS at 1064 nm in a case study on a patient with severe traumatic brain injury admitted to the neuro-intensive care unit (neuroICU). We showed a significant correlation between TG-DCS early (ρ = 0.67) and late (ρ = 0.76) gated against invasive thermal diffusion flowmetry. We also analyzed TG-DCS at high temporal resolution (50 Hz) to elucidate pulsatile flow data. Overall, this study demonstrates the first clinical translation capability of the TG-DCS system at 1064 nm using a superconducting nanowire single-photon detector.

Neuromonitoring in Severe Traumatic Brain Injury: A Bibliometric Analysis

Traumatic brain injury (TBI) is the leading cause of mortality and disability among trauma-related injuries. Neuromonitoring plays an essential role in the management and prognosis of patients with severe TBI. Our bibliometric study aimed to identify the knowledge base, define the research front, and outline the social networks on neuromonitoring in severe TBI. We conducted an electronic search for articles related to neuromonitoring in severe TBI in Scopus. A descriptive analysis retrieved evidence on the most productive authors and countries, the most cited articles, the most frequently publishing journals, and the most common author's keywords. Through a three-step network extraction process, we performed a collaboration analysis among universities and countries, a cocitation analysis, and a word cooccurrence analysis. A total of 1884 records formed the basis of our bibliometric study. We recorded an increasing scientific interest in the use of neuromonitoring in severe TBI. Czosnyka, Hutchinson, Menon, Smielewski, and Stocchetti were the most productive authors. The most cited document was a review study by Maas et al. There was an extensive collaboration among universities. The most common keywords were "intracranial pressure," with an increasing interest in magnetic resonance imaging and cerebral perfusion pressure monitoring. Neuromonitoring constitutes an area of active research. The present findings indicate that intracranial pressure monitoring plays a pivotal role in the management of severe TBI. Scientific interest shifts to magnetic resonance imaging and individualized patient care on the basis of optimal cerebral perfusion pressure.

Levetiracetam Prophylaxis for Children Admitted With Traumatic Brain Injury

BACKGROUND

Prophylactic antiseizure medications (ASMs) for pediatric traumatic brain injury (TBI) are understudied. We evaluated clinical and radiographic features that inform prescription of ASMs for pediatric TBI. We hypothesized that despite a lack of evidence, levetiracetam is the preferred prophylactic ASM but that prophylaxis is inconsistently prescribed.

METHODS

This retrospective study assessed children admitted with TBI from January 1, 2017, to December 31, 2019. TBI severity was defined using Glasgow Coma Scale (GCS) scores. Two independent neuroradiologists reviewed initial head computed tomography and brain magnetic resonance imaging. Fisher exact tests and descriptive and regression analyses were conducted.

RESULTS

Among 167 children with TBI, 44 (26%) received ASM prophylaxis. All 44 (100%) received levetiracetam. Prophylaxis was more commonly prescribed for younger children, those with neurosurgical intervention, and abnormal neuroimaging (particularly intraparenchymal hematoma) (odds ratio = 10.3, confidence interval 1.8 to 58.9), or GCS ≤12. Six children (13.6%), all on ASM, developed early posttraumatic seizures (EPTSs). Of children with GCS ≤12, four of 17 (23.5%) on levetiracetam prophylaxis developed EPTSs, higher than the reported rate for phenytoin.

CONCLUSIONS

Although some studies suggest it may be inferior to phenytoin, levetiracetam was exclusively used for EPTS prophylaxis. Intraparenchymal hematoma >1 cm was the single neuroimaging feature associated with ASM prophylaxis regardless of the GCS score. Yet these trends are not equivalent to optimal evidence-based management. We still observed important variability in neuroimaging characteristics and TBI severity for children on prophylaxis. Thus, further study of ASM prophylaxis and prevention of pediatric EPTSs is warranted.

Role of Brain Natriuretic Peptide in the Prediction of Early Postoperative Seizures Following Surgery for Traumatic Acute Subdural Hematoma: A Prospective Study

INTRODUCTION

Brain natriuretic peptide (BNP) is a reliable biomarker in the acute phase of traumatic brain injury. However, the relationship between BNP and traumatic acute subdural hematoma (aSDH) has not yet been addressed. This study aimed to analyze BNP levels on admission in surgically treated patients and assess their relationship with early postoperative seizures (EPS) and functional outcomes.

METHODS

Patients with unilateral traumatic aSDH who were surgically treated in our department between July 2017 and May 2020 were included in the study. BNP was preoperatively measured. Patients' neurologic condition, radiographic variables on initial cranial computed tomography, sodium serum levels on admission, and occurrence of EPS were prospectively assessed. Functional outcome was assessed using the modified Rankin Scale (mRS) at discharge and follow-up (at 2-3 months). A poor outcome was defined by a mRS score > 3.

RESULTS

EPS occurred in 20 (19.6%) of 102 surgically treated patients in the final cohort on the median day 3. A significant association between EPS and a poor Glasgow Coma Scale score at the 7th postoperative day was found, which in turn independently predicted a poor functional outcome at discharge and follow-up. Nonetheless, EPS were not associated with poor functional outcomes. The multivariate analysis revealed BNP > 95.4 pg/ml (aOR = 5.7, p = 0.003), sodium < 137.5 mmol/l (aOR = 4.6, p = 0.009), and left-sided aSDH (aOR = 4.4, p = 0.020) as independent predictors of EPS.

CONCLUSION

In the early postoperative phase of traumatic aSDH, EPS were associated with worse neurologic conditions, which in turn independently predicted poor outcomes at discharge and follow-up. Although several EPS risk factors have already been elucidated, this study presents BNP as a novel reliable predictor of EPS. Further larger studies are needed to determine whether a more precise estimate of EPS risk using BNP levels can be reached.

Cerebral and systemic hemodynamic effect of recurring seizures

The increase in neuronal activity induced by a single seizure is supported by a rise in the cerebral blood flow and tissue oxygenation, a mechanism called neurovascular coupling (NVC). Whether cerebral and systemic hemodynamics are able to match neuronal activity during recurring seizures is unclear, as data from rodent models are at odds with human studies. In order to clarify this issue, we used an invasive brain and systemic monitoring to study the effects of chemically induced non-convulsive seizures in sheep. Despite an increase in neuronal activity as seizures repeat (Spearman’s ρ coefficient 0.31, P < 0.001), ictal variations of cerebral blood flow remained stable while it progressively increased in the inter-ictal intervals (ρ = 0.06, P = 0.44 and ρ = 0.22; P = 0.008). We also observed a progressive reduction in the inter-ictal brain tissue oxygenation (ρ =  − 0.18; P = 0.04), suggesting that NVC was unable to compensate for the metabolic demand of these closely repeating seizures. At the systemic level, there was a progressive reduction in blood pressure and a progressive rise in cardiac output (ρ =  − 0.22; P = 0.01 and ρ = 0.22; P = 0.01, respectively), suggesting seizure-induced autonomic dysfunction.

Epilepsy in prolonged disorders of consciousness: a systematic review

To date, no guideline exists for the management of epilepsy in patients with prolonged Disorders of Consciousness (DoC). This review aimed to assess the occurrence of epilepsy and epileptic abnormalities (EA) in these patients, to determine their impact on recovery; and to review the effect of antiepileptic drugs (AED) and therapeutic interventions on seizure occurrence and consciousness recovery. A structured search for studies on prolonged DoC and epilepsy was undertaken following PRISMA guidelines. From an initial search resulting in 5,775 titles, twelve studies met inclusion criteria. The occurrence of epilepsy and EA in DoC was poorly and inconsistently reported across studies. The results estimated a seizure prevalence of 27% in DoC. No conclusive data were found for the effects of AED on recovery nor on the influence of any therapeutic interventions on seizure occurrence. Given the scarcity of data, it is premature to make evidence-based recommendations on epilepsy in prolonged DoC. Based on this review and current clinical practices the following are recommended: (1) repeated standard EEG for detecting seizures and EA; (2) treating epilepsy while avoiding AEDs with sedating or cognitive side-effects. Future research should use standardized classification systems for seizures and EA.

Noninvasive Optical Monitoring of Cerebral Blood Flow and EEG Spectral Responses after Severe Traumatic Brain Injury: A Case Report

Survivors of severe brain injury may require care in a neurointensive care unit (neuro-ICU), where the brain is vulnerable to secondary brain injury. Thus, there is a need for noninvasive, bedside, continuous cerebral blood flow monitoring approaches in the neuro-ICU. Our goal is to address this need through combined measurements of EEG and functional optical spectroscopy (EEG-Optical) instrumentation and analysis to provide a complementary fusion of data about brain activity and function. We utilized the diffuse correlation spectroscopy method for assessing cerebral blood flow at the neuro-ICU in a patient with traumatic brain injury. The present case demonstrates the feasibility of continuous recording of noninvasive cerebral blood flow transients that correlated well with the gold-standard invasive measurements and with the frequency content changes in the EEG data.

Biomarkers for posttraumatic epilepsy

A biomarker is a characteristic that can be objectively measured as an indicator of normal biologic processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions. Biomarker modalities include molecular, histologic, radiographic, or physiologic characteristics. To improve the understanding and use of biomarker terminology in biomedical research, clinical practice, and medical product development, the Food and Drug Administration (FDA)-National Institutes of Health (NIH) Joint Leadership Council developed the BEST Resource (Biomarkers, EndpointS, and other Tools). The seven BEST biomarker categories include the following: (a) susceptibility/risk biomarkers, (b) diagnostic biomarkers, (c) monitoring biomarkers, (d) prognostic biomarkers, (e) predictive biomarkers, (f) pharmacodynamic/response biomarkers, and (g) safety biomarkers. We hypothesize some potential overlap between the reported biomarkers of traumatic brain injury (TBI), epilepsy, and posttraumatic epilepsy (PTE). Here, we tested this hypothesis by reviewing studies focusing on biomarker discovery for posttraumatic epileptogenesis and epilepsy. The biomarker modalities reviewed here include plasma/serum and cerebrospinal fluid molecular biomarkers, imaging biomarkers, and electrophysiologic biomarkers. Most of the reported biomarkers have an area under the receiver operating characteristic curve greater than 0.800, suggesting both high sensitivity and high specificity. Our results revealed little overlap in the biomarker candidates between TBI, epilepsy, and PTE. In addition to using single parameters as biomarkers, machine learning approaches have highlighted the potential for utilizing patterns of markers as biomarkers. Although published data suggest the possibility of identifying biomarkers for PTE, we are still in the early phase of the development curve. Many of the seven biomarker categories lack PTE-related biomarkers. Thus, further exploration using proper, statistically powered, and standardized study designs with validation cohorts, and by developing and applying novel analytical methods, is needed for PTE biomarker discovery.

Seizures and Cognitive Outcome After Traumatic Brain Injury: A Post Hoc Analysis

INTRODUCTION

Seizures and abnormal periodic or rhythmic patterns are observed on continuous electroencephalography monitoring (cEEG) in up to half of patients hospitalized with moderate to severe traumatic brain injury (TBI). We aimed to determine the impact of seizures and abnormal periodic or rhythmic patterns on cognitive outcome 3 months following moderate to severe TBI.

METHODS

This was a post hoc analysis of the multicenter randomized controlled phase 2 INTREPID²⁵⁶⁶ clinical trial conducted from 2010 to 2016 across 20 United States Level I trauma centers. Patients with nonpenetrating TBI and postresuscitation Glasgow Coma Scale scores 4-12 were included. Bedside cEEG was initiated per protocol on admission to intensive care, and the burden of ictal-interictal continuum (IIC) patterns, including seizures, was quantified. A summary global cognition score at 3 months following injury was used as the primary outcome.

RESULTS

142 patients (age mean + / - standard deviation 32 + / - 13 years; 131 [92%] men) survived with a mean global cognition score of 81 + / - 15; nearly one third were considered to have poor functional outcome. 89 of 142 (63%) patients underwent cEEG, of whom 13 of 89 (15%) had severe IIC patterns. The quantitative burden of IIC patterns correlated inversely with the global cognition score (r =  - 0.57; p = 0.04). In multiple variable analysis, the log-transformed burden of severe IIC patterns was independently associated with the global cognition score after controlling for demographics, premorbid estimated intelligence, injury severity, sedatives, and antiepileptic drugs (odds ratio 0.73, 95% confidence interval 0.60-0.88; p = 0.002).

CONCLUSIONS

The burden of seizures and abnormal periodic or rhythmic patterns was independently associated with worse cognition at 3 months following TBI. Their impact on longer-term cognitive endpoints and the potential benefits of seizure detection and treatment in this population warrant prospective study.

A model of metabolic supply-demand mismatch leading to secondary brain injury

Secondary brain injury (SBI) is defined as new or worsening injury to the brain after an initial neurologic insult, such as hemorrhage, trauma, ischemic stroke, or infection. It is a common and potentially preventable complication following many types of primary brain injury (PBI). However, mechanistic details about how PBI leads to additional brain injury and evolves into SBI are poorly characterized. In this work, we propose a mechanistic model for the metabolic supply demand mismatch hypothesis (MSDMH) of SBI. Our model, based on the Hodgkin-Huxley model, supplemented with additional dynamics for extracellular potassium, oxygen concentration, and excitotoxity, provides a high-level unified explanation for why patients with acute brain injury frequently develop SBI. We investigate how decreased oxygen, increased extracellular potassium, excitotoxicity, and seizures can induce SBI and suggest three underlying paths for how events following PBI may lead to SBI. The proposed model also helps explain several important empirical observations, including the common association of acute brain injury with seizures, the association of seizures with tissue hypoxia and so on. In contrast to current practices which assume that ischemia plays the predominant role in SBI, our model suggests that metabolic crisis involved in SBI can also be nonischemic. Our findings offer a more comprehensive understanding of the complex interrelationship among potassium, oxygen, excitotoxicity, seizures, and SBI.NEW & NOTEWORTHY We present a novel mechanistic model for the metabolic supply demand mismatch hypothesis (MSDMH), which attempts to explain why patients with acute brain injury frequently develop seizure activity and secondary brain injury (SBI). Specifically, we investigate how decreased oxygen, increased extracellular potassium, excitotoxicity, seizures, all common sequalae of primary brain injury (PBI), can induce SBI and suggest three underlying paths for how events following PBI may lead to SBI.

Review and Updates on the Treatment of Refractory and Super Refractory Status Epilepticus

Refractory and super-refractory status epilepticus (RSE and SRSE) are life-threatening conditions requiring prompt initiation of appropriate treatment to avoid permanent neurological damage and reduce morbidity and mortality. RSE is defined as status epilepticus that persists despite administering at least two appropriately dosed parenteral medications, including a benzodiazepine. SRSE is status epilepticus that persists at least 24 h after adding at least one appropriately dosed continuous anesthetic (i.e., midazolam, propofol, pentobarbital, and ketamine). Other therapeutic interventions include immunotherapy, neuromodulation, ketogenic diet, or even surgical intervention in certain cases. Continuous electroencephalogram is an essential monitoring tool for diagnosis and treatment. In this review, we focus on the diagnosis and treatment of RSE and SRSE.

Structure and Outcomes of Educational Programs for Training Non-electroencephalographers in Performing and Screening Adult EEG: A Systematic Review

OBJECTIVE

To qualitatively and quantitatively summarize curricula, teaching methods, and effectiveness of educational programs for training bedside care providers (non-experts) in the performance and screening of adult electroencephalography (EEG) for nonconvulsive seizures and other patterns.

METHODS

PRISMA methodological standards were followed. MEDLINE, EMBASE, Cochrane, CINAHL, WOS, Scopus, and MedEdPORTAL databases were searched from inception until February 26, 2020 with no restrictions. Abstract and full-text review was completed in duplicate. Studies were included if they were original research; involved non-experts performing, troubleshooting, or screening adult EEG; and provided qualitative descriptions of curricula and teaching methods and/or quantitative assessment of non-experts (vs gold standard EEG performance by neurodiagnostic technologists or interpretation by neurophysiologists). Data were extracted in duplicate. A content analysis and a meta-narrative review were performed.

RESULTS

Of 2430 abstracts, 35 studies were included. Sensitivity and specificity of seizure identification varied from 38 to 100% and 65 to 100% for raw EEG; 40 to 93% and 38 to 95% for quantitative EEG, and 95 to 100% and 65 to 85% for sonified EEG, respectively. Non-expert performance of EEG resulted in statistically significant reduced delay (86 min, p < 0.0001; 196 min, p < 0.0001; 667 min, p < 0.005) in EEG completion and changes in management in approximately 40% of patients. Non-experts who were trained included physicians, nurses, neurodiagnostic technicians, and medical students. Numerous teaching methods were utilized and often combined, with instructional and hands-on training being most common.

CONCLUSIONS

Several different bedside providers can be educated to perform and screen adult EEG, particularly for the purpose of diagnosing nonconvulsive seizures. While further rigorous research is warranted, this review demonstrates several potential bridges by which EEG may be integrated into the care of critically ill patients.

Clinical and advanced neurophysiology in the prognostic and diagnostic evaluation of disorders of consciousness: review of an IFCN-endorsed expert group

The analysis of spontaneous EEG activity and evoked potentialsis a cornerstone of the instrumental evaluation of patients with disorders of consciousness (DoC). Thepast few years have witnessed an unprecedented surge in EEG-related research applied to the prediction and detection of recovery of consciousness after severe brain injury,opening up the prospect that new concepts and tools may be available at the bedside. This paper provides a comprehensive, critical overview of bothconsolidated and investigational electrophysiological techniquesfor the prognostic and diagnostic assessment of DoC.We describe conventional clinical EEG approaches, then focus on evoked and event-related potentials, and finally we analyze the potential of novel research findings. In doing so, we (i) draw a distinction between acute, prolonged and chronic phases of DoC, (ii) attempt to relate both clinical and research findings to the underlying neuronal processes and (iii) discuss technical and conceptual caveats.The primary aim of this narrative review is to bridge the gap between standard and emerging electrophysiological measures for the detection and prediction of recovery of consciousness. The ultimate scope is to provide a reference and common ground for academic researchers active in the field of neurophysiology and clinicians engaged in intensive care unit and rehabilitation.

A Trial of Real-Time Electrographic Seizure Detection by Neuro-ICU Nurses Using a Panel of Quantitative EEG Trends

BACKGROUND

Non-convulsive seizures (NCS) are a common occurrence in the neurologic intensive care unit (Neuro-ICU) and are associated with worse outcomes. Continuous electroencephalogram (cEEG) monitoring is necessary for the detection of NCS; however, delays in interpretation are a barrier to early treatment. Quantitative EEG (qEEG) calculates a time-compressed simplified visual display from raw EEG data. This study aims to evaluate the performance of Neuro-ICU nurses utilizing bedside, real-time qEEG interpretation for detecting recurrent NCS.

METHODS

This is a prospective, single-institution study of patients admitted to the Duke Neuro-ICU between 2016 and 2018 who had NCS identified on traditional cEEG review. The accuracy of recurrent seizure detection on hourly qEEG review by bedside Neuro-ICU nurses was compared to the gold standard of cEEG interpretation by two board-certified neurophysiologists. The nurses first received brief qEEG training, individualized for their specific patient. The bedside qEEG display consisted of rhythmicity spectrogram (left and right hemispheres) and amplitude-integrated EEG (left and right hemispheres) in 1-h epochs.

RESULTS

Twenty patients were included and 174 1-h qEEG blocks were analyzed. Forty-seven blocks contained seizures (27%). The sensitivity was 85.1% (95% CI 71.1-93.1%), and the specificity was 89.8% (82.8-94.2%) for the detection of seizures for each 1-h block when compared to interpretation of conventional cEEG by two neurophysiologists. The false positive rate was 0.1/h. Hemispheric seizures (> 4 unilateral EEG electrodes) were more likely to be correctly identified by nurses on qEEG than focal seizures (≤ 4 unilateral electrodes) (p = 0.03).

CONCLUSIONS

After tailored training sessions, Neuro-ICU nurses demonstrated a good sensitivity for the interpretation of bedside real-time qEEG for the detection of recurrent NCS with a low false positive rate. qEEG is a promising tool that may be used by non-neurophysiologists and may lead to earlier detection of NCS.

Prevalence of electrographic seizure in dogs and cats undergoing electroencephalography and clinical characteristics and outcome for dogs and cats with and without electrographic seizure: 104 cases (2009-2015)

OBJECTIVE

To determine the prevalence of electrographic seizure (ES) and electrographic status epilepticus (ESE) in dogs and cats that underwent electroencephalography (EEG) because of suspected seizure activity and to characterize the clinical characteristics, risk factors, and in-hospital mortality rates for dogs and cats with ES or ESE.

DESIGN

Retrospective case series.

ANIMALS

89 dogs and 15 cats.

PROCEDURES

Medical records of dogs and cats that underwent EEG at a veterinary neurology service between May 2009 and April 2015 were reviewed. Electrographic seizure was defined as ictal discharges that evolved in frequency, duration, or morphology and lasted at least 10 seconds, and ESE was defined as ES that lasted ≥ 10 minutes. Patient signalment and history, physical and neurologic examination findings, diagnostic test results, and outcome were compared between patients with and without ES or ESE.

RESULTS

Among the 104 patients, ES and ESE were diagnosed in 21 (20%) and 12 (12%), respectively. Seventeen (81%) patients with ES had no or only subtle signs of seizure activity. The in-hospital mortality rate was 48% and 50% for patients with ES and ESE, respectively, compared with 19% for patients without ES or ESE. Risk factors for ES and ESE included young age, overt seizure activity within 8 hours before EEG, and history of cluster seizures.

CONCLUSIONS AND CLINICAL REVELANCE

Results indicated that ES and ESE were fairly common in dogs and cats with suspected seizure activity and affected patients often had only subtle clinical signs. Therefore, EEG is necessary to detect patients with ES and ESE.

Electrographic seizures and ictal-interictal continuum (IIC) patterns in critically ill patients

Critical care long-term continuous electroencephalogram (cEEG) monitoring has expanded dramatically in the last several decades spurned by technological advances in EEG digitalization and several key clinical findings: 1-Seizures are relatively common in the critically ill-large recent observational studies suggest that around 20% of critically ill patients placed on cEEG have seizures. 2-The majority (~75%) of patients who have seizures have exclusively "electrographic seizures", that is, they have no overt ictal clinical signs. Along with the discovery of the unexpectedly high incidence of seizures was the high prevalence of EEG patterns that share some common features with archetypical electrographic seizures but are not uniformly considered to be "ictal". These EEG patterns include lateralized periodic discharges (LPDs) and generalized periodic discharges (GPDs)-patterns that at times exhibit ictal-like behavior and at other times behave more like an interictal finding. Dr. Hirsch and colleagues proposed a conceptual framework to describe this spectrum of patterns called the ictal-interictal continuum (IIC). In the following years, investigators began to answer some of the key pragmatic clinical concerns such as which patients are at risk of seizures and what is the optimal duration of cEEG use. At the same time, investigators have begun probing the core questions for critical care EEG-what is the underlying pathophysiology of these patterns, at what point do these patterns cause secondary brain injury, what are the optimal treatment strategies, and how do these patterns affect clinical outcomes such as neurological disability and the development of epilepsy. In this review, we cover recent advancements in both practical concerns regarding cEEG use, current treatment strategies, and review the evidence associating IIC/seizures with poor clinical outcomes.

Continuous Electroencephalography After Moderate to Severe Traumatic Brain Injury

OBJECTIVES

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.

DESIGN

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.

SETTING

Twenty U.S. level I trauma centers.

PATIENTS

Patients with nonpenetrating traumatic brain injury and postresuscitation Glasgow Coma Scale score of 4-12 were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

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.

CONCLUSIONS

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.

Clinical Characteristics and Nonconvulsive Seizures in Young Children With Abusive Head Trauma

AIM

We aimed to evaluate putative predictors of symptoms and signs at admission for nonconvulsive seizure and to examine the impact of nonconvulsive seizures on short-term outcomes.

METHOD

We retrospectively collected consecutive abusive head trauma patients (<36 months of age) from the trauma registry at Children's Healthcare of Atlanta between 2009 and 2014. Multiple logistic regression was performed to assess the putative predictors for the occurrence of nonconvulsive seizures including clinical seizures, altered mental status, respiratory difficulty, and cardiac arrest at admission, while controlling for age, sex, and injury severity. The Mann-Whitney U test and the Fisher exact test were used to compare the short-term outcomes between patients with and without nonconvulsive seizures.

RESULTS

Two hundred seventy patients with abusive head trauma were identified (male = 55.6%). The median age was 4 months (interquartile range = 2-8 months). Among 70 patients who underwent continuous electroencephalography (EEG), 40 had nonconvulsive seizures (57%) and 21 developed nonconvulsive status epilepticus (30%). Altered mental status at admission was associated with the occurrence of nonconvulsive seizures (odds ratio = 6.8, 95% confidence interval = 1.2-38.2, P = .03). Comparing patients with no seizures, those with nonconvulsive seizures were more likely to stay longer at hospital (9 days vs 14 days, P = .04) and to need rehabilitation (50.0% vs 63.2%, P = .03).

CONCLUSIONS

Nonconvulsive seizures and nonconvulsive status epilepticus was highly prevalent in young pediatric patients with abusive head trauma. Presenting with altered mental status at admission was found to predict the occurrence of nonconvulsive seizures. Nonconvulsive seizures had an unfavorable impact on short-term outcomes.

Multimodality Monitoring in the Neurocritical Care Unit

PURPOSE OF REVIEW

This article focuses on the multiple neuromonitoring devices that can be used to collect bedside data in the neurocritical care unit and the methodology to integrate them into a multimodality monitoring system. The article describes how to apply the collected data to appreciate the physiologic changes and develop therapeutic approaches to prevent secondary injury.

RECENT FINDINGS

The neurologic examination has served as the primary monitor for secondary brain injury in patients admitted to the neurocritical care unit. However, the International Multidisciplinary Consensus Conference on Multimodality Monitoring in Neurocritical Care concluded that frequent bedside examinations are not sufficient to detect and prevent secondary brain injury and that integration of multimodality monitoring with advanced informatics tools will most likely enhance our assessments compared to the clinical examinations alone. This article reviews the invasive and noninvasive technologies used to monitor focal and global neurophysiologic cerebral alterations.

SUMMARY

Multimodal monitoring is still in the early stages of development. Research is still needed to establish more advanced monitors with the bioinformatics to identify useful trends from data gathered to predict clinical outcome or prevent secondary brain injury.

Anesthetic considerations for extracranial injuries in patients with associated brain trauma

Patients with severe traumatic brain injury often presents with extracranial injuries, which may contribute to fatal outcome. Anesthetic management of such polytrauma patients is extremely challenging that includes prioritizing the organ system to be dealt first, reducing on-going injury, and preventing secondary injuries. Neuroprotective and neurorescue measures should be instituted simultaneously during extracranial surgeries. Selection of anesthetic drugs that minimally interferes with cerebral dynamics, maintenance of hemodynamics and cerebral perfusion pressure, optimal utilization of multimodal monitoring techniques, and aggressive rehabilitation approach are the key factors for improving overall patient outcome.

Design paper of the "Blood pressure targets in post-resuscitation care and bedside monitoring of cerebral energy state: a randomized clinical trial"

BACKGROUND

Neurological injuries remain the leading cause of death in comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA). Adequate blood pressure is of paramount importance to optimize cerebral perfusion and to minimize secondary brain injury. Markers measuring global cerebral ischemia caused by cardiac arrest and consecutive resuscitation and reflecting the metabolic variations after successful resuscitation are needed to assist a more individualized post-resuscitation care. Currently, no technique is available for bedside evaluation of global cerebral energy state, and until now blood pressure targets have been based on limited clinical evidence. Recent experimental and clinical studies indicate that it might be possible to evaluate cerebral oxidative metabolism from measuring the lactate-to-pyruvate (LP) ratio of the draining venous blood. In this study, jugular bulb microdialysis and immediate bedside biochemical analysis are introduced as new diagnostic tools to evaluate the effect of higher mean arterial blood pressure on global cerebral metabolism and the degree of cellular damage after OHCA.

METHODS/DESIGN

This is a single-center, randomized, double-blinded, superiority trial. Sixty unconscious patients with sustained return of spontaneous circulation after OHCA will be randomly assigned in a one-to-one fashion to low (63 mm Hg) or high (77 mm Hg) mean arterial blood pressure target. The primary end-point will be a difference in mean LP ratio within 48 h between blood pressure groups. Secondary end-points are (1) association between LP ratio and all-cause intensive care unit (ICU) mortality and (2) association between LP ratio and survival to hospital discharge with poor neurological function.

DISCUSSION

Markers measuring cerebral ischemia caused by cardiac arrest and consecutive resuscitation and reflecting the metabolic changes after successful resuscitation are urgently needed to enable a more personalized post-resuscitation care and prognostication. Jugular bulb microdialysis may provide a reliable global estimate of cerebral metabolic state and can be implemented as an entirely new and less invasive diagnostic tool for ICU patients after OHCA and has implications for early prognosis and treatment.

TRIAL REGISTRATION

ClinicalTrials.gov (ClinicalTrials.gov Identifier: NCT03095742 ). Registered March 30, 2017.

Intensive Care in Traumatic Brain Injury Including Multi-Modal Monitoring and Neuroprotection

Moderate to severe traumatic brain injuries (TBI) require treatment in an intensive care unit (ICU) in close collaboration of a multidisciplinary team consisting of different medical specialists such as intensivists, neurosurgeons, neurologists, as well as ICU nurses, physiotherapists, and ergo-/logotherapists. Major goals include all measurements to prevent secondary brain injury due to secondary brain insults and to optimize frame conditions for recovery and early rehabilitation. The distinction between moderate and severe is frequently done based on the Glascow Coma Scale and therefore often is just a snapshot at the early time of assessment. Due to its pathophysiological pathways, an initially as moderate classified TBI may need the same sophisticated surveillance, monitoring, and treatment as a severe form or might even progress to a severe and difficult to treat affection. As traumatic brain injury is rather a syndrome comprising a range of different affections to the brain and as, e.g., age-related comorbidities and treatments additionally may have a great impact, individual and tailored treatment approaches based on monitoring and findings in imaging and respecting pre-injury comorbidities and their therapies are warranted.

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.

Non-electrographic Seizures Due to Subdural Hematoma: A Case Series and Review of the Literature

Seizures due to subdural hematoma (SDH) are a common finding, typically diagnosed using electroencephalography (EEG). At times, aggressive management of seizures is necessary to improve neurologic recovery and outcomes. Here, we present three patients who had undergone emergent SDH evacuation and showed postoperative focal deficits without accompanying electrographic epileptiform activity. After infarction and recurrent hemorrhage were ruled out, seizures were suspected despite a negative EEG. Patients were treated aggressively with AEDs and eventually showed clinical improvement. Long-term monitoring with EEG revealed electrographic seizures in a delayed fashion. EEG recordings are an important tool for seizure detection, but should be used as an adjunct to, rather than a replacement for, the clinical examination in the acute setting. At times, aggressive treatment of suspected postoperative seizures is warranted despite lack of corresponding electrographic activity and can improve clinical outcomes.

Neuroimaging Correlates of Periodic Discharges

Despite being first described over 50 years ago, periodic discharges continue to generate controversy as to whether they are always, sometimes, or never "ictal." Investigators and clinicians have proposed adjunctive markers to help clarify this distinction-in particular measures of perfusion and metabolism. Here, we review the growing number of neuroimaging studies using Fluorodeoxyglucose-PET, MRI diffusion, Magnetic resonance perfusion, Single Photon Emission Computed Tomography, and Magnetoencepgalography to gain further insight into the physiology and clinical significance of periodic discharges. To date, however, no definitive consensus exists regarding the features of periodic discharges that warrant treatment intensification. However, an emerging consilience among neuroimaging modalities suggests that periodic discharges can induce a hyperexcitatory state with associated hypermetabolism and hyperperfusion, which may result in local metabolic failure.

Novel Metabolomic Comparison of Arterial and Jugular Venous Blood in Severe Adult Traumatic Brain Injury Patients and the Impact of Pentobarbital Infusion

Treatment of severe traumatic brain injury (TBI) in the intensive care unit focuses on controlling intracranial pressure, ensuring sufficient cerebral perfusion, and monitoring for secondary injuries. However, there are limited prognostic tools and no biomarkers or tests of the evolving neuropathology. Metabolomics has the potential to be a powerful tool to indirectly monitor evolving dysfunctional metabolism. We compared metabolite levels in simultaneously collected arterial and jugular venous samples in acute TBI patients undergoing intensive care as well as in healthy control volunteers. Our results show that, first, many circulating metabolites are decreased in TBI patients compared with healthy controls days after injury; both proline and hydroxyproline were depleted by ≥60% compared with healthy controls, as was gluconate. Second, both arterial and jugular venous plasma metabolomic analysis separates TBI patients from healthy controls and shows that distinct combinations of metabolites are driving the group separation in the two blood types. Third, TBI patients under heavy sedation with pentobarbital at the time of blood collection were discernibly different from patients not receiving pentobarbital. These results highlight the importance of accounting for medications in metabolomics analysis. Jugular venous plasma metabolomics shows potential as a minimally invasive tool to identify and study dysfunctional cerebral metabolism after TBI.

Unraveling the complexities of invasive multimodality neuromonitoring

Acute brain injuries are a major cause of death and disability worldwide. Survivors of life-threatening brain injury often face a lifetime of dependent care, and novel approaches that improve outcome are sorely needed. A delayed cascade of brain damage, termed secondary injury, occurs hours to days and even weeks after the initial insult. This delayed phase of injury provides a crucial window for therapeutic interventions that could limit brain damage and improve outcome. A major barrier in the ability to prevent and treat secondary injury is that physicians are often unable to target therapies to patients' unique cerebral physiological disruptions. Invasive neuromonitoring with multiple complementary physiological monitors can provide useful information to enable this tailored, precision approach to care. However, integrating the multiple streams of time-varying data is challenging and often not possible during routine bedside assessment. The authors review and discuss the principles and evidence underlying several widely used invasive neuromonitors. They also provide a framework for integrating data for clinical decision making and discuss future developments in informatics that may allow new treatment paradigms to be developed.

Traumatic Brain Injury in the Pediatric Intensive Care Unit

Head trauma is a leading cause of brain injury in children, and it can have profound lifelong physical, cognitive, and behavioral consequences. Optimal acute care of children with traumatic brain injury (TBI) requires rapid stabilization and early neurosurgical evaluation by a multidisciplinary team. Meticulous attention is required to limit secondary brain injury after the initial trauma. This review discusses pathophysiology, acute stabilization, and monitoring, as well as supportive and therapeutic measures to help minimize ongoing brain injury and optimize recovery in children with TBI. [Pediatr Ann. 2018;47(7):e274-e279.].

Early seizures and temporal lobe trauma predict post-traumatic epilepsy: A longitudinal study

OBJECTIVE

Injury severity after traumatic brain injury (TBI) is a well-established risk factor for the development of post-traumatic epilepsy (PTE). However, whether lesion location influences the susceptibility of seizures and development of PTE longitudinally has yet to be defined. We hypothesized that lesion location, specifically in the temporal lobe, would be associated with an increased incidence of both early seizures and PTE. As secondary analysis measures, we assessed the degree of brain atrophy and functional recovery, and performed a between-group analysis, comparing patients who developed PTE with those who did not develop PTE.

METHODS

We assessed early seizure incidence (n = 90) and longitudinal development of PTE (n = 46) in a prospective convenience sample of patients with moderate-severe TBI. Acutely, patients were monitored with prospective cEEG and a high-resolution Magnetic Resonance Imaging (MRI) scan for lesion location classification. Chronically, patients underwent a high-resolution MRI, clinical assessment, and were longitudinally monitored for development of epilepsy for a minimum of 2 years post-injury.

RESULTS

Early seizures, occurring within the first week post-injury, occurred in 26.7% of the patients (n = 90). Within the cohort of subjects who had evidence of early seizures (n = 24), 75% had a hemorrhagic temporal lobe injury on admission. For longitudinal analyses (n = 46), 45.7% of patients developed PTE within a minimum of 2 years post-injury. Within the cohort of subjects who developed PTE (n = 21), 85.7% had a hemorrhagic temporal lobe injury on admission and 38.1% had early (convulsive or non-convulsive) seizures on cEEG monitoring during their acute ICU stay. In a between-group analysis, patients with PTE (n = 21) were more likely than patients who did not develop PTE (n = 25) to have a hemorrhagic temporal lobe injury (p < 0.001), worse functional recovery (p = 0.003), and greater temporal lobe atrophy (p = 0.029).

CONCLUSION

Our results indicate that in a cohort of patients with a moderate-severe TBI, 1) lesion location specificity (e.g. the temporal lobe) is related to both a high incidence of early seizures and longitudinal development of PTE, 2) early seizures, whether convulsive or non-convulsive in nature, are associated with an increased risk for PTE development, and 3) patients who develop PTE have greater chronic temporal lobe atrophy and worse functional outcomes, compared to those who do not develop PTE, despite matched injury severity characteristics. This study provides the foundation for a future prospective study focused on elucidating the mechanisms and risk factors for epileptogenesis.

Mechanisms of Endogenous Neuroprotective Effects of Astrocytes in Brain Injury

Astrocytes, once believed to serve only as "glue" for the structural support of neurons, have been demonstrated to serve critical functions for the maintenance and protection of neurons, especially under conditions of acute or chronic injury. There are at least seven distinct mechanisms by which astrocytes protect neurons from damage; these are (1) protection against glutamate toxicity, (2) protection against redox stress, (3) mediation of mitochondrial repair mechanisms, (4) protection against glucose-induced metabolic stress, (5) protection against iron toxicity, (6) modulation of the immune response in the brain, and (7) maintenance of tissue homeostasis in the presence of DNA damage. Astrocytes support these critical functions through specialized responses to stress or toxic conditions. The detoxifying activities of astrocytes are essential for maintenance of the microenvironment surrounding neurons and in whole tissue homeostasis. Improved understanding of the mechanisms by which astrocytes protect the brain could lead to the development of novel targets for the development of neuroprotective strategies.

Diagnostic utility of eight-channel EEG for detecting generalized or hemispheric seizures and rhythmic periodic patterns

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Current practice lacks rapid detection tools to screen for seizures.

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High agreement exists between neurologists’ diagnoses using full and reduced montage EEG.

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Reduced channel EEG can be used to screen for generalized or hemispheric or rhythmic and periodic abnormalities.

Objectives

To compare the diagnostic utility of electroencephalography (EEG) using reduced, 8-channel montage (rm-EEG) to full, 18-channel montage (fm-EEG) for detection of generalized or hemispheric seizures and rhythmic periodic patterns (RPPs) by neurologists with extensive EEG training, neurology residents with minimal EEG exposure, and medical students without EEG experience.

Methods

We presented EEG samples in both fm-EEG (bipolar montage) and rm-EEG (lateral leads of bipolar montage) to 20 neurologists, 20 residents, and 42 medical students. Unanimous agreement of three senior epileptologists defined samples as seizures (n = 7), RPPs (n = 10), and normal or slowing (n = 20). Differences in median accuracy, sensitivity, and specificity were assessed using Wilcoxon signed-rank tests.

Results

Full and reduced EEG demonstrated similar accuracy when read by neurologists (fm-EEG: 95%, rm-EEG: 95%, p = 0.29), residents (fm-EEG: 80%, rm-EEG: 80%, p = 0.05), and students (fm-EEG: 60%, rm-EEG: 51%, p = 0.68). Moreover, neurologists’ sensitivity for detecting seizure activity was comparable between fm-EEG (100%) and rm-EEG (98%) (p = 0.17). Furthermore, the specificity of rm-EEG for seizures and RPP (neurologists: 100%, residents: 90%, students: 86%) was significantly greater than that of fm-EEG (neurologists: 93%, p = 0.03; residents: 80%, p = 0.01; students: 69%, p < 0.001).

Conclusions

The reduction of the number of EEG channels from 18 to 8 does not compromise neurologists’ sensitivity for detecting seizures that are often a core reason for performing urgent EEG. It may also increase their specificity for detecting rhythmic and periodic patterns, and thereby providing important diagnostic information to guide patient’s management.

Significance

Our study is the first to document the utility of a reduced channel EEG above the hairline compared to full montage EEG in aiding medical staff with varying degrees of EEG training to detect generalized or hemispheric seizures.

Management of traumatic brain injury patients

Traumatic brain injury (TBI) has been called the ‘silent epidemic’ of modern times, and is the leading cause of mortality and morbidity in children and young adults in both developed and developing nations worldwide. In recent years, the treatment of TBI has undergone a paradigm shift. The management of severe TBI is ideally based on protocol-based guidelines provided by the Brain Trauma Foundation. The aims and objectives of its management are prophylaxis and prompt management of intracranial hypertension and secondary brain injury, maintenance of cerebral perfusion pressure, and ensuring adequate oxygen delivery to injured brain tissue. In this review, the authors discuss protocol-based approaches to the management of severe TBI as per recent guidelines.

Time to continuous electroencephalogram in repeated admissions to the pediatric intensive care unit

PURPOSE

Describe timing from intensive care unit (ICU) admission to initiation of continuous electroencephalogram (cEEG) in repeated ICU admissions.

METHOD

We performed a retrospective observational study in pediatric patients who underwent repeated ICU admissions with cEEG from 2011 to 2013. The main outcome measure was time from ICU admission to cEEG.

RESULTS

There were 41 patients (54% males) with at least 2 ICU admissions with cEEG (median (p25-p75) age at first admission: 3.3 (0.3-8.4) years, at second admission: 3.9 (1.1-9.4) years), 7 patients (57% males, 9.9 (2.9-11.5) years) with at least 3 ICU admissions, and 5 patients (60% males, 10.1 (4-10.5) years) with at least 4 ICU admissions. One patient had 21 ICU admissions. The median (p25-p75) time from ICU admission to cEEG was not different during the first and second ICU admissions [10.7 (1.9-22.9) hours versus 13 (0.2-36.7) hours; p=0.908]. Among patients with electrographic seizures on first admission, time to cEEG was not different during the first and second admissions [7.9 (0.5-23.4) hours versus 14.5 (-2 to 44.5) hours; p=0.636]. Among patients with status epilepticus during the first admission, time to cEEG was not different between the first and second admissions [15.3 (9-79) hours versus 40.7 (19.3-42.6) hours; p=0.75].

CONCLUSIONS

The time from ICU admission to the initiation of cEEG did not decrease in second or subsequent ICU admissions, even in patients with seizures or status epilepticus on the first admission.

Hungry Neurons: Metabolic Insights on Seizure Dynamics

Epilepsy afflicts up to 1.6% of the population and the mechanisms underlying the appearance of seizures are still not understood. In past years, many efforts have been spent trying to understand the mechanisms underlying the excessive and synchronous firing of neurons. Traditionally, attention was pointed towards synaptic (dys)function and extracellular ionic species (dys)regulation. Recently, novel clinical and preclinical studies explored the role of brain metabolism (i.e., glucose utilization) of seizures pathophysiology revealing (in most cases) reduced metabolism in the inter-ictal period and increased metabolism in the seconds preceding and during the appearance of seizures. In the present review, we summarize the clinical and preclinical observations showing metabolic dysregulation during epileptogenesis, seizure initiation, and termination, and in the inter-ictal period. Recent preclinical studies have shown that 2-Deoxyglucose (2-DG, a glycolysis blocker) is a novel therapeutic approach to reduce seizures. Furthermore, we present initial evidence for the effectiveness of 2-DG in arresting 4-Aminopyridine induced neocortical seizures in vivo in the mouse.

The pharmacogenomics of severe traumatic brain injury

Pharmacotherapy for traumatic brain injury (TBI) is focused on resuscitation, prevention of secondary injury, rehabilitation and recovery. Pharmacogenomics may play a role in TBI for predicting therapies for sedation, analgesia, seizure prevention, intracranial pressure-directed therapy and neurobehavioral/psychiatric symptoms. Research into genetic predictors of outcomes and susceptibility to complications may also help clinicians to tailor therapeutics for high-risk individuals. Additionally, the expanding use of genomics in the drug development pipeline has provided insight to novel investigational and repurposed medications that may be useful in the treatment of TBI and its complications. Genomics in the context of treatment and prognostication for patients with TBI is a promising area for clinical progress of pharmacogenomics.

Utility of Clinical Features for the Diagnosis of Seizures in the Intensive Care Unit

PURPOSE

Seizures in the intensive care unit are often subtle, and may have little or no clinical correlate. This study attempts to determine what clinical features are most strongly associated with the presence of electrographic seizures on continuous EEG (cEEG) monitoring.

METHODS

A retrospective review for all patients who underwent cEEG monitoring between January 2003 and March 2009 for either characterization of clinical events or altered mental status was performed. Clinical events were categorized as (1) limb myoclonus/tremor, (2) extremity weakness, (3) eye movement abnormalities, (4) facial/periorbital twitching, and (5) other abnormal movements. The presence of associated dyscognitive event features was also recorded.

RESULTS

Records from 626 patients who underwent cEEG were reviewed-154 for event characterization and 472 for altered mental status. Seizures were captured in 48 patients (31.2%) undergoing cEEG monitoring for characterization of clinical events. This was not significantly different from the incidence of seizures in patients undergoing cEEG for altered mental status (N = 133, 28.2%). Patients undergoing cEEG monitoring for facial/periorbital twitching were significantly more likely to have electrographic seizures (78.9%, P < 0.005) than patients undergoing cEEG for altered mental status or characterization of other types of events.

CONCLUSIONS

The incidence of seizures in patients in the intensive care unit with clinical events is generally not significantly higher than the incidence of seizures in patients in the intensive care unit with altered mental status. However, the presence of facial/periorbital twitching was associated a higher incidence of electrographic seizures.

Acute glucose and lactate metabolism are associated with cognitive recovery following traumatic brain injury

Traumatic brain injury (TBI) is associated with acute cerebral metabolic crisis (ACMC). ACMC-related atrophy appears to be prominent in frontal and temporal lobes following moderate-to-severe TBI. This atrophy is correlated with poorer cognitive outcomes in TBI. The current study investigated ability of acute glucose and lactate metabolism to predict long-term recovery of frontal-temporal cognitive function in participants with moderate-to-severe TBI. Cerebral metabolic rate of glucose and lactate were measured by the Kety-Schmidt method on days 0-7 post-injury. Indices of frontal-temporal cognitive processing were calculated for six months post-injury; 12 months post-injury; and recovery (the difference between the six- and 12-month scores). Glucose and lactate metabolism were included in separate regression models, as they were highly intercorrelated. Also, glucose and lactate values were centered and averaged and included in a final regression model. Models for the prediction frontal-temporal cognition at six and 12 months post-injury were not significant. However, average glucose and lactate metabolism predicted recovery of frontal-temporal cognition, accounting for 23% and 22% of the variance, respectively. Also, maximum glucose metabolism, but not maximum lactate metabolism, was an inverse predictor in the recovery of frontal-temporal cognition, accounting for 23% of the variance. Finally, the average of glucose and lactate metabolism predicted frontal-temporal cognitive recovery, accounting for 22% of the variance. These data indicate that acute glucose and lactate metabolism both support cognitive recovery from TBI. Also, our data suggest that control of endogenous fuels and/or supplementation with exogenous fuels may have therapeutic potential for cognitive recovery from TBI.

Neuroprotection and anti-seizure effects of levetiracetam in a rat model of penetrating ballistic-like brain injury

PURPOSE

We assessed the therapeutic efficacy of FDA-approved anti-epileptic drug Levetiracetam (LEV) to reduce post-traumatic nonconvulsive seizure (NCS) activity and promote neurobehavioral recovery following 10% frontal penetrating ballistic-like brain injury (PBBI) in male Sprague-Dawley rats.

METHODS

Experiment 1 anti-seizure study: 50 mg/kg LEV (25 mg/kg maintenance doses) was given twice daily for 3 days (LEV3D) following PBBI; outcome measures included seizures incidence, frequency, duration, and onset. Experiment 2 neuroprotection studies: 50 mg/kg LEV was given twice daily for either 3 (LEV3D) or 10 days (LEV10D) post-injury; outcome measures include motor (rotarod) and cognitive (water maze) functions.

RESULTS

LEV3D treatment attenuated seizure activity with significant reductions in NCS incidence (54%), frequency, duration, and delayed latency to seizure onset compared to vehicle treatment. LEV3D treatment failed to improve cognitive or motor performance; however extending the dosing regimen through 10 days post-injury afforded significant neuroprotective benefit. Animals treated with the extended LEV10D dosing regimen showed a twofold improvement in rotarod task latency to fall as well as significantly improved spatial learning performance (24%) in the MWM task.

CONCLUSIONS

These findings support the dual anti- seizure and neuroprotective role of LEV, but more importantly identify the importance of an extended dosing protocol which was specific to the therapeutic targets studied.

EEG utilization in Canadian intensive care units: A multicentre prospective observational study

PURPOSE

We have previously shown that electroencephalography (EEG) may be an underutilized monitoring modality in a single general medical-surgical ICU, that does not have a specific neurocritical care consultation service or neurocritical care unit. The present study was designed to describe the pattern of EEG utilization across 3 academic ICUs in Ontario, Canada that use different models of neurocritical care.

METHOD

In this prospective multicentre observational study, ICU patients were screened weekly for 6 non-consecutive weeks to determine if they met the ESICM's recommendations or suggestions for EEG monitoring. If EEGs were performed, the results were recorded. Three models of neurocritical care provision were examined in 3 academic tertiary ICUs. Site 1 is an intensivist-led, medical-surgical ICU with no specific neurocritical care consultation service. The second site is also an intensivist led medical-surgical ICU, but with a formal neurocritical care consultation service. The third site is a virtual neurological and neurotrauma ICU within a medical-surgical ICU, staffed by rotating neurointensivists and general intensivists.

RESULTS

Of the 375 patients who were screened, 127 patients (34%) met at least one ESICM indication for EEG monitoring. Among the 127 patients, 46 patients (37%) had an EEG performed. Site 1 had the highest proportion of EEGs performed. The most common indication for EEG monitoring was for patients with unexplained altered level of consciousness, in the absence of primary brain injury. For the EEGs performed per ESICM indication, the majority of epileptiform abnormalities were found in patients admitted with status epilepticus.

CONCLUSIONS

EEG may be underutilized in Canadian ICUs. The impact on patient management and outcomes are unknown.

Nonconvulsive status epilepticus in adults - insights into the invisible

Nonconvulsive status epilepticus (NCSE) is a state of continuous or repetitive seizures without convulsions. Owing to the nonspecific symptoms and considerable morbidity and mortality associated with NCSE, clinical research has focused on early diagnosis, risk stratification and seizure termination. The subtle symptoms and the necessity for electroencephalographic confirmation of seizures result in under-diagnosis with deleterious consequences. The introduction of continuous EEG to clinical practice, and the characterization of electrographic criteria have delineated a number of NCSE types that are associated with different prognoses in several clinical settings. Epidemiological studies have uncovered risk factors for NCSE; knowledge of these factors, together with particular clinical characteristics and EEG observations, enables tailored treatment. Despite these advances, NCSE can be refractory to antiepileptic drugs, necessitating further escalation of treatment. The presumptive escalation to anaesthetics, however, has recently been questioned owing to an association with increased mortality. This Review compiles epidemiological, clinical and diagnostic aspects of NCSE, and considers current treatment options and prognosis.