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In the case of suspicion of nonconvulsive status epilepticus (NCSE), reactivity on electroencephalograms (EEGs) can provide valuable diagnostic information. Reactivity refers to responses to auditory or somatosensory stimulation, with changes in amplitude and frequency of background activity. Because of self‐perpetuating processes and the failure of self‐terminating mechanisms, status epilepticus is unlikely to cease when patients spontaneously move, and it cannot typically be stopped by external stimulation (i.e., auditory and tactile stimuli). The defining EEG characteristic of absence status epilepticus is the presence of bilateral, synchronous, symmetric, rhythmic paroxysmal activity that shows little or no reactivity to sensory stimulation. On the other hand, in metabolic/toxic or multifactorial encephalopathies, triphasic waves (TWs) are influenced by the level of vigilance. TWs may be transiently abolished when patients increase their level of alertness from a drowsy/lethargic state to a state of wakefulness. This reactivity is only observed when patients can be aroused by a somatosensory or auditory stimulus. This reactivity tends to disappear with increasing severity of the disease and in comatose patients. In patients without preexisting developmental and epileptic encephalopathy, this pattern of stimulus‐induced wakefulness with transient improvement of the EEG is a major criterion in determining that the EEG patterns are not ictal. This criterion of reactivity on EEGs, beyond the classical clinical/EEG criteria of NCSE (Salzburg criteria), should now be systematically added. [ABSTRACT FROM AUTHOR]

Objective: The Salzburg criteria for nonconvulsive status epilepticus (NCSE) and the American Clinical Neurophysiology Society (ACNS) Standardized Critical Care EEG Terminology 2021 include a diagnostic trial with intravenous (IV) antiseizure medications (ASMs) to assess electroencephalographic (EEG) and clinical response as a diagnostic criterion for definite NCSE and possible NCSE. However, how to perform this diagnostic test and assessing the EEG and clinical responses have not been operationally defined. Methods: We performed a Delphi process involving six experts to standardize the diagnostic administration of IV ASM and propose operational criteria for EEG and clinical response. Results: Either benzodiazepines (BZDs) or non‐BZD ASMs can be used as first choice for a diagnostic IV ASM trial. However, non‐BZDs should be considered in patients who already have impaired alertness or are at risk of respiratory depression. Levetiracetam, valproate, lacosamide, brivaracetam, or (if the only feasible drug) fosphenytoin or phenobarbital were deemed appropriate for a diagnostic IV trial. The starting dose should be approximately two thirds to three quarters of the full loading dose recommended for treatment of status epilepticus, with an additional smaller dose if needed. ASMs should be administered during EEG recording under supervision. A monitoring time of at least 15 min is recommended. If there is no response, a second trial with another non‐BDZ or BDZs may be considered. A positive EEG response is defined as the resolution of the ictal–interictal continuum pattern for at least three times the longest previously observed spontaneous interval of resolution (if any), but minimum of one continuous minute. For a clinical response, physicians should use a standardized examination before and after IV ASM administration. We suggest a definite time‐locked improvement in a focal deficit or at least one‐step improvement on a new dedicated one‐domain 10‐level NCSE response scale. Significance: The proposed standardized approach of a diagnostic IV ASM trial further refines the ACNS and Salzburg diagnostic criteria for NCSE. [ABSTRACT FROM AUTHOR]

Summary: Objective: To characterize a critically ill cohort with status epilepticus (SE) by the illness severity scoring systems SAPS II (Simplified Acute Physiology Score II), APACHE II (Acute Physiology and Chronic Health Evaluation II), and SOFA (Sequential Organ Failure Assessment), and to compare their performance with the STESS (Status Epilepticus Severity Score) for outcome prediction. Methods: The prospective cohort study was carried out at the University Hospital Basel, a Swiss tertiary academic medical care center. Consecutive adult SE patients hospitalized in the intensive care units from 2011 to 2016 were included. Illness severity scores and additional clinical data were recorded. Logistic regression models using automated variable selection were applied to identify scores associated with no return to functional and neurological baseline and death. Measures of discrimination and calibration were assessed. Results: Among 184 patients, 33% returned to baseline. Median scores of the illness severity scores were within the lowest third of the possible scoring ranges, and all differed significantly between patients with and without return to baseline. The areas under the receiver operating curves for the prediction of no return to baseline and death ranged from 0.64 to 0.73, with the highest value for the STESS predicting no return to baseline. Measures of calibration revealed adequate model fit for all analyses. Among integral components of the scoring systems, only the Glasgow Coma Scale (GCS) differed significantly between patients with and without return to baseline. In multivariable analyses, decreasing GCS and increasing STESS had the strongest associations (odds ratio [OR] = 0.84, 95% confidence interval [CI] = 0.77‐0.93 and OR = 1.34, 95% CI = 1.05‐1.68, respectively) with no return to baseline independent of all other scoring systems, whereas the APACHE II revealed the strongest association with death (OR = 1.15, 95% CI = 1.06‐1.25). Significance: Although complex illness severity scoring systems in SE patients facilitate benchmarking and comparisons with other severely ill patient cohorts, they offer no advantages over the STESS and GCS regarding prediction of no return to baseline. [ABSTRACT FROM AUTHOR]

Summary: Objectives: Early identification of patients who are at risk of prolonged status epilepticus (SE) and patients with high chances of full recovery despite prolonged SE may urge clinicians to intensify treatment rather than to withdraw care. We aimed to develop prediction models based on readily available clinical parameters to predict prolonged SE at seizure onset and to identify patients with high chances for full recovery. Methods: From 2005 to 2016, all adult SE patients treated at the University Hospital Basel, a Swiss medical care center, were included. Multivariable Poisson regression was performed to identify predictors of prolonged SE (defined as SE for >12, >24, and >48 hours) and return to baseline from prolonged SE. The area under the receiver‐operating characteristic curves (AUROC) for prediction models was calculated. Results: Of 467 patients, the median age was 66.7 years and mortality was 12%. Relative risk (RR) for death was 1.06 (P < 0.0001) with every SE day. In multivariable analysis, nonconvulsive SE with coma, SE severity score ≥3, and acute brain lesions at SE onset independently predicted prolonged SE with an AUROC of 0.68 for >12, 0.67 for >24, and 0.72 for >48 hours of SE. Absence of nonconvulsive SE with coma and a decreasing Charlson comorbidity index were independent predictors for return to baseline in prolonged SE with an AUROC of 0.82 and 0.76 following cross‐validation. Both associations remained significant despite adjustments for determinants of adverse outcome, such as anesthetics and vasopressors (nonconvulsive SE with coma RR = 0.24, 95% confidence interval [CI] 0.07‐0.86; comorbidity index RR = 0.87, 95% CI 0.76‐0.99). Significance: Although our data indicate that identification of prolonged SE at seizure onset is unreliable, timely recognition of patients with high chances of good outcome despite prolonged SE is promising on the basis of comorbidities, type of SE, and level of consciousness. Further external validation of this prediction model is needed. [ABSTRACT FROM AUTHOR]

Objective: Clinical absences are now classified as "generalized nonmotor (absence) seizures" by the International League Against Epilepsy (ILAE). The aim of this paper is to critically review the concept of absences and to put the accompanying focal and motor symptoms into the context of the emerging pathophysiological knowledge. Methods: For this narrative review we performed an extensive literature search on the term "absence," and analyzed the plethora of symptoms observed in clinical absences. Results: Arising from the localization and the involved cortical networks, motor symptoms may include bilateral mild eyelid fluttering and mild myoclonic jerks of extremities. These motor symptoms may also occur unilaterally, analogous to a focal motor seizure with Jacksonian march. Furthermore, electroencephalography (EEG) abnormalities may exhibit initial frontal focal spikes and consistent asymmetries. Electroclinical characteristics support the cortical focus theory of absence seizures. Simultaneous EEG/functional magnetic resonance imaging (fMRI) measurements document cortical deactivation and thalamic activation. Cortical deactivation is related to slow waves and disturbances of consciousness of varying degrees. Motor symptoms correspond to the spike component of the 3/s spike-and-wave-discharges. Thalamic activation can be interpreted as a response to overcome cortical deactivation. Furthermore, arousal reaction during drowsiness or sleep triggers spikes in an abnormally excitable cortex. An initial disturbance in arousal mechanisms ("dyshormia") might be responsible for the start of this abnormal sequence. Significance: The classification as "generalized nonfocal and nonmotor (absence) seizure" does not covey the complex semiology of a patient's clinical events. [ABSTRACT FROM AUTHOR]

Objective Approximately 25 million individuals older than age 15 identify as transgender, representing about 0.3-0.9% of the world's population. The aim of this paper is to identify and describe important medical and social considerations facing transgender persons with epilepsy. Methods We performed literature searches on the following terms: transgender AND epilepsy, transgender AND neurology, gender dysphoria AND epilepsy, gender dysphoria AND neurology. We also performed literature searches for common feminizing or masculinizing treatment regimens, and searched for interactions of those treatment regimens with antiepileptic drugs ( AEDs) and with seizures. Results There are multiple bidirectional interactions between AEDs and the commonly used treatments for aligning external sex characteristics with identified gender. The scope of the transgender population with epilepsy remains to be elucidated. Significance Transgender patients with epilepsy face significant social and medical challenges. Interactions between medical gender-affirming treatments and AEDs are common, and management must depend on knowledge of these interactions to provide appropriate treatment. [ABSTRACT FROM AUTHOR]

Proceeding from the proposed classification of status epilepticus syndromes by Shorvon in 1994, we performed a systematic search for reports presenting electroencephalography ( EEG) patterns of nonconvulsive status epilepticus ( NCSE) on all syndromes in the classification, where possible. Using the online medical search engine Pub Med for 22 different search strategies, EEG patterns supporting a diagnosis of NCSE were sought. From a total of 4,328 search results, 123 cases with corresponding EEG patterns could be allocated to underlying epilepsy syndromes. Based on the characteristic EEG patterns found for the different NCSE syndromes, we present a synthesis of the significant EEG morphologies and evolutions in the individual NCSE syndromes. [ABSTRACT FROM AUTHOR]

There have been many attempts at defining the electroencephalography (EEG) characteristics of nonconvulsive status epilepticus (NCSE) without a universally accepted definition. This lack of consensus arises because the EEG expression of NCSE does not exist in isolation, but reflects status epilepticus under the variety of pathologic conditions that occur with age, cerebral development, encephalopathy, and epilepsy syndrome. Current NCSE definitions include 'boundary conditions,' in which electroencephalographic seizure activity occurs without apparent clinical seizures. Furthermore, what appears to one interpreter as status epilepticus, is not to another reader, reflecting the 'art' of EEG interpretation. Seizures and epilepsy syndromes have undergone an evolution that has moved beyond a classification of focal or generalized conditions into a syndromic approach. It seems appropriate to make similar changes in the EEG analysis of the syndromes of NCSE. In effect, the literature on epilepsy classification has progressed to incorporate the different NCSE types with clinical descriptions, but the specific EEG evidence for these types is found largely in individual reports, and often by description only. NCSE classification of EEG patterns should derive from the aggregate of published EEG patterns in the respective clinical subtype, supported by an analysis of these EEG studies. The analysis that follows presents clinical descriptions and EEG patterns of NCSE in the neonatal period, infancy, childhood, adulthood, and late adulthood from a syndromic perspective based on age, encephalopathy, cerebral development, etiology, and syndrome. Proceeding from the proposed classification of status epilepticus syndromes in 'Status epilepticus: its clinical features and treatment in children and adults' (published in 1994 by Cambridge University Press, New York), we have performed a systematic search for reports presenting EEG patterns of NCSE using the online medical search engine PubMed for 22 different search strategies. EEG patterns were reviewed by two board-certified epileptologists who reached consensus regarding presence of NCSE. From a total of 4,328 search results, 123 cases with corresponding EEG patterns could be allocated to underlying epilepsy syndromes. Typical characteristic, prominent electrographic patterns, and sequential arrangements are elucidated for the different NCSE syndromes. This compendium of patterns by NCSE syndrome classification with illustration of EEGs, and delineation of electroencephalographic features helps define the characteristics and semiologic borderlines among the types of NCSE. [ABSTRACT FROM AUTHOR]

A committee assembled by the American Academy of Neurology (AAN) reassessed the evidence related to the care of women with epilepsy (WWE) during pregnancy, including the risk of pregnancy complications or other medical problems during pregnancy, change in seizure frequency, the risk of status epilepticus, and the rate of remaining seizure-free during pregnancy. The committee evaluated the available evidence according to a structured literature review and classification of relevant articles. For WWE who are taking antiepileptic drugs (AEDs), there is probably no substantially increased risk (>2 times expected) of cesarean delivery or late pregnancy bleeding, and probably no moderately increased risk (>1.5 times expected) of premature contractions or premature labor and delivery. There is possibly a substantially increased risk of premature contractions and premature labor and delivery during pregnancy for WWE who smoke. WWE should be counseled that seizure freedom for at least 9 months prior to pregnancy is probably associated with a high likelihood (84–92%) of remaining seizure-free during pregnancy. WWE who smoke should be counseled that they possibly have a substantially increased risk of premature contractions and premature labor and delivery. [ABSTRACT FROM AUTHOR]

A committee assembled by the American Academy of Neurology (AAN) reassessed the evidence related to the care of women with epilepsy (WWE) during pregnancy, including antiepileptic drug (AED) teratogenicity and adverse perinatal outcomes. It is highly probable that intrauterine first-trimester valproate (VPA) exposure has higher risk of major congenital malformations (MCMs) compared to carbamazepine (CBZ), and possibly compared to phenytoin (PHT) or lamotrigine (LTG). It is probable that VPA as part of polytherapy and possible that VPA as monotherapy contribute to the development of MCMs. AED polytherapy probably contributes to the development of MCMs and reduced cognitive outcomes compared to monotherapy. Intrauterine exposure to VPA monotherapy probably reduces cognitive outcomes and monotherapy exposure to PHT or phenobarbital (PB) possibly reduces cognitive outcomes. Neonates of WWE taking AEDs probably have an increased risk of being small for gestational age and possibly have an increased risk of a 1-minute Apgar score of <7. If possible, avoidance of VPA and AED polytherapy during the first trimester of pregnancy should be considered to decrease the risk of MCMs. If possible, avoidance of VPA and AED polytherapy throughout pregnancy should be considered and avoidance of PHT and PB throughout pregnancy may be considered to prevent reduced cognitive outcomes. [ABSTRACT FROM AUTHOR]

A committee assembled by the American Academy of Neurology (AAN) reassessed the evidence related to the care of women with epilepsy (WWE) during pregnancy, including preconceptional folic acid and prenatal vitamin K use and the clinical implications of placental and breast-milk transfer of antiepileptic drugs (AEDs). The committee evaluated the available evidence based on a structured literature review and classification of relevant articles. Preconceptional folic acid supplementation is possibly effective in preventing major congenital malformations in the newborns of WWE taking AEDs. There is inadequate evidence to determine if the newborns of WWE taking AEDs have a substantially increased risk of hemorrhagic complications. Primidone and levetiracetam probably transfer into breast milk in clinically important amounts. Valproate, phenobarbital, phenytoin, and carbamazepine probably are not transferred into breast milk in clinically important amounts. Pregnancy probably causes an increase in the clearance and a decrease in the concentrations of lamotrigine, phenytoin, and, to a lesser extent carbamazepine, and possibly decreases the level of levetiracetam and the active oxcarbazepine metabolite, the monohydroxy derivative (MHD). Supplementing WWE with at least 0.4 mg of folic acid before pregnancy may be considered. Monitoring of lamotrigine, carbamazepine, and phenytoin levels during pregnancy should be considered, and monitoring of levetiracetam and oxcarbazepine (as MHD) levels may be considered. A paucity of evidence limited the strength of many recommendations. [ABSTRACT FROM AUTHOR]

Lithium therapy can cause a confusional state by direct toxicity, precipitation of nonconvulsive status epilepticus, or by interplay with other neuroleptic medications to produce neuroleptic malignant syndrome or serotonin syndrome. These conditions resemble each other clinically, but EEG may help differentiate among them. We reviewed the EEG patterns with triphasic waves or rhythmic delta activity in lithium toxic patients and discuss clinical and EEG differentiation among syndromes. Lithium toxicity poses significant diagnostic challenges from EEG and clinical perspectives. [ABSTRACT FROM AUTHOR]

The article focuses on the diagnosis of nonconvulsive status epilepticus (NCSE) based on electroencephalographic (EEG) features. Several studies have been conducted to examine EEG borderlands that represent seizures or interictal patterns. The characteristics of EEG include typical spike-and-wave (TSW) patterns at 3-3.5 Hz. Further the interictal patterns, periodic epilepticus form discharges (PEDs) are considered as a pattern found in temporal proximity to seizures.

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

The diagnosis of nonconvulsive status epilepticus ( NCSE) relies largely on electroencephalography ( EEG) findings. The lack of a unified EEG terminology, and of evidence-based EEG criteria, leads to varying criteria for and ability to diagnose NCSE. We propose a unified terminology and classification system for NCSE, using, as a template, the Standardised Computer-based Organised Reporting of EEG ( SCORE). This approach integrates the terminology recently proposed for the rhythmic and periodic patterns in critically ill patients, the electroclinical classification of NCSE (type of NCSE) and the context for the pathologic conditions and age-related epilepsy syndromes. We propose flexible EEG criteria that employ the SCORE system to assemble a database for determining evidence-based EEG criteria for NCSE. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article about the difficulties of distinguishing triphasic waves (TWs) from some cases of nonconvulsive status epilepticus (NCSE) with blunted sharp-slow wave morphologies that was published in the previous issue.