Levetiracetam versus fosphenytoin as a second-line treatment after diazepam for adult convulsive status epilepticus: a multicentre non-inferiority randomised control trial.

OBJECTIVE: Status epilepticus (SE) is an emergency condition for which rapid and secured cessation is crucial. Although fosphenytoin (FPHT) is recommended as a second-line treatment, levetiracetam (LEV) reportedly has similar efficacy, but higher safety. Therefore, we herein compared LEV with FPHT in adult SE. METHODS: We initiated a multicentre randomised control trial in emergency departments with adult patients with convulsive SE. Diazepam was initially administered, followed intravenously by FPHT at 22.5 mg/kg or LEV at 1000-3000 mg. The primary outcome was assigned as the seizure cessation rate within 30 min of the administration of the study drug. RESULTS: A total of 176 adult patients with SE were enrolled (82 FPHT and 94 LEV), and 3 were excluded from the full analysis set. Seizure cessation rates within 30 min were 83.8% (67/80) in the FPHT group and 89.2% (83/93) in the LEV group. The difference in these rates was 5.5% (95% CI -4.7 to 15.7, p=0.29). The non-inferiority of LEV to FPHT was confirmed with p<0.001 by the Farrington-Manning test. No significant differences were observed in the seizure recurrence rate or intubation rate within 24 hours. Serious adverse events developed in three patients in the FPHT group and none in the LEV group (p=0.061). CONCLUSION: The efficacy of LEV was similar to that of FPHT for adult SE following the administration of diazepam. LEV may be recommended as a second-line treatment for SE along with phenytoin/FPHT. TRIAL REGISTRATION NUMBER: jRCTs031190160.

Long-Term Outcomes of Patients with Stroke Predicted by Clinicians to have no Chance of Meaningful Recovery: A Japanese Cohort Study.

BACKGROUND: Little is known about the natural history of comatose patients with brain injury, as in many countries most of these patients die in the context of withdrawal of life-sustaining therapies (WLSTs). The accuracy of predicting recovery that is used to guide goals-of-care decisions is uncertain. We examined long-term outcomes of patients with ischemic or hemorrhagic stroke predicted by experienced clinicians to have no chance of meaningful recovery in Japan, where WLST in patients with isolated neurological disease is uncommon. METHODS: We retrospectively reviewed the medical records of all patients admitted with acute ischemic stroke, intracerebral hemorrhage, or nontraumatic subarachnoid hemorrhage between January 2018 and December 2020 to a neurocritical care unit at Toda Medical Group Asaka Medical Center in Saitama, Japan. We screened for patients who were predicted by the attending physician on postinjury day 1-4 to have no chance of meaningful recovery. Primary outcome measures were disposition at hospital discharge and the ability to follow commands and functional outcomes measured by the Glasgow Outcome Scale-Extended (GOS-E), which was assessed 6 months after injury. RESULTS: From 860 screened patients, we identified 40 patients (14 with acute ischemic stroke, 19 with intracerebral hemorrhage, and 7 with subarachnoid hemorrhage) who were predicted to have no chance of meaningful recovery. Median age was 77 years (interquartile range 64-85), 53% (n = 21) were women, and 80% (n = 32) had no functional deficits prior to hospitalization. Six months after injury, 17 patients were dead, 14 lived in a long-term care hospital, 3 lived at home, 2 lived in a rehabilitation center, and 2 lived in a nursing home. Three patients reliably followed commands, two were in a vegetative state (GOS-E 2), four fully depended on others and required constant assistance (GOS-E 3), one could be left alone independently for 8 h per day but remained dependent (GOS-E 4), and one was independent and able to return to work-like activities (GOS-E 5). CONCLUSIONS: In the absence of WLST, almost half of the patients predicted shortly after the injury to have no chance of meaningful recovery were dead 6 months after the injury. A small minority of patients had good functional recovery, highlighting the need for more accurate neurological prognostication.

Dual pathology in a patient with temporal lobe epilepsy associated with neocortical glial scar after brain abscess and end folium sclerosis/hippocampal sclerosis type 3.

End folium sclerosis or hippocampal sclerosis (HS) type 3 is often associated with another coexisting epileptogenic lesion (dual pathology); however, the pathogenesis of HS type 3 remains elusive. A 46-year-old man presented with medically intractable focal aware seizures and focal impaired awareness seizures (FIAS) with occasional focal to bilateral tonic-clonic seizures (FBTCS) two years after surgical treatment with extensive cranial reconstruction for a brain abscess in the right temporal lobe associated with intracranial extension of ipsilateral cholesteatoma. Head magnetic resonance imaging (MRI) at age 49 revealed atrophy of the right cerebral hemisphere including the hippocampus and amygdala. The patient's first epilepsy surgery was a lateral temporal lobectomy, in which the mesial temporal structures were preserved because no epileptiform discharge was detected on the intraoperative electrocorticogram. However, FIAS with FBTCS started 15 months after the operation. The second surgery, amygdalohippocampectomy, at age 52, resulted in the patient being seizure-free again for one year before seizures of the right lateral temporal origin recurred. He underwent a third surgery, resection of the Heschl's and supramarginal gyri, at age 53, but he continued to have drug-resistant epilepsy over two years after that. Histopathological examination revealed dual pathology consisting of glial scar in the lateral temporal lobe and ipsilateral HS type 3 with an unusually severe lesion in the subiculum. No significant inflammatory change was observed. The clinicopathological features in the present case indicate that HS developed secondarily in the context of neocortical epilepsy due to glial scar, suggesting a role of repetitive abnormal electrical input from neocortical epileptogenic lesions into the hippocampus finally via the perforant pathway in the pathogenesis of HS type 3. Severe hippocampal atrophy on preoperative MRI together with its silent electrocorticogram recording at initial epilepsy surgery may represent clinically pre-epileptogenic HS in a seizure-free "silent or latent period" before completion of hippocampal epileptogenesis to the extent that clinical epileptic seizures occur.

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

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

Nonconvulsive Status Epilepticus in Acute Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Patients with acute intracerebral hemorrhages (ICHs) often develop nonconvulsive status epilepticus (NCSE). We aimed to identify determinants and the prognostic significance of NCSE among patients with acute ICH. METHODS: Consecutive patients with acute spontaneous ICH who were admitted to a comprehensive stroke center were enrolled. We diagnosed NCSE using the modified Salzburg Consensus Criteria. Factors associated with NCSE and their significance in relation to clinical outcomes were assessed using multivariate logistic regression models. RESULTS: Of 228 patients (136 men; mean age, 68±14 years), 20 (8.8%) developed NCSE during their hospital stays. In logistic regression models, the adjusted odds ratios (95% confidence intervals) for NCSE were 3.5 (1.2-10.7) for craniotomy and 7.0 (2.2-31.2) for lobar involvement. The patients with NCSE had higher modified Rankin Scale scores at discharge, but NCSE was not independently associated with poor functional outcomes (modified Rankin Scale score, 4-5) or mortality after adjusting for confounders. CONCLUSIONS: NCSE is not a rare complication of acute ICH. Craniotomy and lobar involvement are independently associated with NCSE in patients with acute ICH.

Efficacy, safety, and outcomes in 17 pediatric cases treated with the free radical scavenger edaravone.

SUBJECTS: Edaravone is a free radical scavenger with brain protection properties and is recommended by "The Japanese Guidelines for the Management of Stroke 2009" for administration to adult patients, in whom it has been shown to improve neurological deficits after cerebral infarction. However, its dosage and effects have not yet been established in children. METHODS: Seventeen pediatric patients with cerebral ischemia were administered edaravone at a dose based on body weight from the standard dose given to adults. Functional outcomes were evaluated using mRS and PSOM (modified ranking scale and pediatric stroke outcome scale, respectively). RESULTS: Immediate post-treatment results were mostly positive, with no liver or renal complications. In some cases, neurological symptoms markedly improved after the administration of edaravone. CONCLUSIONS: The efficacy of edaravone has not yet been examined in pediatric patients. The results of the present study suggest that edaravone has potential in the treatment of children safely with promising results similar to those in adults.

Chronological Changes in Transcranial Motor Evoked Potential during Anterior Temporal Lobectomy in Patients with Temporal Lobe Epilepsy: A Single Center Cross-Sectional Analytic Study.

OBJECTIVE: Despite the benefits of anterior temporal lobectomy with amygdalohippocampectomy (ATL+AH) in patients with temporal lobe epilepsy (TLE), approximately up to 5% may have hemiparesis as its postoperative complication. This paper aims to describe which step/s of the ATL with AH have the highest probability of having greatest decrease in MEP amplitude. METHODS: This study utilized a cross-sectional design of obtaining data from TLE patients who underwent ATL+AH with TcMEP monitoring. Each of the following steps were evaluated for reduction in MEP amplitude: 1) Dural Opening, 2) Opening the inferior horn, 2) Vertical temporal lobe resection 3) Subpial dissection, 4) Temporal lobe stem resection, 5) Lateral temporal lobe resection, 6) Hippocampal Resection, 7) Amygdala Resection, 8) Uncus resection and 9) Dural Closure. RESULTS: Nineteen patients were included in the study. Based on Friedman Test, one or more steps had significantly different average MEP amplitude reductions (Friedman=50.7, p=0.0001). When compared to baseline (100%, cut off p=0.005), hippocampal resection (z=-3.81, p<0.0001), T1 subpial dissection (z=-3.2, p=0.0010), uncus resection (z=-3.48, p=0.0002), temporal stem resection (z=-3.26, p=0.001), lateral temporal lobe resection (z=-3.13, p=0.002) and amygdalectomy (-z=-3.37, p=0.0005) were significantly lower. Of these, hippocampal resection, uncus resection and amygdalectomy were deemed highly significant. CONCLUSIONS: MEP amplitude tends to decrease during amygdala, hippocampal and uncal resection because of surgical manipulation of choroidal arteries which can potentially cause hemiparesis so careful attention should be paid to changes in MEP during these steps.

Retrospective Observational Study of Patients With Subdural Hematoma Treated With Idarucizumab.

Use of anticoagulants is increasing with the aging of societies. The safe first-line drug is likely to be a direct oral anticoagulant (DOAC), but outcomes of treatment of traumatic brain injury (TBI) with anticoagulants are uncertain. Therefore, we examined the clinical effect of idarucizumab as reversal therapy in elderly patients with TBI who were treated with dabigatran. A retrospective multi-center observational study was performed in patients ≥65 years of age who developed acute traumatic subdural hematoma during treatment with dabigatran and underwent reversal therapy with idarucizumab. The items examined included patient background, neurological and imaging findings at arrival, course after admission, complications, and outcomes. A total of 23 patients were enrolled in the study. The patients had a mean age of 78.9 years. Cause of TBI was fall in 60.9% of the subjects. Mean Glasgow Coma Scale score at arrival was 8.7; anisocoria was present in 31.8% of cases. Exacerbation of consciousness was found in 30.4%, but only in 13.3% of subjects treated with idarucizumab before consciousness and imaging findings worsened. Dabigatran was discontinued in 81.8% of cases after hematoma development, with a mean withdrawal period of 12.1 days. The favorable outcome rate was 21.7%, and mortality was 39.1%. In multi-variate analysis, timing of idarucizumab administration was associated with a favorable outcome. There were ischemic complications in 3 cases (13.1%), and all three events occurred ≥7 days after administration of idarucizumab. These findings suggest that in cases that develop hematoma during treatment with dabigatran, it is important to administer idarucizumab early and restart dabigatran after conditions stabilize.

Non-lesional late-onset epilepsy in the elderly Japanese patients: Presenting characteristics and seizure outcomes with regard to comorbid dementia.

The objective of the present retrospective study was analysis of clinical, radiological, and electrophysiological characteristics of the non-lesional late-onset epilepsy (NLLOE) in the elderly Japanese patients, and comparison of the seizure outcomes in this population with regard to presence of comorbid dementia. The study cohort comprised 89 consecutive patients with NLLOE aged ≥ 65 years. In 49 cases (55%), NLLOE manifested with a single type of seizure. Focal impaired awareness seizures (FIAS) were encountered most often (in 69 patients; 78%). Ten patients (11%) had a history of the status epilepticus. Comorbid dementia was diagnosed in 31 patients (35%). Localized or diffuse white matter hyperintensity was the most common imaging finding (66 cases). Epileptiform discharges in the temporal area represented the most frequent abnormality on interictal EEG (24 cases). Seizure-free status for ≥ 12 months was attained in 46 out of 64 patients (72%), who were followed for ≥ 12 months (range, 12 - 110 months), and 42 of them received monotherapy, mainly with levetiracetam (21 patients), carbamazepine (10 patients), or lacosamide (8 patients). In comparison to their counterparts, the rate of seizure-free status for ≥ 12 months was significantly lower in patients with comorbid dementia (81% vs. 52%; P = 0.0205). In conclusion, the NLLOE among Japanese patients aged ≥ 65 years has variable presenting characteristics, and comorbid dementia is diagnosed in one-third of cases. Seizure-free status for ≥ 12 months may be attained in more than two-thirds of treated patients, but comorbid dementia is associated with significantly worse response to antiseizure therapy.

Focal atonic seizures originated in the posterior temporoparietal area: A case report.

Atonic seizures are typically observed in younger children with Lennox-Gastaut syndrome and have been rarely described in adults. Herein we present a case of the adolescent-onset drug-resistant focal epilepsy in a 31-year-old woman with focal atonic seizures originating in the left posterior temporoparietal area and manifesting without aura with abrupt impairment of consciousness and slow falling down. According to the video-EEG monitoring, the seizure began with the medium amplitude spikes principally at T5 area evolving onto the left centroparietal area, which was immediately followed by the diffuse suppression of the background EEG activity. The underlying mechanism might be related to high-frequency electrical stimulation of the negative motor areas within the inferior frontal gyrus or anterior to the supplementary sensorimotor area.

Nonconvulsive status epilepticus after surgery for ruptured intracranial aneurysms: Incidence, associated factors, and impact on the outcome.

OBJECTIVE: To evaluate the incidence of nonconvulsive status epilepticus (NCSE) after surgery for ruptured intracranial aneurysms, to define factors associated with this complication, and to determine its impact on the outcome. PATIENTS AND METHODS: Clinical and neurophysiological data of 66 patients with aneurysmal subarachnoid hemorrhage (aSAH) who underwent continuous EEG (cEEG) monitoring after microsurgical clipping (53 cases) or endovascular coiling (13 cases) of the ruptured aneurysm were analyzed retrospectively. The diagnosis of NCSE was based on the American Clinical Neurophysiology Society and Salzburg Consensus criteria. RESULTS: NCSE was revealed in 10 patients (15 %), all of whom underwent craniotomy and aneurysm clipping. In comparison to the subgroup without NCSE, among those who were diagnosed with this complication there was a significantly greater proportion of men (70 % vs. 34 %; P = 0.041), cases with the Glasgow Coma Scale score at admission < 13 (90 % vs. 36 %; P = 0.004), the Hunt and Hess aSAH grades 3-5 (90 % vs. 45 %; P = 0.013), and hydrocephalus (70 % vs. 29 %; P = 0.044). In addition, they required a significantly longer hospital stay (medians, 62.5 vs. 39.5 days; P = 0.015) and showed trend for the lower rate of favorable disability outcomes (20 % vs. 54 %; P = 0.084). CONCLUSIONS: NCSE is encountered rather often after the microsurgical clipping of ruptured intracranial aneurysms, especially in severely disabled patients with high-grade aSAH and/or associated hydrocpephalus, and may significantly affect the clinical course and prolong recovery. cEEG monitoring may be helpful for timely diagnosis and treatment of this complication.

Eagle syndrome with hidden stylocarotid syndrome examined using dynamic ultrasonography: illustrative case.

BACKGROUND: Eagle syndrome, or elongated styloid process syndrome, is a rare cause of cerebral infarction. When the styloid process is elongated but the internal carotid artery (ICA) is morphologically normal on three-dimensional computed tomography angiography (3D-CTA), determining the causal relationship between elongation and cerebral infarction is difficult. OBSERVATIONS: The patient was a 27-year-old man who experienced two left cerebral infarctions in 3 months. On 3D-CTA, the styloid process was elongated, but the structure of the ICA was normal. When the patient's neck was rotated leftward, the peak systolic velocity and pulsatility index increased (shown via dynamic subtraction ultrasonography) and ICA stenosis was evident (shown via subtraction angiography). The styloid process was removed, and the cerebral infarction did not recur in the 2 years after surgery. LESSONS: This is the first report to document that indirect compression of ICA by the styloid process can cause Eagle syndrome. The blood flow changes of the ICA on dynamic ultrasonography revealed morphological changes that were hidden on 3D-CTA or nondynamic subtraction angiography.

[A case of cardiac arrest due to the appearance of Brugada-type electrocardiogram during epilepsy treatment].

The appearance of arrhythmias in epilepsy practice can lead to sudden death. This time, we experienced a case of cardiac arrest caused by lethal arrhythmia and resuscitation, and captured changes in the electrocardiogram over time from outpatient, before and after sudden change, after resuscitation, to convalescent period. QT prolongation and Brugada-type waveforms were confirmed in the changes over time in the electrocardiogram. Focusing on the importance of recognizing the pharmacological and pharmacokinetic interactions with Na channel blockers and psychotropic drugs that may induce electrocardiographic changes, we emphasized the importance of electrocardiogram in epilepsy treatment.

Efficacy of Vagal Nerve Stimulation for Pharmacoresistant Poststroke Epilepsy.

BACKGROUND: Vagal nerve stimulation (VNS) is an alternative palliative therapy for pharmacoresistant epilepsy. It has been reported to be effective for both focal and generalized epilepsy; however, most of the relevant studies have involved children or young patients. Some patients develop intractable epilepsy after stroke, despite taking antiepileptic drugs (AEDs). In this study, we investigated the efficacy of VNS for pharmacoresistant poststroke epilepsy (PPSE). METHODS: We retrospectively studied 10 patients who underwent vagal nerve stimulator implantation for poststroke epilepsy after the seizures had proved refractory to appropriate AEDs. The seizure outcome was evaluated using the McHugh classification 2 years after the implantation. RESULTS: In total, 4 patients (40%) remained seizure-free throughout the 2-year duration. In addition, seizures were reduced by >50% after 2 years in 6 patients (60%). McHugh classification was class I for 5 patients and class II for 5 patients. Neither intraoperative complications nor postoperative adverse effects were reported. The average intensity of VNS was 1.75 mA. CONCLUSIONS: In this small study, VNS proved to be a safe and effective therapy for PPSE. Patients with poststroke epilepsy experience physical or mental decline; therefore, it is important to control seizures in them to avoid deterioration in their quality of daily life.

Mechanical Thrombectomy for Middle Cerebral Artery Occlusion Suspected of Ovarian Hyperstimulation Syndrome: Case Report and Review of the Literature.

BACKGROUND: Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic disorder associated with infertility treatment. The main pathology of OHSS is intravascular dehydration and hyperestrogenemia. In mild cases, abdominal symptoms are the main symptoms, but in severe cases, thrombosis such as cerebral infarction may occur. CASE DESCRIPTION: A 36-year-old woman was undergoing infertility treatment in obstetrics and gynecology for infertility. She received HMG-HCG therapy and artificial insemination 1 week before onset, and on the day of onset she had mild abdominal distension and was suspected of having OHSS. She was prescribed aspirin for prevention of thrombosis. She presented with right upper hemiparesis and aphasia. Magnetic resonance imaging showed left middle cerebral artery occlusion. We performed mechanical thrombectomy and finally achieved Thrombolysis in Cerebral Infarction 3 recanalization. We suspected embolism as the etiology of cerebral infarction and started anticoagulation therapy. Various examinations were conducted to investigate the embolism source, but no anatomic abnormality or thrombophilia factors were observed. Because the patient had OHSS since admission, we concluded that OHSS was suspected as the cause of the stroke. CONCLUSIONS: We experienced the first case of mechanical thrombectomy for middle cerebral artery occlusion suspected to be caused by OHSS. It is necessary to suspect OHSS involvement if young women, especially those on infertility treatment, show neurologic deficits.

Ictal vomiting after cerebellar hemorrhage: A case report.

Vomiting is a typical symptom of cerebellar hemorrhage. Usually only supportive care such as antiemetic drugs are available. A 76-year-old woman presented in a light coma. A head CT demonstrated right cerebellar hemorrhage and the hematoma was surgically evacuated. Her intractable vomiting started 3 weeks after surgery. Because her vomiting was unexplained, we checked her EEG, which demonstrated generalized periodic discharges. We diagnosed her with ictal vomiting. Anti-seizure medication was administered and vomiting was rapidly controlled. In conclusion, physicians must be aware that vomiting may rarely occur as a sign of seizures and status epilepticus.

Continuous EEG monitoring in ICU.

BACKGROUND: Continuous electroencephalogram (CEEG) monitoring is increasingly being used for brain monitoring in neurocritical care setting. This is because of the proven effectiveness of CEEG in diagnosing nonconvulsive status epilepticus (NCSE) as a cause of unexplained consciousness disorder. CEEG has been demonstrated to be effective in determining the response to, and outcome of, NCSE treatment. MAIN BODY: In this review article, the authors described the indication and methods of CEEG and diagnosis based on EEG pattern. As a condition characterized by unexplained consciousness disorder, NCSE is frequently encountered in the neurocritical care setting and is only accompanied by an altered EEG change without any clinically apparent manifestation, such as convulsion. Thus, it is considered a form of status epilepticus manifesting mainly with consciousness disorder. This is a diagnostic challenge but should not be overlooked as NCSE is a curable condition. However, CEEG is required for the correct diagnosis of NCSE, which is difficult to perform in daily clinical practice. There also are several challenges regarding urgent EEG monitoring in the intensive care unit setting, including system-related problems, such as the preparation of mobile EEG devices and collodion-applied electrodes; human resource-related problems, such as staffing of EEG technicians and physicians who can respond flexibly to unscheduled needs; and EEG-specific difficulties in interpretation/diagnosis. These issues preclude the wide spread of CEEG in daily practice. CONCLUSION: Recently, importance of CEEG was well accepted; however, no definitive diagnostic criteria exist for identifying EEG patterns suggestive of NCSE, especially the ambiguous significance of periodic discharges (PDs) further complicates the diagnosis of NCSE. Thus, analyzing the change in EEG patterns over time is important for the correct diagnosis of NCSE. Further studies are needed to collect sufficient CEEG data and assess the outcome of patients who have undergone therapeutic interventions.

Nonconvulsive Status Epilepticus in the Neurosurgical Setting.

Herein, we review the current state of nonconvulsive status epilepticus (NCSE). NCSE has recently been recognized as one of the causes of unexplained impaired consciousness in the neurosurgical or neurocritical setting. The causes of NCSE include not only central nervous system disorders such as craniotomy, stroke, traumatic brain injury, and central nervous system inflammation, but also severe critical conditions such as sepsis and uremia, among others. NCSE shows no overt clinical manifestations; therefore, prompt and correct diagnosis is difficult. The diagnosis of NCSE should be made by electroencephalogram (EEG), especially continuous EEG (CEEG) monitoring, because NCSE is caught only by prolonged recording. However, the interpretation of the EEG findings is also challenging because of the varying EEG characteristic of NCSE. While the diagnosis should be based on temporal or spatial EEG changes, several definitions and criteria have been proposed, and uniform, universal criteria are still lacking. Once NCSE is diagnosed, antiepileptic drugs (AEDs) should be aggressively administrated. Although there are no standardized international therapeutic guidelines, several AEDs have been attempted in clinical practice in other countries, including fosphenytoin, midazolam, levetiracetam, and valproate. Particularly, several AEDs should be considered prior to using anesthetics. Finally, the prognosis of NCSE depends on the cause thereof; however, in general, earlier intervention for NCSE appears important in terms of better recovery.

[Electroencephalographic features of nonconvulsive status epilepticus].

Continuous EEG monitoring (cEEG) has been recently applied in a neurocritical care setting in the US. The purpose of cEEG is primarily to detect nonconvulsive status epilepticus (NCSE) and secondarily, to evaluate the treatment of NCSE. It is difficult to diagnose NCSE in cEEG because of its variability. In the American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology 2012, EEG localization is placed under major term 1 and is classified as Lateralized (L), Generalized (G), Bilateral Independent (BI), and Multifocal (Mf). Morphology is placed under major term 2 and is classified as periodic, rhythmic, and spike-and-wave. Although there are no unequivocal criteria for the diagnosis of NCSE, the appearance of spatial and temporal changes in the EEG is essential for diagnosis.