Nonconvulsive Seizures Research Articles

Should Posterior Reversible Encephalopathy Syndrome Be Mainly Considered an Epileptic Disorder? Results of a Sequential Neurophysiological Study in a Pediatric Cohort.

Despite a wide number of studies trying to define clinical, physiopathological, and neuroradiological features of posterior reversible encephalopathy syndrome (PRES), the true nature of symptoms is still not fully understood. We studied a standard cohort of 24 pediatric patients, affected by hemato-oncological diseases, with a neuroradiological diagnosis consistent with PRES identified from 2006 to 2013. Ten of them developed PRES after hematopoietic stem cell transplantation. We analyzed the sequence of clinical, radiological, and electrophysiological data. In all the patients who were recorded at the onset of the first symptoms, electroencephalograms showed focal nonconvulsive seizures or status epilepticus (SE). We found a sensitivity of 100% for electroencephalogram (EEG) with a good correlation between clinical signs and the localization of seizures, whereas computed tomography scans showed a sensitivity of 50% only. Following prompt treatment, intensive care unit admission rate was only 8%. PRES is a multifactorial neurologic event with focal nonconvulsive seizures or SE as the main feature in pediatric patients. Clinical manifestations are epileptic in nature, and prompt EEG recording is useful for diagnosis and supports an earlier treatment, potentially preventing the appearance of complications such as generalized seizures or refractory SE.

The intrahippocampal kainate mouse model of mesial temporal lobe epilepsy: Lack of electrographic seizure-like events in sham controls.

SummaryObjectiveThere is an ongoing debate about definition of seizures in experimental models of acquired epilepsy and how important adequate sham controls are in this respect. For instance, several mouse and rat strains exhibit high‐voltage rhythmic spike or spike‐wave discharges in the cortical electroencephalogram (EEG), which has to be considered when using such strains for induction of epilepsy by status epilepticus, traumatic brain injury, or other means. Mice developing spontaneous recurrent nonconvulsive and convulsive seizures after intrahippocampal injection of kainate are increasingly being used as a model of mesial temporal lobe epilepsy. We performed a prospective study in which EEG alterations occurring in this model were compared with the EEGs in appropriate sham controls, using hippocampal electrodes and video‐EEG monitoring.MethodsExperiments with intrahippocampal kainate (or saline) injections started when mice were about 8 weeks of age. Continuous video‐EEG recording via hippocampal electrodes was performed 6 weeks after surgery in kainate‐injected mice and sham controls, that is, at an age of about 14 weeks. Three days of continuous video‐EEG monitoring were compared between kainate‐injected mice and experimental controls.ResultsAs reported previously, kainate‐injected mice exhibited two types of highly frequent electrographic seizures: high‐voltage sharp waves, which were often monomorphic, and polymorphic hippocampal paroxysmal discharges. In addition, generalized convulsive clinical seizures were infrequently observed. None of these electrographic or electroclinical seizures were observed in sham controls. The only infrequently observed EEG abnormalities in sham controls were isolated spikes or spike clusters, which were also recorded in epileptic mice.SignificanceThis study rigorously demonstrates, by explicit comparison with the EEGs of sham controls, that the nonconvulsive paroxysmal events observed in this model are consequences of the induced epilepsy and not features of the EEG expected to be seen in some experimental control mice or unintentionally induced by surgical procedures.

Continuous electroencephalography in a mixed non-neurological intensive care population, an observational study

PurposeContinuous electroencephalography (cEEG) improves monitoring of the brain in unconscious patients, but implementation at ICU is difficult. The present investigation shows a way to introduce cEEG at an anesthesiological ICU and discusses the first experiences. Materials and methodsThe study analyzed the feasibility of cEEG, assessed the interpretable cEEG time, importance of automatic seizure detection, the incidence of seizures, the predominant background EEG activity, incidence of delirium and mortality. ResultsFifty-three cEEGs of 50 patients with a median interpretable length of 24 hours [IQR 20 to 42 hours] were recorded. One patient had status epilepticus, while 5 patients had non-convulsive seizures. Automated seizure detection recognized the status epilepticus and 3 of 10 non-convulsive seizures, however, detected 42 false positive seizures. Predominant background EEG activity was alpha (9%), theta (17%), delta (26%), burst-suppression (17%), and suppressed background activity (30%). EEG activity correlated neither with dosage of analgo-sedative drugs nor with incidence of delirium or mortality. ConclusionContinuous electroencephalography recording is feasible and manageable. Automatic seizure detection was often false negative/positive; therefore, the interpretation of the cEEG should be supported by EEG-trained neurologists. Background EEG activity was not associated with outcome parameters, which suggests that background activity is a poor outcome predictor.

Abstract TP426: Impact of Electrographic Seizure Activity on Outcomes Among Critically-ill Patients with Stroke

Introduction: Patients with severe acute stroke can suffer secondary neurological injury due to a variety of causes. The clinical impact of electrographic seizures among critically-ill stroke patients remains unclear. Methods: We retrospectively analyzed a cohort of consecutive stroke patients admitted to the Neuroscience Intensive Care Unit (NSICU) at the Mount Sinai Hospital who underwent ≥24 hours of continuous video EEG (cEEG) monitoring for alteration in level of consciousness or suspected non-convulsive seizures between May 2013 and June 2015. Results: Of 106 consecutive severe stroke patients admitted to the NSICU who underwent cEEG monitoring, 15 (14%) had clinical or electrographic seizures. The median duration of cEEG monitoring was 1.2 days. Observed seizures included purely electrographic seizures with no clinical correlate in 53%, subtle twitching or altered mental status in 33%, and generalized tonic-clonic seizures with an EEG correlate in 13%. Generalized or lateralized periodic discharges (PEDs) were present in 93% (14/15) of patients in the seizure group, compared to 20% (18/89) in the non-seizure group (P= 0.00). The survival rate at discharge was 53% in the seizure group compared to 73% in the non-seizure group (p = 0.12). Mean ICU length of stay was 16 days in both groups. Of the 11 survivors in the seizure group 100% were severely disabled at discharge (mRS 4 or 5) compared to 75% of the 65 survivors in the non-seizure group.(P=0.06). Conclusion: Critically-ill stroke patients with clinical or electrographic seizures in the ICU tend to have higher mortality and worse functional outcome at the time of discharge. PEDS are an important marker of patients at high risk for ictal activity. Careful identification of acute stroke patients that might benefit from seizure prophylaxis is warranted.

Can patients with non-convulsive seizure be identified in the emergency department?

Non-convulsive seizure (NCS) is an underdiagnosed, potentially treatable emergency with significant mortality and morbidity. The objective of this study is to examine the characteristics of patients with NCS presenting with altered mental status (AMS) and diagnosed with electroencephalography (EEG), to identify the factors that could increase the pre-test probability of NCS. Retrospective study using the data collected prospectively. Inclusion criteria: patients older than 13 years with AMS. Exclusion criteria: (1) immediately correctable AMS (e.g., hypoglycemia, opiod overdose); (2) inability to undergo EEG; (3) hemodynamic instability. Outcomes compared between NCS and non-NCS cases: vital signs, lactate level, gender, witnessed seizure, use of anticonvulsive in the field or in the ED, history of seizure or stroke, head injury, abnormal neurological finding and new abnormal findings on head CT. Data presented as medians and quartiles for categorical and percentages with 95%CI for continuous variables. Univariate analyses were performed with Man-Whitney U and Fisher's Exact tests. A multivariate analysis model was used to test the predictive value of clinical variables in identifying NCS. From 332 patients (median age 66 years, quartiles 50-78), 16 were diagnosed with NCS (5%, 95%CI 3%-8%). Only age was significantly different between the NCS vs. non-NCS groups in both univariate (P=0.032) and multivariate analyses (P=0.016). Other than age, no other clinically useful variable could identify patients at high risk of NCS. ED physicians should have a high suspicion for NCS and should order EEG for these patients more liberally.

Late Seizures after Stroke in Clinical Practice: The Prevalence of Non-convulsive Seizures

Objective The prevalence of the non-convulsive type of late seizure after stroke is unknown. The aim of the present study was to clarify the characteristics of late seizure in clinical practice, mainly focusing on the prevalence of non-convulsive seizure. Methods A total of 178 consecutive patients who were admitted and diagnosed with late seizure after stroke were retrospectively enrolled, and the data of 127 patients for whom the complete seizure was observed by a bystander were analyzed. Clinical information was obtained from the medical records and nursing notes. Results A non-convulsive seizure was observed in 37 patients (29%). A focal seizure and its secondary generalization accounted for 79% of the seizure types. Status epilepticus was observed in 60 patients (47%), including 11 patients (9%) without convulsion. The patients with non-convulsive seizures were significantly younger than those with convulsive seizures, but there were no other significant differences between the two groups with respect to sex, classification or the lesion of stroke. Conclusion There was a high rate of non-convulsive seizures in patients with late seizure after stroke. A non-convulsive seizure may be caused by any type or location of preceding stroke. More attention is needed in the differential diagnosis of neurological deterioration after stroke.

Chapter 34 - Neurologic complications of polytrauma

Neurologic complications in polytrauma can be classified by etiology and clinical manifestations: neurovascular, delirium, and spinal or neuromuscular problems. Neurovascular complications include ischemic strokes, intracranial hemorrhage, or the development of traumatic arteriovenous fistulae. Delirium and encephalopathy have a reported incidence of 67-92% in mechanically ventilated polytrauma patients. Causes include sedation, analgesia/pain, medications, sleep deprivation, postoperative state, toxic ingestions, withdrawal syndromes, organ system dysfunction, electrolyte/metabolic abnormalities, and infections. Rapid identification and treatment of the underlying cause are imperative. Benzodiazepines increase the risk of delirium, and alternative agents are preferred sedatives. Pharmacologic treatment of agitated delirium can be achieved with antipsychotics. Nonconvulsive seizures and status epilepticus are not uncommon in surgical/trauma intensive care unit (ICU) patients, require electroencephalography for diagnosis, and need timely management. Spinal cord ischemia is a known complication in patients with traumatic aortic dissections or blunt aortic injury requiring surgery. Thoracic endovascular aortic repair has reduced the paralysis rate. Neuromuscular complications include nerve and plexus injuries, and ICU-acquired weakness. In polytrauma, the neurologic examination is often confounded by pain, sedation, mechanical ventilation, and distracting injuries. Regular sedation pauses for examination and maintaining a high index of suspicion for neurologic complications are warranted, particularly because early diagnosis and management can improve outcomes.

Multi-Biosignal Analysis for Epileptic Seizure Monitoring

Persons who suffer from intractable seizures are safer if attended when seizures strike. Consequently, there is a need for wearable devices capable of detecting both convulsive and nonconvulsive seizures in everyday life. We have developed a three-stage seizure detection methodology based on 339 h of data (26 seizures) collected from 10 patients in an epilepsy monitoring unit. Our intent is to develop a wearable system that will detect seizures, alert a caregiver and record the time of seizure in an electronic diary for the patient's physician. Stage I looks for concurrent activity in heart rate, arterial oxygenation and electrodermal activity, all of which can be monitored by a wrist-worn device and which in combination produce a very low false positive rate. Stage II looks for a specific pattern created by these three biosignals. For the patients whose seizures cannot be detected by Stage II, Stage III detects seizures using limited-channel electroencephalogram (EEG) monitoring with at most three electrodes. Out of 10 patients, Stage I recognized all 11 seizures from seven patients, Stage II detected all 10 seizures from six patients and Stage III detected all of the seizures of two out of the three patients it analyzed.

Is long-term electroencephalogram more appropriate than standard electroencephalogram in the elderly?

To compare the diagnostic accuracy of standard (st) and long-term video (lt) EEG in elderly patients with suspected non-convulsive seizures. Over a 12-month period, we prospectively included all elderly (over-65) hospitalized patients having undergone lt-EEG for suspected non-convulsive seizures (n=43). st-EEG was defined as the first 20min of each lt-EEG. We recorded the patients' clinical and imaging characteristics and final diagnosis and assessed the respective diagnostic values of st-EEG and lt-EEG. Epileptiform discharges were detected on standard EEG in only 7% of patients and in 28% of patients on Lt-EEG (p=0.004). Non-convulsive seizures were recorded in 1 case vs. 4, respectively. Nine of 40 negative standard EEG showed later epileptiform activities. The median time to occurrence of the first epileptiform activities was 46.5min (interquartile range: 36.5-239.75min). Epileptiform activity occurred during sleep only in 33% patients with a negative st-EEG. Dementia was associated with a positive lt-EEG (p:0.047). Lt-EEG was clearly superior to standard EEG for detecting epileptiform activity in elderly when suspecting non convulsive seizures. St-EEG has a low diagnostic yield in elderly patients with suspected non-convulsive seizures and so lt-EEG is preferable in this situation.

Absence epilepsy – electroclinical features and current advances

The purpose of this article is to provide an overview of the electroclinical features and pathophysiological findings, as well as the neuropsychological characteristics of absence epilepsies. Absence seizures are primary generalized, non-convulsive seizures. The classical clinical manifestations of typical absence seizures are a transient impairment of consciousness (with abrupt onset and offset) accompanied by staring, blinking and various forms of head/limb automatism. Atypical absence attacks are characterized by a milder beginning and end of the attack, more expressed changes in muscular tone, less severe disorders of consciousness, and longer duration compared to typical attacks. EEG findings in absence epilepsies have a characteristic pattern, demonstrating generalized spike and wave complexes that are typically 2.5-4 Hz. Treatment depends on the type of epilepsy, but usually includes valproic acid and ethosuximide. Because of their benign nature and lack of clinical presentation that resembles “real” epilepsy, absence attacks are often interpreted as daydreaming or simply a lack of attention, and therefore often the first signs of the disease are often not recognized. Conclusion : A better understanding of absence epilepsies is very important in order to develop strategies that will improve these children’s quality of life.

Latency to treatment of status epilepticus is associated with mortality and functional status

IntroductionStatus epilepticus (SE) is a life-threatening neurologic emergency. Despite advances in management, in-hospital mortality remains unchanged. This is partly due to the pharmacoresistance which develops the longer that seizures persist. Therefore, rapid antiseizure medication (ASM) administration may represent a beneficial treatment option. The purpose of this study was to determine: 1) whether in-hospital mortality is reduced with shorter latencies to initial treatment of SE with an ASM (LTSE); and 2) the critical time frame during which LTSE is associated with reduced in-hospital mortality. Materials and methodsThis was a retrospective, single-center study of adults diagnosed with SE between 1/1/2005 and 10/31/2012. Demographic characteristics included seizure history, etiology, semiology, and duration. Subjects were assigned to LTSE groups at the time frames of 5, 10, 30 and 60min. The primary outcome was in-hospital mortality, with poor functional status (mRS 3–6) as a secondary measure. Pearson's chi-square, Mann-Whitney-U, two-sample-t-tests, and binary logistic regression analysis were used as appropriate, with p<0.05. ResultsIn unadjusted analysis, LTSE>30min demonstrated increased risk of mortality (OR 2.06, CI 1.01–4.17, p=0.046) and poor functional status (OR 2.48, CI 1.05–5.85, p=0.038) compared to LTSE≤30min. Increased mortality risk remained after adjusting for SE duration (OR 2.07, CI 1.01–4.26, p=0.047) and nonconvulsive seizures (OR 2.28, CI 1.08–4.80, p=0.03). Compared to subjects treated within 60min, those treated after 60min were at increased risk of poor functional status, regardless of the presence of nonconvulsive seizures (OR 2.96, CI 1.14–7.73, p=0.026). In addition, when acute symptomatic SE was stratified by cardiac versus non-cardiac etiologies, subjects with non-cardiac acute symptomatic SE demonstrated worse functional outcome when treated after 60min (OR 7.20, CI 1.13–46.07, p=0.037). ConclusionsTreatment of SE within 30min of onset is associated with reduced risk of in-hospital mortality and poor functional status, although this may be attenuated by acute symptomatic seizures related to cardiac arrest. This represents a therapeutic option which has the potential to benefit patient outcomes.

Utility of Continuous EEG Monitoring in Noncritically lll Hospitalized Patients.

Continuous EEG (cEEG) monitoring is used in the intensive care unit (ICU) setting to detect seizures, especially nonconvulsive seizures and status epilepticus. The utility and impact of such monitoring in non-ICU patients are largely unknown. Hospitalized patients who were not in an ICU and underwent cEEG monitoring in the first half of 2011 and 2014 were identified. Reason for admission, admitting service (neurologic and nonneurologic), indication for cEEG, comorbid conditions, duration of recording, EEG findings, whether an event/seizure was recorded, and impact of EEG findings on management were reviewed. We evaluated the impact of the year of recording, admitting service, indication for cEEG, and neurologic comorbidity on the yield of recordings based on whether an event was captured and/or a change in antiepileptic drug management occurred. Two hundred forty-nine non-ICU patients had cEEG monitoring during these periods. The indication for cEEG was altered mental status (60.6%), observed seizures (26.5%), or observed spells (12.9%); 63.5% were on neuro-related services. The average duration of recording was 1.8 days. EEG findings included interictal epileptiform discharges (14.9%), periodic lateralized discharges (4%), and generalized periodic discharges (1.6%). Clinical events were recorded in 28.1% and seizures in 16.5%. The cEEG led to a change in antiepileptic drug management in 38.6% of patients. There was no impact of type of admitting service; there was no significant impact of indication for cEEG. In non-ICU patients, cEEG monitoring had a relatively high yield of event/seizures (similar to ICU) and impact on management. Temporal trends, admitting service, and indication for cEEG did not alter this.

P.1.g.074 - The effects of etanercept on absence epilepsy

Wistar rats of a strain inbred for spontaneous generalized non-convulsive seizures present EEG spike-wave discharges (SWDs), 7–10 c/sec, occurring about once/min and lasting about 15 sec. They are bilateral and synchronous and can be recorded over the entire neocortex and in the lateral thalamic nuclei. After corpus callosum section, only a few bilateral SWDs persisted. Asymmetrical SWDs were most often recorded: bilateral SWDs starting asynchronously, or unilateral SWDs, which were also seen to alternate abruptly between hemispheres. The thalamic SWDs were always synchronized with the ipsilateral cortical pattern. These findings suggest that while the corpus callosum has a major role in bilateral synchronization of SWD in this model of epilepsy, occasional synchronization may still occur through other pathways after callosal transection.

Review: Cav2.3 R-type Voltage-Gated Ca2+ Channels - Functional Implications in Convulsive and Non-convulsive Seizure Activity.

Background:Researchers have gained substantial insight into mechanisms of synaptic transmission, hyperexcitability, excitotoxicity and neurodegeneration within the last decades. Voltage-gated Ca2+ channels are of central relevance in these processes. In particular, they are key elements in the etiopathogenesis of numerous seizure types and epilepsies. Earlier studies predominantly targeted on Cav2.1 P/Q-type and Cav3.2 T-type Ca2+ channels relevant for absence epileptogenesis. Recent findings bring other channels entities more into focus such as the Cav2.3 R-type Ca2+ channel which exhibits an intriguing role in ictogenesis and seizure propagation. Cav2.3 R-type voltage gated Ca2+ channels (VGCC) emerged to be important factors in the pathogenesis of absence epilepsy, human juvenile myoclonic epilepsy (JME), and cellular epileptiform activity, e.g. in CA1 neurons. They also serve as potential target for various antiepileptic drugs, such as lamotrigine and topiramate.Objective: This review provides a summary of structure, function and pharmacology of VGCCs and their fundamental role in cellular Ca2+ homeostasis. We elaborate the unique modulatory properties of Cav2.3 R-type Ca2+ channels and point to recent findings in the proictogenic and proneuroapoptotic role of Cav2.3 R-type VGCCs in generalized convulsive tonic–clonic and complex-partial hippocampal seizures and its role in non-convulsive absence like seizure activity.Conclusion:Development of novel Cav2.3 specific modulators can be effective in the pharmacological treatment of epilepsies and other neurological disorders.

EEG power as a biomarker to predict the outcome after cardiac arrest and cardiopulmonary resuscitation induced global ischemia

AimsCardiac arrest (CA) is a major cause of mortality and survivors often develop neurologic deficits. The objective of this study was to determine the effect of CA and cardiopulmonary resuscitation (CPR) in mice on the EEG and neurologic outcomes, and identify biomarkers that can prognosticate poor outcomes. Main methodsVideo-EEG records were obtained at various periods following CA-CPR and examined manually to determine the presence of spikes and sharp-waves, and seizures. EEG power was calculated using a fast Fourier transform (FFT) algorithm. Key findingsFifty percent mice died within 72h following CA and successful CPR. Universal suppression of the background EEG was observed in all mice following CA-CPR, however, a more severe and sustained reduction in EEG power occurred in the mice that did not survive beyond 72h than those that survived until sacrificed. Spikes and sharp wave activity appeared in the cortex and hippocampus of all mice, but only one out of eight mice developed a purely electrographic seizure in the acute period after CA-CPR. Interestingly, none of the mice that died experienced any acute seizures. At 10days after the CA-CPR, 25% of the mice developed spontaneous convulsive and nonconvulsive seizures that remained restricted to the hippocampus. The frequency of nonconvulsive seizures was higher than that of convulsive seizures. SignificanceA strong association between changes in EEG power and mortality following CA-CPR were observed in our study. Therefore, we suggest that the EEG power can be used to prognosticate mortality following CA-CPR induced global ischemia.

Functional State of the Heart during Spontaneous Nonconvulsive Seizure Activity at Various Times of the Day.

Circadian peculiarities of HR regulation and functional capacities of the heart in WAG/Rij rats with genetically determined absence epilepsy are related to spike-wave activity of the brain. The number of spike-wave discharges (SWD) is maximum at night, early morning, and evening time and decreases to minimum at 08.00-16.00. At night, functional capacities of the heart are reduced and stress test at night induces ischemic changes in the myocardium at a lower functional load than in the daytime (low level of SWD activity). The decrease in the number of SWD and spike-wave index during the daytime contributes to the central mechanisms of autonomic regulation of the heart. However, these capacities are reduced against the background of increased seizure activity during nighttime.

Continuous spike‐waves during slow‐wave sleep in a mouse model of focal cortical dysplasia

To examine if mice with focal cortical dysplasia (FCD) develop spontaneous epileptic seizures and, if so, determine the key electroencephalography (EEG) features. Unilateral single freeze lesions to the S1 region (SFLS1R) were made in postnatal day 0-1 pups to induce a neocortical microgyrus in the right cortical hemisphere. Continuous 24-h recordings with intracranial EEG electrodes and behavioral tests were performed in adult SFLS1R and sham-control mice to assess neurologic status. A high percentage of adult SFLS1R animals (89%, 40/45) exhibited at least one or more spontaneous nonconvulsive seizure events over the course of 24 h. Of these animals, 60% (27/45) presented with a chronic seizure state that was persistent throughout the recording session, consisting of bursts of rhythmic high-amplitude spike-wave activities and primarily occurring during periods of slow-wave sleep. In comparison, none of the control, age-matched, mice (0/12) developed seizures. The epileptic discharge pattern closely resembled a pattern of continuous spike-waves during slow-wave sleep (CSWS) of the human syndrome described as an electrical status epilepticus during slow-wave sleep (ESES). Key findings in the SFLS1R model indicated that the observed CSWS (1) were more prevalent in female (18/23) versus male (9/22, p < 0.05), (2) were strongest in the right S1 region although generalized to other brain regions, (3) were associated with significant cognitive and behavioral deficits, (4) were temporarily alleviated by ethosuximide treatment or optogenetic activation of cortical γ-aminobutyric acid (GABA)ergic neurons, and (5) theta and alpha band rhythms may play a key role in the generalization of spike-wave activities. This is the first report of an in vivo animal FCD model that induces chronic spontaneous electrographic brain seizures. Further characterization of the abnormal oscillations in this mouse model may lead to a better understanding of the mechanisms of CSWS/ESES.

34. Guidelines and nomenclature in critical care continuous EEG monitoring

Nomenclature is key to describing clearly the clinical events in a critical care continuous EEG recording. Uniform nomenclature facilitates multicenter studies. It allows clinicians to understand better the meaning of studies performed at another institution. Recent clearer nomenclature proposed definition of many terms, such as for rhythmic or periodic patterns, prevalence, frequency, duration, amplitude, symmetry, and other terms for critical care monitoring (Hirsch, J Clin Neurophys; 2013). A consensus guideline recommends continuous EEG recording (a) to identify nonconvulsive seizures, (b) to assess efficacy of therapy, (c) to identify ischemia in high-risk patients (d), to assess depth of coma or sedation, (e) and for prognosis after cardiac arrest (Herman, J Clin Neurophys; 2015). The consensus guideline also describes personnel qualifications, e.g. for interpreting physicians, technical specification for equipment, and how recordings should be acquired, reviewed and interpreted. These are meant to provide guidance for quality patient care services.

The effects of carbamazepine in the intrahippocampal kainate model of temporal lobe epilepsy depend on seizure definition and mouse strain.

SummaryObjectiveMesial temporal lobe epilepsy (TLE) with hippocampal sclerosis is a predominant form of acquired epilepsy, characterized by recurrent simple and complex partial seizures that are often resistant to treatment. Mice developing spontaneous recurrent nonconvulsive and convulsive seizures after intrahippocampal injection of the excitotoxic glutamate agonist kainate are thought to represent a valuable model of mesial TLE. Epileptic electroencephalogram (EEG) activity recorded in this model from the kainate focus in the ipsilateral hippocampus is resistant to antiseizure drugs such as carbamazepine (CBZ). We compared the efficacy of CBZ in this model in two different mouse strains (FVB/N and NMRI). Furthermore, we evaluated whether changes in the definition of electrographic seizures affect the antiseizure efficacy of CBZ.MethodsAs in previous studies, two types of epileptic EEG activity were defined: high‐voltage sharp waves (HVSWs) and hippocampal paroxysmal discharges (HPDs). The characteristics of these paroxysmal EEG events in epileptic mice were compared with EEG criteria for nonconvulsive seizures in patients. For HVSWs, different spike frequencies, interevent intervals, and amplitudes were used as inclusion and exclusion criteria. In addition to CBZ, some experiments were performed with diazepam (DZP) and phenobarbital (PB).ResultsFemale epileptic FVB/N mice predominantly exhibited frequent HVSWs, but only infrequent HPDs or secondarily generalized convulsive seizures. Slight changes in HVSW definition determined whether they were resistant or responsive to CBZ. Male NMRI mice exhibited both HVSWs and HPDs. HVSWs were more resistant than HPDs to suppression by CBZ. Both types of epileptic EEG activity were rapidly suppressed by DZP and PB.SignificanceThe data demonstrate that focal electrographic seizures in the intrahippocampal kainate mouse model are less resistant than previously thought. Both mouse strain and the criteria chosen for definition of EEG seizures determine whether such seizures are drug‐resistant or ‐responsive.

The outcomes of early aneurysm repair in World Federation of Neurosurgical Societies grade V subarachnoid haemorrhage patients with emphasis on those presenting with a Glasgow Coma Scale score of 3

Grade V subarachnoid haemorrhage (SAH) patients may be dichotomised into those with temporary deterioration and those with irreversible injury, and only the former have a chance of favourable outcomes by aneurysm obliteration. One method of differentiating the two conditions is to wait and observe potential recovery for 12–48hours. However, early rebleeding and non-convulsive seizures may occur during this period. In our institution, grade V SAH patients receive immediate treatment (general anaesthesia induction and aneurysm obliteration within 24hours of onset) to minimise those risks. We focused on therapeutic outcomes in SAH patients presenting with a Glasgow Coma Scale score of 3 (GCS-3). Between January 2006 and December 2013, 82 GCS-3 SAH patients were admitted, among whom 51 (62%) underwent immediate aneurysm obliteration. Their outcomes 90days after onset were evaluated with the Glasgow Outcome Scale, with either good recovery or moderate disability regarded as favourable outcomes. Multivariate logistic regression analysis was performed to identify variables correlated with favourable outcomes. Among the 51 patients, 11 (22%) had favourable 90-day outcomes. Age (odds ratio [OR], 0.838; 95% confidence interval [CI], 0.733–0.959; p=0.010) and intact pupillary light reflex (OR, 21.939; 95% CI, 1.465–328.576; p=0.025) were correlated with favourable outcomes. By contrast, neither intact respiratory pattern nor isocoric pupils was correlated with favourable outcomes. The current results indicate that vigorous intervention may be worth attempting in young GCS-3 SAH patients with intact pupillary light reflex. It remains unclear, however, whether the seemingly high frequency of favourable outcomes was truly due to reduction in early rebleeding or seizures.