Extratemporal Epilepsy Research Articles

Pre- and postoperative cognitive function scores in resective and destructive surgeries for pharmacoresistant epilepsy (as assessed by MoCA)

Epilepsy is associated with comorbid diseases and cognitive impairment, which, even with successful compensation of seizures by medication and/or surgery, continue to have a negative impact on the quality of life of patients. The cognitive outcomes of surgery are variable: they may include positive changes or no changes, but there is also a risk of increasing cognitive dysfunction. Purpose of the study. To ascertain the impact of resective and destructive surgeries in pharmacoresistant epilepsy on cognitive functions, as assessed using the Montreal Cognitive Assessment (MoCA) screening scale. Materials and Methods. The article presents the results of an investigation into the impact of resective and destructive surgeries in pharmacoresistant epilepsy on cognitive functions, as assessed by the MoCA. The study comprised 50 patients with a verified diagnosis of focal pharmacoresistant epilepsy, divided into two groups: group 1 (25 patients) underwent resective surgery, while group 2 (25 patients) had destructive surgery. Cognitive function was evaluated using the Montreal Cognitive Assessment Scale (MoCA) prior to surgery and at intervals between six months and five years post-operatively. Results. The mean age of the subjects at the time of surgery was 33.2 ± 10.05 years, and the mean duration of epilepsy was 20.7 ± 10.98 years. In 50 % of patients, the epileptic focus was localized to the left side of the brain, while in 44 % of cases, it was localized to the right side. In 6 % of patients, the epileptic focus was bilateral. The majority of patients (70 %) exhibited temporal epilepsy, while 18 % demonstrated extratemporal epilepsy and 4 % showed both temporal and extratemporal epilepsy. At the preoperative stage, cognitive deficit was observed in the majority of patients (76 %), with an average score of 23.1 points. In the postoperative period, cognitive impairment was also observed in 76 % of patients, with no change in the mean MoCA score of 23.1. In group 1, 80 % of patients exhibited cognitive deficits prior to the operation, with an average score of 22.2. In the postoperative period, the score showed an increase, reaching 23.4. In group 2, cognitive deficit was also observed in the majority of patients (72 %) at the preoperative stage. The average score in group 2 was 21.7 points, which increased to 22.2 points after the operation. Conclusion. The practice of delaying surgical treatment for pharmacoresistant epilepsy persists, with cognitive functions preserved at the time of hospitalization in only a quarter of patients. The mean score on the Cognitive Function Assessment Screening Scale did not decline as a result of surgical intervention. However, a negative effect was observed in patients who did not show cognitive deficits prior to surgery. The findings will assist physicians in making informed decisions regarding the timing and approach to pharmacoresistant epilepsy treatment.

Acute effects of Mozart K.448 on interictal epileptiform discharges in adult patients with drug-resistant focal epilepsy: A crossover randomized controlled trial

BackgroundThis study aimed to validly assess the efficacy of Mozart K.448 on reducing interictal epileptiform discharges (IEDs) in adult patients with drug-resistant focal epilepsy (DRE). MethodsThis is a crossover RCT study. Adults with DRE were included. Stratified 1:1 randomization by epileptic foci i.e., temporal versus extratemporal foci, was performed. Intervention consisted of two study arms i.e., “Mozart arm” and “Control arm”. Study period encompassed 2 consecutive nights, each night consisted of baseline and intervention period. Outcomes were IED number and proportion of patients with significant IED reduction i.e., reduction ≥ 25 %. Within-group, within-subject and between-group analyses were used to test differences of IED number when listened to the Mozart piece as compared with baseline or with Control. ResultsTwenty-six patients were randomized; 13 in Mozart and 13 in Control arm. Overall, 16 (61.54 %) out of 26 patients had significant IED reduction when listening to the Mozart piece, as compared with only 7 (26.92 %) when continuing sleep (silence). Between-group analysis showed that IED number during intervention period i.e., listening to the Mozart piece in Mozart arm and silence in Control arm was significantly different, with a lower number in Mozart arm, 39.5 (IQR 89) vs 56.5 (IQR 114); p = 0.007. ConclusionsOur study demonstrates an acute effect of the Mozart K.448 on reducing IEDs in adult patients with DRE. Patients with temporal rather than extratemporal lobe epilepsy better responded to the Mozart piece. Mozart K.448 is safe and feasible in real practice. Further RCT study assessing its long-term effect is warranted. Trial registrationThai Clinical Trials Registry, TCTR20231019005, 19 October 2023, “retrospectively registered”

Augmented Reality in Extratemporal Lobe Epilepsy Surgery.

Background: Epilepsy surgery for extratemporal lobe epilepsy (ETLE) is challenging, particularly when MRI findings are non-lesional and seizure patterns are complex. Invasive diagnostic techniques are crucial for accurately identifying the epileptogenic zone and its relationship with surrounding functional tissue. Microscope-based augmented reality (AR) support, combined with navigation, may enhance intraoperative orientation, particularly in cases involving subtle or indistinct lesions, thereby improving patient outcomes and safety (e.g., seizure freedom and preservation of neuronal integrity). Therefore, this study was conducted to prove the clinical advantages of microscope-based AR support in ETLE surgery. Methods: We retrospectively analyzed data from ten patients with pharmacoresistant ETLE who underwent invasive diagnostics with depth and/or subdural grid electrodes, followed by resective surgery. AR support was provided via the head-up displays of the operative microscope, with navigation based on automatic intraoperative computed tomography (iCT)-based registration. The surgical plan included the suspected epileptogenic lesion, electrode positions, and relevant surrounding functional structures, all of which were visualized intraoperatively. Results: Six patients reported complete seizure freedom following surgery (ILAE 1), one patient was seizure-free at the 2-year follow-up, and one patient experienced only auras (ILAE 2). Two patients developed transient neurological deficits that resolved shortly after surgery. Conclusions: Microscope-based AR support enhanced intraoperative orientation in all cases, contributing to improved patient outcomes and safety. It was highly valued by experienced surgeons and as a training tool for less experienced practitioners.

Multi-Graph Assessment of Temporal and Extratemporal Lobe Epilepsy in Resting-State fMRI

Epilepsy is a common neurological disorder that affects millions of people worldwide, disrupting brain networks and causing recurrent seizures. In this regard, investigating the distinctive characteristics of brain connectivity is crucial to understanding the underlying neural processes of epilepsy. However, the various graph-theory frameworks and different estimation measures may yield significant variability among the results of different studies. On this premise, this study investigates the brain network topological variations between patients with temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE) using both directed and undirected network connectivity methods as well as different graph-theory metrics. Our results reveal distinct topological differences in connectivity graphs between the two epilepsy groups, with TLE patients displaying more disassortative graphs at lower density levels compared to ETLE patients. Moreover, we highlight the variations in the hub regions across different network metrics, underscoring the importance of considering various centrality measures for a comprehensive understanding of brain network dynamics in epilepsy. Our findings suggest that the differences in brain network organization between TLE and ETLE patients could be attributed to the unique characteristics of each epilepsy type, offering insights into potential biomarkers for type-specific epilepsy diagnosis and treatment.

Occipital lobe epilepsy surgery: treating seizures in the posterior cortex.

Occipital lobe epilepsy (OLE) is an uncommon type of extratemporal epilepsy constituting roughly 2-13% of symptomatic partial epilepsies and epilepsy surgery cases. Over two-thirds of patients with OLE present with two characteristics: (1) ictal semiology compatible with an occipital seizure focus (e.g., ictal blindness, visual perceptual disturbance, eye blinking, nystagmus), and (2) lateralizing features referable to the posterior cortex (e.g., visual field defects, contralateral head deviation). The remaining one-third of patients present with ≥ 2 seizure types, indicative of spread to other lobes. A common representation of this cortical spread is the altered mental status and generalized tonic-clonic activity seen in patient with OLE. While the key clinical symptoms include visual hallucinations, it may be difficult to elicit on history, especially from children, and are not always present.

Extra-temporal pediatric low-grade gliomas and epilepsy.

Low-grade gliomas, especially glioneuronal tumors, are a common cause of epilepsy in children. Seizures associated with low-grade pediatric tumors are medically refractory and present a significant burden to patients. Often, morbidity and patients´ quality of life are determined rather by the control of seizures than the oncological process itself and the resolution of epilepsy represents an important part in the treatment of LGGs. The pathogenesis of tumor-related seizures in focal LGG tumors is multifactorial, and mechanisms differ probably among patients and tumor types. Pediatric low-grade tumors associated with epilepsy include a series of neoplasms that have a pure astrocytic or glioneuronal lineage. They are usually benign tumors with a neocortical localization typically in the temporal lobes, but also in other supratentorial locations. Gangliogliomas and dysembryoplastic neuroepithelial tumors (DNET) are the most common entities together with astrocytic gliomas (pilocytic astrocytomas and pleomorphic xanthoastrocytoma) and angiocentric gliomas, and dual pathology is found in up to 40% of glioneuronal tumors. The treatment of low-grade gliomas and associated epilepsy is based mainly on resection and the extent of surgery is the main predictor of postoperative seizure control in patients with a LGG. Long-term epilepsy-associated tumors (LEATs) tend to be well-circumscribed, and therefore, the chances for a complete resection and epilepsy control with a safe approach are very high. New treatments have emerged as alternatives to open microsurgical approaches, including laser thermal ablation or the use of BRAF inhibitors. Future advances in identifying seizure-related biomarkers and molecular tumor pathways will facilitate targeted treatment strategies that will have a deep impact both in oncologic and epilepsy outcomes.

Interictal blood-brain barrier dysfunction in piriform cortex of people with epilepsy.

The piriform cortex is considered to be highly epileptogenic. Its resection during epilepsy surgery is a predictor for postoperative seizure freedom in temporal lobe epilepsy. Epilepsy is associated with a dysfunction of the blood-brain barrier. We investigated blood-brain barrier dysfunction in the piriform cortex of people with temporal lobe epilepsy using quantitative T1-relaxometry. Gadolinium-based contrast agent was administered ictally and interictally in 37 individuals before undergoing quantitative T1-relaxometry. Postictal and interictal images were co-registered, and subtraction maps were created as biomarkers for peri-ictal (∆qT1interictal-postictal) and interictal (∆qT1noncontrast-interictal) blood-brain barrier dysfunction. Values were extracted for the piriform cortex, hippocampus, amygdala, and the whole cortex. In temporal lobe epilepsy (n = 14), ∆qT1noncontrast-interictal was significantly higher in the piriform cortex than in the whole cortex (p = 0.02). In extratemporal lobe epilepsy (n = 23), ∆qT1noncontrast-interictal was higher in the hippocampus than in the whole cortex (p = 0.05). Across all individuals (n = 37), duration of epilepsy was correlated with ∆qT1noncontrast-interictal (ß = 0.001, p < 0.001) in all regions, while the association was strongest inthe piriform cortex. Impaired verbal memory was associated with ∆qT1noncontrast-interictal only in the piriform cortex (p = 0.04). ∆qT1interictal-postictal did not show differences in any region. Interictal blood-brain barrier dysfunction occurs in the piriform cortex in temporal lobe epilepsy. This dysfunction is linked to longer disease duration and worse cognitive deficits, emphasizing the central role of the piriform cortex in the epileptogenic network of temporal lobe epilepsy.

White matter brain-age in diverse forms of epilepsy and interictal psychosis

Abnormal brain aging is suggested in epilepsy. Given the brain network dysfunction in epilepsy, the white matter tracts, which primarily interconnect brain regions, could be of special importance. We focused on white matter brain aging in diverse forms of epilepsy and comorbid psychosis. We obtained brain diffusion tensor imaging (DTI) data at 3 T-MRI in 257 patients with epilepsy and 429 healthy subjects. The tract-based fractional anisotropy values of the healthy subjects were used to build a brain-age prediction model, and we calculated the brain-predicted age difference (brain-PAD: predicted age—chronological age) of all subjects. As a result, almost all epilepsy categories showed significantly increased brain-PAD (p < 0.001), including temporal lobe epilepsy (TLE) with no MRI-lesion (+ 4.2 yr), TLE with hippocampal sclerosis (+ 9.1 yr), extratemporal focal epilepsy (+ 5.1 yr), epileptic encephalopathy or progressive myoclonus epilepsy (+ 18.4 yr), except for idiopathic generalized epilepsy (IGE). Patients with psychogenic non-epileptic seizures also presented increased brain-PAD. In TLE, interictal psychosis significantly raised brain-PAD by 8.7 years. In conclusion, we observed increased brain aging in most types of epilepsy, which was generally consistent with brain morphological aging results in previous studies. Psychosis may accelerate brain aging in TLE. These findings may suggest abnormal aging mechanisms in epilepsy and comorbid psychotic symptoms.

Two-Year Follow-up Outcomes of Non-lesional Epilepsy Surgery in Iran

Background: Despite treatment with anti-epileptic drugs, 30% of epileptic patients continue to experience seizures, making surgery a viable option. Surgery has shown efficacy even in non-lesional epileptic individuals, although there is limited research on this topic. Objectives: This study aimed to investigate surgical outcomes in individuals with drug-resistant epilepsy (DRE) who undergo surgery despite having non-lesional magnetic resonance imaging (MRI) findings. Methods: This observational longitudinal study was conducted between 2017 and 2020 at a referral hospital in Tehran, Iran. Using census sampling, we screened 750 epilepsy cases and enrolled 80 patients (42 women and 38 men) with DRE and non-lesional MRI findings who underwent epilepsy surgery. We collected patients' demographics and seizure characteristics. A 2-year follow-up was conducted to assess the seizure freedom rate. We compared seizure-free and non-seizure-free patients who underwent temporal epilepsy surgery, extratemporal epilepsy surgery, corpus callosotomy, and Vagus nerve stimulation (VNS) using chi-square, Fisher exact, and binary logistic regression tests. Results: The seizure freedom rate was 62.7% for temporal surgery, 83.33% for extratemporal surgery, 26.66% for corpus callosotomy, and none for patients who underwent VNS. There was no difference between seizure-free and non-seizure-free patients in terms of their baseline characteristics, seizure semiology, lesion features, and post-operative findings (P-values &gt; 0.05), except that patients without a history of febrile convulsions tended to experience more seizure freedom after extratemporal surgery (P = 0.007). Additionally, older patients tended to experience more seizure freedom after temporal surgery (P = 0.03). Conclusions: This study underscores the potential benefits of epilepsy surgery in non-lesional DRE patients. Further research is needed to establish criteria for patient selection in this context.

The value of ictal scalp EEG in focal epilepsies surgery: a retrospective analysis.

To describe the association between preoperative ictal scalp electroencephalogram (EEG) results and surgical outcomes in patients with focal epilepsies. The data of consecutive patients with focal epilepsies who received surgical treatments at our center from January 2012 to December 2021 were retrospectively analyzed. Our data showed that 44.2% (322/729) of patients had ictal EEG recorded on video EEG monitoring during preoperative evaluation, of which 60.6% (195/322) had a concordant ictal EEG results. No significant difference of surgery outcomes between patients with and without ictal EEG was discovered. Among MRI-negative patients, those with concordant ictal EEG had a significantly better outcome than those without ictal EEG (75.7% vs. 43.8%, p = 0.024). Further logistic regression analysis showed that concordant ictal EEG was an independent predictor for a favorable outcome (OR = 4.430, 95%CI 1.175-16.694, p = 0.028). Among MRI-positive patients, those with extra-temporal lesions and discordant ictal EEG results had a worse outcome compared to those without an ictal EEG result (44.7% vs. 68.8%, p = 0.005). Further logistic regression analysis showed that discordant ictal EEG was an independent predictor of worse outcome (OR = 0.387, 95%CI 0.186-0.807, p = 0.011) in these patients. Furthermore, our data indicated that the number of seizures was not associated with the concordance rates of the ictal EEG, nor the surgical outcomes. The value of ictal scalp EEG for epilepsy surgery varies widely among patients. A concordant ictal EEG predicts a good surgical outcome in MRI-negative patients, whereas a discordant ictal EEG predicts a poor postoperative outcome in lesional extratemporal lobe epilepsy.

Analysis of the performance of PET/CT using 18F-fluorodeoxyglucose in comparison with other diagnostic methods in drug-resistant epilepsy in children

Background. Epilepsy is one of the most common neurological diseases characterized by a persistent predisposition to epileptic seizures and the neurobiological, cognitive, psychological, and social consequences. In recent decades, despite the continuous development of antiepileptic drugs, there are still many patients with epilepsy that progresses to drug-resistant epilepsy. Currently, surgical treatment is one of the most important ways to treat such epilepsy. Collaboration between multidisciplinary teams and the combination of multiple neuroimaging methods are key to determining the exact localization of the epileptogenic zone. New diagnostic methods are being developed and the number of indications for their use is growing. The purpose of the study was to analyze the scientific literature on the effectiveness of positron emission tomography combined with computed tomography (PET/CT) using 18F-fluorodeoxyglucose compared to other diagnostic methods in drug-resistant epilepsy in children. Materials and methods. A literature search using keywords was conducted in Web of Science, Scopus, PubMed, and Elsevier databases. Results. Surgical treatment of drug-resistant epilepsy in children has become a specialized area in neurosurgery. Surgical removal or disconnection of a part of the brain, in which the epileptogenic zone is suspected, allows for a complete cure or a significant reduction in seizure frequency. It has been shown that a prerequisite for postoperative success is the accurate determination of the epileptogenic zone during a multistage preoperative diagnosis. Among many studies, nuclear medicine technologies play an important role in the presurgical examination of children with drug-resistant epilepsy. In combination with other methods, nuclear medicine helps identify the epileptogenic zone, especially in case of conflicting data, negative magnetic resonance imaging — negative epilepsy, focal cortical dysplasia or extratemporal lobe epilepsy. Single-photon emission CT and PET using functional neuroimaging with nuclear medicine indicators are classical methods and are recommended by neuroimaging specialists. In addition, one of the leading modern methods is PET/CT with 18F-fluorodeoxyglucose. It provides information that might be missed when using anatomical methods such as magnetic resonance imaging, and the area of hypometabolism detected with 18F-fluorodeoxyglucose PET/CT may be larger than the area of anatomical lesion detected on magnetic resonance imaging. Conclusions. For children with drug-resistant epilepsy, PET/CT using 18F-fluorodeoxyglucose is the most optimal method of preoperative diagnosis.

Lateralizing value and clinicoradiological features of asymmetric last clonic jerks in temporal and extratemporal epilepsy

Seizure semiology and electroencephalograph (EEG) are very important for determining seizure type, hemisphere lateralization, or localization. Clinical symptoms of focal seizures, as well as findings at the onset or end of a focal to bilateral tonic–clonic seizure (FBTCS), are highly informative for lateralization. This study aimed to investigate the relationship of asymmetric last clonic jerk in patients with temporal or extratemporal lobe epilepsy with pathologies, localization, lateralization, or other semiological findings detected in neuroimaging or neuro psychometric tests and its positive predictive value for the detection of hemisphere lateralization based on seizure onset ictal EEG activation. 44 patients with asymmetric last clonic jerks (aLCJ) who were followed up in our VEM unit were randomized 1:1 with epilepsy patients without. In patients with ipsilateral automatism and contralateral posture or gustatory and olfactory hallucinations aLCJ was less or absent. In patients with unilateral tonic activity, aLCJ was more common. The positive predictive value of aLCJ for ictal EEG activation lateralization was 86.36%. In conclusion, asymmetric last clonic beat is valuable for lateralization of FBTCS and should be considered. Its presence strongly and reliably lateralizes to the side of seizure onset.

Surgical Management of Extratemporal Epilepsy

Surgical Management of Extratemporal Epilepsy

Incidence, Severity, and Risk Factors of Hemorrhagic Complications of Epilepsy Surgery After 2026 Craniotomies from 2003 to 2019: A Single Center Experience

Surgery is effective in the treatment of epilepsy, particularly focal epilepsy. The aim of this work was to report the incidence and grade of severity of hemorrhagic complications after cranial epilepsy surgery, and investigate the risk factors. Patients who underwent epilepsy surgery via craniotomy between October 2003 and April 2019 were retrospectively analyzed. The incidence of hemorrhagic complications occurring in a 3-month period after cranial surgery was recorded. Other outcomes included the grade of hemorrhagic severity and risk factors. During the inclusion period, 2026 surgical procedures were performed. Sixty-six hemorrhagic complications were recorded. The total incidence of hemorrhagic complications after cranial epilepsy surgery was 3.3%. The most common type of hemorrhagic complications was epidural hemorrhage (57.6%), followed by intraparenchymal hemorrhage (33.3%). Forty-five patients (68.2%) had grade I complications, 4 (6.1%) grade II, 16 (24.2%) grade III, and 1 (1.5%) grade IV. The mortality due to hemorrhagic complications was 1.5% (1 of 66) and hemorrhagic mortality among all cranial surgery was 0.05% (1 of 2026). Left craniotomy induced a higher percentage of severe hemorrhage than the right (34.2% vs. 14.3%). Extratemporal lobe epilepsy induced a higher percentage of severe hemorrhage than other epilepsy type (34.2% vs. 14.3%). However, no statistically significant difference was observed between these two factors (P= 0.067). Hemorrhagic complications were uncommon after open surgery for epilepsy. Most hemorrhagic complications were mild while the severe were rare. Patients with hemorrhagic complications had a good prognosis after effective treatment.

Patterns of subregional cerebellar atrophy across epilepsy syndromes: An ENIGMA-Epilepsy study.

The intricate neuroanatomical structure of the cerebellum is of longstanding interest in epilepsy, but has been poorly characterized within the current corticocentric models of this disease. We quantified cross-sectional regional cerebellar lobule volumes using structural magnetic resonance imaging in 1602 adults with epilepsy and 1022 healthy controls across 22 sites from the global ENIGMA-Epilepsy working group. A state-of-the-art deep learning-based approach was employed that parcellates the cerebellum into 28 neuroanatomical subregions. Linear mixed models compared total and regional cerebellar volume in (1) all epilepsies, (2) temporal lobe epilepsy with hippocampal sclerosis (TLE-HS), (3) nonlesional temporal lobe epilepsy, (4) genetic generalized epilepsy, and (5) extratemporal focal epilepsy (ETLE). Relationships were examined for cerebellar volume versus age at seizure onset, duration of epilepsy, phenytoin treatment, and cerebral cortical thickness. Across all epilepsies, reduced total cerebellar volume was observed (d = .42). Maximum volume loss was observed in the corpus medullare (dmax = .49) and posterior lobe gray matter regions, including bilateral lobules VIIB (dmax = .47), crus I/II (dmax = .39), VIIIA (dmax = .45), and VIIIB (dmax = .40). Earlier age at seizure onset ( = .05) and longer epilepsy duration ( = .06) correlated with reduced volume in these regions. Findings were most pronounced in TLE-HS and ETLE, with distinct neuroanatomical profiles observed in the posterior lobe. Phenytoin treatment was associated with reduced posterior lobe volume. Cerebellum volume correlated with cerebral cortical thinning more strongly in the epilepsy cohort than in controls. We provide robust evidence of deep cerebellar and posterior lobe subregional gray matter volume loss in patients with chronic epilepsy. Volume loss was maximal for posterior subregions implicated in nonmotor functions, relative to motor regions of both the anterior and posterior lobe. Associations between cerebral and cerebellar changes, and variability of neuroanatomical profiles across epilepsy syndromes argue for more precise incorporation of cerebellar subregional damage into neurobiological models of epilepsy.

Factors influencing quality of life in extratemporal lobe epilepsy and mesial temporal lobe epilepsy: a cross-sectional study using medical records.

This study aimed to examine differences in factors influencing quality of life (QOL) in people with extratemporal lobe epilepsy (ETLE) and mesial temporal lobe epilepsy (MTLE). We obtained data from the medical records of 84 (47 ETLE and 37 MTLE) people with epilepsy. The data included age, sex, employment, seizure frequency, number of antiseizure medication (ASM), Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) score, and Quality of Life in Epilepsy Inventory-31 (QOLIE-31) score. Multiple regression analyses were performed using QOLIE-31 as the dependent variable and age, sex, employment, seizure frequency, number of ASM, and NDDI-E score as the independent variables in ETLE or MTLE. From the results of the multiple regression analyses, QOLIE-31 in ETLE was associated with NDDI-E (β = -0.757, p < 0.001) and employment (β = 0.388, p = 0.008). Meanwhile, QOLIE-31 in MTLE was associated with NDDI-E (β = -0.625, p < 0.001), employment (β = 0.396, p = 0.041), and number of ASMs (β = -0.399, p = 0.018). Overall, our findings indicate that the number of ASMs is potentially an influence on QOL of MTLE but similar effect is not observed in ETLE.

Advocacy for Epilepsy Surgery in Africa: Moroccan Experience of 132 Cases

In Africa, epilepsy is a real burden. Temporal lobe epilepsy is the most common drug-resistant focal epilepsy disorder, and temporal lobectomy are the most common effective treatment on patients with drug-resistant epilepsy. We aim to highlight the Moroccan experience in epilepsy surgery and to ascertain its long-term outcome. Through the results of surgical treatment in our series, we expect to raise awareness of the need of epilepsy surgery in Africa and contribute to its development. We present a retrospective study of 132 patients who underwent surgery for epilepsy from January 2005 to December 2021 at our institution. The presurgical evaluation was based on clinical screening, interictal EEG, VEEG, neuropsychological tests, MRI and Pet Scan in some cases. Data are presented as the median and ranges. For all analyses, P-values < 0.05 were considered statistically significant. Our series includes 132 patients (69 males, 52.27%), median age at surgery was 24 years (range: 1-64). One hundred -fifteen patients (87%) were operated for temporal lobe epilepsy, among them, 98 (85%) had anterior temporal lobectomy, and 17 (15%) had a lesionectomy. Seventeen patients (13%) were operated for extratemporal epilepsy, among them, 4 had lesionectomy, 7 functional hemispherotomy, and 5 patients had Gamma Knife Stereotactic Radiosurgery. Our postoperative outcomes 3 months after surgery found 113 patients (85.6%), seizure-free (Engel I), 16 Engel II (12.1%), and 3 Engel III (2.3 %) in temporal lobe epilepsy. In extratemporal lobe epilepsy, 12 (70.5%) were Engel I, seizure-free, 4 Engel II (23.5%) and 1 Engel III (6%). These results confirm that a majority of patients with drug-resistant epilepsy may benefit from surgical treatment without submitting to preoperative invasive explorations. This should help develop epilepsy surgery widely in Africa.

Epileptogenic networks in extra temporal lobe epilepsy.

Extra temporal lobe epilepsy (eTLE) may involve heterogenous widespread cerebral networks. We investigated the structural network of an eTLE cohort, at the postulated epileptogenic zone later surgically removed, as a network node: the resection zone (RZ). We hypothesized patients with an abnormal connection to/from the RZ to have proportionally increased abnormalities based on topological proximity to the RZ, in addition to poorer post-operative seizure outcome. Structural and diffusion MRI were collected for 22 eTLE patients pre- and post-surgery, and for 29 healthy controls. The structural connectivity of the RZ prior to surgery, measured via generalized fractional anisotropy (gFA), was compared with healthy controls. Abnormal connections were identified as those with substantially reduced gFA (z < -1.96). For patients with one or more abnormal connections to/from the RZ, connections with closer topological distance to the RZ had higher proportion of abnormalities. The minority of the seizure-free patients (3/11) had one or more abnormal connections, while most non-seizure-free patients (8/11) had abnormal connections to the RZ. Our data suggest that eTLE patients with one or more abnormal structural connections to/from the RZ had more proportional abnormal connections based on topological distance to the RZ and associated with reduced chance of seizure freedom post-surgery.

Breath-Hold-Triggered BOLD fMRI in Drug-Resistant Nonlesional Focal Epilepsy-APilot Study.

Individuals with drug-resistant epilepsy may benefit from epilepsy surgery. In nonlesional cases, where no epileptogenic lesion can be detected on structural magnetic resonance imaging, multimodal neuroimaging studies are required. Breath-hold-triggered BOLD fMRI (bh-fMRI) was developed to measure cerebrovascular reactivity in stroke or angiopathy and highlights regional network dysfunction by visualizing focal impaired flow increase after vasodilatory stimulus. This regional dysfunction may correlate with the epileptogenic zone. In this prospective single-center single-blind pilot study, we aimed to establish the feasibility and safety of bh-fMRI in individuals with drug-resistant non-lesional focal epilepsy undergoing presurgical evaluation. In this prospective study, 10consecutive individuals undergoing presurgical evaluation for drug-resistant focal epilepsy were recruited after case review at amultidisciplinary patient management conference. Electroclinical findings and results of other neuroimaging were used to establish the epileptogenic zone hypothesis. To calculate significant differences in cerebrovascular reactivity in comparison to the normal population, bh-fMRIs of 16healthy volunteers were analyzed. The relative flow change of each volume of interest (VOI) of the atlas was then calculated compared to the flow change of the whole brain resulting in an atlas of normal cerebral reactivity. Consequently, the mean flow change of every VOI of each patient was tested against the healthy volunteers group. Areas with significant impairment of cerebrovascular reactivity had decreased flow change and were compared to the epileptogenic zone localization hypothesis in asingle-blind design. Acquisition of bh-fMRI was feasible in 9/10cases, with one patient excluded due to noncompliance with breathing maneuvers. No adverse events were observed, and breath-hold for intermittent hypercapnia was well tolerated. On blinded review, we observed full or partial concordance of the local network dysfunction seen on bh-fMRI with the electroclinical hypothesis in 6/9cases, including cases with extratemporal lobe epilepsy and those with nonlocalizing 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). This represents the first report of bh-fMRI in individuals with epilepsy undergoing presurgical evaluation. We found bh-fMRI to be feasible and safe, with apromising agreement to electroclinical findings. Thus, bh-fMRI may represent apotential modality in the presurgical evaluation of epilepsy. Further studies are needed to establish clinical utility.

Cannabidiol Modifies the Glutamate Over-Release in Brain Tissue of Patients and Rats with Epilepsy: A Pilot Study.

Drug-resistant epilepsy (DRE) is associated with high extracellular levels of glutamate. Studies support the idea that cannabidiol (CBD) decreases glutamate over-release. This study focused on investigating whether CBD reduces the evoked glutamate release in cortical synaptic terminals obtained from patients with DRE as well as in a preclinical model of epilepsy. Synaptic terminals (synaptosomes) were obtained from the epileptic neocortex of patients with drug-resistant temporal lobe epilepsy (DR-TLE, n = 10) or drug-resistant extratemporal lobe epilepsy (DR-ETLE, n = 10) submitted to epilepsy surgery. Synaptosomes highly purified by Percoll-sucrose density gradient were characterized by confocal microscopy and Western blot. Synaptosomes were used to estimate the high KCl (33 mM)-evoked glutamate release in the presence of CBD at different concentrations. Our results revealed responsive tissue obtained from seven patients with DR-TLE and seven patients with DR-ETLE. Responsive tissue showed lower glutamate release (p < 0.05) when incubated with CBD at low concentrations (less than 100 µM) but not at higher concentrations. Tissue that was non-responsive to CBD (DR-TLE, n = 3 and DR-ELTE, n = 3) showed high glutamate release despite CBD exposure at different concentrations. Simultaneously, a block of the human epileptic neocortex was used to determine its viability through whole-cell and extracellular electrophysiological recordings. The electrophysiological evaluations supported that the responsive and non-responsive human epileptic neocortices used in the present study exhibited proper neuronal viability and stability to acquire electrophysiological responses. We also investigated whether the subchronic administration of CBD could reduce glutamate over-release in a preclinical model of temporal lobe epilepsy. Administration of CBD (200 mg/kg, p.o. every 24 h for 7 days) to rats with lithium-pilocarpine-evoked spontaneous recurrent seizures reduced glutamate over-release in the hippocampus. The present study revealed that acute exposure to low concentrations of CBD can reduce the glutamate over-release in synaptic terminals obtained from some patients with DRE. This effect is also evident when applied subchronically in rats with spontaneous recurrent seizures. An important finding was the identification of a group of patients that were non-responsive to CBD effects. Future studies are essential to identify biomarkers of responsiveness to CBD to control DRE.