Temporal Lobe Epilepsy Surgery Research Articles

Progressive postoperative atrophy of ipsilateral thalamus, putamen, and globus pallidus in patients with temporal lobe epilepsy: A volumetric analysis.

Cortical atrophy close to medial temporal structures has been described consistently in patients with temporal lobe epilepsy (TLE). Successful TLE surgery may have a neuroprotective effect preventing further atrophy of temporal and extratemporal cortex. However, the effects of epilepsy surgery on subcortical structures demand additional enlightenment. This work aimed to determine how epilepsy surgery affects volumes of subcortical structures in medically refractory temporal lobe epilepsy patients. We compared MRI volumes of subcortical structures in 62 patients with TLE (36 left, 26 right) before and after anterior temporal lobectomy with 38 TLE patients (20 left, 18 right) who were considered to be good surgical candidates and had at least two brain MRIs. There were no volume differences in subcortical structures on preoperative and initial MRIs of non-operated TLE patients. At baseline, the ipsilateral thalamus and putamen in TLE patients were marginally smaller than contralateral structures. Operated patients showed a significant postoperative volume reduction in ipsilateral thalamus, putamen, and globus pallidus. In contrast, there were no significant volumetric reductions in non-operated patients longitudinally. There were no volumetric changes associated with different surgical outcomes or different postoperative cognitive outcomes. Our study demonstrated postoperative volume loss of thalamus, putamen and globus pallidus ipsilaterally to the side of resection. Our findings suggest surgery-related changes, likely Wallerian degeneration within subcortical networks not related to seizure or cognitive outcome. We studied 100 patients with epilepsy, comparing those who had surgery to those who did not. After surgery, the thalamus, putamen and globus pallidus on the same side as the surgery shrank significantly, but not in non-surgery patients. This suggests surgery-related changes in deeper brain structures, unrelated to seizure freedom or cognitive outcomes. This research sheds additional light on the response of the subcortical structure to epilepsy surgery, highlighting potential areas for further study.

Lesion and lesion network localization of dysnomia after epilepsy surgery.

Temporal lobe (TL) epilepsy surgery is an effective treatment option for patients with drug-resistant epilepsy. However, neurosurgery poses a risk for cognitive deficits - up to one third of patients have a decline in naming ability following TL surgery. In this study, we aimed to better understand the neural correlates associated with reduced naming performance after TL surgery, with the goal of informing surgical planning strategies to mitigate the risk of dysnomia. We retrospectively identified 85 patients who underwent temporal lobe (TL) resective surgery (49 left TL, 36 right TL) for whom naming ability was assessed before and >3 months post-surgery using the Boston Naming Test (BNT). We used multivariate lesion-symptom mapping to identify resection sites associated with naming decline, and we used lesion-network mapping to evaluate the broader functional and structural connectivity profiles of resection sites associated with naming decline. We validated our findings in an independent cohort of 59 individuals with left temporal lobectomy, along with repeating all analyses after combining the cohorts. Lesion laterality and location were important predictors of post-surgical naming performance. Naming performance significantly improved after right temporal lobectomy (P = 0.015) while a decrement in performance was observed following left temporal lobectomy (P = 0.002). Declines in naming performance were associated with surgical resection of the left anterior middle temporal gyrus (Brodmann area 21, r =0.41, P = <.001), along with a previously implicated basal temporal language area. Resection sites linked to naming decline showed a functional connectivity profile featuring a left-lateralized network closely resembling the extended semantic \ default mode network, and a structural connectivity profile featuring major temporo-frontal association white matter tracts coursing through the temporal stem. This extends prior work by implicating the left anterior middle temporal gyrus in naming decline and provides additional support for the role of the previously identified basal temporal language area in naming decline. Importantly, the structural and functional connectivity profiles of these regions suggest they are key nodes of a broader extended semantic network. Together these regional and network findings may help in surgical planning and discussions of prognosis.

Novel technique of switching TIVA and sevoflurane during epilepsy surgery for combined intraoperative motor evoked potentials monitoring and electrocorticography: an illustrative case report

BackgroundDuring epilepsy surgery, it is equally important to record electrocorticography (ECoG) for detecting epileptogenic activity and guiding brain resection, and to evaluate neuromonitoring data, particularly motor evoked potentials (MEP), for avoidance of postoperative neurological complications. However, sevoflurane, which is commonly used during recording of ECoG, may attenuate the MEP response. It enforces anesthesiologists and neurosurgeons to select one anesthetic agent over another, facilitating either ECoG or MEP monitoring.Case presentationIn the presented case of a 20-year-old man, who underwent surgery for temporal lobe epilepsy, a novel technique of neuroanesthesia was introduced, integrating initial induction of the total intravenous anesthesia (TIVA) with propofol (effect-site concentration, 2.3–3.0 μg/ml), its subsequent switching to sevoflurane (end-tidal concentration, 2.5%) for ECoG recording, and further change back to TIVA for MEP monitoring during brain resection.ConclusionsIntraoperative switch of anesthetic agents according to specific intraoperative requirements may be useful for cases of brain surgery requiring both ECoG recordings and MEP monitoring.

Resective surgery for mesial temporal lobe epilepsy associated with hippocampal sclerosis in patients over 50 years: a case-control study.

Mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE/HS) is the most common cause of drug-resistant focal seizures and surgical resection is the primary treatment option, with seizure-free rates ranging from 60 to 80%. However, data on postsurgical seizure outcomes in patients ≥ 50years of age are limited. This study aimed to assess the efficacy and safety of surgery in this age group compared to younger patients. We performed a retrospective analysis of data from resective surgeries conducted in patients with MTLE/HS between 1990 and 2022. We focused on patients aged ≥ 50years and compared the surgical safety and efficacy variables between this group and a control group of patients aged < 50years through a case-control study. Among the 450 MTLE/HS patients who underwent surgery during the inclusion period, 61 (13.6%) were aged ≥ 50years and matched with 183 younger patients, totaling 244 study participants. The two groups had similar characteristics. At the last follow-up (median 5.7years), Engel I outcomes were achieved in 80.3% of the older patients and 81.4% of the younger patients, with no significant difference (p = 0.85). Postoperative cognitive and psychiatric outcomes did not differ between the groups. Major complication rates were also comparable, at 3.3% in the older group and 2.7% in the younger group (p = 0.83). The extratemporal ictal abnormalities observed on video-EEG were the only variable that demonstrated a significant association with an unfavorable seizure outcome in the older group (OR 9.3, 95% CI [1.8-47.6], p = 0.005). This study provides grade 3 evidence that resective surgery for MTLE/HS patients aged ≥ 50years is as effective and safe as it is for younger patients, and thus should be considered as the primary treatment option for drug-resistant cases.

The Role of Preoperative Scalp Video-Electroencephalography and Intraoperative Electrocorticography in Mapping of Epileptogenic Zone in Temporal Lobe Epilepsy Surgery

The Role of Preoperative Scalp Video-Electroencephalography and Intraoperative Electrocorticography in Mapping of Epileptogenic Zone in Temporal Lobe Epilepsy Surgery

Hypometabolism in the Posteromedial Temporal and Medial Occipital Cortex on Preoperative 2-Deoxy-2-(18F) Fluoro-D-Glucose Positron Emission Tomography Suggests Exacerbation of Visual Field Defects After Surgery for Temporal Lobe Epilepsy: A Retrospective Long-Term Follow-Up Study

ObjectiveSurgery is a good treatment option for drug-resistant temporal lobe epilepsy (TLE). 2-deoxy-2-(18F) fluoro-D-glucose (FDG) positron emission tomography (PET) is used to detect epileptic foci as hypometabolic lesions in presurgical evaluation. Visual field defects (VFDs) in the contralateral homonymous upper quadrant are common postoperative complications in TLE. This study aimed to quantify VFDs using pattern deviation probability plots (PDPPs) and examine the effect of hypometabolism in FDG-PET on VFDs. MethodsThis study included 40 patients. Both visual fields were assessed using the Humphrey field analyzer (HFA) preoperatively and 3 months and 2 years postoperatively. PDPPs with <0.5% confidence level counted in the contralateral homonymous upper quadrant. FDG-PET results were compared between groups with (15 patients) and without (24 patients) hypometabolism in the optic radiation. ResultsAll 40 patients were evaluated by HFA at 3 months postoperatively and 39 at 2 years postoperatively. The incidence of VFDs 3 months postoperatively was 35/40 (87.5%), and 17/40 (42.5%) patients had severe VFDs. In cases of surgery on the left temporal lobe, ipsilateral eyes appeared to be more significantly affected than contralateral eyes. VFDs were more severe in patients with FDG hypometabolism than in those without hypometabolism in posteromedial temporal and medial occipital cortex (P < 0.01); however, 85% of patients with FDG hypometabolism had a reduced VFD 2 years postoperatively. ConclusionPDPP counting is useful for quantifying VFDs. Preoperative dysfunction indicated by preoperative FDG-PET in the posteromedial temporal and medial occipital cortex could enhance VFDs early after TLE surgery.

A PET-based radiomics nomogram for individualized predictions of seizure outcomes after temporal lobe epilepsy surgery

PurposeTo establish and validate a novel nomogram based on clinical characteristics and [18F]FDG PET radiomics for the prediction of postsurgical seizure freedom in patients with temporal lobe epilepsy (TLE). Patients and Methods234 patients with drug-refractory TLE patients were included with a median follow-up time of 24 months after surgery. The correlation coefficient redundancy analysis and LASSO Cox regression were used to characterize risk factors. The Cox model was conducted to develop a Clinic-PET nomogram to predict the relapse status in the training set (n = 171). The nomogram's performance was estimated through discrimination, calibration, and clinical utility. The prognostic prediction model was validated in the test set (n = 63). ResultsEight radiomics features were selected to assess the radiomics score (radscore) of the operation side (Lat_radscore) and the asymmetric index (AI) of the radiomics score (AI_radscore). AI_radscor, Lat_radscor, secondarily generalized seizures (SGS), and duration between seizure onset and surgery (Durmon) were significant predictors of seizure-free outcomes. The final model had a C-index of 0.68 (95 %CI: 0.59–0.77) for complete freedom from seizures and time-dependent AUROC was 0.65 at 12 months, 0.65 at 36 months, and 0.59 at 60 months in the test set. A web application derived from the primary predictive model was displayed for economic and efficient use. ConclusionsA PET-based radiomics nomogram is clinically promising for predicting seizure outcomes after temporal lobe epilepsy surgery.

Defining benchmark outcomes for mesial temporal lobe epilepsy surgery: A global multicenter analysis of 1119 cases.

Benchmarking has been proposed to reflect surgical quality and represents the highest standard reference values for desirable results. We sought to determine benchmark outcomes in patients after surgery for drug-resistant mesial temporal lobe epilepsy (MTLE). This retrospective multicenter study included patients who underwent MTLE surgery at 19 expert centers on five continents. Benchmarks were defined for 15 endpoints covering surgery and epilepsy outcome at discharge, 1 year after surgery, and the last available follow-up. Patients were risk-stratified by applying outcome-relevant comorbidities, and benchmarks were calculated for low-risk ("benchmark") cases. Respective measures were derived from the median value at each center, and the 75th percentile was considered the benchmark cutoff. A total of 1119 patients with a mean age (range) of 36.7 (1-74) years and a male-to-female ratio of 1:1.1 were included. Most patients (59.2%) underwent anterior temporal lobe resection with amygdalohippocampectomy. The overall rate of complications or neurological deficits was 14.4%, with no in-hospital death. After risk stratification, 377 (33.7%) benchmark cases of 1119 patients were identified, representing 13.6%-72.9% of cases per center and leaving 742 patients in the high-risk cohort. Benchmark cutoffs for any complication, clinically apparent stroke, and reoperation rate at discharge were ≤24.6%, ≤.5%, and ≤3.9%, respectively. A favorable seizure outcome (defined as International League Against Epilepsy class I and II) was reached in 83.6% at 1 year and 79.0% at the last follow-up in benchmark cases, leading to benchmark cutoffs of ≥75.2% (1-year follow-up) and ≥69.5% (mean follow-up of 39.0 months). This study presents internationally applicable benchmark outcomes for the efficacy and safety of MTLE surgery. It may allow for comparison between centers, patient registries, and novel surgical and interventional techniques.

Mass Spectrometric Imaging of Anionic Phospholipids Desorbed from Human Hippocampal Sections: Discrimination between Temporal and Nontemporal Lobe Epilepsies.

Temporal lobe epilepsy (TLE) is one of the most common neurological disorders, often accompanied by hippocampal sclerosis. The molecular processes underlying this epileptogenesis are poorly understood. To examine the lipid profile, 39 fresh frozen sections of the human hippocampus obtained from epilepsy surgery for TLE (n = 14) and non-TLE (control group; n = 25) patients were subjected to desorption electrospray ionization mass spectrometry imaging in the negative ion mode. In contrast to our earlier report that showed striking downregulation of positively charged phospholipids (e.g., phosphatidylcholine and phosphatidylethanolamine, etc.) in the TLE hippocampus, this study finds complementary upregulation of negatively charged phospholipids, notably, phosphatidylserine and phosphatidylglycerol. This result may point to an active metabolic pool in the TLE hippocampus that produces these anionic phospholipids at the expense of the cationic phospholipids. This metabolic shift could be due to the dysregulation of the Kennedy and CDP-DG pathways responsible for biosynthesizing these lipids. Thus, this study further opens up opportunities to investigate the molecular hallmarks and potential therapeutic targets for TLE.

Predictive Effect of Preoperative Abdominal and Emotional Aura on Temporal Lobe Epilepsy Surgery

Objective: Temporal lobe epilepsy surgery is the most common type of epilepsy surgery. This study evaluates the relationship between preoperative auras and surgical prognosis. Materials and Methods: The follow-up data of 100 patients who underwent anterior temporal lobectomy surgery after 2 years was reviewed. The patients were divided into two groups based on the presence or absence of abdominal-emotional (AE) aura. Each patient was evaluated with a detailed history, video-electroencephalography (EEG), neuroimaging, and postsurgical outcomes according to Engel classification to predict postsurgical seizure freedom. Results: After 2 years of follow-up, 71 patients were seizure-free, Based on aura types, univariate analysis showed that the age of disease onset and history of febrile convulsion were higher in the AE (+) group (p=0.013, p&lt;0.001). Additionally, MTS was more frequently observed in the MRI, MRS, and pathology results (p= &lt;0.001, p=0.01, p=0.009). No correlation was found between the presence or type of aura and postoperative seizure-free state. Conclusion: Our results showed that the presence or type of aura had no prognostic significance for seizure freedom after TLE surgery. However, further studies with larger patient numbers are needed to confirm these findings.

Verbal episodic memory in children undergoing temporal lobe epilepsy surgery: a one-year follow-up study.

Verbal episodic memory (VEM) is often unimpaired in children with focal epilepsy undergoing left temporal lobe resections, unlike what we might expect in the adult brain. The latter findings suggest that epileptiform activity in early life disrupts memory system lateralization, leading to the development of bilateral memory representation. The present study aims to analyze whether the laterality of epilepsy is a major predictor for post-operative VEM prognosis in pediatric temporal lobe epilepsy (TLE) surgery. This research also pretends to provide evidence about the relationship of VEM performance with other relevant demographical and clinical factors such as sex, age at onset of seizures, age at surgery and duration of epilepsy, as well as to study the impact of presurgical VEM performance on postsurgical outcomes. Pre-operative and one-year follow-up post-operative word-list recall scores from 25 children who underwent TLE surgery (left-sided, n = 11; right-sided, n = 14) were extracted from the Hospital Sant Joan de Deu database and were retrospectively analyzed. No significant presurgical intergroup differences were found when comparing VEM scores by laterality of epilepsy (p > 0.5). Looking at the left TLE group, a high negative correlation was found between the onset age and the pre-operative long-term free recall score (rho = -0.72, p = 0.01). No significant pre- to post-operative intragroup changes were found regarding VEM performance, regardless of epilepsy laterality (left TLE group, p > 0.56; right TLE group, p > 0.12). The laterality of epilepsy does not show to be a significant factor in and of itself regarding presurgical VEM outcome and its prognosis one year after surgery, thus supporting the bilateral memory representation hypothesis. Furthermore, a younger age at onset of seizures seems to be related with a better pre-operative VEM performance, likely due to a more efficient reorganization of memory system induced by a greater brain plasticity at lower ages; however, this relationship has been only reported for the left-sided epilepsies in our sample.

An exploration of anomia rehabilitation in drug-resistant temporal lobe epilepsy

Around 40% of patients who undergo a left temporal lobe epilepsy (LTLE) surgery suffer from anomia (word-finding difficulties), a condition that negatively impacts quality of life. Despite these observations, language rehabilitation is still understudied in LTLE. We assessed the effect of a four-week rehabilitation on four drug-resistant LTLE patients after their surgery. The anomia rehabilitation was based on cognitive descriptions of word finding deficits in LTLE. Its primary ingredients were psycholinguistic tasks and a psychoeducation approach to help patients cope with daily communication issues. We repeatedly assessed naming skills for trained and untrained words, before and during the therapy using an A-B design with follow-up and replication. Subjective anomia complaint and standardized language assessments were also collected. We demonstrated the effectiveness of the rehabilitation program for trained words despite the persistence of seizures. Furthermore, encouraging results were observed for untrained items. Variable changes in anomia complaint were observed. One patient who conducted the protocol as self-rehabilitation responded similarly to the others, despite the different manner of intervention. These results open promising avenues for helping epileptic patients suffering from anomia. For example, this post-operative program could easily be adapted to be conducted preoperatively.

32 Prediction of Seizure Outcome with Presurgical IAT, MRI, and PET in Patients with Temporal Lobe Epilepsy Undergoing Surgery

Objective:Anterior temporal lobectomy is a common surgical approach for medication-resistant temporal lobe epilepsy (TLE). Prior studies have shown inconsistent findings regarding the utility of presurgical intracarotid sodium amobarbital testing (IAT; also known as Wada test) and neuroimaging in predicting postoperative seizure control. In the present study, we evaluated the predictive utility of IAT, as well as structural magnetic resonance imaging (MRI) and positron emission tomography (PET), on long-term (3-years) seizure outcome following surgery for TLE.Participants and Methods:Patients consisted of 107 adults (mean age=38.6, SD=12.2; mean education=13.3 years, SD=2.0; female=47.7%; White=100%) with TLE (mean epilepsy duration =23.0 years, SD=15.7; left TLE surgery=50.5%). We examined whether demographic, clinical (side of resection, resection type [selective vs. non-selective], hemisphere of language dominance, epilepsy duration), and presurgical studies (normal vs. abnormal MRI, normal vs. abnormal PET, correctly lateralizing vs. incorrectly lateralizing IAT) were associated with absolute (cross-sectional) seizure outcome (i.e., freedom vs. recurrence) with a series of chi-squared and t-tests. Additionally, we determined whether presurgical evaluations predicted time to seizure recurrence (longitudinal outcome) over a three-year period with univariate Cox regression models, and we compared survival curves with Mantel-Cox (log rank) tests.Results:Demographic and clinical variables (including type [selective vs. whole lobectomy] and side of resection) were not associated with seizure outcome. No associations were found among the presurgical variables. Presurgical MRI was not associated with cross-sectional (OR=1.5, p=.557, 95% CI=0.4-5.7) or longitudinal (HR=1.2, p=.641, 95% CI=0.4-3.9) seizure outcome. Normal PET scan (OR= 4.8, p=.045, 95% CI=1.0-24.3) and IAT incorrectly lateralizing to seizure focus (OR=3.9, p=.018, 95% CI=1.2-12.9) were associated with higher odds of seizure recurrence. Furthermore, normal PET scan (HR=3.6, p=.028, 95% CI =1.0-13.5) and incorrectly lateralized IAT (HR= 2.8, p=.012, 95% CI=1.2-7.0) were presurgical predictors of earlier seizure recurrence within three years of TLE surgery. Log rank tests indicated that survival functions were significantly different between patients with normal vs. abnormal PET and incorrectly vs. correctly lateralizing IAT such that these had seizure relapse five and seven months earlier on average (respectively).Conclusions:Presurgical normal PET scan and incorrectly lateralizing IAT were associated with increased risk of post-surgical seizure recurrence and shorter time-to-seizure relapse.

Performance of hippocampal radiomics models based on T2-FLAIR images in mesial temporal lobe epilepsy with hippocampal sclerosis

PurposePreoperative identification of hippocampal sclerosis (HS) is crucial to successful surgery for mesial temporal lobe epilepsy (MTLE). We aimed to investigate the diagnostic performance of hippocampal radiomics models based on T2 fluid-attenuated inversion recovery (FLAIR) images in MTLE with HS. MethodsWe analysed 210 cases, including 172 HS pathology-confirmed cases (100 magnetic resonance imaging [MRI]-positive cases [MRI + HS], 72 MRI-negative HS cases [MRI − HS]), and 38 healthy controls (HC). The hippocampus was delineated slice by slice on an oblique coronal plane by a T2-FLAIR sequence, perpendicular to the hippocampus’s long axis, to obtain a three-dimensional region of interest. Radiomics were processed using Artificial Intelligence Kit software; logistic regression radiomics models were constructed. The model evaluation indexes included the area under the curve (AUC), accuracy, sensitivity, and specificity. ResultsThe respective AUC, accuracy, sensitivity, and specificity were 0.863, 81.4%, 78.0%, and 84.6% between the MRI − HS and HC groups in the training set and 0.855, 75.0%, 68.2%, and 81.8% in the test set; 0.975, 95.0%, 92.9%, and 98.0% between the MRI + HS and HC groups in the training set and 0.954, 88.7%, 90.0%, and 87.0% in the test set; and 0.912, 84.3%, 83.3%, and 86.5% between the MTLE and HC groups in the training set and 0.854, 79.7%, 80.8%, and 77.3% in the test set. The AUC values of the comparative radiomics models were > 0.85, indicating good diagnostic efficiency. ConclusionThe hippocampal radiomics models based on T2-FLAIR images can help diagnose MTLE with HS. They can be used as biological markers for MTLE diagnosis.

Temporal Lobe Surgery for Epilepsy in a Resource-Limited Vietnamese Cohort

Epilepsy surgery is traditionally difficult to pursue in resource-limited countries but is nevertheless essential in the treatment of medication-refractory, surgically amenable epilepsy. With the help of international collaboration, a successful epilepsy program was started in Vietnam. This article comprises a retrospective chart review, combined with prospective longitudinal follow-up of 35 cases of unilateral drug-resistant epilepsy in the temporal lobe who underwent temporal lobectomy, in Viet Duc University Hospital from May 2018 to September2022. The female/male ratio was 0.6:1, and focal seizures with impaired awareness accounted for 97.14% of patients. Of patients with focal awareness seizures, 51.41% were localized and detected by electroencephalography. Postoperatively, 80% of patients were seizure free (Engel I) at 1 year, and the remaining 20% had worthwhile seizure improvement (Engel II). Postoperative temporal lobe pathology was categorized as follows: mesial temporal sclerosis (48.57%), focal cortical dysplasia (25.71%), and low-grade neoplasms (25.71%). Of patients, 17.14% had postoperative complications (5 infections and 1 transient extremity paresis), and there were no deaths. Even in low-resource environments, effective and safe surgical care can be provided for drug-resistant epilepsy caused by temporal lobe disease. This study serves as a model of international collaboration and support for future hospitals in low-resource environments to replicate.

Psychiatric changes after stereotactic laser amygdalohippocampotomy for medial temporal lobe epilepsy

PurposeStereotactic laser amygdalohippocampotomy (SLAH) is a minimally invasive surgical treatment for drug-resistant temporal lobe epilepsy (TLE) that has comparable rates of seizure freedom to traditional open resective TLE surgery. The objective of this study was to determine psychiatric outcome (i.e., depression and anxiety changes, psychosis) after SLAH, to explore possible contributory factors to these changes, and to determine the prevalence of de novo psychopathology. MethodsWe explored mood and anxiety in 37 adult patients with TLE undergoing SLAH using the Beck psychiatric symptoms scales (i.e., Beck Depression Inventory-II [BDI-II] and Beck Anxiety Inventory [BAI]) preoperatively and 6 months following surgery. Multivariable regression analysis was conducted to identify predictors of worse depression or anxiety symptoms following SLAH. The prevalence of de novo psychopathology following SLAH was also determined. ResultsWe found a significant decrease in BDI-II (mean decline from 16.3 to 10.9, p = 0.004) and BAI (mean decline from 13.3 to 9.0, p = 0.045) scores following SLAH at the group level.While the rate of resolution of depression (from 62% to 49%) did not achieve statistical significance (p = 0.13, McNemar’s), the rate of resolution of anxiety (from 57% to 35%) was statistically significant (p = 0.03, McNemar’s). The de novo rate of psychopathology (i.e., new onset depression or anxiety) following SLAH was 1 of 7 (14%). Using a metric of meaningful change rather than complete symptom resolution, 16 of 37 (43%) patients experienced improvement in depression and 6 of 37 (16%) experienced worsening. For anxiety, 14 of 37 (38%) experienced meaningful improvement and 8 of 37 (22%) experienced worsening. Baseline performance on the Beck Scales was the only factor contributing to outcome status. DiscussionIn one of the first studies to evaluate psychiatric outcomes after SLAH, we found promising overall trends toward stability or significant improvement in symptom burden at the group level for both depression and anxiety. There was also a significant improvement in clinical anxiety, though the decrease in clinical depression was not significant, likely owing to the limitations of sample size. SLAH may improve overall psychiatric symptoms, similarly to traditional resective TLE surgery, but de novo psychopathology and postoperative psychiatric morbidity remain significant issues, and larger samples are necessary to determine causal contributory factors.

SHORT-TERM SURGICAL OUTCOMES IN PATIENTS WITH DRUG-RESISTANT EPILEPSY DUE TO LESIONAL TEMPORA

Objectives: To describe the outcome of 35 cases of drug-resistant epilepsy due to the lesional temporal lobe surgery at Vietduc University Hospital from May 2018 to September 2022. Methods: A prospective description combined with retrospective, longitudinal follow-up of all patients diagnosed with drug resistance due to lesional temporal lobe epilepsy undergoing surgery at Vietduc University Hospital was conducted. Results: 35 cases of intractable lesional temporal lobe epilepsy surgery, male/female 1.5/1, partial seizures with loss of consciousness accounted for 99%, and 2/3 of cases occurred without aura. Seizure-free (post-operation 1 month) (Engel I) accounted for 74.3%, and the remaining (25.7%) had improved seizures (Engel 2, 3). Complications after surgery accounted for 17.1%, and there were no cases of death. Conclusion: Surgical treatment for drug resistance due to lesional temporal lobe epilepsy is safe and very effective, with a low complication rate.

Long-term Remission and Resolution of Epilepsy following Surgery for Drug Resistant Lesional Temporal Lobe Epilepsy. (P2-1.001)

<h3>Objective:</h3> To determine the long-term seizure freedom and resolution of epilepsy in patients with drug resistant Temporal Lobe Epilepsy (TLE) and a clear-cut MRI lesion. <h3>Background:</h3> The long-term seizure free outcomes following surgery for TLE varied widely from 41% – 80% following surgery for TLE. <h3>Design/Methods:</h3> In a retrospective, longitudinal cohort study, we analysed the presurgical, surgical and post-surgical parameters to determine the seizure freedom and resolution of epilepsy in patients with ‘drug resistant lesional TLE with at least 10 years or more of post-surgery follow-up. The Study period was from June 2001 to 2012 <h3>Results:</h3> Of the 259 patients who formed the study population, 46% were women. The duration of follow-up ranged from 10 to 21 years. The average age at surgery was 25.80 ± 11.32 yrs; 49% had an aura, 61% had only hypomotor seizures and 38% had psychiatric comorbidity. The commonest pathology was hippocampal sclerosis(70%) followed by tumoral lesions and focal cortical dysplasia; 9.8% had acute post-operative seizures. At latest follow-up 75.6% were seizure free of which 52% had resolution of epilepsy. Presence of an aura , hippocampal sclerosis and longer time to first post-operative seizure were strong predictors for resolution of epilepsy while acute post-operative seizures and an abnormal post-surgery EEG at 1 year were predictors of persistent seizures. On survival analysis, the time to first seizure was significantly early in patients with persistent seizures. Seizure freedom both at three and five years predicted seizure freedom at 10 years. <h3>Conclusions:</h3> Resective surgery for drug resistant lesional TLE was associated with higher rate of seizure-freedom in ~75% and resolution of epilepsy in 52.15% even at long term follow-up. Longer time to first seizure, presence of aura at presentation and hippocampal sclerosis are strong predictors for resolution of epilepsy. APOS and abnormal Post-Surgery inter-ictal EEG are predictors of unfavourable outcome. <b>Disclosure:</b> Dr. Sattaluri has nothing to disclose. Dr. Patil has nothing to disclose. Dr. Choudhary has nothing to disclose. Dr. Vooturi has nothing to disclose.

Distinguishing TLE and TLE+ using magnetoencephalography virtual sensors (P8-9.010)

<h3>Objective:</h3> This study observes whether user-defined virtual sensors (UDvs) beamforming, using expert reader analysis, is superior to the conventional equivalent current dipole (ECD) for non-invasively differentiating between TLE and TLE+. This could result in decreased failure rates in temporal lobe epilepsy surgery and improved seizure-free outcomes. <h3>Background:</h3> Temporal lobe epilepsy (TLE) is the most common seizure disorder. 44% of TLE+ pediatric patients that undergo resective surgery fail to achieve seizure freedom. It is imperative to identify TLE vs TLE+ in children pre-surgically, since the invasive monitoring plan to identify the seizure onset zone (SOZ) would differ. <h3>Design/Methods:</h3> Ten patients who underwent magnetoencephalography (MEG) as part of non-invasive pre-surgical evaluation and intracranial electroencephalography (iEEG) monitoring were included in this retrospective analysis. Five patients each were assigned to two groups: TLE and TLE+. Virtual sensors were placed symmetrically in the bilateral mesial temporal structures, temporal gyri, and neighboring structures. We reconstructed virtual sensor waveforms and analyzed three ten-minute segments of MEG recordings to classify them as positive or negative for epileptiform activity. A chart review of iEEG data was also classified as either positive or negative spikes. The primary analysis calculated the sensitivity and specificity of each method to determine the predictive value of UDvs-beamforming. <h3>Results:</h3> Ten patients (mean age 9.8 ± 4.2 years) with TLE or TLE+ were included. Across the ten patients, the UDvs method had a mean sensitivity of 93.1% and specificity of 53.3% compared to the ECD method which had a sensitivity of 71.1% and specificity of 88.3% (P = 0.031, 0.002). <h3>Conclusions:</h3> The ECD method has greater specificity than UDvs while UDvs had greater sensitivity than ECD in determining the presence of interictal epileptic spikes compared to the gold standard, iEEG. Future work will examine increasing sample size, performing connectivity analysis of interictal spikes, and correlating surgical resection with patient outcomes. <b>Disclosure:</b> Miss Hong has nothing to disclose. The institution of Paul Horn has received research support from NIH. Dr. Tenney has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Wilson Smith Cochran Dickerson. The institution of Dr. Tenney has received research support from NIH.

Remote effects of temporal lobe epilepsy surgery: Long-term morphological changes after surgical resection.

Epilepsy surgery is an effective treatment for drug-resistant patients. However, how different surgical approaches affect long-term brain structure remains poorly characterized. Here, we present a semiautomated method for quantifying structural changes after epilepsy surgery and compare the remote structural effects of two approaches, anterior temporal lobectomy (ATL), and selective amygdalohippocampectomy (SAH). We studied 36 temporal lobe epilepsy patients who underwent resective surgery (ATL = 22, SAH = 14). All patients received same-scanner MR imaging preoperatively and postoperatively (mean 2 years). To analyze postoperative structural changes, we segmented the resection zone and modified the Advanced Normalization Tools (ANTs) longitudinal cortical pipeline to account for resections. We compared global and regional annualized cortical thinning between surgical treatments. Across procedures, there was significant cortical thinning in the ipsilateral insula, fusiform, pericalcarine, and several temporal lobe regions outside the resection zone as well as the contralateral hippocampus. Additionally, increased postoperative cortical thickness was seen in the supramarginal gyrus. Patients treated with ATL exhibited greater annualized cortical thinning compared with SAH cases (ATL: -0.08 ± 0.11 mm per year, SAH: -0.01 ± 0.02 mm per year, t = 2.99, P = 0.006). There were focal postoperative differences between the two treatment groups in the ipsilateral insula (P = 0.039, corrected). Annualized cortical thinning rates correlated with preoperative cortical thickness (r = 0.60, P < 0.001) and had weaker associations with age at surgery (r = -0.33, P = 0.051) and disease duration (r = -0.42, P = 0.058). Our evidence suggests that selective procedures are associated with less cortical thinning and that earlier surgical intervention may reduce long-term impacts on brain structure.