Predictors Of Seizure Outcome Research Articles

Epilepsy and COVID-19: predictors of a positive outcome in patients with epilepsy (based on analysis of clinical cases)

Background. Many patients with neurological disorders have an increased risk of infection and the severe course of COVID-19. Studies on positive predictors of seizure outcomes with the 2019 novel coronavirus disease remain limited.The objective is to study predictors for positive health outcomes after COVID infection in patients with epilepsy based on analysis of clinical observations.Design and Methods. Study design - the work is a part of a prospective observational study of seizure dynamics after COVID infection in patients with epilepsy.Results. The presented clinical observation demonstrates a positive health outcome after COVID infection in a young patient with the genetic generalized epilepsy with sustained clinical and electroencephalographic seizure remission on the next generation AED monotherapy (brivaracetam).Conclusion. Predictors for positive health outcome after the 2019 novel coronavirus disease in patients with epilepsy include a young age, absence of somatic comorbidities, seizure remission, modern drug use with no interaction among AEDs and antibiotics and antivirals for the coronavirus disease treatment. Despite the encouraging data on the favourable course of epilepsy in cases of developing COVID-19, further research is needed to continue.

Apparent diffusion coefficient is associated with seizure outcome after magnetic resonance-guided laser interstitial thermal therapy for mesial temporal lobe epilepsy

BackgroundMagnetic resonance-guided laser interstitial thermal therapy (MRgLiTT) is becoming a first-line surgical therapy for mesial temporal lobe epilepsy (mTLE) due to good seizure control and low complication risk. However, seizure outcomes after MRgLiTT remain highly variable and there is a need to improve patient selection and post-operative prognostication. In this retrospective study, we investigated whether the pre-operative MRI-derived apparent diffusion coefficient (ADC), used as a marker of tissue pathology in the mesial temporal structures could help predict seizure outcome. MethodsThirty-five patients who underwent MRgLiTT at our institution between 2014 and 2019 were included in the study. Demographic and clinical data were retrospectively collected. Seizure outcome was defined as good (ILAE Class I-II) and poor (ILAE Class III-VI). Volumetrics were performed on pre-ablation hippocampus and amygdala. Ablation volumes, and the proportion of ablated hippocampus and amygdala calculated via their respective mean voxel-wise ADC intensities were quantified from pre-operative and intra-operative post-ablation MRIs and statistically compared between the two outcome cohorts. Univarate and multivariate regression analysis was performed to identify demographic, clinical, and radiographic predictors of seizure outcome. ResultsMean age at LiTT was 36 years and 14 (40 %) were female. Mean follow-up duration was 1.90 ± 0.17 years. Twenty-seven (77 %) patients had mesial temporal sclerosis. There was no significant difference in the ablation volumes and proportion of ablated volume of hippocampus and amygdala between the two outcome groups. Patients with good seizure outcome had significantly higher normalized ADC intensities in the ablated mesial temporal structures compared to those with poor outcome (0.01 ± 0.08 vs.−0.29 ± 0.06; p = 0.015). ConclusionsmTLE patients with higher ADC intensities in the ablated regions of the hippocampus and the amygdala are more likely to have good seizure outcome following MRgLiTT. Our results suggest that pre-operative ADC analysis may improve both patient selection and epileptogenic zone targeting during MRgLiTT. Further investigation with large, prospective cohorts is needed to validate the clinical utility of ADC in improving seizure outcome following MRgLiTT.

Blinded study: prospectively defined high-frequency oscillations predict seizure outcome in individual patients

Interictal high-frequency oscillations are discussed as biomarkers for epileptogenic brain tissue that should be resected in epilepsy surgery to achieve seizure freedom. The prospective classification of tissue sampled by individual electrode contacts remains a challenge. We have developed an automated, prospective definition of clinically relevant high-frequency oscillations in intracranial EEG from Montreal and tested it in recordings from Zurich. We here validated the algorithm on intracranial EEG that was recorded in an independent epilepsy centre so that the analysis was blinded to seizure outcome. We selected consecutive patients who underwent resective epilepsy surgery in Geneva with post-surgical follow-up > 12 months. We analysed long-term recordings during sleep that we segmented into intervals of 5 min. High-frequency oscillations were defined in the ripple (80–250 Hz) and the fast ripple (250–500 Hz) frequency bands. Contacts with the highest rate of ripples co-occurring with fast ripples designated the relevant area. As a validity criterion, we calculated the test–retest reliability of the high-frequency oscillations area between the 5 min intervals (dwell time ≥50%). If the area was not fully resected and the patient suffered from recurrent seizures, this was classified as a true positive prediction. We included recordings from 16 patients (median age 32 years, range 18–53 years) with stereotactic depth electrodes and/or with subdural electrode grids (median follow-up 27 months, range 12–55 months). For each patient, we included several 5 min intervals (median 17 intervals). The relevant area had high test–retest reliability across intervals (median dwell time 95%). In two patients, the test–retest reliability was too low (dwell time < 50%) so that outcome prediction was not possible. The area was fully included in the resected volume in 2/4 patients who achieved post-operative seizure freedom (specificity 50%) and was not fully included in 9/10 patients with recurrent seizures (sensitivity 90%), leading to an accuracy of 79%. An additional exploratory analysis suggested that high-frequency oscillations were associated with interictal epileptic discharges only in channels within the relevant area and not associated in channels outside the area. We thereby validated the automated procedure to delineate the clinically relevant area in each individual patient of an independently recorded dataset and achieved the same good accuracy as in our previous studies. The reproducibility of our results across datasets is promising for a multicentre study to test the clinical application of high-frequency oscillations to guide epilepsy surgery.

Neuroimaging in pediatric temporal lobe epilepsy: Does neuroimaging accurately predict pathology and surgical outcome?

Temporal lobe epilepsy (TLE) in children is considered different from that in adults. As such, characterizing the structural lesions present in pediatric patients with TLE and their association with long-term seizure control is important. Here, we aimed to assess the concordance between preoperative imaging and postoperative histopathological diagnoses and their associations with seizure outcomes in pediatric patients with TLE undergoing temporal lobe surgery.We retrospectively reviewed the charts of pediatric patients with TLE who underwent surgical treatment between 1988 and 2020 as a part of the Comprehensive Epilepsy Program at the University of Alberta. Demographic, age at seizure onset, age at surgery, preoperative electroencephalography (EEG), long-term video EEG, imaging (magnetic resonance imaging [MRI] and computed tomography), neuropathology, and long-term seizure outcome data were acquired and analyzed.One hundred and seventeen patients underwent surgery for refractory TLE; the preoperative MRI diagnosis was concordant with the histopathological diagnosis in 76 % of cases. Tumors were identified with high accuracy (91 %). Mesial temporal sclerosis (MTS) was strongly associated with an excellent outcome after surgery (94 %). Patients with normal imaging results or non-specific pathologies were more likely to experience poor seizure outcomes after surgery (50 %).The radiological identification of lesions was associated with good long-term seizure outcomes, whereas normal MRI results were associated with significantly poorer long-term seizure outcomes. An accurate preoperative MRI is essential to epilepsy surgery since it impacts all stages of management; these results will thereafter help inform practitioners’ efforts to predict seizure outcome.

Subclinical seizures detected on intracranial EEG: Patient characteristics and impact on surgical outcome in a single pediatric epilepsy surgery center

ObjectiveSubclinical seizures (SCS) are often captured during intracranial EEG monitoring of pediatric patients with refractory focal epilepsy. However, their clinical significance remains uncertain. We aimed to characterize features associated with SCS and whether their presence impacts epilepsy outcomes post-surgically. MethodsA single center retrospective chart review of patients with refractory focal epilepsy who underwent intracranial EEG monitoring at Boston Children’s Hospital between 2004 and 2014 was conducted. Patient and seizure characteristics as well as post-operative outcome data were collected. ResultsOf the 104 patients included in the study, SCS were recorded in 66 (63%). Fifty-eight had electroclinical seizures (ECS) and SCS (ECS + SCS), and eight patients only had SCS. There were no significant patient characteristics associated with the presence of SCS. One hundred one of the 104 patients (97%) underwent surgical resection after the intracranial EEG monitoring, 53 of which had Engel 1 outcomes (52%). Incomplete resection (OR 0.15, 95% confidence interval (CI) [0.06, 0.40], p < 0.001) or presence of temporal plus epilepsy (OR 0.23, 95% CI [0.06, 0.80], p = 0.04) was associated with poor Engel outcomes (Engel 2–4). Presence of SCS was not associated with epilepsy surgical outcomes (p = 0.99). SignificanceNearly 2/3 of patients in our study had SCS captured on intracranial EEG monitoring, and arose in overlapping regions with the ictal onset zone of ECS. Completeness of resection remains the most important predictor of seizure outcome, regardless of the presence of SCS. In the absence of ECS during intracranial EEG monitoring, SCS onset zones may provide useful localization information to guide surgical resection plans. This is the largest cohort reported in the literature describing characteristics associated with the presence of SCS and the impact of SCS on pediatric epilepsy surgery outcomes.

MRI Predictors of Seizure Outcomes in ECT

Seizure generalization appears to be important for successful antidepressant response to ECT, and seizure indicators are closely monitored to inform treatment course. Yet, little is known about the neurobiology of ECT-induced seizures, despite a rich MRI literature measuring long-term neuroplasticity after ECT. This presentation discusses prediction of seizure and antidepressant outcomes in ECT using pre-treatment MRI.

Automated analysis of cortical volume loss predicts seizure outcomes after frontal lobectomy.

Patients undergoing frontal lobectomy demonstrate lower seizure-freedom rates than patients undergoing temporal lobectomy and several other resective interventions. We attempted to utilize automated preoperative quantitative analysis of focal and global cortical volume loss to develop predictive volumetric indicators of seizure outcome after frontal lobectomy. Ninety patients who underwent frontal lobectomy were stratified based on seizure freedom at a mean follow-up time of 3.5 (standard deviation [SD] 2.5) years. Automated quantitative analysis of cortical volume loss organized by distinct brain region and laterality was performed on preoperative T1-weighted magnetic resonance imaging (MRI) studies. Univariate statistical analysis was used to select potential predictors of seizure freedom. Backward variable selection and multivariate logistical regression were used to develop models to predict seizure freedom. Forty-eight of 90 (53.3%) patients were seizure-free at the last follow-up. Several frontal and extrafrontal brain regions demonstrated statistically significant differences in both volumetric cortical volume loss and volumetric asymmetry between the left and right sides in the seizure-free and non-seizure-free cohorts. A final multivariate logistic model utilizing only preoperative quantitative MRI data to predict seizure outcome was developed with a c-statistic of 0.846. Using both preoperative quantitative MRI data and previously validated clinical predictors of seizure outcomes, we developed a model with a c-statistic of 0.897. This study demonstrates that preoperative cortical volume loss in both frontal and extrafrontal regions can be predictive of seizure outcome after frontal lobectomy, and models can be developed with excellent predictive capabilities using preoperative MRI data. Automated quantitative MRI analysis can be quickly and reliably performed in patients with frontal lobe epilepsy, and further studies may be developed for integration into preoperative risk stratification.

Epileptic High-Frequency Oscillations in Intracranial EEG Are Not Confounded by Cognitive Tasks.

Rationale: High-frequency oscillations (HFOs) in intracranial EEG (iEEG) are used to delineate the epileptogenic zone during presurgical diagnostic assessment in patients with epilepsy. HFOs are historically divided into ripples (80–250 Hz), fast ripples (FR, >250 Hz), and their co-occurrence (FRandR). In a previous study, we had validated the rate of FRandRs during deep sleep to predict seizure outcome. Here, we ask whether epileptic FRandRs might be confounded by physiological FRandRs that are unrelated to epilepsy.Methods: We recorded iEEG in the medial temporal lobe MTL (hippocampus, entorhinal cortex, and amygdala) in 17 patients while they performed cognitive tasks. The three cognitive tasks addressed verbal working memory, visual working memory, and emotional processing. In our previous studies, these tasks activated the MTL. We re-analyzed the data of these studies with the automated detector that focuses on the co-occurrence of ripples and FRs (FRandR).Results: For each task, we identified those channels in which the HFO rate was modulated during the task condition compared to the control condition. However, the number of these channels did not exceed the chance level. Interestingly, even during wakefulness, the HFO rate was higher for channels within the seizure onset zone (SOZ) than for channels outside the SOZ.Conclusion: Our prospective definition of an epileptic HFO, the FRandR, is not confounded by physiological HFOs that might be elicited by our cognitive tasks. This is reassuring for the clinical use of FRandR as a biomarker of the EZ.

Physiological Ripples Associated With Sleep Spindles Can Be Identified in Patients With Refractory Epilepsy Beyond Mesio-Temporal Structures.

Introduction: High frequency oscillations (HFO) are promising biomarkers of epileptic tissue. While group analysis suggested a correlation between surgical removal of HFO generating tissue and seizure free outcome, HFO could not predict seizure outcome on an individual patient level. One possible explanation is the lack of differentiation between physiological and epileptic HFO. In the mesio-temporal lobe, a proportion of physiological ripples can be identified by their association with scalp sleep spindles. Spike associated ripples in contrast can be considered epileptic. This study investigated whether categorizing ripples by the co-occurrence with sleep spindles or spikes improves outcome prediction after surgery. Additionally, it aimed to investigate whether spindle-ripple association is limited to the mesio-temporal lobe structures or visible across the whole brain.Methods: We retrospectively analyzed EEG of 31 patients with chronic intracranial EEG. Sleep spindles in scalp EEG and ripples and epileptic spikes in iEEG were automatically detected. Three ripple subtypes were obtained: SpindleR, Non-SpindleR, and SpikeR. Rate ratios between removed and non-removed brain areas were calculated. We compared the distinct ripple subtypes and their rates in different brain regions, inside and outside seizure onset areas and between patients with good and poor seizure outcome.Results: SpindleR were found across all brain regions. SpikeR had significantly higher rates in the SOZ than in Non-SOZ channels. A significant positive correlation between removal of ripple-events and good outcome was found for the mixed ripple group (rs = 0.43, p = 0.017) and for ripples not associated with spindles (rs=0.40, p = 0.044). Also, a significantly high proportion of spikes associated with ripples were removed in seizure free patients (p = 0.036).Discussion: SpindleR are found in mesio-temporal and neocortical structures, indicating that ripple-spindle-coupling might have functional importance beyond mesio-temporal structures. Overall, the proportion of SpindleR was low and separating spindle and spike associated ripples did not improve outcome prediction in our patient group. SpindleR analysis therefore can be a tool to identify physiological events but needs to be used in combination with other methods to have clinical relevance.

Analysis of surgical strategies for children with epileptic spasms.

To investigate surgical prognostic factors in order to establish a surgical plan for children with drug-resistant epileptic spasms. We retrospectively analysed 64 children with drug-resistant spasms who were operated on in Beijing; the electroclinical features, surgical procedures, and surgical outcomes of these children were discussed in detail. We divided the seizure-free patients into several groups according to imaging, aetiology, and application of stereo-electroencephalography in order to investigate the extent of the various influencing factors. Fifty-three (82.8%) patients had favourable outcome, and 11 (17.2%) had unfavourable outcome. Based on the univariate analysis, the factors associated with favourable seizure outcome were interictal high γ frequency (χ 2 = 4.161; p = 0.041), concordance between MRI and interictal epileptic discharges (IEDs) (χ 2 = 6.148; p =0.013), and concordance between PET and IEDs (χ 2 = 4.281; p = 0.039). Concordance between MRI and IEDs (OR = 0.083, 95%CI = 0.014-0.483; p = 0.006) and continuous discharges on electrocorticography (OR = 0.109, 95%CI = 0.019-0.639; p = 0.014) were important factors associated with a favourable surgical outcome. Resective surgery is an effective treatment for drug-resistant ES in children. A deeper understanding of the predictors of seizure outcome is beneficial for establishing a standard, one-stage resection procedure for spasms in order to benefit more patients who have not previously considered surgery. We propose a workflow for presurgical evaluation in children with epileptic spasms.

Molecular Imaging of Brain Tumor-Associated Epilepsy.

Epilepsy is a common clinical manifestation and a source of significant morbidity in patients with brain tumors. Neuroimaging has a pivotal role in neuro-oncology practice, including tumor detection, differentiation, grading, treatment guidance, and posttreatment monitoring. In this review, we highlight studies demonstrating that imaging can also provide information about brain tumor-associated epileptogenicity and assist delineation of the peritumoral epileptic cortex to optimize postsurgical seizure outcome. Most studies focused on gliomas and glioneuronal tumors where positron emission tomography (PET) and advanced magnetic resonance imaging (MRI) techniques can detect metabolic and biochemical changes associated with altered amino acid transport and metabolism, neuroinflammation, and neurotransmitter abnormalities in and around epileptogenic tumors. PET imaging of amino acid uptake and metabolism as well as activated microglia can detect interictal or peri-ictal cortical increased uptake (as compared to non-epileptic cortex) associated with tumor-associated epilepsy. Metabolic tumor volumes may predict seizure outcome based on objective treatment response during glioma chemotherapy. Advanced MRI, especially glutamate imaging, can detect neurotransmitter changes around epileptogenic brain tumors. Recently, developed PET radiotracers targeting specific glutamate receptor types may also identify therapeutic targets for pharmacologic seizure control. Further studies with advanced multimodal imaging approaches may facilitate development of precision treatment strategies to control brain tumor-associated epilepsy.

Temporal lobe epilepsy surgery in children and adults: A multicenter study.

To assess seizure and cognitive outcomes and their predictors in children (<16years at surgery) and adults undergoing temporal lobe epilepsy (TLE) surgery in eight Italian centers. This is a retrospective multicenter study. We performed a descriptive analysis and subsequently carried out multivariable mixed-effect models corrected for multiple comparisons. We analyzed data from 511 patients (114 children) and observed significant differences in several clinical features between adults and children. The possibility of achieving Engel class IA outcome and discontinuing antiepileptic drugs (AEDs) at last follow-up (FU) was significantly higher in children (P=.006 and<.0001). However, percentages of children and adults in Engel class I at last FU (mean ± SD, 45.9 ± 17 months in children; 45.9 ± 20.6 months in adults) did not differ significantly. We identified different predictors of seizure outcome in children vs adults and at short- vs long-term FU. The only variables consistently associated with class I outcome over time were postoperative electroencephalography (EEG) in adults (abnormal, improved,odds ratio [OR]= 0.414, P=.023, Q=0.046 vs normal, at 2-year FU and abnormal, improved, OR=0.301, P=.001, Q=0.002 vs normal, at last FU) and the completeness of resection of temporal magnetic resonance (MR) abnormalities other than hippocampal sclerosis in children (OR=7.93, P=.001, Q=0.003, at 2-year FU and OR=45.03, P<.0001, Q<0.0001, at last FU). Cognitive outcome was best predicted by preoperative performances in either age group. Clinical differences between adult and pediatric patients undergoing TLE surgery are reflected in differences in long-term outcomes and predictors of failures. Children are more likely to achieve sustained seizure freedom and withdraw AEDs after TLE surgery. Earlier referral should be encouraged as it can improve surgical outcome.

Cross-national disparities contribute to heterogeneity in patient outcomes following invasive monitoring: A hierarchical mixed-effects analysis.

There is substantial variability in outcomes following invasive monitoring and surgical treatment of drug-resistant epilepsy (DRE). Patients with DRE are uniquely vulnerable to cross-national health care disparities, as their epilepsy is difficult to treat and requires extensive resources. In a large cross-national database of patients undergoing invasive monitoring for epilepsy surgery, we sought to evaluate the association between social, economic, and educational indicators of the country of treatment and patient outcomes following invasive monitoring. We performed a mixed-effects analysis of an individual patient database of 595 subjects enrolled in 33 studies encompassing 25 neurosurgical centers in 10 countries of invasive monitoring for epilepsy from 1996 to 2019. Upon preliminary univariate analysis, significant nation-level predictors of seizure outcome following either stereoelectroencephalography or subdural electrodes were hospital beds per 100,000 population, physician density, gross domestic product (GDP) growth, male and female educational attainment, and unemployment rate. On multivariate mixed-effects logistic regression, physician density (β=-0.5112, P<.00697) and GDP growth (β=0.53822, P<.00404) were the only nation-level covariates of significance associated with seizure outcome. A higher physician density was associated with lesser seizure freedom rates, whereas higher GDP growth was associated with greater seizure freedom rates. Although patient-specific variables were the primary determinant of seizure outcomes, cross-national disparities also contribute to heterogeneities. Our findings highlight the importance of a systems-level dialogue to improve surgical outcomes for DRE patients.

Predictors of Outcome in Juvenile Myoclonic Epilepsy.

BackgroundJuvenile myoclonic epilepsy (JME) is the most common idiopathic generalized epilepsy syndrome, accounting for 10% of all epilepsy. However, there is limited information regarding the predictors of seizure outcome. The aim of this study was to determine the predictors of seizure outcome in JME patients.MethodsA population-based retrospective study of JME patients who were treated at the Department of Neurology of affiliated Zhongshan Hospital, Xiamen University from 2008 to 2013.ResultsSixty-three patients (30 women and 33 men) were enrolled in this study. The median age at seizure onset was 14 years old, and the average duration of epilepsy was 5 years. The onset of JME at age <16 years was found in 63.5% of patients. The epileptiform runs ≥3 s were observed in 35.8% patients. Febrile seizure was noted in 28.9% of patients. Among 63 patients, 40 patients (63.5%) had remission. Multivariate analysis identified the following factors as significant predictors of seizure outcome: the onset of JME at age <16 years, epileptiform runs ≥3 s runs, and febrile seizure.ConclusionThe onset of JME at age <16 years, febrile seizures and epileptiform runs ≥3 s might be associated with poor long-term seizure outcome in patients with JME.

Seizures severity during rewarming can predict seizure outcomes of infants with neonatal hypoxic-ischemic encephalopathy following therapeutic hypothermia

BackgroundThe aim of this study was to examine the predictive value of amplitude-integrated electroencephalography (aEEG) on 12-month seizure outcomes of infants with neonatal hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia. MethodsWe conducted this retrospective cohort study in a tertiary neonatal intensive care unit between May 2012 and September 2017. Neonates with HIE who received both therapeutic hypothermia (TH) and aEEG were enrolled. ResultsA total of 23 infants (14 boys, nine girls) with a mean gestational age of 38.9 weeks were enrolled. Fifteen (65%) infants had moderate HIE and eight (35%) had severe HIE according to modified Sarnat staging. The mean aEEG recording time was 107.5 h. Twenty (86.9%) infants had seizure activity during the first 24 h after cooling and 14 (60.8%) had seizure activity during the first 24 h after rewarming. At 12 months, five (21.7%) infants had poor seizure outcomes. Repetitive seizures or status epilepticus pattern during the first 24 h after rewarming, but not the first 24 h after cooling, were associated with the presence of epilepsy at 12 months (p = 0.037). ConclusionsWe identified a high incidence of electrographic seizures in infants with neonatal HIE treated with therapeutic hypothermia, and post-neonatal epilepsy in the children who survived after HIE. Repetitive seizures or status epilepticus pattern during the first 24 h after rewarming, but not in the first 24 h after cooling, were associated with the presence of epilepsy at 12 months.

Prognostic factors of postoperative seizure outcomes in older patients with temporal lobe epilepsy.

The authors of this study aimed to investigate surgical outcomes and prognostic factors in older patients with drug-resistant temporal lobe epilepsy (TLE) who had undergone resective surgery. Data on patients older than 45 years of age with drug-resistant TLE who had undergone resective surgery at Sanbo Brain Hospital, Capital Medical University, between January 2009 and August 2017 were retrospectively collected. Postoperative seizure outcomes were evaluated according to the International League Against Epilepsy (ILAE) classification. Patients belonging to ILAE classes 1 and 2 were classified as having a favorable outcome, whereas patients belonging to ILAE classes 3-6 were classified as having an unfavorable outcome. Univariate analysis and multivariate logistic regression analysis were used to identify the potential predictors of seizure outcomes. A total of 45 patients older than 45 years of age who had undergone resective epilepsy surgery for TLE were included in the present study. Eight (17.8%) of 45 patients had preoperative comorbidity in addition to seizures. The average age at the time of surgery was 51.76 years, and the average duration of epilepsy at the time surgery was 18.01 years. After an average follow-up period of 4.53 ± 2.82 years (range 2-10 years), 73.3% (33/45) of patients were seizure free. Surgical complications were observed in 13.3% of patients. Univariate and multivariate analyses revealed that an MRI-negative finding is the only independent predictor of unfavorable seizure outcomes (OR 0.06, 95% CI 0.01-0.67, p = 0.023). Resective surgery is a safe and effective treatment for older patients with drug-resistant TLE. An MRI-negative finding independently predicts unfavorable seizure outcomes.

FV20 Prospectively defined high frequency oscillations to predict seizure outcome in the individual patient

FV20 Prospectively defined high frequency oscillations to predict seizure outcome in the individual patient

Resective surgery for drug-resistant posttraumatic epilepsy: predictors of seizure outcome.

The object of this study was to evaluate surgical outcomes and prognosis factors in patients with drug-resistant posttraumatic epilepsy (PTE) who had undergone resective surgery. The authors retrospectively reviewed the records of all patients with drug-resistant PTE who had undergone resective surgery at Sanbo Brain Hospital, Capital Medical University, in the period from January 2008 to December 2016. All patients had a follow-up period of at least 2 years. Seizure outcomes were evaluated according to the International League Against Epilepsy (ILAE) classification. Patients in ILAE classes 1 and 2 during the last 2 years of follow-up were classified as having a favorable outcome; patients in all other classes were considered to have an unfavorable outcome. Univariate analysis and a multivariate logistic regression model in a backward fashion were used to identify the potential predictors of seizure outcomes. Among 90 patients with a follow-up of 2-10 years (mean ± standard deviation, 5.79 ± 2.84 years), 70% (63 patients) were seizure free, of whom 68.9% (62 patients) had an ILAE class 1 outcome and 1.1% (1 patient) had an ILAE class 2 outcome. Permanent neurological deficits were observed in 10 patients (11.1%). Univariate and multivariate analyses revealed that only the duration of seizures ≤ 8 years was an independent predictor of a favorable seizure outcome (OR 0.34, 95% CI 0.13-0.92). Resective surgery is an effective treatment for patients with drug-resistant PTE with an acceptable incidence of complications. The information on prognosis factors suggests that early surgery may offer more benefits to patients with drug-resistant PTE.

Operculoinsular cortectomy for refractory epilepsy. Part 1: Is it effective?

Patients with refractory epilepsy of operculoinsular origin are often denied potentially effective surgical treatment with operculoinsular cortectomy (also termed operculoinsulectomy) because of feared complications and the paucity of surgical series with a significant number of cases documenting seizure control outcome. The goal of this study was to document seizure control outcome after operculoinsular cortectomy in a group of patients investigated and treated by an epilepsy team with 20 years of experience with this specific technique. Clinical, imaging, surgical, and seizure control outcome data of all patients who underwent surgery for refractory epilepsy requiring an operculoinsular cortectomy were retrospectively reviewed. Tumors and progressive encephalitis cases were excluded. Descriptive and uni- and multivariate analyses were done to determine seizure control outcome and predictors. Forty-three patients with 44 operculoinsular cortectomies were studied. Kaplan-Meier estimates of complete seizure freedom (first seizure recurrence excluding auras) for years 0.5, 1, 2, and 5 were 70.2%, 70.2%, 65.0%, and 65.0%, respectively. With patients with more than 1 year of follow-up, seizure control outcome Engel class I was achieved in 76.9% (mean follow-up duration 5.8 years; range 1.25-20 years). With multivariate analysis, unfavorable seizure outcome predictors were frontal lobe-like seizure semiology, shorter duration of epilepsy, and the use of intracranial electrodes for invasive monitoring. Suspected causes of recurrent seizures were sparing of the language cortex part of the focus, subtotal resection of cortical dysplasia/polymicrogyria, bilateral epilepsy, and residual epileptic cortex with normal preoperative MRI studies (insula, frontal lobe, posterior parieto-temporal, orbitofrontal). The surgical treatment of operculoinsular refractory epilepsy is as effective as epilepsy surgeries in other brain areas. These patients should be referred to centers with appropriate experience. A frontal lobe-like seizure semiology should command more sampling with invasive monitoring. Recordings with intracranial electrodes are not always required if the noninvasive investigation is conclusive. The complete resection of the epileptic zone is crucial to achieve good seizure control outcome.

High-density ECoG improves the detection of high frequency oscillations that predict seizure outcome

ObjectivesResidual fast ripples (FR) in the intraoperative ECoG are highly specific predictors of postsurgical seizure recurrence. However, a FR is generated by a small patch of cortical tissue. Spatial sampling with standard electrodes may thus miss clinically relevant information. MethodsWe analyzed FR rates in the intraoperative ECoG of 22 patients that underwent resective epilepsy surgery. We used standard electrodes with 10 mm inter-contact spacing (standard ECoG) in 14 surgeries and high-density grid electrodes with 5 mm spacing (hd-ECoG) in 8 surgeries. We detected FR using a previously validated automatic detector. ResultsPostoperative seizure freedom was achieved in 14/22 (64%) cases. Across all 42 ECoG recordings, FR rates were higher for hd-ECoG than for standard ECoG. In the 14 seizure free patients (ILAE 1), no residual FR were detected (specificity = 100%). In the 8 patients with seizure recurrence (ILAE > 1), residual FR were detected in 1/7 standard ECoG and 1/1 hd-ECoG (Accuracy ACCstandard ECoG = 57%, CI [29% 82%], ACChd-ECoG = 100%, CI [63% 100%]). ConclusionDenser spatial sampling by hd-ECoG improved FR detection compared to standard ECoG. SignificanceHd-ECoG may advance seizure freedom after epilepsy surgery.