Mesial Temporal Lobe Sclerosis Research Articles

Correlation of magnetic resonance spectroscopy and magnetic resonance imaging with findings of electroencephalography in patients with temporal lobe epilepsy.

This research aimed to see how well magnetic resonance spectroscopy (MRS) could identify the lateralization side in individuals with temporal lobe epilepsy (TLE) compared to electroencephalography (EEG) and magnetic resonance imaging (MRI) results. Twenty-three individuals were included in this research and diagnosed with TLE (both clinically and by EEG). Clinical exams, interictal EEG, and MRI were performed on all patients. In addition, the individuals were also subjected to proton MRS. The age range of 23 participants was 20-55 years (mean = 34.6 ± 8.5); 10 were male (44%), and 13 were female (56%). The right temporal lobe MRI showed a sensitivity and specificity of 60% and 55% for detecting mesial temporal lobe sclerosis (MTS) foci, respectively (positive predictive value (PPV) of 27% and negative predictive value (NPV) of 83%). MRI showed 83% sensitivity and 35% specificity for MTS foci in the left temporal lobe (PPV of 31% and NPV of 86%). MRS showed 61% sensitivity and 100% specificity in the right temporal lobe (PPV 100%) and 80% sensitivity and specificity in the left temporal lobe (PPV 100%) for identifying MTS foci. Overall, MRS (both left and right) results matched EEG findings. MRS is a potential noninvasive neuroradiology technique for assessing epilepsy patients because it is more sensitive than structural MRI in identifying MTS. The results of the study overall appears to be of interest but still need further support from future studies with larger sample sizes.

Translocator protein PET imaging in temporal lobe epilepsy: A reliable test-retest study using asymmetry index.

Translocator protein (TSPO) targeting positron emission tomography (PET) imaging radioligands have potential utility in epilepsy to assess the efficacy of novel therapeutics for targeting neuroinflammation. However, previous studies in healthy volunteers have indicated limited test-retest reliability of TSPO ligands. Here, we examine test-retest measures using TSPO PET imaging in subjects with epilepsy and healthy controls, to explore whether this biomarker can be used as an endpoint in clinical trials for epilepsy. Five subjects with epilepsy and confirmed mesial temporal lobe sclerosis (mean age 36 years, 3 men) were scanned twice-on average 8 weeks apart-using a second generation TSPO targeting radioligand, [11C]PBR28. We evaluated the test-retest reliability of the volume of distribution and derived hemispheric asymmetry index of [11C]PBR28 binding in these subjects and compared the results with 8 (mean age 45, 6 men) previously studied healthy volunteers. The mean (± SD) of the volume of distribution (VT), of all subjects, in patients living with epilepsy for both test and retest scans on all regions of interest (ROI) is 4.49 ± 1.54 vs. 5.89 ± 1.23 in healthy volunteers. The bias between test and retest in an asymmetry index as a percentage was small (-1.5%), and reliability is demonstrated here with Bland-Altman Plots (test mean 1.062, retest mean 2.56). In subjects with epilepsy, VT of [11C]PBR28 is higher in the (ipsilateral) hippocampal region where sclerosis is present than in the contralateral region. When using TSPO PET in patients with epilepsy with hippocampal sclerosis (HS), an inter-hemispheric asymmetry index in the hippocampus is a measure with good test-retest reliability. We provide estimates of test-retest variability that may be useful for estimating power where group change in VT represents the clinical outcome.

Intraoperative electrocorticography during laser-interstitial thermal therapy predicts seizure outcome in mesial temporal lobe epilepsy

ObjectiveMagnetic resonance-guided laser interstitial thermal therapy (MRLiTT) for treating temporal lobe epilepsy has recently gained popularity. We aimed to investigate the predictive value of pre-and post-MRLiTT epileptiform discharges (EDs) on intraoperative electrocorticography (iECoG) in seizure outcomes for patients with mesial temporal lobe epilepsy (mTLE). MethodsWe conducted a pilot, prospective single-center cohort study on seven consecutive patients with mTLE that underwent MRLiTT. Pre- and post-MRLiTT iECoG was performed using a 1x8 contact depth electrode along the same trajectory used for the laser catheter. ResultsThe responders had a robust reduction in ED frequency compared to pre-MRLiTT iECoG (86% vs 13%, p < 0.01). Clinical characteristics, including risk factors for epilepsy, duration of epilepsy, presence of mesial temporal lobe sclerosis, prior intracranial monitoring, the absolute frequency of pre- or post-MRLiTT EDs, and ablation volume were not significantly associated with responder status. ConclusionsThis is the first demonstration that intraoperative reduction in EDs during mesial temporal lobe MRLiTT may potentially predict seizure outcomes and may serve as an intraoperative biomarker for satisfactory ablation. However, larger prospective studies are needed to confirm our findings and evaluate the utility of iECoG during MRLiTT. SignificanceiECoG during mesial temporal lobe MRLiTT may help assess seizure outcomes.

Prevalence of mesial temporal sclerosis in patients with epilepsy who underwent magnetic resonance imaging in Gondar university hospital, North-West Ethiopia 2020

Background- Mesial temporal lobe sclerosis is commonly associated with intractable temporal lobe epilepsy and is seen in about 60% to 80% of cases. This study is aimed at determining the prevalence of mesial temporal sclerosis on MRI among all epilepsy patients. Methods- Hospital based retrospective cross-sectional study in adult patients referred for MRI of the brain from January 2019 - September 2020 were conducted. The study is carried out at the University of Gondar Referral Hospital with a 1.5T Philips MRI machine, in Gondar town located 741 k.m. northwest of Addis Ababa. Results - A total of 77 patients were included, out of which 61 had generalized tonic clonic epilepsy, 7 had focal impaired awareness seizures, 6 had focal to bilateral tonic clonic and 2 had focal aware. Features of mesial temporal sclerosis were identified in 8 of 77 (10.4 %) of the cases, all of them had generalized tonic-clonic epilepsy &amp; none of our participants with mesial temporal sclerosis had focal impaired awareness seizures. Mesial temporal sclerosis in our study is found to equally involve the right (50 %) and left (50 %) sides and none of our patients have bilateral involvement, and the most common findings are hippocampal atrophy in 6 out of 8 (75 %) of the cases and increased hippocampal signal intensity in 5 of 8 (62.5 %). Conclusion - The prevalence of mesial temporal sclerosis in patients with epilepsy is found to be less than what is documented in most literatures.

Post-ictal subtle ptosis ipsilateral to mesial temporal lobe sclerosis.

Post-ictal subtle ptosis ipsilateral to mesial temporal lobe sclerosis.

Robust chronic convulsive seizures, high frequency oscillations, and human seizure onset patterns in an intrahippocampal kainic acid model in mice

Intrahippocampal kainic acid (IHKA) has been widely implemented to simulate temporal lobe epilepsy (TLE), but evidence of robust seizures is usually limited. To resolve this problem, we slightly modified previous methods and show robust seizures are common and frequent in both male and female mice. We employed continuous wideband video-EEG monitoring from 4 recording sites to best demonstrate the seizures. We found many more convulsive seizures than most studies have reported. Mortality was low. Analysis of convulsive seizures at 2–4 and 10–12 wks post-IHKA showed a robust frequency (2–4 per day on average) and duration (typically 20–30 s) at each time. Comparison of the two timepoints showed that seizure burden became more severe in approximately 50% of the animals. We show that almost all convulsive seizures could be characterized as either low-voltage fast or hypersynchronous onset seizures, which has not been reported in a mouse model of epilepsy and is important because these seizure types are found in humans. In addition, we report that high frequency oscillations (>250 Hz) occur, resembling findings from IHKA in rats and TLE patients. Pathology in the hippocampus at the site of IHKA injection was similar to mesial temporal lobe sclerosis and reduced contralaterally. In summary, our methods produce a model of TLE in mice with robust convulsive seizures, and there is variable progression. HFOs are robust also, and seizures have onset patterns and pathology like human TLE. SignificanceAlthough the IHKA model has been widely used in mice for epilepsy research, there is variation in outcomes, with many studies showing few robust seizures long-term, especially convulsive seizures. We present an implementation of the IHKA model with frequent convulsive seizures that are robust, meaning they are >10 s and associated with complex high frequency rhythmic activity recorded from 2 hippocampal and 2 cortical sites. Seizure onset patterns usually matched the low-voltage fast and hypersynchronous seizures in TLE. Importantly, there is low mortality, and both sexes can be used. We believe our results will advance the ability to use the IHKA model of TLE in mice. The results also have important implications for our understanding of HFOs, progression, and other topics of broad interest to the epilepsy research community. Finally, the results have implications for preclinical drug screening because seizure frequency increased in approximately half of the mice after a 6 wk interval, suggesting that the typical 2 wk period for monitoring seizure frequency is insufficient.

Valproate-Induced Pancytopenia and Phenytoin Toxicity in a Young Adult With Intellectual Disability and Mesial Temporal Lobe Sclerosis.

Valproate-Induced Pancytopenia and Phenytoin Toxicity in a Young Adult With Intellectual Disability and Mesial Temporal Lobe Sclerosis.

The Diagnostic Efficacy of MRI Dedicated-Epilepsy Protocol in Evaluation of Seizures

Aims: The aims of this study were to identify the diagnostic efficacy of dedicated epilepsy protocol in detecting possible structural abnormalities that underlie seizure disorders, and compare the diagnostic yields of MRI and electroencephalogram individually and in combination.&#x0D; Study Design: This was a cross-sectional analytic study.&#x0D; Place and Duration of Study: Medical Imaging and Diagnostic Radiology Department at Tishreen University Hospital, Lattakia, Syria; between July 2019 and July 2020.&#x0D; Methodology: Our study included 100 cases (58 females, 41 males, age range 13-77 years) who presented with seizure over 18 months. Patients underwent complete neurological examination, EEG, and MRI with a standard and dedicated epilepsy protocol.&#x0D; Results: We found epileptogenic lesions in MRI in 55.5%. MRI detected epileptogenic lesions in 74.5% patients who had focal onset seizures. Mesial temporal lobe sclerosis was the most common epileptogenic lesion (45.5%). The diagnostic efficacy of MRI had increased with dedicated epilepsy protocol compared to standard protocol. Abnormal MRI and EEG were compatible in 21%.&#x0D; Conclusion: Dedicated epilepsy protocol increased the diagnostic efficacy of brain MRI in detecting a structural epileptogenic lesion, with 100% of mesial temporal sclerosis, the most common lesion in our study, was detected only in dedicated epilepsy protocol and missed in standard protocol.

Evaluation of memory in persons with mesial temporal lobe sclerosis: A combined fMRI and VBM study

Persons with drug refractory TLE have the option of being managed by surgery. They may develop memory impairment with specific etiology of mesial temporal sclerosis and anterior temporal lobe resection (ATLR). The study evaluated the semantic verbal memory outcomes in pre- and post-surgery temporal lobe epilepsy (TLE) patients using functional MRI and voxel morphometric methods. Twenty consecutive persons with drug-resistant epilepsy (DRE) and 20 healthy controls were recruited after obtaining the institute ethics approval. The fMRI scans were performed on a 1.5 T MR Scanner using standardized semantic verbal memory tasks using a native Hindi paradigm, before and after an anterior temporal lobectomy (in cases). A task-based functional connectivity (FC) was estimated using a conn toolbox. Data analysis was carried out using the statistical parametric imaging (SPM12) and CAT12 toolbox. Post-surgery TLE group showed increased robust FC in the right middle and posterior temporal regions as compared to pre-surgery session. A significant reduction in grey matter volume was observed in the left temporal lobe post-operatively as compared to presurgery and healthy control groups. In the post-surgery TLE group, neuropsychological scores were reduced in specific PGI domains such as visuospatial, working memory, and executive functioning. Our results may help in understanding of memory reorganization in TLE post-operatively.

Comparative Evaluation of Conventional and Advanced Magnetic Resonance Imaging (MRI) Sequences in Mesial Temporal Lobe Sclerosis Patients with Seizure

Background: Diffusion Tensor Imaging (DTI) is a new noninvasive dimension of magnetic resonance imaging (MRI) that provides insight into the white matter microstructure. In epilepsy, widespread DTI abnormalities have been reported in multiple studies in medical literature. In mesial temporal lobe sclerosis (MTLS) patients, conventional MRI may show enlargement of ipsilateral temporal horn &amp; reduction in volume of hippocampus in later stages of disease. However, DTI has been found to be useful in demonstrating the focus of epileptiform activity in brain especially in white matter very early in disease. Since DTI is a sensitive technique to detect subtle structural abnormalities causing epilepsy, hence it can be used to plan more successful epilepsy surgery. Therefore, we conducted a pilot study on twenty patients with seizure disorder using DTI where focal organic brain lesions were ruled-out. Aim: To assess the role of DTI in patients of MLTS with seizures.Subjects and Methods:Twenty patients with seizure disorder secondary to MLTS were evaluated using conventional MRI and DTI. We compared the final diagnosis achieved by clinical parameters correlated with EEG localization.Results:Ten out of twenty patients revealed abnormality on DTI that correlated with EEG correlation without obvious abnormality on conventional MRI representing a significant impact of DTI.Conclusion: DTI can sensitively detect structural changes in MLTS with epilepsy often undetectable on conventional MRI. Hence, DTI can serve as an important radiological tool guiding in management and presurgical evaluation of epilepsy patients considered as idiopathic or and refractory medication.

Reduced left amygdala volume in patients with dissociative seizures (psychogenic nonepileptic seizures)

PurposeThis study specifically investigated differences of amygdalar and hippocampal volumes between patients with dissociative seizures (DS), mesial temporal lobe sclerosis (MTS), and normal controls (NC). MethodsBetween 2003 and 2018, 127 patients diagnosed with DS and 278 with MTS were recruited. An additional 52 NC subjects were recruited between 2015 and 2018. We retrospectively selected 29 patients with DS (male:female, 6:23) with absence of structural confounding factors and obtained sex- and age-matched MTS and NC. We used Neuroreader to assess the volume of the amygdala and hippocampus as a percentage of total intracranial volume based on thin-slice (0.9–1.2 mm) T1-weighted images. Statistical analyses controlled for psychiatric comorbidity and logistic regression were used to evaluate efficacy of these values for individual-level diagnosis. ResultsThe left amygdala and right hippocampus were significantly smaller in DS compared to NC (both p = 0.04), which was not explained by differences in psychiatric comorbidity. When controlling for ipsilateral hippocampal or amygdala volume, which was seen equally in all groups (Spearman, p < 0.02), these differences were no longer significant (amygdala, p = 0.16, hippocampus, p = 0.18), suggesting that amygdalar and hippocampal atrophy may reflect network or regional changes rather than focal abnormalities. The three-way accuracy for differentiating DS, MTS, and NC using these data was 64 % (95 % confidence interval: 54–74 %). ConclusionVolumetric analysis demonstrates smaller left amygdalar and right hippocampal volumes in patients with DS compared to NC, which may mirror abnormalities in functional networks seen in conversion disorders and post-traumatic stress disorder.

The visuospatial pattern of temporal lobe epilepsy

PurposeUnlike temporal lobe lesions, temporal lobe epilepsy (TLE) has no definite effects on visuospatial functions. This retrospective study evaluated these functions in patients with TLE, aiming to clarify their relationships to TLE laterality and magnetic resonance imaging (MRI)-detected brain lesions. MethodsThe Raven Colored Progressive Matrices (RCPM), Attentive Matrices (AM), Trail Making Test A (TMTA), Street Completion Test (SCT), Rey Complex Figure Copying (RCFC) and Delayed Reproduction (RCFDR), and Corsi Blocks Span (CBS) and Supraspan Learning (CBSSL) were used to assess different visuospatial functions in 198 patients with TLE and 90 healthy subjects. ResultsIn 169 patients (83 left), MRI revealed focal temporal lobe lesions [unilateral mesial temporal lobe sclerosis (MTLS) in 88 cases]. The patients with left or right TLE obtained normal scores on the RCPM, AM, TMTA, SCT, and RCFC, but their scores were significantly low on the CBS, CBSSL, and RCFDR. The patients with MTLS obtained lower scores in comparison with the controls and the patients without lesions, whereas those with other lesions obtained low scores only on the CBSSL and those without lesions performed normally. ConclusionsTemporal lobe epilepsy does not affect nonmemory visuospatial functions but significantly impairs visuosopatial memory and learning. This pattern is independent of TLE laterality, in keeping with a modality-specific memory model. On the contrary, the type of temporal lobe lesion is relevant to the severity of impairment.

Trajectories of brain remodeling in temporal lobe epilepsy.

Temporal lobe epilepsy has been usually associated with progressive brain atrophy due to neuronal cell loss. However, recent animal models demonstrated a dual effect of epileptic seizures with initial enhancement of hippocampal neurogenesis followed by abnormal astrocyte proliferation and neurogenesis depletion in the chronic stage. Our aim was to test for the hypothesized bidirectional pattern of epilepsy-associated brain remodeling in the context of the presence and absence of mesial temporal lobe sclerosis. We acquired MRIs from a large cohort of mesial temporal lobe epilepsy patients with or without hippocampus sclerosis on radiological examination. The statistical analysis tested explicitly for common and differential brain patterns between the two patients' cohorts and healthy controls within the computational anatomy framework of voxel-based morphometry. The main effect of disease was associated with continuous hippocampus volume loss ipsilateral to the seizure onset zone in both temporal lobe epilepsy cohorts. The post hoc simple effects tests demonstrated bilateral hippocampus volume increase in the early epilepsy stages in patients without hippocampus sclerosis. Early age of onset and longer disease duration correlated with volume decrease in the ipsilateral hippocampus. Our findings of seizure-induced hippocampal remodeling are associated with specific patterns of mesial temporal lobe atrophy that are modulated by individual clinical phenotype features. Directionality of hippocampus volume changes strongly depends on the chronicity of disease. Specific anatomy differences represent a snapshot within a progressive continuum of seizure-induced structural remodeling.

Type IIB focal cortical dysplasia with balloon cells in medial temporal lobe epilepsy: Clinical, neuroimaging, and histopathological findings

PurposeType IIB focal cortical dysplasia (FCD) is an important cause of drug-resistant epilepsy. However, balloon cells located in the medial temporal lobe have been seldom reported. We aimed to discuss the clinical and pathological features of Type IIB FCD with balloon cells in the medial temporal lobe (MTLE-FCDIIB) and the differential diagnosis with other types of mesial temporal lobe epilepsy. MethodsThree MTLE-FCDIIB cases were enrolled from Peking Union Medical College Hospital. Clinical and neuroimaging data were analyzed and histology features observed on hematoxylin-eosin (H&E) staining and immunochemical staining, including vimentin, nestin, S-100, CD34, neuronal nuclei antigen (Neun), glial fibrillary acidic protein (GFAP), neurofilament heavy chain (SMI32), were discussed. ResultsAll cases involved drug-resistant epilepsy patients with childhood onset. The semiology of the epileptic seizure was a highly frequent partial seizure with or without generalized tonic-clonic seizures. Magnetic resonance imaging showed hyper-intensity in the medial temporal lobe without atrophy, different from mesial temporal sclerosis. Histological examination indicated the presence of balloon cells in the white matter of the para-hippocampal gyrus, subiculum, and cornu ammonis with cortical disorganization, and SMI32 positive dysmorphic neurons in the gray matter. Balloon cells were immunohistochemically stained with vimentin and nestin. Granular cell dispersion and pyramidal cell loss were not found. ConclusionsThe presence of balloon cells in the medial temporal lobe is observed in a rare subgroup of FCD, named MTLE-FCDIIB. It has distinct clinical manifestations, neuroimaging features, pathological changes, and prognosis, which should be differentiated from mesial temporal lobe sclerosis and mesial temporal lobe tumors. Our findings enable more accurate diagnosis of mesial temporal lobe epilepsy.

Profile of intractable epilepsy in a tertiary referral center in upper Assam

Introduction: Epilepsy is a common and diverse disorder with many different causes.Outcomes are varied with 60—70% of newly diagnosed people rapidly entering remission after starting treatment, and 20—30% developing a drug-resistant epilepsy with consequent clinical and psychosocial distress. Methods: It is a Descriptive Cross-sectional study which was conducted in Assam Medical College and Hospital, Dibrugarh from April 2014 to April 2016. A total of 42 patients of IE attending the neurology, paediatrics and medicine department were included in the study. Results: Forty-two patients (males 24, females 18) with intractable epilepsy were included for the study. Maximum patients were in between 20-40 years of age (42.9%) and their mean duration of epilepsy was13.2 ± 7.13 years. The seizure frequency varied from once every month to more than 200 per (mean 26.2 ± 24.17) month. Twenty-six patients (61.9%) had partial seizures, 8 (19.1%) patients had generalized seizures and 8(19.1%) had multiple seizure semiology. Thirty-six patients had risk factors of intractable epilepsy. Seven (16.6%) patients were having family history of epilepsy and 4(9.5%) patients had history of febrile seizures. Mesial temporal lobe sclerosis (MTLS) and birth hypoxia are the two major risk factors for intractable epilepsy. EEG was abnormal in 66.7% cases, with generalized background slowing in 19.1%, focal slowing in 14.2%, generalized epileptiform discharges in 9.5% and focal epileptiform discharges in 23.8%. CT brain was abnormal in 18(42.9%) patients. MRI brains were abnormal in 25 out-off 36 patients (69.4%). Carbamazepine was the most commonly used drug (57.1%) followed by clobazam (47.6%). Phenytoin, levetiracetum, Phenobarbitone, oxcarbazepine, zonisemide, lacosemide are the other AEDs used in combination. Conclusion: This study showed, patients with partial seizures, birth hypoxia, history of febrile seizures, family history of seizures, structural brain abnormalities and background EEG abnormalities were the most common risk factors for development of intractable epilepsy.

Comment: Epilepsy surgery programs in resource-limited settings: When less is more.

In this issue of Neurology® Clinical Practice , Habibabadi et al.1 provide an overview of their experience establishing an epilepsy surgery program in Iran. Their approach has focused on surgical treatment of lesional, refractory epilepsy—primarily temporal lobe epilepsy and mesial temporal lobe sclerosis

Hippocampus and Insula Are Targets in Epileptic Patients With Glutamic Acid Decarboxylase Antibodies.

Background: Antibodies to glutamic acid decarboxylase (GAD ab) have been found in patients with limbic encephalitis (LE) and chronic pharmacoresistant focal epilepsy (FE). The objectives of the study were to: (1) analyze the clinical and neuroimaging course of patients with FE+GAD ab, (2) compare these characteristics with a control group, and (3) describe the most affected cerebral areas with structural and functional imaging.Methods: Patients with FE + high titers of GAD ab and a follow-up of at least 5 years were selected. Titers of serum GAD ab exceeding 2,000 UI/ml were considered high. Evolutive clinical and radiological characteristics were studied in comparison to two different control groups: patients with bilateral or with unilateral mesial temporal sclerosis (BMTS or UMTS) of a non-autoimmune origin.Results: A group of 13 patients and 17 controls were included (8 BMTS, 9 UMTS). The most frequent focal aware seizures (FAS) reported by patients were psychic (5/13: 33%). Somatosensorial, motor, and visual FAS (4/13:32%) (p: 0.045), musicogenic reflex seizures (MRS), and a previous history of cardiac syncope were reported only patients (2/13:16% each) (p: NS). Comparing EEG characteristics between patients and controls, a more widespread distribution of interictal epileptiform discharges (IED) was observed in FE+ GAD ab patients than in controls (p:0.01). Rhythmic delta activity was observed in all controls in anterior temporal lobes while in patients this was less frequent (p: 0.001). No IED, even in 24 h cVEEG, was seen in 6 patients (46%).First MRI was normal in 4/5 (75%) patients. During the follow-up mesial temporal lobe (MTsL) sclerosis was observed in 5/8 (62%) of patients. All patients had abnormal FDG-PET study. MTL hypometabolism was observed in 10/11 (91%) patients, being bilateral in 7/11 (63%). In controls, this was observed in 16/17 (94%), and it was bilateral in 8/17 (47%) (p: NS). Insular hypometabolism was observed in 5/11 (45%) patients (P:0.002).Conclusions: Clinical, EEG, and FDG-PET findings in FE+GAD ab suggest a widespread disease not restricted to the temporal lobe. Progressive MTL sclerosis may be observed during follow-up. In comparison to what is found in patients with non-autoimmune MTL epilepsy, insular hypometabolism is observed only in patients with GAD ab, so it may be an important diagnostic clue.

Current Surgical Options for Patients with Epilepsy

Surgery for epilepsy dates back to 1886 and has undergone significant developments. Today it is considered a key treatment modality in patients who are resistant to pharmacological intervention. It improves seizure control, cognition and quality of life. New technologies, advances in surgical technique and progress in scientific research underlie the expansion of surgery in epilepsy treatment. Effectiveness of surgical treatment depends on several factors including the type of epilepsy, the underlying pathology and the localisation of the epileptogenic zone. Timely referral to an experienced epilepsy surgery centre is important to allow the greatest chance of seizure control and to minimise associated morbidity and mortality. Following referral, patients undergo thorough presurgical investigation to evaluate their suitability for surgery. The commonest form of epilepsy treated by surgery is mesial temporal lobe sclerosis and there is Class I evidence for the medium-term efficacy of temporal lobe resection from two randomised control trials. Various other forms of epilepsy are now considered for resective and neuromodulatory surgical intervention due to favourable results. In this article, the authors review the current status of surgical treatment for epilepsy including the presurgical evaluation of patients, surgical techniques and the future directions in epilepsy surgery.

Earlier seizure onset and longer epilepsy duration correlate with the degree of temporal hypometabolism in patients with mesial temporal lobe sclerosis

ObjectiveTo study the relationship of glucose metabolism and volume of the temporal lobes with age at epilepsy onset, epilepsy duration, and seizure frequency in patients with mesial temporal sclerosis (MTS). MethodsWe evaluated the pre-surgical 18F-fluoro-deoxyglucose (FDG) positron emission tomography (PET) and magnetic resonance imaging (MRI) of 18 patients with epilepsy and MRI findings of MTS, who were seizure-free for at least 2-years after temporal lobectomy. We calculated the volume of the hippocampi and amygdalae on MRI. On PET we studied their mean standard uptake values (SUV), and relative metabolic activity as compared to normal subjects in terms of Z-scores. We compared the PET and MRI metrics in the bilateral structures using the Wilcoxon sign rank test. We studied the relationship between the imaging metrics and age of epilepsy onset, epilepsy duration, and seizure frequency via Spearman correlation analyses. ResultsYounger age at onset correlated with decreased hippocampal glucose metabolism (rs=0.64, p=0.008). Longer epilepsy duration correlated with decreased hippocampal glucose metabolism (rs=−0.55, p=0.024). There was no correlation between age at onset of epilepsy, epilepsy duration, or seizure frequency and volumetrics. Z-score in the sclerotic hippocampus (−3.51±2.2vs −0.7±1.7) and amygdala (−3.26±2.3 vs −0.68±1.8) was smaller than the contralateral (p<0.001). The diseased hippocampus (2.84±0.49 vs 3.52±0.4ml) and ipsilateral amygdala (1.49±0.24 vs 1.72±0.3ml) were significantly smaller than the contralateral (p<0.02). SignificanceEarlier epilepsy onset correlated with hippocampal hypometabolism. Longer epilepsy duration correlated with amygdalar hypometabolism suggesting an ongoing progressive disease in MTLE.

P257 Smell triggered seizure in a patient with temporal lobe epilepsy

Introduction Among the reflex seizures, those triggered by smell are very rarely reported. We aimed to present a patient with temporal lobe epilepsy (TLE), who experienced a video-EEG recorded seizure while smelling ylang-ylang extract during a study protocol. Patient and methods The patient is a 34-year-old woman with drug-resistant TLE, which had started when she was 9 years old. Her MRI revealed left mesial temporal lobe sclerosis. She had 1–5 focal seizures impairing awareness per month. Stress and sadness were the only reported seizure triggers. During her routine pre-surgical evaluation, a standardized video-EEG study protocol was also applied after taking her consent. Baseline, hyperventilation, intermittent photic stimulation and olfactory stimulations (OS) were performed with a published standard protocol. One ml of odorant solution of ylan-ylang extract was dropped on a cotton ball, and was applied to the middle of both nostrils during 3 min. This activation was repeated twice and followed by 15 min of resting records (post-OS1 and post-OS2). We investigated modulation of epileptiform discharges by OS by counting the interictal spikes. However, a focal seizure has occurred in the first minute of smelling. After 5 months, video-EEG with the same protocol was repeated and increase in spike counts during post-OS periods was documented. Moreover, she was found to have hypo-osmia with Sniffin Sticks test, despite she had no complaints. Conclusion Our results suggested that olfactory stimulation may trigger reflex seizures and increase interictal spikes in some patients with TLE.