Temporal Lobe Resection Research Articles

Long-term memory plasticity in a decade-long connectivity study post anterior temporal lobe resection

Approximately 40% of individuals undergoing anterior temporal lobe resection for temporal lobe epilepsy experience episodic memory decline. There has been a focus on early memory network changes; longer-term plasticity and its impact on memory function are unclear. Our study investigates neural mechanisms of memory recovery and network plasticity over nearly a decade post-surgery. We assess memory network changes, from 3–12 months to 10 years postoperatively, in 25 patients (12 left-sided resections) relative to 10 healthy matched controls, using longitudinal task-based functional MRI and standard neuropsychology assessments. We observe key adaptive changes in memory networks of a predominantly seizure-free cohort. Ongoing neuroplasticity in posterior medial temporal regions and contralesional cingulum or pallidum contribute to long-term verbal and visual memory recovery. Here, we show the potential for sustained cognitive improvement and importance of strategic approaches in epilepsy treatment, advocating for conservative surgeries and long-term use of cognitive rehabilitation for ongoing recovery.

Object naming after epilepsy surgery in the dominant left temporal lobe: risk factors, time course and long-term outcome

BackgroundDeterioration in naming function is a common sequelae after epilepsy surgery in the language-dominant temporal lobe but information on recovery and long-term outcome is scarce. We, therefore, assessed short-term and...

SURG-14. PATTERNS OF PROGRESSION OF TEMPORAL LOBE GLIOBLASTOMAS: EVIDENCE FOR THE ROLE OF TEMPORAL LOBECTOMY

Abstract Glioblastomas extend beyond the contrast-enhancing tumor, and supramaximal resections into non-enhancing (NE) tumor improves survival. Yet, supramaximal resection is difficult to achieve in most cases. For temporal lobe tumors, supramaximal anterior temporal lobe resection is feasible and safe. Case series have shown a survival advantage by resecting the anterior temporal lobe. This study aims to explore patterns of tumor progression in temporal lobe glioblastomas and whether the presence of NE tumor in the temporal tip could be used as a biomarker to predict the site of progression. We searched a single institution tumor database looking for patients who had glioblastomas in the temporal lobe, who underwent complete resection of enhancing tumor, and went on to have chemoradiotherapy. Patients needed to have imaging demonstrating first progression. We determined pre-operatively if NE tumor had extended into the temporal tip. At progression, the direction of tumor progression was recorded and assessed if it would have been resected should a lobectomy have been performed. We identified 55 patients that fulfilled our entry criteria (mean age 57.7 years, range 19.6-72.9; 37 male). In 16 cases, the anterior temporal lobe was resected; these patients were not used in further assessments. In 25 cases (64.1%), the tumor progressed into the residual anterior temporal lobe. In 16 cases (41.0%), a lobectomy would have encompassed the area of progression. NE tumor was seen in the tip in 28 cases (71.8%). This could predict progression into the anterior temporal lobe with a sensitivity of 76.2% (95%CI: 54.9-90.6%) and specificity of 33.1% (95%CI: 11.8-61.6%). The likelihood ratio of tumor progression was 1.14 (95%CI: 0.75-1.74). We conclude that temporal lobe glioblastomas most commonly progress into the anterior temporal lobe, but NE tumor is not a suitable predictive biomarker. Developing suitable biomarkers and biomarker-driven trials of temporal lobectomy for glioblastomas are needed.

Long-term neuroplasticity in language networks after anterior temporal lobe resection.

Anterior temporal lobe resection (ATLR) is an effective treatment for drug-resistant temporal lobe epilepsy (TLE), although language deficits may occur after both left and right ATLR. Functional reorganization of the language network has been observed in the ipsilateral and contralateral hemispheres within 12 months after ATLR, but little is known of longer-term plasticity effects. Our aim was to examine the plasticity of language functions up to a decade after ATLR, in relation to cognitive profiles. We examined 24 TLE patients (12 left [LTLE]) and 10 controls across four time points: pre-surgery, 4 months, 12 months, and ~9 years post-ATLR. Participants underwent standard neuropsychological assessments (naming, phonemic, and categorical fluency tests) and a verbal fluency functional magnetic resonance imaging (fMRI) task. Using a flexible factorial design, we analyzed longitudinal fMRI activations from 12 months to ~9 years post-ATLR, relative to controls, with separate analyses for people with hippocampal sclerosis (HS). Change in cognitive profiles was correlated with the long-term change in fMRI activations to determine the "efficiency" of reorganized networks. LTLE patients had increased long-term engagement of the left extra-temporal and contralateral temporal regions, with better language performance linked to bilateral activation. Those with HS exhibited more widespread bilateral activations. RTLE patients showed plasticity in the left extra-temporal regions, with better language outcomes associated with these areas. Both groups of patients achieved cognitive stability over 9 years, with more than 50% of LTLE patients improving. Older age, longer epilepsy duration, and lower pre-operative cognitive reserve negatively affected long-term language performance. Neuroplasticity continues for up to ~9 years post-epilepsy surgery in LTLE and RTLE, with effective language recovery linked to bilateral engagement of temporal and extra-temporal regions. This adaptive reorganization is associated with improved cognitive outcomes, challenging the traditional view of localized surgery effects. These findings emphasize the need for early intervention, tailored pre-operative counseling, and the potential for continued cognitive gains with extended post-ATLR rehabilitation.

Amyloid deposition in adults with drug-resistant temporal lobe epilepsy.

Pathological amyloid-β (Aβ) accumulation and hyperphosphorylated tau proteins have been described in resected temporal lobe specimens of epilepsy patients. We aimed to determine cerebrospinal fluid (CSF) Aβ1-42 and p181-tau levels and cerebral Aβ deposits on positron emission tomography (Aβ PET) and correlate these findings with cognitive performance in adults with drug-resistant temporal lobe epilepsy (TLE). In this cross-sectional study, we enrolled individuals with drug-resistant TLE who were 25-55 years old. Each participant underwent 18F-flutemetamol PET, determination of CSF Aβ1-42, p181-tau, and total tau, and a comprehensive neuropsychological assessment. We evaluated normalized standard uptake value ratios (SUVRs) for different brain regions on Aβ PET. Thirty patients (mean age = 41.9 ± SD 8.1 years, 57% men) were included. The median disease duration was 9.5 (interquartile range = 4-24) years. Twenty-six patients (87%) had a clinically significant cognitive impairment on neuropsychological evaluation, 18 (69%) of the amnesic type. On Aβ PET, high uptake was observed in both mesial temporal regions (ipsilateral: SUVR z-score = .90, 95% confidence interval [CI] = .60-1.20; contralateral: SUVR z-score = .92, 95% CI = .57-1.27; p < .001), which was higher when compared to SUVR z-scores in all the remaining regions (p < .001) and in the ipsilateral anterior cingulate (SUVR z-score = .27, 95% CI = .04-.49, p = .020). No significant deposition was observed in other regions. Seven patients (23%) had low Aβ1-42 levels, and two (7%) had elevated p181-tau levels in CSF. Higher p181-tau levels correlated with poorer verbal fluency (R = -.427, p = .044). Our findings reveal a considerable Aβ deposition in mesial temporal regions and ipsilateral anterior cingulate among adults with drug-resistant TLE. Additionally, abnormal CSF Aβ1-42 levels were observed in a significant proportion of patients, and p181-tau levels were associated with verbal fluency. These results suggest that markers of neuronal damage can be observed in adults with TLE, warranting further investigation.

Temporal Lobe Surgery in Pediatric Patients: From Temporal Lobe Epilepsy to Temporal Plus Epilepsy

Purpose: Temporal lobe resection can be categorized as either temporal lobe epilepsy (TLE), which involves cortical resection confined to the temporal lobe, or temporal plus epilepsy (TPE), which entails temporal resection along with involvement of additional extratemporal regions. We compared these forms within a pediatric population.Methods: We identified 136 patients who underwent temporal resection over a 17-year period and investigated the differences in the clinical profiles and seizure outcomes between TLE and TPE.Results: Of the total sample, 110 patients (80.9%) presented with TLE and 26 (19.1%) with TPE. Significant differences were observed between the groups in age at seizure onset (TLE: 6.3 years, TPE: 0.9 years; P=0.001), age at epilepsy surgery (TLE: 14.2 years, TPE: 9.2 years; P=0.002), the proportion of patients with a history of infantile epileptic spasm syndrome (IESS) (TLE: 6 [5.5%], TPE: 8 [30.3%]; P&lt;0.001), electroclinical presentation with IESS or Lennox-Gastaut syndrome (LGS) (TLE: 11 [10.0%], TPE: 13 [50.0%]; P&lt;0.001), the presence of focal temporal hypometabolism on positron emission tomography (TLE: 74 [68.5%], TPE: 11 [44.0%], P=0.021), and the use of intracranial electroencephalogram monitoring (TLE: 58 [52.7%], TPE: 21 [80.8%]; P=0.009). Furthermore, multivariate analysis identified the epileptic presentation of IESS or LGS as a significant predictor of TPE (P=0.049). The rates of seizure outcomes of International League Against Epilepsy class 1–3 at 1 year of follow-up were 83.8% for the entire cohort, 89.1% for TLE, and 61.5% for TPE (P=0.002).Conclusion: TPE appears to represent a substantial subset of pediatric temporal resections. The variation in seizure outcomes between groups underscores the importance of predicting TPE in advance, with implications for effective treatment planning.

Machine learning algorithm for predicting seizure control after temporal lobe resection using peri-ictal electroencephalography

Brain resection is curative for a subset of patients with drug resistant epilepsy but up to half will fail to achieve sustained seizure freedom in the long term. There is a critical need for accurate prediction tools to identify patients likely to have recurrent postoperative seizures. Results from preclinical models and intracranial EEG in humans suggest that the window of time immediately before and after a seizure (“peri-ictal”) represents a unique brain state with implications for clinical outcome prediction. Using a dataset of 294 patients who underwent temporal lobe resection for seizures, we show that machine learning classifiers can make accurate predictions of postoperative seizure outcome using 5 min of peri-ictal scalp EEG data that is part of universal presurgical evaluation (AUC 0.98, out-of-group testing accuracy > 90%). This is the first approach to seizure outcome prediction that employs a routine non-invasive preoperative study (scalp EEG) with accuracy range likely to translate into a clinical tool. Decision curve analysis (DCA) shows that compared to the prevalent clinical-variable based nomogram, use of the EEG-augmented approach could decrease the rate of unsuccessful brain resections by 20%.

Seizure outcome in surgically treated pediatric gangliogliomas and dysembryoplastic neuroepitheliomas according to imaging and resection strategies

PurposeImaging and resection strategies for pediatric gangliogliomas (GG) and dysembryoplastic neuroepitheliomas (DNET) presenting with epilepsy were retrospectively analyzed in a consecutive institutional series of surgically treated patients. MethodsTwenty-two children (median 8 years, 3–18 years) presented with seizures for 30 months median (14–55.2 months) due to a histologically verified GG/DNET. ResultsThere were 20 GG and 2 DNT, 68 % located temporal, 32 % extra-temporal. Seizure history was significantly longer in temporal cases (38 versus 14 months median, p < 0.01). MRI contrast enhancement was present in 50 % and methionine (MET) positron emission tomography (PET) uptake in 70 % (standard uptake values (SUVs) 2.92 mean, from 1.6 to 6.4). 27 % had glucose PET hypometabolism. Primarily, in temporal GG, ECoG (electrocorticography) -guided lesionectomies were performed in 87 % and antero-mesial temporal lobe resections (AMTLR) in 13 %, whereas in extra-temporal GG/DNETs, lesionectomies were performed in 100 %. ILAE Class 1 seizure outcome was primarily achieved in 73 % of the temporal cases, and was increased to 93 % by performing six repeat surgeries using AMTLR. Extratemporal patients experienced ILAE Class 1 seizure outcomes in 86 % without additional surgeries, although harboring significantly more residual tumor (p < 0.005, mean follow-up 28 months). ConclusionIn children, MET PET imaging for suspected GG is proposed preoperatively showing a high diagnostic sensitivity and an option to delineate the lesions for navigated resection, whereas MRI contrast behavior was of no differential diagnostic use. As a surgical strategy we propose primarily lesionectomies for extratemporal but AMTLR for temporal GG respecting eloquent brain areas.

Giant unruptured middle cerebral artery aneurysm revealed by intracranial hypertension: is a systematic decompressive hemicraniotomy mandatory?

Our study aimed to evaluate the postoperative outcome of patients with unruptured giant middle cerebral artery (MCA) aneurysm revealed by intracranial hypertension associated to midline brain shift. From 2012 to 2022, among the 954 patients treated by a microsurgical procedure for an intracranial aneurysm, our study included 9 consecutive patients with giant MCA aneurysm associated to intracranial hypertension with a midline brain shift. Deep hypothermic circulatory flow reduction (DHCFR) with vascular reconstruction was performed in 4 patients and cerebral revascularization with aneurysm trapping was the therapeutic strategy in 5 patients. Early (< 7 days) and long term clinical and radiological monitoring was done. Good functional outcome was considered as mRS score ≤ 2 at 3 months. The mean age at treatment was 44 yo (ranged from 17 to 70 yo). The mean maximal diameter of the aneurysm was 49 mm (ranged from 33 to 70 mm). The mean midline brain shift was 8.6 mm (ranged from 5 to 13 mm). Distal MCA territory hypoperfusion was noted in 6 patients. Diffuse postoperative cerebral edema occurred in the 9 patients with a mean delay of 59 h and conducted to a postoperative neurological deterioration in 7 of them. Postoperative death was noted in 3 patients. Among the 6 survivors, early postoperative decompressive hemicraniotomy was required in 4 patients. Good functional outcome was noted in 4 patients. Complete aneurysm occlusion was noted in each patient at last follow-up. We suggest to discuss a systematic decompressive hemicraniotomy at the end of the surgical procedure and/or a partial temporal lobe resection at its beginning to reduce the consequences of the edema reaction and to improve the postoperative outcome of this specific subgroup of patients. A better intraoperative assessment of the blood flow might also reduce the occurrence of the reperfusion syndrome.

Predictors of long-term memory and network connectivity 10 years after anterior temporal lobe resection.

Anterior temporal lobe resection (ATLR) effectively controls seizures in medically refractory temporal lobe epilepsy but risks significant episodic memory decline. Beyond 1 year postoperatively, the influence of preoperative clinical factors on episodic memory and long-term network plasticity remain underexplored. Ten years post-ATLR, we aimed to determine biomarkers of successful memory network reorganization and establish presurgical features' lasting impact on memory function. Twenty-five ATLR patients (12 left-sided) and 10 healthy controls underwent a memory-encoding functional magnetic resonance imaging paradigm alongside neuropsychometry 10 years postsurgery. Generalized psychophysiological interaction analyses modeled network functional connectivity of words/faces remembered, seeding from the medial temporal lobes (MTLs). Differences in successful memory connectivity were assessed between controls and left/right ATLR. Multivariate regressions and mixed-effect models probed preoperative phenotypes' effects on long-term memory outcomes. Ten years post-ATLR, lower baseline functioning (verbal and performance intelligence quotient) and a focal memory impairment preoperatively predicted worse long-term memory outcomes. Poorer verbal memory was significantly associated with longer epilepsy duration and earlier onset age. Relative to controls, successful word and face encoding involved increased functional connectivity from both or remnant MTL seeds and contralesional parahippocampus/hippocampus after left/right ATLR. Irrespective of surgical laterality, successful memory encoding correlated with increased MTL-seeded connectivity to frontal (bilateral insula, right anterior cingulate), right parahippocampal, and bilateral fusiform gyri. Ten years postsurgery, better memory performance was correlated with contralateral frontal plasticity, which was disrupted with longer epilepsy duration. Our findings underscore the enduring nature of functional network reorganizations to provide long-term cognitive support. Ten years post-ATLR, successful memory formation featured stronger connections near resected areas and contralateral regions. Preoperative network disruption possibly influenced effectiveness of postoperative plasticity. These findings are crucial for enhancing long-term memory prediction and strategies for lasting memory rehabilitation.

Cisternal, vascular, and parenchymal landmarks in amygdalohippocampectomy for mesial temporal sclerosis: an index case with learnings from 820 resections.

Cortico-amygdalo-hippocampectomy is the most common epilepsy surgery resection in adults and offers excellent outcomes. Seizure outcome benefits range from 75% to 88% with a 2%-4% adverse event rate. The safety profile and outcomes could be enhanced further by clearly defining key surgical landmarks that could also aid tumoral resections in the mesial temporal lobe and selective mesial resections. The authors present their learnings of intraoperative landmarks (cisternal, parenchymal, and vascular) and surgical substeps through an index case of cortico-amygdalo-hippocampectomy with lessons from 820 resections. The video can be found here: https://stream.cadmore.media/r10.3171/2024.4.FOCVID2428.

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

Despite the benefits of anterior temporal lobectomy with amygdalohippocampectomy in patients with temporal lobe epilepsy (TLE), approximately up to 5% may have hemiparesis as its postoperative complication. This paper aims to describe which step/s of the anterior temporal lobectomy with amygdalohippocampectomy have the highest probability of having the greatest decrease in motor evoked potential (MEP) amplitude. This study used a cross-sectional design of obtaining data from TLE patients who underwent anterior temporal lobectomy with amygdalohippocampectomy with transcranial MEP monitoring. Each of the following steps were evaluated for reduction in MEP amplitude: 1) dural opening, 2) opening the inferior horn, 2) vertical temporal lobe resection 3) subpial dissection, 4) temporal lobe stem resection, 5) lateral temporal lobe resection, 6) hippocampal resection, 7) amygdala resection, 8) uncus resection, and 9) dural closure. Nineteen patients were included in the study. Based on the Friedman Test, 1 or more steps had significantly different average MEP amplitude reductions (Friedman= 50.7, P= 0.0001). When compared with baseline (100%, cutoff P= 0.005), hippocampal resection (z= -3.81, P < 0.0001), T1 subpial dissection (z= -3.2, P= 0.0010), uncus resection (z= -3.48, P= 0.0002), temporal stem resection (z= -3.26, P= 0.001), lateral temporal lobe resection (z= -3.13, P= 0.002), and amygdalectomy (-z= -3.37, P= 0.0005) were significantly lower. Of these, hippocampal resection, uncus resection, and amygdalectomy were deemed highly significant. MEP amplitude tends to decrease during amygdala, hippocampal, and uncal resection because of surgical manipulation of anterior choroidal arteries, which can potentially cause hemiparesis. Careful attention should be paid to changes in MEP during these steps.

Naming assessment in bilinguals for epilepsy surgery-adaptation and standardization of Boston Naming Test in India

Purpose Naming difficulty is associated with temporal lobe epilepsy and a decline in naming ability is reported following dominant temporal lobe resections. The Boston Naming Test (BNT) is the most frequently used test for assessing naming ability. Evaluating naming ability in bilingual/multilingual populations is a challenge when participants are restricted to responding in one language. The study aimed to adapt and standardize the BNT as a valid clinical tool for evaluating bilingual/multilingual people undergoing epilepsy surgery in urban India. Results Culture-appropriate adaptations were done, and participants were allowed to respond in any language. Data from 197 participants showed a strong education effect. The adaptation showed strong internal consistency, reliability, construct validity, and high sensitivity to left temporal lobe epilepsy performance. Conclusions The adapted version that allowed for flexible use of more than one language is a useful clinical tool for evaluating bilingual people undergoing epilepsy surgery.

Naming fMRI-guided white matter language tract volumes influence naming decline after temporal lobe resection

ObjectiveThe aim of this study was to explore the relation of language functional MRI (fMRI)-guided tractography with postsurgical naming decline in people with temporal lobe epilepsy (TLE).MethodsTwenty patients with unilateral TLE (9 left) were studied with auditory and picture naming functional MRI tasks. Activation maxima in the left posterobasal temporal lobe were used as seed regions for whole-brain fibre tractography. Clinical naming performance was assessed preoperatively, 4 months, and 12 months following temporal lobe resection. Volumes of white matter language tracts in both hemispheres as well as tract volume laterality indices were explored as moderators of postoperative naming decline using Pearson correlations and multiple linear regression with other clinical variables.ResultsLarger volumes of white matter language tracts derived from auditory and picture naming maxima in the hemisphere of subsequent surgery as well as stronger lateralization of picture naming tract volumes to the side of surgery correlated with greater language decline, which was independent of fMRI lateralization status. Multiple regression for picture naming tract volumes was associated with a significant decline of naming function with 100% sensitivity and 93% specificity at both short-term and long-term follow-up.InterpretationNaming fMRI-guided white matter language tract volumes relate to postoperative naming decline after temporal lobe resection in people with TLE. This can assist stratification of surgical outcome and minimize risk of postoperative language deficits in TLE.

1139 Retrospective Review of Stereotactic Electroencephalogram Recordings in Temporal Lobectomy Patients Demonstrates the Predictive Value of Interictal Cross-frequency Correlations

INTRODUCTION: Positive correlations between low and high frequency spectra in invasive electroencephalogram (EEG) have been implicated in pathological brain activity interictally and have been used for ictal detection in both focal and network models. METHODS: We retrospectively analyzed interictal signals from 22 patients who underwent SEEG at our institution between 12/2/14 to 12/8/20. We then analyzed significant HG/Beta cross-frequency correlations using similar processing to our previous publication. These signals were then separated based on temporal and extra-temporal locations. We further evaluated any statistical differences between the seizure free (SF) and non-seizure free (NSF) groups, and mesial (M) versus mesial temporal-plus (M+) onset location. RESULTS: 1) Clinical recordings from SEEG electrodes can detect cross-frequency correlations between HG/Beta using our previous methodology. 2) Positive correlations are significantly increased in temporal versus other sampled areas. 3) Positive correlations are more predictive of seizure onset during asleep recordings. 4) NSF patients show a significantly higher proportion of positive electrodes in the resected temporal lobe than SF patients. 5) SF patients have a greater proportion of significant contacts in the mesial versus the lateral temporal lobe than NSF patients. 6) Significant HG/Beta correlations in the mesial versus lateral temporal lobe predict seizure freedom better than ictal SEEG localization of seizure onset to M or M+ locations. CONCLUSIONS: We present preliminary data that local HG/Beta correlations may be predictive for epilepsy focus and surgical outcome and may have utility as adjunct methods to conventional SEEG analysis. Further studies are needed to determine strategies for prospective studies and clinical use.

Impaired Response to Mismatch Novelty in the Li2+-Pilocarpine Rat Model of TLE: Correlation with Hippocampal Monoaminergic Inputs.

Novelty detection, crucial to episodic memory formation, is impaired in epileptic patients with mesial temporal lobe resection. Mismatch novelty detection, that activates the hippocampal CA1 area in humans and is vital for memory reformulation and reconsolidation, is also impaired in patients with hippocampal lesions. In this work, we investigated the response to mismatch novelty, as occurs with the new location of known objects in a familiar environment, in the Li2+-pilocarpine rat model of TLE and its correlation with hippocampal monoaminergic markers. Animals showing spontaneous recurrent seizures (SRSs) for at least 4 weeks at the time of behavioural testing showed impaired spatial learning in the radial arm maze, as described. Concurrently, SRS rats displayed impaired exploratory responses to mismatch novelty, yet novel object recognition was not significantly affected in SRS rats. While the levels of serotonin and dopamine transporters were mildly decreased in hippocampal membranes from SRS rats, the levels on the norepinephrine transporter, tyrosine hydroxylase and dopamine-β-hydroxylase were enhanced, hinting for an augmentation, rather than an impairment in noradrenergic function in SRS animals. Altogether, this reveals that mismatch novelty detection is particularly affected by hippocampal damage associated to the Li2+-pilocarpine model of epilepsy 4-8 weeks after the onset of SRSs and suggests that deficits in mismatch novelty detection may substantially contribute to cognitive impairment in MTLE. As such, behavioural tasks based on these aspects of mismatch novelty may prove useful in the development of cognitive therapy strategies aiming to rescue cognitive deficits observed in epilepsy.

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.

Polygenic burden and its association with baseline cognitive function and postoperative cognitive outcome in temporal lobe epilepsy

ObjectiveDemographic and disease factors are associated with cognitive deficits and postoperative cognitive declines in adults with pharmacoresistant temporal lobe epilepsy (TLE), but the role of genetic factors in cognition in TLE is not well understood. Polygenic scores (PGS) for neurological and neuropsychiatric disorders and IQ have been associated with cognition in patient and healthy populations. In this exploratory study, we examined the relationship between PGS for Alzheimer’s disease (AD), depression, and IQ and cognitive outcomes in adults with TLE. Methods202 adults with pharmacoresistant TLE had genotyping and completed neuropsychological evaluations as part of a presurgical work-up. A subset (n = 116) underwent temporal lobe resection and returned for postoperative cognitive testing. Logistic regression was used to determine if PGS for AD, depression, and IQ predicted baseline domain-specific cognitive function and cognitive phenotypes as well as postoperative language and memory decline. ResultsNo significant findings survived correction for multiple comparisons. Prior to correction, higher PGS for AD and depression (i.e., increased genetic risk for the disorder), but lower PGS for IQ (i.e., decreased genetic likelihood of high IQ) appeared possibly associated with baseline cognitive impairment in TLE. In comparison, higher PGS for AD and IQ appeared as possible risk factors for cognitive decline following temporal lobectomy, while the possible relationship between PGS for depression and post-operative cognitive outcome was mixed. SignificanceWe did not observe any relationships of large effect between PGS and cognitive function or postsurgical outcome; however, results highlight several promising trends in the data that warrant future investigation in larger samples better powered to detect small genetic effects.

Surgical Outcome of Pharmaco Refractory Epilepsy in the National Epilepsy Center of Sri Lanka

IntroductionThe National Epilepsy Center (NEC) in Sri Lanka was established in 2017. Seizure outcome, effects on quality of life (QOL) and surgical complications among non-pediatric patients who underwent epilepsy surgery from October 2017 to February 2023 are described. Material and methodsNineteen patients (≥14 years) underwent epilepsy surgery at the NEC. We used Engel classification and Quality of Life in Epilepsy 31 (QOLIE-31) questionnaire to assess seizure outcome and QOL respectively. Surgical complications were categorized into neurological and complications related to surgery. ResultsNine female and 10 male patients underwent surgery (mean age 27.5 years (range 14-44years). The mean follow-up duration was 10.5 months (range 6-55 months). Twelve patients underwent temporal lobe resections. At 6-months follow-up, 83.3% (10/12) had favorable seizure outcomes with Engel class I/II. At 1-year follow-up 6/8 patients (75.0 %) and at 2-year follow-up, 5/7 patients (71.4%) had a favorable outcome. Seven patients had extra-temporal lobe surgeries and one defaulted. Seizure freedom was observed in 6/6 at 6 months, 3/3 at one-year, and 2/2 at 2-year follow-up. Five patients (26.3%) experienced minor post-operative surgical site infection. Two (11.1%) had persistent quadrantanopia. Meaningful improvement in QOL (change in QOLIE-31 score ≥11.8) was observed irrespective of seizure outcome or type of surgery (P <0.001). ConclusionsEpilepsy surgery is effective in developing countries. Seizure outcomes in our patients are comparable to those worldwide. Clinically important QOL improvement was observed in our series. This is the first published data on epilepsy surgery outcomes in non-pediatric patients from Sri Lanka.

Management of autoimmune temporal lobe epilepsy with GAD65 antibody: four case reports.

Glutamate decarboxylase (GAD) enzyme can be a target intracellular antigen in autoimmune focal epilepsy. GAD65 antibody is in found patients diagnosed with drug-refractory temporal lobe epilepsy (TLE). We explore the clinical features of the disease and therapeutic options. We present the cases of four TLE patients, two of them with type 1 diabetes. All of them were drug-resistant and therefore underwent presurgical evaluation, which revealed GAD65 antibody positivity. We discuss the four GAD65 antibody positive temporal lobe epilepsy patients' electroclinical data, the treatments, and their effectiveness. One of them became seizure-free after right anterior temporal lobe resection, two of them did not show significant improvement with immunmodulatory agents, and the fourth patient with the shortest duration of disease had significant improvement in seizure status and normalisation of cognitive status with IVIg therapy. Our cases show that the earlier a GAD65 antibody is detected, the greater the chance of achieving seizure freedom or improvements in both seizure and cognitive status with immunomodulatory agents. However, in some cases, surgery may also bring seizure freedom, but with a risk of cognitive deterioration.