MRI evidence of mesial temporal sclerosis in sporadic "benign" temporal lobe epilepsy

Temporal Lobe Epilepsy Perturbs the Brain-Wide Excitation-Inhibition Balance: Associations with Microcircuit Organization, Clinical Parameters, and Cognitive Dysfunction

Excitation-inhibition (E/I) imbalance is theorized as a key mechanism in the pathophysiology of epilepsy, with ample research focusing on elucidating its cellular manifestations. However, few studies investigate E/I imbalance at the macroscale, whole-brain level, and its microcircuit-level mechanisms and clinical significance remain incompletely understood. Here, the Hurst exponent, an index of the E/I ratio, is computed from resting-state fMRI time series, and microcircuit parameters are simulated using biophysical models. A broad decrease in the Hurst exponent is observed in pharmaco-resistant temporal lobe epilepsy (TLE), suggesting more excitable network dynamics. Connectome decoders point to temporolimbic and frontocentral cortices as plausible network epicenters of E/I imbalance. Furthermore, computational simulations reveal that enhancing cortical excitability in TLE reflects atypical increases in recurrent connection strength of local neuronal ensembles. Mixed cross-sectional and longitudinal analyses show stronger E/I ratio elevation in patients with longer disease duration, more frequent electroclinical seizures as well as interictal epileptic spikes, and worse cognitive functioning. Hurst exponent-informed classifiers discriminate patients from healthy controls with high accuracy (72.4% [57.5%-82.5%]). Replicated in an independent dataset, this work provides in vivo evidence of a macroscale shift in E/I balance in TLE patients and points to progressive functional imbalances that relate to cognitive decline.

Machine learning-based algorithm of drug-resistant prediction in newly diagnosed patients with temporal lobe epilepsy

OBJECTIVES

To develop a predicted algorithm for drug-resistant epilepsy (DRE) in newly diagnosed temporal lobe epilepsy (TLE) patients.

METHODS

A total of 139 newly diagnosed TLE patients were prospectively enrolled, and long-term video EEG monitoring was recorded. Clinical evaluations, including seizure frequency and antiseizure medications (ASMs) usage, were collected and prospectively followed up for 24 months. Interictal EEG data were used for feature extraction, identifying 216 EEG network features. Traditional machine learning and ensemble learning techniques were employed to predict DRE outcomes.

RESULTS

Over two years, TLE patients with DRE exhibited significant EEG differences, particularly in frontotemporal θ-band networks, characterized by increased connectivity metrics such as phase lag index (P = 0.000), etc. The predictive algorithm based on EEG features achieved accuracies between 59.2 %-84.6 % (AUC: 0.60-0.87). When compared to the whole brain, EEG features of the frontotemporal network showed improved classification performance in Naïve Bayes (P = 0.032), Tree Bagger (P = 0.021), and Subspace Discriminant (P = 0.022) models. The ensemble learning technique (Tree Bagger) delivered the best prediction results, achieving 91.5 % accuracy, 97 % sensitivity, 81 % specificity, and AUC of 0.92.

CONCLUSIONS

Increased frontotemporal EEG connectivity was observed in TLE patients with 2-year DRE. A predictive model based on routine EEG provides an accessible method for forecasting ASMs efficacy.

SIGNIFICANCE

This study highlights the clinical utility of EEG-based algorithms in identifying DRE early, aiding personalized treatment strategies and improving patient outcomes.

Long-term outcome of treatment-naïve patients with mesial temporal lobe epilepsy with hippocampal sclerosis: A retrospective study in a single center

PURPOSE

This study aimed to describe long-term treatment outcomes of treatment-naïve patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS).

METHODS

A retrospective review was conducted of treatment-naïve patients with MTLE-HS who visited the Yonsei Epilepsy Clinic from April 2000 to April 2022 and were followed up for at least 2 years. Seizure freedom (SF) was defined as no seizures or auras only for >1 year, and complete SF was defined as no seizures including auras for >1 year.

RESULTS

Eighty-four treatment-naïve patients with MTLE-HS with a median follow-up of 122 months were included. Except for one patient who underwent early surgical treatment, of the remaining 83 patients, 31 (37.3 %) achieved SF and remained in remission, 38 (45.8 %) had fluctuations in seizure control, and 14 (16.9 %) never achieved SF. Additionally, 18 (21.7 %) patients achieved complete SF and remained in remission, 42 (50.6 %) showed fluctuations, and 23 (27.7 %) never achieved complete SF. Fifty-three (63.9 %) patients achieved SF and 34 (41.0 %) achieved complete SF at their last visit. Older age at epilepsy onset, male sex, low pretreatment seizure density, history of central nervous system infection before age 5, absence of aura, and fewer antiseizure medications in the final regimen were associated with favorable outcome. Of the 84 patients, 11 (13.1 %) underwent temporal lobectomy.

CONCLUSIONS

Medical treatment outcomes in treatment-naïve MTLE-HS were relatively better than previously reported outcomes in MTLE-HS, although frequent fluctuations in seizure control were observed.

Laser Interstitial Thermal Therapy for Epilepsy

Laser interstitial thermal therapy is an important new technique with a diverse use in epilepsy. This article gives an up-to-date evaluation of the current use of the technique within epilepsy, as well as provides some guidance to novice users appropriate clinical cases for its use.

Early identification of seizure freedom with medical treatment in patients with mesial temporal lobe epilepsy and hippocampal sclerosis

BACKGROUND

Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is usually associated with a poor response to antiseizure medications. We focused on MTLE-HS patients who were seizure free on medication to: (1) determine the clinical factors associated with seizure freedom and (2) develop a machine-learning classifier to better earlier identify those patients.

METHODS

We performed a retrospective, multicentric study comparing 64 medically treated seizure-free MTLE-HS patients with 200 surgically treated drug-resistant MTLE-HS patients. First, we collected medical history and seizure semiology data. Then, we developed a machine-learning classifier based on clinical data.

RESULTS

Medically treated seizure-free MTLE-HS patients were seizure-free for at least 2 years, and for a median time of 7 years at last follow-up. Compared to drug-resistant MTLE-HS patients, they exhibited: an older age at epilepsy onset (22.5 vs 8.0 years, p < 0.001), a lesser rate of: febrile seizures (39.0% vs 57.5%, p = 0.035), focal aware seizures (previously referred to as aura)(56.7% vs 90.0%, p < 0.001), autonomic focal aware seizures in presence of focal aware seizure (17.6% vs 59.4%, p < 0.001), dystonic posturing of the limbs (9.8% vs 47.0%, p < 0.001), gestural (27.4% vs 94.0%, p < 0.001), oro-alimentary (32.3% vs 75.5%, p < 0.001) or verbal automatisms (12.9% vs 36.0%, p = 0.001). The classifier had a positive predictive value of 0.889, a sensitivity of 0.727, a specificity of 0.962, a negative predictive value of 0.893.

CONCLUSIONS

Medically treated seizure-free MTLE-HS patients exhibit a distinct clinical profile. A classifier built with readily available clinical data can identify them accurately with excellent positive predictive value. This may help to individualize the management of MTLE-HS patients according to their expected pharmacosensitivity.

Sleep-deprived electroencephalography, a forgotten investigation in psychiatry; a case series

OBJECTIVES

Many patients with psychiatric disorders may have epileptic disorders; however, clinical diagnosis without imaging investigation may result in misdiagnosis and thus resistance to treatment. We investigated electroencephalography (EEG) abnormalities in the patients with psychiatric disorders referred to us with treatment resistance.

METHODS

In this case series study, nine patients with mood and psychotic symptoms who were referred to us at Belmont Private Hospital, Australia, from August 2018 to July 2020, were evaluated.

RESULTS

Complete examination showed the presence of undiagnosed temporal lobe epilepsy. Notably, the seizure symptoms had been assumed as part of other psychiatric co-morbidities.

CONCLUSIONS

This study suggests the necessity of paying attention to the biological etiologies of mental illnesses in the initial assessments in psychiatric and neurological practice. Performing electroencephalogram and treating such patients with mood stabilizers, which have antiepileptic properties, can change the course of the mental illness decisively.

Association between Clinical Features and Magnetic Resonance Imaging Findings in Patients with Temporal Lobe Epilepsy

BACKGROUND

Temporal lobe epilepsy (TLE) is the most common cause of partial seizures. However, there is a paucity of data on the correlation of clinical and semiological features of TLE with specific imaging findings on magnetic resonance imaging (MRI).

OBJECTIVE

In this study, we sought to evaluate the association between the semiology of TLE with specific etiological findings as identified on MRI.

MATERIALS AND METHODS

This was a single-center, observational study in which consecutive patients presenting with clinical features diagnostic of TLE underwent a brain MRI on a 1.5 T scanner. The data collected from the various MR parameters were then correlated with history.

RESULTS

A total of 90 patients were included in the study. The mean age of the study population was 29.1 years. Females comprised 45% of the study population. Mesial temporal sclerosis (MTS) was the most common imaging finding in about 60% of patients. Four out of five patients had aura whereas 70% had automatisms. The presence of aura in TLE patients was significantly associated with MTS on MRI (p = 0.042). The presence of automatism and history of childhood febrile seizure did not have a significant association with any specific etiological findings on MRI (p = 0.254 and 0.731, respectively). Drug-refractory epilepsy was commonly associated with the presence of MTS on MRI (p = 0.004). The presence of dual pathology on MRI was associated with drug-refractory epilepsy (p = 0.031).

CONCLUSIONS

The presence of aura and drug-refractory epilepsy point towards the presence of MTS. Dual pathology, on MRI, in TLE patients may be a risk factor for drug-refractory epilepsy.

Clinical and Instrumental Characterization of Patients With Late-Onset Epilepsy

Epilepsy is classically considered a childhood disease. However, it represents the third most frequent neurological condition in the elderly, following stroke, and dementia. With the progressive aging of the general population, the number of patients with Late-Onset Epilepsy (LOE) is constantly growing, with important economic and social consequences, in particular for the more developed countries where the percentage of elderly people is higher. The most common causes of LOE are structural, mainly secondary to cerebrovascular or infectious diseases, brain tumors, trauma, and metabolic or toxic conditions. Moreover, there is a growing body of evidence linking LOE with neurodegenerative diseases, particularly Alzheimer's disease (AD). However, despite a thorough characterization, the causes of LOE remain unknown in a considerable portion of patients, thus termed as Late-Onset Epilepsy of Unknown origin (LOEU). In order to identify the possible causes of the disease, with an important impact in terms of treatment and prognosis, LOE patients should always undergo an exhaustive phenotypic characterization. In this work, we provide a detailed review of the main clinical and instrumental techniques for the adequate characterization of LOE patients in the clinical practice. This work aims to provide an easy and effective tool that supports routine activity of the clinicians facing LOE.

Consanguinity in patients with mesial temporal lobe epilepsy due to hippocampal sclerosis in a Saudi population

Objectives:

To investigate if there is an association between consanguinity and hippocampal sclerosis (HS) in the Saudi population.

Methods:

A retrospective case-control study was conducted by assessing the prevalence of consanguinity in patients with pathologically proven HS, who underwent epilepsy surgery at King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia, between January 2004 and December 2015. We reviewed the medical records to extract data, which included; age, gender, duration of epilepsy, history of febrile seizure, family history of epilepsy in a first or second-degree relative, and pathology reports.

Results:

A total of 120 patients, out of which 40 patients (65% male) having mesial temporal lobe epilepsy due to HS, and 80 controls (56% male) with cryptogenic epilepsy, were identified. Twenty-two patients (53.5%) in the HS group had a history of consanguinity. In the control group, 30 patients (37.5%) had a history of consanguinity. The odds ratio was 2.04 (95% confidence interval = 0.94 - 4.4, p = 0.052). A family history of epilepsy was found in 28% of the patients with HS and 32.5% cryptogenic epilepsy. Only 8 patients (19.5%) with HS reported a history of febrile seizure.

Conclusion:

Our retrospective case-control study suggests that consanguinity might increase the likelihood of developing HS.

NR4A1 Methylation Associated Multimodal Neuroimaging Patterns Impaired in Temporal Lobe Epilepsy

DNA hypermethylation has been widely observed in temporal lobe epilepsy (TLE), in which NR4A1 knockdown has been reported to be able to alleviate seizure severity in mouse model, while the underlying methylation-imaging pathway modulated by aberrant methylation levels of NR4A1 remains to be clarified in patients with TLE. Here, using multi-site canonical correlation analysis with reference, methylation levels of NR4A1 in blood were used as priori to guide fusion of three MRI features: functional connectivity (FC), fractional anisotropy (FA), and gray matter volume (GMV) for 56 TLE patients and 65 healthy controls. Post-hoc correlations were further evaluated between the identified NR4A1-associated brain components and disease onset. Results suggested that higher NR4A1 methylation levels in TLE were related with impaired temporal-cerebellar and occipital-cerebellar FC strength, lower FA in cingulum (hippocampus), and reduced GMV in putamen, temporal pole, and cerebellum. Moreover, findings were also replicated well in both patient subsets with either right TLE or left TLE only. Particularly, right TLE patients showed poorer cognitive abilities and more severe brain impairment than left TLE patients, especially more reduced GMV in thalamus. In summary, this work revealed a potential imaging-methylation pathway modulated by higher NR4A1 methylation in TLE via data mining, which may impact the above-mentioned multimodal brain circuits and was also associated with earlier disease onset and more cognitive deficits.

An intensive education program for caregivers ameliorates anxiety, depression, and quality of life in patients with drug-resistant temporal lobe epilepsy and mesial temporal sclerosis who underwent cortico-amygdalohippocampectomy

This study aimed to investigate the effect of a caregiver intensive education program (CIEP) on anxiety, depression, and quality of life (QOL) in patients with drug-resistant temporal lobe epilepsy and mesial temporal sclerosis (TLE-MTS) who underwent cortico-amygdalohippocampectomy (CAH). Ninety patients with drug-resistant TLE-MTS who underwent CAH and their caregivers were recruited and randomly allocated to the CIEP group or control group as 1:1 ratio. Caregivers received the CIEP program or routine guidance/education (control group). Anxiety/depression and QOL in patients at month (M)0, M1, M3, and M6 were assessed by the Hospital Anxiety and Depression Scale (HADS) scale and the QOL in Epilepsy Inventory-31 (QOLIE-31), respectively. Treatment efficacy at M6 was assessed by Engel classification. The HADS-anxiety score at M3 (P=0.049) and M6 (P=0.028), HADS-anxiety score change (M6-M0) (P=0.001), percentage of anxiety patients at M6 (P=0.025), and anxiety severity at M6 (P=0.011) were all decreased in the CIEP group compared with the control group. The HADS-depression score at M6 (P=0.033) and HADS-depression score change (M6-M0) (P=0.022) were reduced, while percentage of depression patients at M6 (P=0.099) and depression severity at M6 (P=0.553) showed no difference in the CIEP group compared with the control group. The QOLIE-31 score at M6 (P=0.043) and QOLIE-31 score change (M6-M0) (P=0.010) were both elevated in the CIEP group compared with the control group. In conclusion, CIEP for caregivers contributed to the recovery of anxiety and depression as well as the improvement of QOL in patients with drug-resistant TLE-MTS who underwent CAH.

Late drug-resistance in mild MTLE: Can it be influenced by preexisting white matter alterations?

OBJECTIVE

To identify early structural alterations preceding the development of drug-resistance in mild mesial temporal lobe epilepsy (mMTLE), a drug-responsive syndrome ideal for investigating epilepsy pathophysiology and potential prognostic markers of long-term clinical outcome, using magnetic resonance imaging (MRI) at baseline and after 12-year follow-up.

METHODS

Since 2002, a total of 55 participants with a baseline diagnosis of mMTLE underwent three-dimensional (3D) T1 1.5T MRI. Based on long-term outcome (follow-up 12 ± 3 years), we identified 39 patients with stable mMTLE (smMTLE) and 16 patients who had developed drug-resistance overtime (refractory MTLE [rMTLE]). At follow-up, 21 smMTLE and 13 rMTLE patients underwent 3T-MRI including diffusion-weighted scans. Structural images were processed using longitudinal voxel-based morphometry and standard Freesurfer analysis. Statistical analyses were carried out accounting for age, age at onset, gender, hippocampal volume, and hippocampal sclerosis (Hs).

RESULTS

Patients presented similar demographic, clinical, and Hs features. White matter volume of the arcuate fasciculi, corticospinal tracts, left retrosplenial cingulum, and left inferior longitudinal fasciculus was reduced only in rMTLE patients before the development of drug-resistance. At follow-up, rMTLE showed decreased fractional anisotropy in the corpus callosum, superior longitudinal fasciculi, and major bundles of the right hemisphere.

SIGNIFICANCE

White matter temporal and extratemporal abnormalities are preexisting in patients with mild MTLE who will develop drug-resistance, independently from the presence of Hs. Thus, these changes might be due to an inherited genetic alteration rather than a subordinate worsening after repeated seizures, multiple antiepileptic drugs, or initial precipitating factors.

Drug-responsive versus drug-refractory mesial temporal lobe epilepsy: a single-center prospective outcome study

Objectives: To evaluate clinical, electrophysiological, and neuroradiological factors which correlate with the prognosis in patients with mesial temporal lobe epilepsy (MTLE). Methods: This was a single-center prospective outcome study in patients with MTLE. The patients' family history, clinical characteristics, neurophysiological data (electroencephalography - EEG), neuroimaging, antiepileptic therapy, and outcome were collected and analyzed. The population was divided into four groups depending on the frequency of the seizures when they attended their last follow up. All variables and outcome measures were compared between the four groups. Results: In total 83 consecutive patients were included within the four groups. Group 1 (seizure-free) consisted of 7 patients, (9%), Group 2 (rare seizures) consisted of 15 patients (18%), Group 3 (often seizures) consisted of 30 patients (36%), and Group 4 (very often seizures) consisted of 31 patients (37%). The groups did not differ significantly in demographic characteristics. There was a strong positive correlation between resistance to therapy and sleep activation on EEG (p = 0.005), occurrence of focal to bilateral seizures (p = 0.007), automatisms (p = 0.004), and the number of previously used antiepileptic drugs (AEDs) (p = 0.002). There was no association between febrile convulsions (FC), hippocampal sclerosis (HS), and the outcome that was found. Conclusion: MTLE is a heterogeneous syndrome. Establishing the factors responsible for, and associated with, drug resistance is important for optimal management and treatment, as early identification of drug resistance should then ensure a timely referral for surgical treatment is made. This prospective study shows that sleep activation on EEG, ictal automatisms, occurrence of focal to bilateral tonic-clonic seizures, and increased number of tried AEDs are negative prognostic factors.

Predicting Response to Treatment of Epileptic Seizures: How Much Time and How Many AEDs Do We Need to Try?

Identification of Patients Who Will Not Achieve Seizure Remission Within 5 Years on AEDs

Hughes DM, Bonnett LJ, Czanner G, Komárek A, Marson AG, García Fiñana M. Neurology. 2018;91(22):e2035-e2044. doi:10.1212/WNL.0000000000006564. Epub 2018 Nov 2. PMID: 30389894.

Objective:

To identify people with epilepsy who will not achieve a 12-month seizure remission within 5 years of starting treatment.

Methods:

The Standard and New Antiepileptic Drug (SANAD) study is the largest prospective study in patients with epilepsy to date. We applied a recently developed multivariable approach to the SANAD data set that takes into account not only baseline covariates describing a patient’s history before diagnosis but also follow-up data as predictor variables.

Results:

Changes in number of seizures and treatment history were the most informative time-dependent predictors and were associated with history of neurologic insult, epilepsy type, age at start of treatment, sex, and having a first-degree relative with epilepsy. Our model classified 95% of patients. Of those classified, 95% of patients observed not to achieve remission at 5 years were correctly classified (95% confidence interval [CI]: 89.5%-100%), with 51% identified by 3 years and 90% within 4 years of follow-up. Ninety-seven percent (95% CI: 93.3%-98.8%) of patients observed to achieve a remission within 5 years were correctly classified. Of those predicted not to achieve remission, 76% (95% CI: 58.5%-88.2%) truly did not achieve remission (positive predictive value). The predictive model achieved similar accuracy levels via external validation in 2 independent United Kingdom-based data sets.

Conclusion:

Our approach generates up-to-date predictions of the patient’s risk of not achieving seizure remission whenever new clinical information becomes available that could influence patient counseling and management decisions.

Psychiatric Assessment in Patients with Mild Temporal Lobe Epilepsy

Objectives

The findings of previous studies focused on personality disorders in epileptic patients are difficult to interpret due to nonhomogeneous samples and noncomparable methods. Here, we aimed at studying the personality profile in patients with mild temporal lobe epilepsy (mTLE) with psychiatric comorbidity.

Materials and Methods

Thirty-five patients with mTLE (22 males, mean age 40.7 ± 12.1) underwent awake and sleep EEG, 3T brain MRI, and an extensive standardized diagnostic neuropsychiatric battery: Temperament and Character Inventory-Revised (TCI-R), Beck Depression Inventory-2, and State-Trait Anxiety Inventory. Drug history was collected in detail. Hierarchical Cluster Analysis was performed on TCI-R data, while all other clinical and psychological variables were compared across the resulting clusters.

Results

Scores of Harm Avoidance (HA), Reward Dependence (RD), Persistence (P), Cooperativeness (C), and Self-Transcendence (ST) allowed the identification of two clusters, describing different personality subtypes. Cluster 1 was characterized by an early onset, more severe anxiety traits, and combined drug therapy (antiepileptic drug and Benzodiazepine/Selective Serotonin Reuptake Inhibitors) compared to Cluster 2.

Conclusions

Our findings suggest that different personality traits may play a role in determining the clinical outcome in patients with mTLE. Specifically, lower scores of HA, RD, P, C, and ST were associated with worse clinical outcome. Thus, personality assessment could serve as an early indicator of greater disease severity, improving the management of mTLE.

Wistar audiogenic rats display abnormal behavioral traits associated with artificial selection for seizure susceptibility

Accumulating evidence from different animal models has contributed to the understanding of the bidirectional comorbidity associations between the epileptic condition and behavioral abnormalities. A strain of animals inbred to enhance seizure predisposition to high-intensity sound stimulation, the Wistar audiogenic rat (WAR), underwent several behavioral tests: forced swim test (FST), open-field test (OFT), sucrose preference test (SPT), elevated plus maze (EPM), social preference (SP), marble burying test (MBT), inhibitory avoidance (IAT), and two-way active avoidance (TWAA). The choice of tests aimed to investigate the correlation between underlying circuits believed to be participating in both WAR's innate susceptibility to sound-triggered seizures and the neurobiological substrates associated with test performance. Comparing WAR with its Wistar counterpart (i.e., resistant to audiogenic seizures) showed that WARs present behavioral despair traits (e.g., increased FST immobility) but no evidence of anhedonic behavior (e.g., increased sucrose consumption in SPT) or social impairment (e.g., no difference regarding juvenile exploration in SP). In addition, tests suggested that WARs are unable to properly evaluate degrees of aversiveness (e.g., performance on OFT, EPM, MBT, IAT, and TWAA). The particularities of the WAR model opens new venues to further untangle the neurobiology underlying the co-morbidity of behavioral disorders and epilepsy. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".

Benign mesial temporal lobe epilepsy: A clinical cohort and literature review

OBJECTIVE

We present a single-center retrospective study of benign mesial temporal lobe epilepsy (bMTLE) between 1995 and 2014.

METHODS

Hospital records and clinic charts were reviewed. The clinical, Eelectroencephalographic (EEG), imaging features, and response to treatment with antiepileptic drugs (AEDs) were documented. Patients were included in this study if they were seizure-free for a minimum of 24months with or without an AED.

RESULTS

Twenty-seven patients were identified. There were 19 (70%) females, mean age at first seizure was 32.2 (range: 15-80years). In all patients, seizures were mild, and seizure freedom was readily achieved with the initiation of AED therapy. Sixteen patients (59%) had mesial temporal sclerosis (MTS). In three patients, we attempted to discontinue AED therapy after a prolonged period of remission (5-8years), but all had seizure recurrence within 2 to 4weeks.

SIGNIFICANCE

Not all temporal lobe epilepsy is refractory to medication, despite the presence of MTS. Until clinical trials indicate otherwise, surgery is not indicated but life-long medical treatment is advocated.

Very Long-Term Outcome of Non-Surgically Treated Patients with Temporal Lobe Epilepsy with Hippocampal Sclerosis: A Retrospective Study

Objective

Surgical intervention can result in complete seizure remission rates of up to 80% in patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). However, certain patients cannot be treated surgically for various reasons. We analyzed the very long-term clinical outcomes of patients with TLE-HS who could not be treated surgically.

Methods

Subjects were selected from among patients with TLE-HS who were actively followed up for >10 years and treated with medication without surgical treatment. Patient medical records were used to retrospectively study seizure frequency, various clinical factors, and social adjustment. Patients who were seizure-free or had only aura were classified into Group 1; the others were classified into Group 2. Clinical factors including both patient and disease-specific factors were compared between the two groups. Current social adjustment, including the education, work, and economic status of each patient, was also investigated.

Results

Forty-one (41) subjects met the criteria for analysis, of which 12 (29%) were classified into Group 1. The average age of patients in Group 1 was higher than that of Group 2 (p = 0.0468). Group 2 included a significantly higher rate of patients who had more than one seizure per week at the onset (p = 0.0328), as well as a greater mean number of anti-epileptic drugs taken (p = 0.0024). Regarding social adjustment, Group 2 contained significantly fewer current jobholders than Group 1 (p = 0.0288).

Conclusions

After very long-term follow-up periods, 29% of patients with TLE-HS had a good outcome through treatment with anticonvulsant medications. Older patients tended to have fewer seizures, and seizure frequency at the onset was the only factor that predicted outcome.

Lacosamide in patients with temporal lobe epilepsy: An observational multicentric open-label study

PURPOSE

The aim of this study was to evaluate the efficacy and tolerability of lacosamide (LCM) both as add-on therapy and monotherapy in patients with temporal lobe epilepsy (TLE) based on an observational, prospective, multicenter study.

METHODS

We enrolled 100 patients (mean age: 43.4±12.53years, 57 females) with nonlesional TLE and TLE with hippocampal sclerosis (HS) that did not respond to the first drug and who were referred to epilepsy centers of the University of Catanzaro, University of Palermo, IRCSS Neuromed of Pozzilli, and Otto-von-Guericke University of Magdeburg. In this open-label, multicenter trial, patients were initiated on oral LCM as add-on therapy to first AED monotherapy or as a later add-on to two concomitant AEDs. Seizure frequency changes and adverse events were recorded for at least six months after LCM was added.

RESULTS

Fourteen patients dropped out because of positive MRI findings other than HS. Patients received LCM at 200-400mg/day. Fifty-eight out of these 86 patients with seizures that were previously drug-resistant had reduced seizure frequency after introduction of LCM. Forty-five out of 86 patients were classified as responders (12 were seizure-free, 33 achieved a reduction >50%). Interestingly, five patients out of 86 achieved seizure freedom for at least one year and progressively switched to monotherapy with LCM, and all five remained seizure-free at follow-up (6-48months).

CONCLUSIONS

Our results may suggest that LCM at doses of 200 to 400mg/day reduces seizure frequency in adults with TLE regardless of the presence of HS, and that it may be considered as a first add-on treatment for patients with pharmacoresistant TLE.

Long-term outcome of mild mesial temporal lobe epilepsy: A prospective longitudinal cohort study

OBJECTIVE

To identify clinical and imaging features at presentation that might predict long-term outcome in patients with mild mesial temporal lobe epilepsy (mMTLE), which is defined by at least 24 seizure-free months with or without antiepileptic medication.

METHODS

In the setting of a prospective, population-based, longitudinal cohort study, we followed up 101 patients, all with mMTLE at enrolment. By protocol, patients underwent clinical evaluation every 3-12 months. Independent t test, Mann-Whitney test, or χ(2) test was used for comparing 2 groups. The incidence rate of refractory MTLE (rMTLE) was expressed as number of cases every 100 person-years.

RESULTS

After a mean follow-up of 12.2 ± 3.7 years, 16 patients dropped out and 85/101 (mean age 46.5 ± 13.3 years) were available for the present analysis. Of these, 64/85 (75%) patients remained seizure-free and 21/85 (25%) became refractory (rMTLE), the latter corresponding to 2.0 cases per 100 persons per year. Patients with rMTLE showed a longer duration of epilepsy (p < 0.001), earlier age at epilepsy onset (p = 0.006), more frequent febrile convulsions (p = 0.02), and hippocampal sclerosis (HS) at MRI (p = 0.004) as compared to those with mMTLE.

CONCLUSIONS

mMTLE is a syndrome representing the mildest form of the wide spectrum of MTLE. Earlier age at onset, history of febrile convulsions, longer duration of epilepsy, and the presence of HS on MRI predict a worse outcome.

Progression of gray matter atrophy in seizure-free patients with temporal lobe epilepsy

OBJECTIVES

To investigate the presence and progression of gray matter (GM) reduction in seizure-free patients with temporal lobe epilepsy (TLE).

METHODS

We enrolled 39 consecutive TLE patients, seizure-free for at least 2 years--20 with magnetic resonance imaging (MRI) signs of hippocampal sclerosis (TLE-HS), 19 with normal MRI (TLE-NL), and 74 healthy controls. For longitudinal analysis, we included individuals who had a second MRI with minimum interval of 18 months: 21 patients (10 TLE-HS, 11 TLE-NL) and 11 controls. Three-dimensional (3D) T1 -weighted images acquired in 3 Tesla MRI were analyzed with voxel-based morphometry (VBM). The images of patients with right-sided interictal epileptogenic zone (EZ) were right-left flipped, as well as a comparable proportion of controls. Cross-sectional analysis: The patients' images from each group were compared to controls to investigate differences in GM volumes. Longitudinal analysis: The first and second images were compared in each group to look for decreased GM volume.

RESULTS

Cross-sectional analysis: Patients with TLE-HS had diffuse GM atrophy, including hippocampus and parahippocampal gyrus, insula, frontal, and occipital lobes ipsilateral to EZ, bilateral thalamus and contralateral orbitofrontal gyrus, and caudate. In contrast, TLE-NL group did not present significant differences compared to controls. Longitudinal analysis: TLE-HS presented progressive GM reduction in ipsilateral insula and occipital lobe, contralateral motor area, and bilateral temporal and frontal lobes. TLE-NL had GM progression in ipsilateral hypothalamus and parietal lobe, contralateral cerebellum, and bilateral temporal lobe. Controls did not show changes in GM volume between MRIs.

SIGNIFICANCE

Diffuse extrahippocampal GM atrophy is present in seizure-free patients with TLE-HS. In addition, there is progressive GM atrophy in patients with and without HS. These results demonstrate that not only ongoing seizures are involved in the progression of GM atrophy. An underlying pathologic mechanism could be responsible for progressive brain volume loss in TLE patients even in seizure-free periods.

Clinical characteristics of patients with benign nonlesional temporal lobe epilepsy

PURPOSE

To evaluate the evolution of nonlesional temporal lobe epilepsy (TLE-NL) in patients treated exclusively with antiepileptic drugs and to elucidate clinical phenotypes related to the prognosis of these patients.

METHODS

Clinical, radiological, and electroencephalographic (EEG) findings in 84 patients with TLE-NL were reviewed. A good response group (GRG) and a poor response group (PRG) were defined if the duration of their seizure-free period was >1 year, or <1 year, respectively.

RESULTS

There were 46 (54.8%) patients in the GRG and 38 (45.2%) patients in the PRG. The number of antiepileptic drugs administered was significantly lower in the GRG than that in the PRG (1.3±0.8 vs 2.8±1.0, respectively; P<0.05). The GRG had a significantly older age of onset than the PRG and a lower occurrence of initial precipitating events, such as febrile seizures, central nervous system infection, and head trauma (P<0.05). The prevalence of EEG abnormality, presence of aura, generalized seizures, and automatism was less frequently observed in the GRG (P<0.05). Multivariate analysis showed that the presence of automatism and initial precipitating events were significantly associated with a poor prognosis (P<0.05).

CONCLUSION

In contrast to the commonly assumed intractability of TLE, we found that more than 54% of patients with TLE-NL achieved a long seizure-free period. Older age at onset of TLE-NL was associated with a better prognosis. However, the presence of automatism and initial precipitating events were related to a poor prognosis. Future prospective studies with a much larger population are warranted.

Association between Vitamin D Receptor Gene Polymorphisms with Childhood Temporal Lobe Epilepsy

Vitamin D (VD) is implicated in multiple aspects of human physiology and vitamin D receptor (VDR) polymorphisms are associated with a variety of neuropsychiatric disorders. Although VD deficiency is highly prevalent in epilepsy patients and converging evidence indicates a role for VD in the development of epilepsy, no data is available on the possible relationship between epilepsy and genetic variations of VDR. In this study, 150 controls and 82 patients with temporal lobe epilepsy (TLE) were genotyped for five common VDR polymorphisms (Cdx-2, FokI, BsmI, ApaI and TaqI) by the polymerase chain reaction-ligase detection reaction method. Our results revealed that the frequency of FokI AC genotype was significantly higher in the control group than in the patients (p = 0.003, OR = 0.39, 95% CI = 0.21–0.73), whereas the AA genotype of ApaI SNP was more frequent in patients than in controls (p = 0.018, OR = 2.92, 95% CI = 1.2–7.1). However, no statistically significant association was found between Cdx-2, BsmI and TaqI polymorphisms and epilepsy. Additionally, in haplotype analysis, we found the haplotype GAT (BsmI/ApaI/TaqI) conferred significantly increased risk for developing TLE (p = 0.039, OR = 1.62, 95% CI = 1.02–2.56). As far as we know, these results firstly underline the importance of VDR polymorphisms for the genetic susceptibility to epilepsy.

Preserved anterograde and remote memory in drug-responsive temporal lobe epileptic patients

PURPOSE

To investigate cognition, particularly anterograde and remote memory, in patients suffering from unilateral drug-responsive mesial temporal lobe epilepsy (mTLE) patients and to compare their performance with that observed in drug-resistant mTLE patients.

METHODS

Sixteen drug-responsive mTLE patients, with only infrequent seizures in their lifetime, were matched for demographic and clinical variables to 18 patients suffering from drug-resistant unilateral mTLE. A comprehensive neuropsychological examination, including baseline, anterograde memory tasks, and a large range of remote memory tests was carried out.

RESULTS

Patients with drug-responsive epilepsy obtained average scores on every anterograde memory test. Although in general, they obtained lower scores than the healthy controls on remote memory tests, the differences failed to reach significance. Moreover, the drug-responsive group performed significantly better than the drug-resistant group on anterograde recall tests and an episodic autobiographical memory test. Performance was not significantly different between the patient groups in personal semantics or memory for public events.

CONCLUSION

Our results show that a mild clinical course of mTLE with no cognitive deficits can occur notwithstanding hippocampal sclerosis. The differences in cognitive function between the two groups are likely due to distinct pathophysiology of the underlying cause of epilepsy. Drug-resistant seizures and cognitive deficits may be the consequence of a more severe underlying cerebral process. Better understanding of the variety of pathogenesis of mTLE could help to answer this open question.

White matter abnormalities differentiate severe from benign temporal lobe epilepsy

OBJECTIVE

Temporal and extratemporal white matter abnormalities have been identified frequently in patients with refractory mesial temporal lobe epilepsy (rMTLE). However, the identification of potential water diffusion abnormalities in patients with drug-responsive, benign MTLE (bMTLE) is still missing. The aim of this study was to identify markers of refractoriness in MTLE.

METHODS

The study group included 48 patients with bMTLE (mean age 42.8 + 13.5 years), 38 with rMTLE (mean age 41.7 + 14.1 years) and 54 healthy volunteers. Diffusion tensor imaging (DTI) was performed to measure mean diffusivity (MD) and fractional anisotropy (FA) in a regions-of-interest analysis comprising hippocampi and temporal lobe gray and white matter regions. The presence of hippocampal sclerosis (Hs) was assessed using automated magnetic resonance imaging (MRI) evaluation. For statistics we used chi-square test; two-tailed, two-sample t-test; and stratified linear regression.

RESULTS

The significant demographic differences between the two patient groups were sex (p = 0.003), duration of epilepsy (p = 0.003) and complex febrile convulsions (p = 0.0001). In rMTLE, temporal white matter MD was higher and FA lower, as compared to bMTLE. The analysis of diagnostic accuracy (area under the receiver operator characteristic [ROC] curve [AUC]) showed that FA had an AUC for discriminating patients affected from those unaffected by refractory MTLE of 74.0% (p < 0.001), a value that was higher than that of temporal MD (64.0%), hippocampus volume (65.0%), and Hs (66.0%).

SIGNIFICANCE

We performed DTI measurements in MTLE and found a significant reduction of FA along the white matter of the temporal lobes in rMTLE, suggesting it as a valuable measure of refractoriness in MTLE.

3-T magnetic resonance imaging simultaneous automated multimodal approach improves detection of ambiguous visual hippocampal sclerosis

BACKGROUND AND PURPOSE

To evaluate if an automatic magnetic resonance imaging (MRI) processing system may improve detection of hippocampal sclerosis (Hs) in patients with mesial temporal lobe epilepsy (MTLE).

METHODS

Eighty consecutive patients with a diagnosis of MTLE and 20 age- and sex-matched controls were prospectively recruited and included in our study. The entire group had 3-T MRI visual assessment of Hs analysed by two blinded imaging epilepsy experts. Logistic regression was used to evaluate the performances of neuroradiologists and multimodal analysis.

RESULTS

The multimodal automated tool gave no evidence of Hs in all 20 controls and classified the 80 MTLE patients as follows: normal MRI (54/80), left Hs (14/80), right Hs (11/80) and bilateral Hs (1/80). Of note, this multimodal automated tool was always concordant with the side of MTLE, as determined by a comprehensive electroclinical evaluation. In comparison with standard visual assessment, the multimodal automated tool resolved five ambiguous cases, being able to lateralize Hs in four patients and detecting one case of bilateral Hs. Moreover, comparing the performances of the three logistic regression models, the multimodal approach overcame performances obtained with a single image modality for both the hemispheres, reaching a global accuracy value of 0.97 for the right and 0.98 for the left hemisphere.

CONCLUSIONS

Multimodal quantitative automated MRI is a reliable and useful tool to depict and lateralize Hs in patients with MTLE, and may help to lateralize the side of MTLE especially in subtle and uncertain cases.

Polymorphism of the multidrug resistance 1 gene MDR1/ABCB1 C3435T and response to antiepileptic drug treatment in temporal lobe epilepsy

PURPOSE

A synonymous C to T variant at position 3435 (c.3435C>T) is one common polymorphism of the multidrug resistant 1 (MDR1) gene, which encodes the major transmembrane efflux transporter P-glycoprotein. It has been suggested that this polymorphism, and more specifically the 3435CC genotype, may be associated with the response to antiepileptic drug treatment. Here we wished to examine the role of such a candidate variant in a cohort of 175 patients (98 women and 76 men; mean ± SD age: 47.90 ± 17.64) with temporal lobe epilepsy (TLE).

METHODS

Patients were classified according to whether they had drug-responsive (n=134) or drug-resistant (n=41) epilepsy. We also enrolled 175 healthy controls (93 women and 82 men; mean ± SD age: 72.5 ± 6.8), matched for sex and ethnicity.

RESULTS

Patients and controls were genotyped for detection of the 3435C>T polymorphism, but the analysis showed no significant association between the CC genotype and the risk of drug-resistant epilepsy.

CONCLUSION

These findings rule out the MDR1 c.3435C>T polymorphism having a major role or increasing the risk of drug-resistance suggesting a revision is required to determine the contribution of this polymorphism in predicting drug response in epilepsy.

Detection of hippocampal atrophy in patients with temporal lobe epilepsy: a 3-Tesla MRI shape

In patients with mesial temporal lobe epilepsy (MTLE), brain MRI often detects hippocampal sclerosis (HS). Almost half of patients with MTLE do not show any hippocampal damage on visual or volumetric assessment. Here, we wished to prospectively assess 65 patients with MTLE (41 women, mean age: 39±10years, range: 21-69; right (12/65 patients) (MRI-negative) nMTLE; right (14/65 patients) (MRI-positive with HS) pMTLE; left (24/65 patients) nMTLE; and left (15/65 patients) pMTLE) using shape analysis (SA). There were significant differences among pMTLE versus nMTLE for age at seizure onset (20.2±12.8 vs. 31.8±16.7years; p=.0029), duration of epilepsy (14.6±12.7 vs. 21.3±9.6years; p=.0227), risk of refractoriness (p=.0067), frequency of antecedent febrile convulsions (FCs) (p<.001), as well as a history of epilepsy or FCs (p=.0104). All the subjects underwent the same 3-Tesla MRI protocol. Shape analysis of hippocampal formation was conducted comparing each group versus 44 matched controls. In all four subgroups, SA detected a significant atrophy in the corresponding hippocampus that coincided with the epileptogenic area. The damage was significantly more severe in patients with pMTLE (F value: 5.00) than in subgroups with nMTLE (F value: 3.50) and mainly corresponded to the CA1 subregion and subiculum. In the patients with MTLE, SA detects hippocampal damage that lateralizes with the epileptogenic area. Such damage is most prominent in the CA1 subregion and subiculum that are crucial in the pathogenesis of MTLE.

Family history and frontal lobe seizures predict long-term remission in newly diagnosed cryptogenic focal epilepsy

PURPOSE

Cryptogenic focal epilepsy (CFE) is a heterogeneous clinical disorder including patients with severe refractory forms and patients with a fairly good prognosis. Predictors of prognosis in CFE are poorly understood. The aim of this retrospective study is to identify long-term (5-year) prognostic predictors in patients with newly diagnosed CFE.

METHODS

Subjects with cryptogenic focal epilepsy (CFE) seen from April 1987 to September 2011 in two twin Epilepsy Centres located in Reggio Calabria and Catanzaro, Calabria, Southern Italy, were screened. Patients were excluded if they had psychogenic seizures, major psychiatric disorders presence of brain lesions except for non-specific white matter T2-hyperintensities, short follow-up (less than five years) or for having received the diagnosis of CFE elsewhere. One hundred and eighty-six patients, firstly diagnosed in our Centres, constituted the study sample. Survival curves were generated according to the Kaplan-Meier method and compared with the log-rank test. The endpoint was the cumulative time-dependent chance of 5-year remission after treatment start. Independent predictors of remission were tested by multivariate analysis using Cox proportional hazards function models. The accuracy of the resulting model was tested with Receiver Operating Characteristics (ROC) curve analysis.

KEY FINDINGS

The cumulative incidence of remission was 23%. At Kaplan-Meier analysis, the only factor predicting remission was family history of epilepsy or febrile seizures (FS; p=0.02). At Cox regression, family history and frontal lobe epilepsy showed to be independent predictors of outcome (p=0.02 and 0.03, respectively). The accuracy of these predictors was good (area under ROC curve 0.648, 95% CI 0.575-0.716). Interestingly, we also found a considerable (7 years) diagnostic delay that did not result in a worse prognosis.

SIGNIFICANCE

About one quarter of subjects with newly diagnosed CFE attains 5-year seizure remission during follow-up. Family history of epilepsy or FS and frontal localization are independent prognostic predictors.

Advanced MRI morphologic study shows no atrophy in healthy individuals with hippocampal hyperintensity

We have already shown that brain MR imaging of healthy individuals frequently reveals either unilateral or bilateral Hh, which is considered a hallmark of hippocampal sclerosis. We performed a follow-up (5-year interval) clinical and advanced imaging study of these individuals to address whether Hh may have masked occult brain atrophy or contributed to a later onset of epilepsy. Subjects with Hh (n = 13) underwent a detailed clinical-imaging protocol, with a 3T scan and were studied with automated hippocampal segmentation (FreeSurfer), whole brain voxel-based morphometry, and shape analysis. All 13 subjects with Hh had normal neurologic examination findings with no cognitive impairment. Multimodal structural neuroimaging methods did not show clear evidence of significant volumetric changes between subjects with or without Hh. We clearly showed that Hh is not associated with any occult brain atrophy; furthermore, none of the healthy subjects with MR imaging evidence of Hh developed epilepsy or trouble with cognition.

Clinical phenotypes within non-surgical patients with mesial temporal lobe epilepsy caused by hippocampal sclerosis based on response to antiepileptic drugs

PURPOSE

To evaluate evolution and elucidate clinical phenotypes related to prognosis of patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) treated exclusively with antiepileptic drugs (AED).

METHODS

Forty-seven out of 68 MTLE-HS patients treated between January 2005 and June 2010 were retrospectively studied for demographic, clinical and outcome data. The population was divided into drug-responder and drug-resistant patients; the latter was divided, according to the duration of the seizure-free periods along their evolution, into patients with at least one seizure-free period longer than one year and those with shorter periods. Variables were compared between drug-responders vs drug-resistants and drug-resistants with long seizure-free periods vs drug-resistants without it.

RESULTS

There were 7 (15%) drug-responders, 39 (83%) drug-resistants and 1 patient (2%) with an undetermined response. Eighteen (46%) drug-resistant individuals had seizure-free periods longer than one year, with mean duration of 46 months (3.8 years). Since no factor was statistically associated with long seizure-free period within drug-resistants, we can clinically distinguish two phenotypes: women with left HS and late onset of seizures, with poor prognosis, and men with right HS and earlier appearance of seizures, attaining a better outcome. Twenty out of 47 (42.5%) patients followed an intermittent pattern of epilepsy.

CONCLUSIONS

Non-surgical MTLE-HS drug-resistant patients can achieve long seizure-free periods with AED, but relapses are common. Female gender, left or bilateral lesion and later onset of seizures seem to be bad prognosis factors within MTLE-HS drug-resistant patients.

Genetics of temporal lobe epilepsy

The most common partial epilepsy, temporal lobe epilepsy (TLE) consists of a heterogeneous group of seizure disorders originating in the temporal lobe. TLE had been thought to develop as a result of acquired structural problems in the temporal lobe. During the past two decades, there has been growing evidence of the important influence of genetic factors, and familial and non-lesional TLE have been increasingly described. Here, we focus on the genetics of TLE and review related genes which have been studied recently. Although its molecular mechanisms are still poorly understood, TLE genetics is a fertile field, awaiting more research.

Hippocampal sclerosis worsens autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) phenotype related to CHRNB2 mutation

BACKGROUND AND PURPOSE

Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is a distinct epileptic syndrome with a broad range of severity even amongst affected members of the same pedigree, and the level of pharmacoresistance may reach 30%, close to that seen in sporadic focal epilepsies.

METHODS

To investigate this issue of phenotypic heterogeneity, we prospectively carried out a high-resolution 3-T magnetic resonance imaging (MRI) study in an ADNFLE family containing 10 affected members including one pharmacoresistant patient and carrying the V287L mutation of the CHRN beta2 subunit (CHRNB2). MRI studies were evaluated in a manner blinded to the electro-clinical data.

RESULTS

The brain MRI showed normal results in all affected individuals except the 22-year-old right-handed woman (member III-7) who had refractory seizures and typical radiological signs of left hippocampal sclerosis. She also had a simple febrile seizure at the age of 10 months.

CONCLUSION

The results of this study illustrate that hippocampal sclerosis has offered a fertile substrate for intractable ADNFLE to develop. The present findings also highlight the importance of acquired factors that are directly relevant to the epilepsy phenotype and its severity even in monogenic epilepsies.

Natural history of temporal lobe epilepsy: antecedents and progression

Temporal lobe epilepsy represents the largest group of patients with treatment resistant/medically intractable epilepsy undergoing epilepsy surgery. The underpinnings of common forms of TLE in many instances begin in early life with the occurrence of an initial precipitating event. The first epileptic seizure often occurs after a variable latency period following this event. The precise natural history and progression following the first seizure to the development of TLE, its subsequent resolution through spontaneous remission or the development of treatment resistant epilepsy remain poorly understood. Our present understanding of the role played by these initial events, the subsequent latency to development of temporal lobe epilepsy, and the emergence of treatment resistance remains incomplete. A critical analysis of published data suggest that TLE is a heterogeneous condition, where the age of onset, presence or absence of a lesion on neuroimaging, the initial precipitating event, association with febrile seizures, febrile status epilepticus, and neurotropic viral infections influence the natural history and outcome. The pathways and processes through which these variables coalesce into a framework will provide the basis for an understanding of the natural history of TLE. The questions raised need to be addressed in future prospective and longitudinal observational studies.