Preoperative Seizure Frequency Research Articles

Trends, outcomes, and complications of surgery for lesional epilepsy in infants and toddlers: A multicenter study.

To assess seizure and developmental outcomes, their predictors, and complications in 160 children who, between 1998 and 2022, underwent surgery for lesional epilepsy with curative intent before the age of 3 years. To compare trends in epilepsy surgery in this age group before and after the year 2014. Retrospective multicenter study. Descriptive and univariate analyses, and multivariable models for all outcomes. These 160 patients (76 F; 47.5%) underwent 169 surgeries (age at surgery 20.4 ± 9.4 months). At the last follow-up (77 ± 57.4 months), 121 patients (75.6%) were in Engel class I, 106 (66.2%) of whom were in Engel class Ia. Antiseizure medications were stopped in 84 patients (52.5%). Complications requiring reoperations were observed in 16 patients (10%; 9.5% of surgeries) and unexpected permanent deficits in 12 (7.5%; 7.1% of surgeries). Postoperative cognitive functions remained unchanged in 56 patients (44.4%), improved in 51 (40.5%), and worsened in 19 (15.1%). Multivariable analyses showed that the probability of achieving Engel class Ia was lower when the duration of epilepsy was longer, patients underwent preoperative video-EEG, and unexpected postoperative permanent deficits occurred. Cognitive improvement after surgery was associated with lower preoperative seizure frequency, better preoperative developmental level, and a longer postoperative follow-up. FCDII and tumors were the histopathologies carrying a higher probability of achieving seizure freedom, while polymicrogyria was associated with a lower probability of cognitive improvement. The number of patients operated on after 2014 was higher than before (61.3% vs. 38.7%), with stable outcomes. Epilepsy surgery is effective and safe in infants and toddlers, although the complication rate is higher than seen in older patients. Shorter duration of epilepsy, lower seizure frequency, no need for video-EEG, tumors, and some malformations of cortical development are robust predictors of seizure and cognitive outcome that may be exploited to increase earlier referral. This study analyzed the results of epilepsy surgery in 160 children who had been operated on before the age of 3 years at four Italian centers between 1998 and 2022. At the last follow-up (77 ± 57.4 months), 121 patients (75.6%) were free from disabling seizures, of which 106 (66.2%) were completely seizure-free since surgery. Major surgical complications occurred in 28 patients (17.5%), which is higher than observed with epilepsy surgery in general, but similar to hemispheric/multilobar surgery. Postoperative cognitive function remained unchanged in 56 patients (44.4%), improved in 51 (40.5%), and worsened in 19 (15.1%). Epilepsy surgery is effective and safe in infants and toddlers.

Comparative effectiveness of stereotactic, subdural, or hybrid intracranial EEG monitoring in epilepsy surgery.

Surgical intervention can be curative or palliative for drug-resistant focal epilepsy. However, if the seizure onset zone (SOZ) cannot be adequately localized via noninvasive tests, intracranial EEG (iEEG) recordings are often carried out to develop surgical plans in appropriate candidates. Stereotactic EEG (SEEG), subdural EEG (SDE), and SDE with depth electrodes (hybrid) are major tools used for investigation, but there is no class 1 or 2 evidence comparing the effectiveness of these modalities. The authors identified an institutional cohort of patients who underwent iEEG monitoring between 2001 and 2022. Demographic data, preoperative clinical features, iEEG intervention, and follow-up data were identified. Primary study endpoints included the following: 1) likelihood of SOZ localization; 2) likelihood of surgical treatment after iEEG; 3) seizure outcomes; and 4) complications. A total of 329 patients were identified (176 in the SEEG, 60 in the SDE, and 93 in the hybrid cohort) who were followed for a median of 5.4 (IQR 6.8) years. Baseline characteristics, including demographics, mean age at epilepsy diagnosis, mean age at iEEG investigation, number of preoperative antiseizure medications, and preoperative seizure frequency, were not statistically different across the 3 cohorts. Patients in the SEEG cohort were more likely to have their SOZ localized than were the patients in the SDE group (OR 2.3) and were less likely to undergo subsequent resection (OR 0.3) or to have complications (OR 0.4), although there was no statistical difference with respect to likelihood of undergoing any subsequent neurosurgical treatment, or with respect to favorable seizure outcomes. Patients in the hybrid cohort were more likely to have SOZ localized than were patients in the SDE group (OR 3.1), but were more likely to undergo resection (OR 4.9) or any neurosurgical treatment (OR 2.5) compared to patients in the SEEG group. Patients in the hybrid cohort had better seizure outcomes compared to the SDE (OR 2.3) but not to the SEEG group. Patients in the SEEG group were more likely to have their SOZ localized and patients in the SDE group were more likely to undergo resection, but they did not differ with respect to seizure outcomes.

Pre-operative predictors of post-operative seizure control in low-grade glioma: a systematic review and meta-analysis.

As many as 80% of low-grade gliomas (LGGs) present with seizures, negatively impacting quality of life. While seizures are associated with gliomas regardless of grade, the importance of minimizing impact of seizures for patients with low grade tumors cannot be understated given the prolonged survival period in this population.The objective of this systematic review and meta-analysis was to summarize existing literature and identify factors associated with post-operative seizure control (defined as Engel I classification) in patients with LGGs, with a focus on pre-operative factors. Patient data extracted include tumor location and histology, pre-operative anti-seizure medication use, extent of resection (EOR), adjuvant treatment, pre-operative seizure type, duration, and frequency, and post-operative Engel classification. A random-effects model was used to calculate the effects of EOR, pre-operative seizure duration, adjuvant radiation, and adjuvant chemotherapy on post-operative seizure control. The effect of tumor location and histology on post-operative Engel I classification was determined using contingency analyses.Thirteen studies including 1628 patients with seizures were included in the systematic review. On meta-analyses, Engel I classification was associated with pre-operative seizure type (OR = 0.79 (0.63-0.99), p = 0.0385, focal versus generalized), frontal lobe LGGs (OR = 1.5 (1.1-2.0), p = 0.0195), and EOR (OR (95% CI) = 4.5 (2.3-6.7), p < 0.0001 gross-total versus subtotal). Pre-operative seizure duration less than one year, adjuvant radiation, adjuvant chemotherapy, and tumor histology were not associated with achieving Engel I classification. In addition to the known effects of EOR, Engel I classification is less likely to be achieved in patients with focal pre-operative seizures and more likely to be achieved in patients with frontal lobe LGGs.

Withdrawal of antiseizure medications after MRI–Guided laser interstitial thermal therapy in extra-temporal lobe epilepsy

PurposeThis study investigated the success rate of antiseizure medications (ASMs) withdrawal following MRI Guided Laser Interstitial Thermal Therapy (MRg-LITT) for extra-temporal lobe epilepsy (ETLE), and identified predictors of seizure recurrence. MethodsWe retrospectively assessed 27 patients who underwent MRg-LITT for ETLE. Patients’ demographics, disease characteristics, and post-surgical outcomes were evaluated for their potential to predict seizure recurrence associated with ASMs withdrawal. ResultsThe median period of observation post MRg-LITT was 3 years (range 18 - 96 months) and the median period to initial ASMs reduction was 0.5 years (range 1–36 months). ASMs reduction was attempted in 17 patients (63%), 5 (29%) of whom had seizure recurrence after initial reduction. Nearly all patient who relapsed regained seizure control after reinstitution of their ASMs regimen. Pre-operative seizure frequency (p = 0.002) and occurrence of acute post-operative seizures (p = 0.01) were associated with increased risk for seizure recurrence post ASMs reduction. At the end of the observation period, 11% of patients were seizure free without drugs, 52% were seizure free with drugs and 37% still experienced seizures despite ASMs. Compared with pre-operative status, the number of ASMs was reduced in 41% of patients, unchanged in 55% of them and increased in only 4% of them. ConclusionsSuccessful MRg-LITT for ETLE allows for ASMs reduction in a significant portion of patients and complete ASMs withdrawal in a subset of them. Patients with higher pre-operative seizure frequency or occurrence of acute post operative seizures exhibit higher chances relapse post ASMs reduction.

Single-Institution Comparative Study of Magnetic Resonance–Guided Laser Interstitial Thermal Therapy and Open Corpus Callosotomy

Open corpus callosotomy (CC) poses a higher risk of perioperative morbidity than does magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) for treatment of drop and generalized seizures without documented superiority. We present a single-institution comparison between open and MRgLITT CC. A 2-year retrospective review was performed of patients who underwent open and MRgLITT CC (January 2019-January 2021). Demographics, surgical outcome data, hospital costs, and interhemispheric connectivity with diffusion tensor imaging were compared. The average age in years was 9.3 and 11.4 for CC (n= 4) and MRgLITT (n= 9), respectively. Preoperative drop seizure frequency was higher in CC (25 vs. 14.5 seizures/day; P= 0.59). At 10 months follow-up, the reduction in drop seizure frequency was better in open CC, but not statistically significant (93.8% vs. 64.3%; P= 0.21). The extent of CC ablation did not correlate with seizure reduction (Pearson coefficient= 0.09). An inverse correlation between interhemispheric connectivity change (diffusion tensor imaging analysis) and drop seizure frequency reduction was noted (Pearson coefficient= -0.97). Total hospital cost was significantly lower in MRgLITT ($67,754 vs. $107,111; P= 0.004), attributed to lower intensive care unit (1.1 vs. 4 days; P= 0.004) and total hospital stay (1.8 vs. 10.5 days; P= 0.0001). Postoperative hydrocephalus was present in 75% of patients in the CC group compared with zero in the MRgLITT group. Our middle-volume single-institution experience shows the safety, efficacy, and cost-effective benefit of MRgLITT compared with the traditional CC with therapeutic equipoise. This study is limited by the number of patients and, hence, further patient enrollment or multicenter study is warranted.

Long-term Outcome of Seizure Control and Neurologic Performance After Limited Hippocampal Radiofrequency Thermocoagulation for Mesial Temporal Lobe Epilepsy

Limited hippocampal radiofrequency thermocoagulation (RFTC) for patients with mesial temporal lobe epilepsy was associated with good short-term seizure control and few complications. We aimed to demonstrate the neuropsychologic outcomes and assess the prognostic factors of long-term seizure control in these patients. We included all patients with mesial temporal lobe epilepsy who underwent limited hippocampal RFTC from January 2016 to December 2020. Clinical data of age, sex, seizure control before and after operation were all corrected. Pre- and postoperative neuropsychologic function including full-scale intelligence quotient (FSIQ), memory quotient, and the Mini-Mental State Examination was used. Thirty-one patients (17 female and 14 male) with a mean epilepsy duration of 22.3 years and seizure frequency of 5.7 times per month were included. The intraoperative seizure rate was 19.3%, and a higher preoperative seizure frequency (P= 0.001) and longer duration of epilepsy (P= 0.042) were associated with the occurrence of intraoperative seizures. The postoperative FSIQ scores were significantly better than preoperative scores (mean 92.1 vs. 89.7, P= 0.014). Nine patients (29%) who underwent limited hippocampal RFTC were seizure-free at 1 year of follow-up. Responders represented 58% (n= 18) of patients at 1 year. The mean follow-up period was 34.7 ± 13.3 months. Five patients remained seizure free and 13 patients are still responders at the last follow-up visits. Long-term seizure frequency was 2.32 ± 2.86 times per month. Limited hippocampal RFTC is a safe stereotactic minimal invasive procedure with good neuropsychologic outcome and acceptable efficacy of seizure reduction in appropriately selected patients.

Corpus Callosotomy for Non-Localizing Drug Resistant Epilepsy with Drop Attacks

Corpus callosotomy (CC) is a surgical palliative procedure done for a selected group of patients with drug resistant epilepsy (DRE) to stop drop attacks and prevent falls. We performed a retrospective chart review of consecutive patients who underwent CC for DRE with drop attacks at our center between 2015 and 2019. Clinical, imaging details and surgical findings were noted. Clinical outcomes and functional status were evaluated. During the study period, 17 patients underwent corpus callosotomy (Male: Female 14:3). The mean age at surgery was 10.3years (standard deviation-5.85, interquartile range [IQR]=6.5). The mean age at onset of seizure was 2.23years (standard deviation-3.42, IQR=1.5). Preoperative seizure frequency ranged from 2 to 60 attacks per day (median: 20, IQR=36). All patients had atonic seizures/drop attacks. One patient underwent anterior CC and 16 underwent complete CC. Three patients had complications in the postoperative period. The median follow-up was 26months. All patients had cessation of drop attacks immediately following surgery. One patient with anterior CC had a recurrence of drop attacks for which she underwent completion CC. Another patient had recurrent drop attacks 3years later and was found to have a residual callosal connection. Three patients had complete seizure freedom and 4 patients had a <50% reduction in seizure frequency. Our study lends additional support to the efficacy of CC in patients with DRE, with the cessation of drop attacks. It also provided a reasonable reduction in seizure frequency. Complete CC led to better control of drop attacks.

Feasibility of Tailored Unilateral Disconnection vs Callosotomy for Refractory Epilepsy in Patients with Bilateral Parieto-Occipital Gliosis Following Perinatal Insult.

Patients with perinatal hypoxia (PH) and drug-refractory epilepsy (DRE) often have bilateral parieto-occipital gliosis. Surgical management of such patients is a dilemma. To identify preoperative determinants for unilateral disconnection vs callosotomy, and analyze the surgical outcome in such patients. This was a retrospective analysis of patients with DRE and history of PH, with MRI abnormalities restricted to bilateral posterior quadrants. Preoperative semiology, epilepsy duration and seizure frequency were recorded. Based on the concordance between the results of non-invasive tests, patients underwent either posterior quadrant disconnection (PQD) or corpus callosotomy (CC). Preoperative variables were analyzed and corelated to the postoperative seizure freedom. Fourteen patients were identified, 6 underwent PQD and 8 underwent CC. At follow up of 39.17 ± 23.75 months, 66.66% of patients (4/6) in the PQD subgroup had an ILAE Class I outcome. While none in the CC group attained seizure freedom, 87.5% (7/8) had more than 50% reduction in seizure frequency (follow up: 42 ± 27.31 months). Patients with a poor outcome had significantly greater seizure frequency (P = 0.05) and history of drop attacks (P = 0.04) in both the groups. Magnetoencephalography (MEG) accurately localized the epileptogenic zone in all of the patients with good outcome (P = 0.015). Concordance with single photon emission tomography (SPECT) was also a predictor of favorable outcome (P = 0.041). A history of drop attacks with high seizure frequency is associated with poor postoperative seizure outcome. Unilateral PQD is feasible and leads to superior seizure-free outcomes, even in cases with widespread and bilateral imaging and electrical abnormalities, provided the other preoperative investigations are concordant in localizing the epileptogenic zone.

Improving the prediction of epilepsy surgery outcomes using basic scalp EEG findings.

This study aims to evaluate the role of scalp electroencephalography (EEG; ictal and interictal patterns) in predicting resective epilepsy surgery outcomes. We use the data to further develop a nomogram to predict seizure freedom. We retrospectively reviewed the scalp EEG findings and clinical data of patients who underwent surgical resection at three epilepsy centers. Using both EEG and clinical variables categorized into 13 isolated candidate predictors and 6 interaction terms, we built a multivariable Cox proportional hazards model to predict seizure freedom 2years after surgery. Harrell's step-down procedure was used to sequentially eliminate the least-informative variables from the model until the change in the concordance index (c-index) with variable removal was less than 0.01. We created a separate model using only clinical variables. Discrimination of the two models was compared to evaluate the role of scalp EEG in seizure-freedom prediction. Four hundred seventy patient records were analyzed. Following internal validation, the full Clinical+EEG model achieved an optimism-corrected c-index of 0.65, whereas the c-index of the model without EEG data was 0.59. The presence of focal to bilateral tonic-clonic seizures (FBTCS), high preoperative seizure frequency, absence of hippocampal sclerosis, and presence of nonlocalizable seizures predicted worse outcome. The presence of FBTCS had the largest impact for predicting outcome. The analysis of the models' interactions showed that in patients with unilateral interictal epileptiform discharges (IEDs), temporal lobe surgery cases had a better outcome. In cases with bilateral IEDs, abnormal magnetic resonance imaging (MRI) predicted worse outcomes, and in cases without IEDs, patients with extratemporal epilepsy and abnormal MRI had better outcomes. This study highlights the value of scalp EEG, particularly the significance of IEDs, in predicting surgical outcome. The nomogram delivers an individualized prediction of postoperative outcome, and provides a unique assessment of the relationship between the outcome and preoperative findings.

Withdrawal of antiepileptic drugs after stereotactic laser amygdalohippocampotomy for mesial temporal lobe epilepsy

ObjectiveThis retrospective study investigated the success rate of withdrawal of antiepileptic drugs (AEDs) following stereotactic laser amygdalohippocampotomy (SLAH) for mesial temporal lobe epilepsy (MTLE), and identified predictors of seizure recurrence. Materials and methodsWe retrospectively assessed 65 patients who underwent SLAH for MTLE (59 lesional). Patients’ demographics, disease characteristics and post-surgical outcomes were evaluated for their potential to predict seizure recurrence associated with withdrawal of AEDs. ResultsThe mean period of observation post SLAH was 51 months (range 12–96 months) and the mean period to initial reduction of AEDs was 21 months (range 12–60 months). Reduction of AEDs was attempted in 37 patients (57 %) who were seizure free post SLAH and it was successful in approximately 2/3 of them. From the remainder 1/3 who relapsed, nearly all regained seizure control after reinstitution of their AEDs. The likelihood of relapse after reduction of AEDs was predicted only by pre-operative seizure frequency. At the end of the observation period, approximately 14 % of all SLAH patients were seizure free without AEDs and approximately 54 % remained seizure free on AEDs. Compared with preoperative status, the number of AEDs were reduced in 37 % of patients, unchanged in 51 % of them and increased in 12 % of them. ConclusionsSuccessful SLAH for MTLE allows for reduction of AEDs in a significant portion of patients and complete withdrawal of AEDs in a subset of them. Patients with higher pre-operative seizure frequency exhibit a greater chance of relapse post reduction of AEDs.

Responsive neurostimulation for the treatment of medically refractory epilepsy in pediatric patients: strategies, outcomes, and technical considerations.

Children with medically refractory partial-onset epilepsy arising from eloquent cortex present a therapeutic challenge, as many are not suitable for resective surgery. For these patients, responsive neurostimulation may prove to be a potential tool. Although responsive neurostimulation has demonstrated utility in adults, little has been discussed regarding its utility in the pediatric population. In this study, the authors present their institution's experience with responsive neurostimulation via the RNS System through a case series of 5 pediatric patients. A single-center retrospective study of patients who underwent RNS System implantation at Children's National Hospital was performed. Five patients underwent RNS System implantation. The mean patient age at treatment was 16.8 years, and the average follow-up was 11.2 months. All patients were considered responders, with a seizure frequency reduction of 64.2% without adverse events. All 5 patients experienced medium-term improvements in seizure control after RNS System implantation with decreases in seizure frequency > 50% from baseline preoperative seizure frequency. The authors demonstrated two primary configurations of electrode placement: hippocampal or amygdala placement via an occipitotemporal trajectory, as well as infratemporal surface electrodes and surface electrodes on the primary motor cortex. No adverse events were experienced in this case series.

Changes of the outcomes of epilepsy surgery within 10 years in the National Institute of Clinical Neurosciences, Hungary

The surgical treatment of medically intractable focal epilepsies is a well established practice. Our aim was to examine the efficacy of epilepsy surgery within a decade long period in our centre in Budapest. Data of drug-resistant patients with resective epilepsy surgery in the National Institute of Clinical Neurosciences were evaluated. The examined 10-year period was divided based on the year of the operation in two parts (2006-2010 and 2011-2016). The following data were collected: demography, beginning and type of epilepsy, magnetic resonance, preoperative seizure frequency, type of surgery and histology. Epileptological outcome was based on modified Engel's classification. Out of 187 surgeries, we identified 137 patients with resective intervention: 65% temporal lobe, 18% frontal, and 7% multilobar epilepsy. Seizure-freedom (Engel I/A) was 68% in the first postoperative year, 64% in the second, and 63% in the fifth year. In the first period, 1-year seizure freedom was 60% (temporal: 67% extratemporal: 50%), while in the second period it was 73% (temporal 79%, extratemporal 62%). Hippocampal sclerosis ratio dropped from 28% to 14%, while focal cortical dysplasia ratio increased from 22% to 31%. Surgical treatment in focal epilepsy - after thorough presurgical evaluation - is generally safe and successful. The most favorable outcome is in temporal localization. The efficacy tended to improve over time despite of the more challenging cases. This can be explained with the development of surgical techniques and improvement of presurgical localization. Orv Hetil. 2021; 162(6): 219-226.

Prophylactic administration of levetiracetam accelerates consciousness level and neurological recovery after neurosurgical operation with supratentorial craniotomy – Preliminary report

BackgroundSeizure frequency after neurosurgery with craniotomy has been widely reported. Postoperative consciousness recovery may be prolonged in such cases due to seizures or factors related to the underlying pathology and/or surgical procedures. However, it remains unclear whether prophylactic administration of antiseizure drugs is effective. Recently, continuous administration of levetiracetam (LEV) was shown to effectively reduce postoperative seizure frequency. Here, we aimed to confirm the postoperative efficacy of LEV and investigate its potential to aid in consciousness level recovery followed by functional recovery. MethodThis retrospective, single-center study analyzed the data of 61 patients who underwent supratentorial craniotomy and were divided into two groups: a continuous prophylactic LEV administration group (LEV group; 2000 mg/day for 14 days; 41 patients) or non-continuous prophylactic administration group (Control group; phenytoin 250 mg/day only on the operative day and postoperative day 1; 20 patients). Seizure frequency, the Glasgow coma scale (GCS), and modified Rankin scale (mRS) were evaluated and compared within and between groups. ResultsAverage age (years ± SD) was 64.0 ± 17.8 in the LEV and 64.3 ± 13.6 in the Control group. Preoperative seizure frequency was 9.8% in the LEV and 0% in the Control group, and postoperatively, it was 4.9% in the LEV and 25% in the Control group. While there were no preoperative differences in GCS between the groups, the postoperative GCS significantly improved in the LEV group starting on postoperative day 3 but only showed improvement in the Control group starting on postoperative day 14. Functional recovery as determined by the mRS indicated significant improvement in the LEV group on postoperative day 8, whereas the control group showed no significant recovery even on postoperative day 14. ConclusionContinuous LEV administration after neurosurgical operation with craniotomy accelerates recovery from consciousness disturbance and could improve outcomes by allowing aggressive early neurorehabilitation.

Seizure outcome in patients with cavernous malformation after early surgery

ObjectiveTo describe seizure outcome and complications in patients with cavernous malformations (CM) undergoing early versus late surgery. MethodsA database was created for all CM patients who presented with seizure referred to the neurosurgical clinic at an academic center. A telephone survey and chart review were conducted to evaluate for preoperative and postoperative seizure frequency. Postoperative seizure-free outcome of patients who had ≤2 preoperative seizures versus those that had >2 preoperative seizures was compared. ResultsA total of 35 CM patients were included for analysis. Nineteen patients had ≤2 preoperative seizures and 16 patients had >2 preoperative seizures, six of them drug resistant for over two years. Among the ≤2 seizure group, 15 had only a single seizure before surgical resection. 94.7% of patients with ≤2 preoperative seizures and 62.5% of patients with >2 preoperative seizures were seizure free one year following surgical resection (p = 0.019). 78.9% of patients with ≤2 preoperative seizures and 25% of patients with >2 preoperative seizures were able to wean off AEDs (p < 0.001). Among those patients who had a single preoperative seizure, 100% of patients were seizure free at one year. ConclusionsEarly surgical resection for CM patients who present after a CM-related seizure is an effective, well tolerated treatment and has good chance to offer seizure freedom without the need for long-term antiepileptic medications. Outcome for patients operated with only one or two preoperative seizures may lead to better results than patients who delay the procedure.

Risk Factors for Seizure Worsening After Epilepsy Surgery in Children and Adults: A Population-Based Register Study.

BACKGROUNDIncreased seizure frequency and new-onset tonic-clonic seizures (TCS) have been reported after epilepsy surgery.OBJECTIVETo analyze potential risk factors for these outcomes in a large cohort.METHODSWe studied prospectively collected data in the Swedish National Epilepsy Surgery Register on increased seizure frequency and new-onset TCS after epilepsy surgery 1990-2015.RESULTSTwo-year seizure outcome was available for 1407 procedures, and data on seizure types for 1372. Increased seizure frequency at follow-up compared to baseline occurred in 56 cases (4.0%) and new-onset TCS in 53 (3.9%; 6.6% of the patients without preoperative TCS). Increased frequency was more common in reoperations compared to first surgeries (7.9% vs 3.1%; P = .001) and so too for new-onset TCS (6.7% vs 3.2%; P = .017). For first surgeries, binary logistic regression was used to analyze predictors for each outcome. In univariable analysis, significant predictors for increased seizure frequency were lower age of onset, lower age at surgery, shorter epilepsy duration, preoperative neurological deficit, intellectual disability, high preoperative seizure frequency, and extratemporal procedures. For new-onset TCS, significant predictors were preoperative deficit, intellectual disability, and nonresective procedures. In multivariable analysis, independent predictors for increased seizure frequency were lower age at surgery (odds ratio (OR) 0.70 per increasing 10-yr interval, 95% CI 0.53-0.93), type of surgery (OR 0.42 for temporal lobe resections compared to other procedures, 95% CI 0.19-0.92), and for new-onset TCS preoperative neurological deficit (OR 2.57, 95% CI 1.32-5.01).CONCLUSIONSeizure worsening is rare but should be discussed when counseling patients. The identified risk factors may assist informed decision-making before surgery.

Increase in cognitive function is seen in many single-operated pediatric patients after epilepsy surgery

PurposeThe recurrent seizures of pediatric drug-resistant epilepsy (DRE) are known to impair brain development and can lead to a loss in cognitive functioning. Surgery is increasingly being used to treat children with DRE. This study investigates the pre- and postoperative cognitive function in a pediatric epilepsy surgery cohort as well as predictive determinants of change in intelligence quotient (IQ) following surgery. MethodsA consecutive series of 91 Danish children who underwent focal resective epilepsy surgery between January 1996 and December 2016 were included. All underwent preoperative cognitive evaluation and were reevaluated at 1-year and/or 2-year follow-up. Single-operated and multi-operated patients were examined separately. Results79 of 91 patients were single-operated. Single-operated patients received less anti-epileptic drugs (AED) and experienced a decrease in seizure frequency postoperatively, p < 0.001. IQ increased postoperatively (IQ change ± standard deviation: 3.3 ± 14.0), p < 0.05. High preoperative seizure frequency was a significant predictor for decreased IQ, p < 0.01. Multi-operated patients did not experience a reduction in AED treatment. Surgery and continued AED treatment did, however, result in significantly better seizure control, p < 0.01. IQ remained unchanged in multi-operated patients. ConclusionEpilepsy surgery allowed for IQ gains in single-operated patients. Preoperative seizure frequency was a significant predictor of IQ change following surgery. Interactions between other, not included, possible predictors remain to be examined. Single-operated patients had the best cognitive outcome. The inclusion of a non-surgical control group is needed to assess the extent of the beneficial effects of surgery on cognitive ability.

Subgroup analysis of seizure and cognitive outcome after vagal nerve stimulator implantation in children.

Vagal nerve stimulator (VNS) implantation at an early age seems to lead to improved quality of life and cognitive outcome. The aim of this analysis is to evaluate whether specific patient or seizure characteristics might lead to better seizure control, cognitive outcome, and higher quality of life in children undergoing VNS implantation. Primary outcome measure was reduction in seizure frequency. Secondary outcome measures were epilepsy outcome assessed by McHugh and Engel classifications, reduction in antiepileptic drugs (AED), developmental and cognitive outcome, as well as quality of life assessed through the pediatric quality of life (PEDSQL™) questionnaire and care giver impression (CGI) scale. Forty-five consecutive children undergoing VNS implantation were analyzed for the following subgroups: age (categorized to 1-2years old, 3-5years old, 6-12years old, and 13-18years old), sex, underlying cause (categorized to idiopathic, encephalitis, stroke, syndromic), duration of preoperative seizures (dichotomized to under or above 89months, corresponding to the median of the whole cohort), and preoperative seizure frequency (dichotomized to under and above 360 seizures per month). Encephalitis as the underlying cause for seizures was the only variable significantly associated with higher reduction rate of seizure frequency. Patients with VNS implantation at the age of ≤ 2years showed a strong association with better developmental and cognitive outcome, as well as quality of life. Shorter duration of preoperative seizures and higher preoperative seizure frequency showed a strong association with better developmental outcome, as well as quality of life. Engel outcome scores were significantly better in patients with epilepsy due to encephalitis (100% Engel I-III). However, patients with epilepsy due to encephalitis showed significantly higher complication rates (71.4%, p = 0.045). Children suffering from epilepsy due to encephalitis show higher seizure reduction rates after VNS implantation when compared with children suffering from epilepsy due to other causes. Developmental and cognitive outcomes as well as quality of life of children undergoing VNS implantation is strongly associated with shorter duration of preoperative seizures and implantation at a young age.

Vagus Nerve Stimulation versus Responsive Neurostimulator System in Patients with Temporal Lobe Epilepsy

Introduction: Patients with medically refractory temporal lobe epilepsy (TLE) are candidates for neuromodulation procedures. While vagus nerve stimulation (VNS) was historically the procedure of choice for this condition, the responsive neurostimulation system (RNS) has come into favor for its more targeted approach. While both VNS and RNS have been reported as efficacious treatments for TLE, the outcomes of these 2 procedures have not been directly compared. This study aims to compare outcomes following VNS versus RNS for TLE. Methods: We retrospectively reviewed the records of all patients with TLE who underwent VNS or RNS placement at our institution from 2003 to 2018. The primary outcome was change in seizure frequency. Other outcomes included Engel score, change in anti-epileptic medications, and complications. Results: Twenty-three patients met inclusion criteria; 11 underwent VNS and 12 underwent RNS. At baseline, the 2 groups were statistically similar regarding age at surgery, epilepsy duration, and preoperative seizure frequency. At last follow-up, both groups displayed reduced seizure frequency (mean reduction of 46.3% for the VNS group and 58.1% for the RNS group, p = 0.49). Responder rate, Engel score, and change in medications were statistically similar between groups. Compared to 0.0% of the VNS group, 13.3% of the RNS group experienced infection requiring re-operation. Conclusion: Despite their different mechanisms, VNS and RNS resulted in similar response rates for patients with TLE. We suggest that VNS should not be excluded as a treatment for patients with medically refractory TLE who are not candidates for resective or ablative procedures.

Short-term outcomes and predictors of post-surgical seizures in patients with supratentorial low-grade gliomas

To explore the predictive factors and short-term outcomes of post-surgical seizures in patients with supratentorial low-grade gliomas (LGGs). A consecutive series of 70 supratentorial LGG patients with seizures were reviewed to determine the predictors and short-term outcomes of seizures. Univariate analyses and multivariate logistic regression analyses were performed to determine the predictive factors associated with postoperative seizure outcomes. We identified the preoperative seizure frequency threshold by plotting a receiver operating characteristic curve. A Kaplan-Meier curve was constructed to illustrate the seizure-free survival rate of our cohort over time. 54 patients who remained seizure -free post-surgery were classified into the Engel class I, and the other 16 patients whose seizures relapsed were classified into Engel classes II–IV. Univariate and multivariate logistic regression analyses showed that the preoperative seizure frequency (X2 = 16.069, P = 0.001), extent of resection (x2 = 5.031, P = 0.025), IDH1 mutation (x2 = 4.435, P = 0.035) and adjuvant chemotherapy of temozolomide (X2 = 4.081, P = 0.043) were related to the postoperative short-term seizure outcome. The ROC curve indicated that the area under the curve for the preoperative seizure frequency test was 0.805 (95% confidence interval 0.690–0.920, p < 0.05), which corresponded to an optimal threshold of 2 preoperative seizures. The IDH1WT status and adjuvant chemotherapy with temozolomide were related to a better post-operative seizure outcome. Within the first year after the surgical resection, seizures reoccurred among 16 patients (22.9%) with a mean time of 10.8 months. The preoperative seizure frequency, extent of resection, IDH1 status, and adjuvant chemotherapy with temozolomide were predictive factors of short-term postoperative seizure outcomes for supratentorial LGGs. To obtain a favorable seizure outcome, early intervention and removal are warranted. IDH1 mutation is the predictive biomarker of postoperative seizure outcomes. The adjuvant chemotherapy with temozolomide appears to be associated with better seizure outcomes, and it may be useful in helping to control the postoperative seizures.

P14-T Mesio-temporal epilepsy with hippocampal sclerosis: Predictors for long term surgical outcome

Background To Study long-term predictors for surgical outcome of Mesio-temporal epilepsy (MTE) with hippocampal sclerosis (HS) in a Moroccan representative sample and compare it with the findings of literature. Material and methods We have examined the files of 8 patients who underwent anterior temporal lobectomy for MTE with HS between 2007 and 2018 at the Neurophysiology department of Rabat’s specialty hospital. All patients had MTE with MRI defined HS. We have used the Engel outcome scale to split the patients into 2 groups; Engel I and non-Engel I patients. The predictive value of; gender, febrile convulsion history, age at onset, age at surgery, duration of epilepsy, preoperative seizure frequency, ictal dystonic posturing, generalized tonic-clonic seizures (SGTCS) and interictal EEG abnormalities was studied. Results the follow up mean was 7.5 years, 5 patients were classified Engel I and 3 were non-Engel I. There was a predominance of males in the Engel I group. In the non-Engel I group, the preoperative seizure frequency was 1.9 higher, the mean age at onset of epilepsy was lower whereas it was higher at the moment of surgery and the duration of epilepsy was longer. In that group; all patients had ictal dystonic posture and EEG abnormalities. There was no difference between the 2 groups concerning the SGTCS and the history of febrile convulsions. Conclusion gender, preoperative seizure frequency, ictal dystonic posturing, and bilateral interictal EEG abnormalities were the significant surgery outcome predictors in our study.