Impact of Seizures While Driving Prior to Diagnosis in People With Focal Epilepsy: Motor Vehicle Accidents and Time to Diagnosis

OBJECTIVES

To identify the type, frequency, and consequences of seizures while driving (SzWD) in people with epilepsy before diagnosis.

METHODS

We performed a retrospective cohort study using the Human Epilepsy Project (HEP) to identify prediagnostic SzWD. Clinical descriptions from seizure diaries and medical records were used to classify seizure types and frequencies, time to diagnosis, and SzWD outcomes. Data were modeled using multiple logistic regression to assess for factors independently associated with SzWD.

RESULTS

32 prediagnostic SzWD were reported among 23/447 (5.1%) participants. Of them, 7 (30.4%) had more than 1. Six participants (26.1%) experienced SzWD as their first lifetime seizure. Most SzWD were focal with impaired awareness (n = 27, 84.4%). Of participants who had motor vehicle accidents (MVAs), 6 (42.9%) had no recollection. SzWD led to hospitalization in 11 people. The median time from first seizure to first SzWD was 304 days (IQR = 0-4,056 days). The median time between first SzWD and diagnosis was 64 days (IQR = 10-176.5 days). Employment was associated with a 3.95-fold increased risk of SzWD (95% CI 1.2-13.2, p = 0.03), and nonmotor seizures were associated with a 4.79-fold increased risk (95% CI 1.3-17.6, p = 0.02).

DISCUSSION

This study identifies the consequences of seizure-related MVAs and hospitalizations people experience before epilepsy diagnosis. This highlights the need for further research aimed at improving seizure awareness and improving time to diagnosis.

Considering the Role of Extracellular Matrix Molecules, in Particular Reelin, in Granule Cell Dispersion Related to Temporal Lobe Epilepsy

The extracellular matrix (ECM) of the nervous system can be considered as a dynamically adaptable compartment between neuronal cells, in particular neurons and glial cells, that participates in physiological functions of the nervous system. It is mainly composed of carbohydrates and proteins that are secreted by the different kinds of cell types found in the nervous system, in particular neurons and glial cells, but also other cell types, such as pericytes of capillaries, ependymocytes and meningeal cells. ECM molecules participate in developmental processes, synaptic plasticity, neurodegeneration and regenerative processes. As an example, the ECM of the hippocampal formation is involved in degenerative and adaptive processes related to epilepsy. The role of various components of the ECM has been explored extensively. In particular, the ECM protein reelin, well known for orchestrating the formation of neuronal layer formation in the cerebral cortex, is also considered as a player involved in the occurrence of postnatal granule cell dispersion (GCD), a morphologically peculiar feature frequently observed in hippocampal tissue from epileptic patients. Possible causes and consequences of GCD have been studied in various in vivo and in vitro models. The present review discusses different interpretations of GCD and different views on the role of ECM protein reelin in the formation of this morphological peculiarity.

Late-life terminal seizure freedom in drug-resistant epilepsy: "Burned-out epilepsy"

The course of established epilepsy in late life is not fully known. One key question is whether the resolution of an epileptic diathesis is a natural outcome in some people with long-standing epilepsy. We investigated this with a view to generating a hypothesis. We retrospectively explored whether terminal seizure-freedom occurs in older people with previous drug-resistant epilepsy at the Chalfont Centre for Epilepsy over twenty years. Of the 226 people followed for a median period of 52 years, 39 (17%) achieved late-life terminal seizure-freedom of at least two years before death, which occurred at a median age of 68 years with a median duration of 7 years. Multivariate analysis suggests that a high initial seizure frequency was a negative predictor (p < 0.0005). Our findings indicate that the 'natural' course of long-standing epilepsy in some people is one of terminal seizure freedom. We also consider the concept of "remission" in epilepsy, its definition challenges, and the evolving terminology used to describe the state of seizure freedom. The intersection of ageing and seizure freedom is an essential avenue of future investigation, especially in light of current demographic trends. Gaining mechanistic insights into this phenomenon may help broaden our understanding of the neurobiology of epilepsy and potentially provide targets for therapeutic intervention.

Diagnostic Delay in Epilepsy: the Scope of the Problem

PURPOSE OF REVIEW

Diagnostic delay is an increasingly recognized issue in epilepsy. At the same time, there is a clear disparity between public awareness of epilepsy and that of other public health issues. A contributing factor for this seems to be a lack of studies testing interventions designed to improve seizure recognition. In this review, we summarize the main findings from recent studies investigating diagnostic delay in epilepsy, highlighting causes, consequences, and potential interventions in future research that may improve quality of care in this population.

RECENT FINDINGS

Building on prior evidence, diagnostic delay in patients with new-onset focal epilepsy has been identified as an important problem for patients with epilepsy. Such delay in diagnosis can lead to delayed treatment and potentially preventable morbidity and mortality including motor vehicle accidents. Nonmotor seizure semiology appears to be a major contributor for delay; such seizures are largely unrecognized when patients present to emergency departments for care. Improving recognition and diagnosis of recurrent nonmotor seizures in emergency departments represents a significant opportunity for improving time to diagnosis, particularly when patients present following a first lifetime motor seizure and meet diagnostic criteria for epilepsy. Diagnostic delay in epilepsy is a significant public health issue and recent studies have highlighted potential areas for intervention.

Occurrence of status epilepticus in persons with epilepsy is determined by sex, epilepsy classification, and etiology: a single center cohort study

Background

Status epilepticus (SE) can occur in persons with or without epilepsy and is associated with high morbidity and mortality.

Methods

This survey aimed to record self-reported frequency of SE in persons with epilepsy, its association with clinical characteristics and patient level of information on SE and rescue medication. 251 persons with epilepsy at a tertiary epilepsy center were included in the study.

Results

87 (35%) had a history of SE defined as seizure duration of more than 5 min. These patients were less likely to be seizure-free, and had a higher number of present and past anti-seizure medication. Female sex, cognitive disability, younger age at epilepsy onset, defined epilepsy etiology, and focal epilepsy were associated with a history of SE. On Cox regression analysis, female sex, defined etiology and focal classification remained significant. 67% stated that they had information about prolonged seizures, and 75% knew about rescue medication. 85% found it desirable to receive information about SE at the time of initial diagnosis of epilepsy, but only 16% had been offered such information at the time.

Conclusion

SE is frequent among persons with epilepsy and there remain unmet needs regarding patient education.

An interictal measurement of cerebral oxygen extraction fraction in MRI-negative refractory epilepsy using quantitative susceptibility mapping

PURPOSE

Oxygen extraction fraction (OEF) can be a factor to identify brain tissue's disability in epileptic patients. This study aimed to assess the OEF's level measurement in refractory epileptic patients (REPs) using a quantitative susceptibility mapping (QSM) method and to determine whether the OEF parameters change.

METHODS

QSM-OEF maps of 26 REPs and 16 healthy subjects were acquired using 3T MRI with a 64-channel coil. Eighteen regions-of-interest (ROIs) were chosen around the cortex in one appropriate slice of the brain and the mean QSM-OEF for each ROI was obtained. The correlations of QSM-OEF among different clinical characteristics of the disease, as well as between the patients and normal subjects, were also investigated.

RESULTS

QSM-OEF was shown to be significantly higher in REPs (44.9 ± 5.8) than that in HS (41.9 ± 6.2) (p < 0.05). Mean QSM-OEF was statistically lower in the ipsilateral side (44.5 ± 6.6) compared to the contralateral side (46.4 ± 6.8) (P < 0.01). QSM-OEF was illustrated to have a strong positive correlation with the attack duration (r = 0.6), and a moderate negative correlation with the attack frequency (r = -0.3). Using an optimized support vector machine algorithm, we could predict the disease in subjects having abnormal OEF values in the brain-selected-ROIs with sensitivity, specificity, AUC, and the precision of 0.96, 1, 0.98, and 1, respectively.

CONCLUSIONS

The results of this study revealed that QSM-OEF of the REPs' brain is higher than that of HS, which indicates that QSM-OEF is associated with disease activity.

The neurophysiology and seizure outcomes of late onset unexplained epilepsy

OBJECTIVE

To investigate neurophysiologic and neuroimaging characteristics of patients with late onset unexplained epilepsy (LOUE).

METHODS

We performed a retrospective chart review of elderly patients with ICD9 diagnosis codes consistent with epilepsy/seizures. Inclusion criteria included unprovoked seizures, and absence of cortical lesions on magnetic resonance imaging (MRI). Electroencephalograms (EEGs) findings were also analyzed. MRI images were scored for degree of white matter hyperintensities (Fazekas Scale) and mesial temporal atrophy (MTA). Vascular risk factors, and Framingham Heart Study general cardiovascular disease (FHS-CVD) risk scores were compared to controls from the Harvard Aging Brain study (HABS).

RESULTS

We identified 224 LOUE patients and 8% were drug resistant. Epileptiform abnormalities were captured on EEG in 35%. The location was temporal with left sided predominance in 49%. Fazekas scale consisted of 25% beginning of confluent lesions, and 10% large confluent lesions. MTA scores consisted of 21% moderate-severe hippocampal atrophy. LOUE patients had on average a 2.3% (adjusted), 7.4% (unadjusted) increased FHS-CVD score.

CONCLUSIONS

Our findings highlight LOUE as pharmacosensitive and left temporal predominant. Given the higher prevalence of vascular risk factors, investigations are needed to study their role in pathophysiology.

SIGNIFICANCE

Physicians caring for patients with LOUE should evaluate for vascular risk factors and investigate the presence of hippocampal atrophy.

SAD-B modulates epileptic seizure by regulating AMPA receptors in patients with temporal lobe epilepsy and in the PTZ-induced epileptic model

α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are the predominant mediators of glutamate-induced excitatory neurotransmission. It is widely accepted that AMPA receptors are critical for the generation and spread of epileptic seizure activity. Dysfunction of AMPA receptors as a causal factor in patients with intractable epilepsy results in neurotransmission failure. Brain-specific serine/threonine-protein kinase 1 (SAD-B), a serine-threonine kinase specifically expressed in the brain, has been shown to regulate AMPA receptor-mediated neurotransmission through a presynaptic mechanism. In cultured rat hippocampal neurons, the overexpression of SAD-B significantly increases the frequency of miniature excitatory postsynaptic currents (mEPSCs). Here, we showed that SAD-B downregulation exerted antiepileptic activity by regulating AMPA receptors in patients with temporal lobe epilepsy (TLE) and in the pentylenetetrazol (PTZ)-induced epileptic model. We first used immunoblotting and immunohistochemistry analysis to demonstrate that SAD-B expression was increased in the epileptic rat brain. Subsequently, to explore the function of SAD-B in epilepsy, we used siRNA to knock down SAD-B protein and observed behavior after PTZ-induced seizures. We found that SAD-B downregulation attenuated seizure severity and susceptibility in the PTZ-induced epileptic model. Furthermore, we showed that the antiepileptic effect of SAD-B downregulation on PTZ-induced seizure was abolished by CNQX (an AMPA receptor inhibitor), suggesting that SAD-B modulated epileptic seizure by regulating AMPA receptors in the brain. Taken together, these findings suggest that SAD-B may be a potential and novel therapeutic target to limit epileptic seizures.

Genetic variants in incident SUDEP cases from a community-based prospective cohort with epilepsy

OBJECTIVE

Sudden unexpected death in epilepsy (SUDEP) is a leading cause of epilepsy-related mortality in young adults. It has been suggested that SUDEP may kill over 20 000 people with epilepsy in China yearly. The aetiology of SUDEP is unclear. Little is known about candidate genes for SUDEP in people of Chinese origin as most studies have ascertained this in Caucasians. No candidate genes for SUDEP in Chinese people have been identified.

METHODS

We performed whole exome sequencing (WES) in DNA samples collected from five incident cases of SUDEP identified in a large epilepsy cohort in rural China. We filtered rare variants identified from these cases as well as screened for SUDEP, epilepsy, heart disease or respiratory disease-related genes from previous published reports and compared them with publicly available data, living epilepsy controls and ethnicity-match non-epilepsy controls, to identify potential candidate genes for SUDEP.

RESULTS

After the filtering process, the five cases carried 168 qualified mutations in 167 genes. Among these genetic anomalies, we identified rare variants in SCN5A (1/5:20% in our cases), KIF6 (1/5:20% in our cases) and TBX18 (1/5:20% in our cases) which were absent in 330 living epilepsy control alleles from the same original cohort and 320 ethnicity-match non-epilepsy control alleles.

CONCLUSIONS

These three genes were previously related to heart disease, providing support to the hypothesis that underlying heart disorder may be a driver of SUDEP risk.

Network connectivity separate from the hypothesized irritative zone correlates with impaired cognition and higher rates of seizure recurrence

INTRODUCTION

Surgery remains an essential option for the treatment of medically intractable temporal lobe epilepsy (TLE). However, only 66% of patients achieve postoperative seizure freedom, perhaps attributable to an incomplete understanding of brain network alterations in surgical candidates. Here, we applied a novel network modeling algorithm and measured key characteristics of epileptic networks correlated with surgical outcomes and objective measures of cognition.

METHODS

Twenty-two patients were prospectively included, and relevant demographic information was attained. Resting state functional magnetic resonance imaging (rsfMRI) and electroencephalography (EEG) data were recorded and preprocessed. Using our novel algorithm, patient-specific epileptic networks were mapped preoperatively, and geographic spread was quantified. Global functional connectivity was also determined using a volumetric functional atlas. Neuropsychological pre- and postsurgical raw and standardized scores obtained blinded to epileptic network status. Key demographic data and features of epileptic networks were then correlated with surgical outcome using Pearson's product-moment correlation.

RESULTS

At an average follow-up of 18.4 months, 15/22 (68%) patients were seizure-free. Connectivity was measured globally using a functional 3D atlas. Higher mean global connectivity correlated with worse scores in preoperative neuropsychological testing of executive functioning (Ruff Figural Fluency Test [RFFT]-ER; R = 0.943, p = 0.005). A higher ratio of highly correlated connections between regions of interest (ROIs) in the hemisphere contralateral to the seizure onset correlated with impairment in executive functioning (RFFT-ER; R = 0.943, p = 0.005). Higher numbers of highly correlated connections between ROIs in the contralateral hemisphere correlated with impairment in both short- and long-term measures of verbal memory (Rey Auditory Verbal Learning Test Trials 6, 7 [RAVLT6, RAVLT7]; R = -0.650, p = 0.020, R = -0.676, p = 0.030). Epilepsy networks were modeled in each patient, and localization of the epilepsy network in the bitemporal lobes correlated with lower scores in neuropsychological tests measuring verbal learning and short-term memory (RAVLT6; R = -0.671, p = 0.024). Higher rates of seizure recurrence correlated with localization of the epilepsy network bitemporally (R = -0.542, p = 0.014), with the stronger correlation found with localization to the contralateral temporal lobe from side of surgery (R = - 0.530, p = 0.016).

CONCLUSION

Increased connectivity contralateral to seizure onset and epilepsy network spread in the bitemporal lobes correlated with lower measures of executive functioning and verbal memory. Epilepsy network localization to the bitemporal lobes, in particular, the contralateral temporal lobe, is associated with higher rates of seizure recurrence. These findings may reflect network-level disruption that has infiltrated the contralateral hemisphere and the bitemporal lobes contributing to impaired cognition and relatively worse surgical outcomes. Further identification of network parameters that predict patient outcomes may aid in patient selection, resection planning, and ultimately the efficacy of epilepsy surgery.

Seizures and epilepsy in multiple sclerosis: epidemiology and prognosis in a large tertiary referral center

BACKGROUND

Seizures and epilepsy may substantially add to the burden of disease in multiple sclerosis (MS), whereas the exact prevalence and prognosis of seizures and epilepsy in patients with MS remains largely unknown.

OBJECTIVES

We aimed to investigate the epidemiology and prognosis of seizures and epilepsy in MS.

METHODS

We retrospectively analyzed a cohort of 4078 MS patients from a single tertiary referral clinic.

RESULTS

After excluding 37 patients with unconfirmed MS and alternative seizure etiologies, we found seizures attributable to MS in 1.5% and epilepsy in 0.9% of patients. 40.4% of patients with a follow-up of at least twelve months experienced only a single seizure and 59.6% had recurring seizures. 39% of patients with recurrent seizures were considered drug-resistant, with 9.7% experiencing status epilepticus. Seizure recurrence after a first seizure depended significantly on the MS subtype and was seen more often if the first seizure occurred simultaneously with a MS relapse than in the absence of a relapse.

CONCLUSION

Our study shows a lower number of seizures and epilepsy in MS than previously reported. While a single seizure in MS usually has a good prognosis, relapse-associated seizures and established epilepsy in MS may not be as benign as previously assumed.

Review: The past, present and future challenges in epilepsy-related and sudden deaths and biobanking

Awareness and research on epilepsy-related deaths (ERD), in particular Sudden Unexpected Death in Epilepsy (SUDEP), have exponentially increased over the last two decades. Most publications have focused on guidelines that inform clinicians dealing with these deaths, educating patients, potential risk factors and mechanisms. There is a relative paucity of information available for pathologists who conduct these autopsies regarding appropriate post mortem practice and investigations. As we move from recognizing SUDEP as the most common form of ERD toward in-depth investigations into its causes and prevention, health professionals involved with these autopsies and post mortem procedure must remain fully informed. Systematizing a more comprehensive and consistent practice of examining these cases will facilitate (i) more precise determination of cause of death, (ii) identification of SUDEP for improved epidemiological surveillance (the first step for an intervention study), and (iii) biobanking and cell-based research. This article reviews how pathologists and healthcare professionals have approached ERD, current practices, logistical problems and areas to improve and harmonize. The main neuropathology, cardiac and genetic findings in SUDEP are outlined, providing a framework for best practices, integration of clinical, pathological and molecular genetic investigations in SUDEP, and ultimately prevention.

Closed-loop Neuropharmacology for Epilepsy: Distant Dream or Future Reality?

Epilepsy is considered the most frequent severe neurological condition but most patients treated with medication become seizure free. The management of treatment, however, is highly empirical, mainly relying on observation. A closed-loop therapy for epilepsy would be very valuable for more efficient treatment regimens. Here we discuss monitoring treatment (therapeutic drug monitoring) and the potential developments in this field, as well as providing a review of potential biomarkers that could be used to monitor the disease activity. Finally, we consider the pharmacogenetic input in epilepsy treatment.

Nocturnal supervision and SUDEP risk at different epilepsy care settings

Objective

To estimate the incidence of sudden unexpected death in epilepsy (SUDEP) in people with intellectual disabilities in residential care settings and to ascertain the effects of nocturnal seizures and nocturnal supervision on SUDEP risk.

Methods

We conducted a nested case-control study reviewing records of all people who died at 2 residential care settings over 25 years. Four controls per case were selected from the same population, matched on age (±5 years) and residential unit. Nocturnal supervision was graded in 3 categories: (1) no supervision; (2) a listening device or a roommate or physical checks at least every 15 minutes; and (3) 2 of the following: a listening device, roommate, additional device (bed motion sensor/video monitoring), or physical checks every 15 minutes. Outcome measures were compared using Mann-Whitney U tests and Fisher exact tests.

Results

We identified 60 SUDEP cases and 198 matched controls. People who died of SUDEP were more likely to have nocturnal convulsive seizures in general (77% of cases vs 33% of controls, p < 0.001) and a higher frequency of nocturnal convulsive seizures. Total SUDEP incidence was 3.53/1,000 patient-years (95% confidence interval [CI] 2.73–4.53). The incidence differed among centers: 2.21/1,000 patient-years (95% CI 1.49–3.27) vs 6.12/1,000 patient-years (95% CI 4.40–8.52). There was no significant difference in nocturnal supervision among cases and controls, but there was a difference among centers: the center with a lowest grade of supervision had the highest incidence of SUDEP.

Conclusions

Having nocturnal seizures, in particular convulsions, may increase SUDEP risk. Different levels of nocturnal supervision may account for some of the difference in incidence.

Validity of health insurance data to identify people with epilepsy

BACKGROUND

Large administrative databases may prove useful to assess epilepsy-related comorbidity and mortality. Despite their increased use, their validity as data source in epilepsy is yet under-ascertained.

METHODS

Achmea is a large Dutch health insurance company covering about 25% of the population. We performed a retrospective cohort study using data from the Achmea Health Insurance Database (AHID) over the period 2006-2009. To assess the validity of epilepsy codes in the AHID, we randomly invited 1000 individuals (age 18-75 years insured by Achmea), attending an epilepsy centre or a district hospital during 2006-2009, to participate. Informed consent was provided and 293 were eligible for inclusion. We compared the diagnostic codes for epilepsy in AHID with the diagnosis in their case-notes (reference standard). As additional measure of validity, we compared prevalence of epilepsy codes in AHID (based on anonymized data of all 26.297 subjects with this code in AHID) with epilepsy prevalence rates in the general Dutch population to estimate an age-specific standardized prevalence ratio.

RESULTS

We identified 293 participants with an epilepsy code in AHID. The majority (278) of them had a definite or possible diagnosis of epilepsy in the case-notes; i.e. a positive predictive value of 0.95 (95% CI 0.92-0.97). The overall prevalence of epilepsy codes in the AHID was slightly higher than the putative prevalence in the general Dutch population (7.4/1.000 vs. 6.8/1.000) with a Standardized Prevalence Ratio of 1.08 (95% CI: 1.08-1.09).

CONCLUSIONS

Our findings demonstrate the validity of AHID data for a diagnosis of epilepsy and confirm previous work on using administrative data for epilepsy research.

Quantitative Proteomic Analysis To Identify Differentially Expressed Proteins in Myocardium of Epilepsy Using iTRAQ Coupled with Nano-LC-MS/MS

Epilepsy is a difficult-to-manage neurological disease that can result in organ damage, such as cardiac injury, that contributes to sudden unexpected death in epilepsy (SUDEP). Although recurrent seizure-induced cardiac dysregulation has been reported, the underlying molecular mechanisms are unclear. We established an epileptic model with Sprague-Dawley rats by applying isobaric tags for a relative and absolute quantification (iTRAQ)-based proteomics approach to identify differentially expressed proteins in myocardial tissue. A total of seven proteins in the acute epilepsy group and 60 proteins in the chronic epilepsy group were identified as differentially expressed. Bioinformatics analysis suggested that the pathogenesis of cardiac injury in acute and chronic epilepsy may be due to different molecular mechanisms. Three proteins, a receptor for activated protein kinase C1 (RACK1), aldehyde dehydrogenase 6 family member A1 (ALDH6A1), and glycerol uptake/transporter 1 (Hhatl), were identified as playing crucial roles in cardiac injury during epilepsy and were successfully confirmed by Western blot and immunohistochemistry analysis. Our study not only provides a deeper understanding of the pathophysiological mechanisms of myocardial damage in epilepsy, but also suggests some potential novel therapeutic targets for preventing cardiac injury and reducing the incidence of sudden death due to heart failure.

Incidence of sudden unexpected death in epilepsy in community-based cohort in China

OBJECTIVE

Sudden unexpected death in epilepsy (SUDEP) is associated with the high premature mortality observed among people with epilepsy. It is, however, considered a rare event in China, probably because of lack of awareness and limitation of studies in the country. We aimed to provide some initial estimation of the burden of SUDEP in China.

METHODS

We established a large Chinese community-based cohort of people with epilepsy between January 2010 and December 2011. For any participant who died during follow-up, detailed information on cause of death was obtained using a specifically designed Verbal Autopsy Questionnaire. All cases were reviewed by a multidisciplinary expert panel and reinvestigated if necessary. Sudden unexpected death in epilepsy incidence rates were estimated and case details provided.

RESULTS

The cohort consisted of 1562 people and during a median 5years follow-up, 72 deaths were reported. The all-causes death incidence was 11.23 (95% CI 8.86-14.07) per 1000 person-years. Fifteen died suddenly and unexpectedly in a reasonable state of health in the week preceding death. We recorded detailed information of these 15 deaths. Thirteen were considered to be probable SUDEP and two possible SUDEP. The incidence of probable SUDEP was 2.03 (95% CI 1.13-3.38) per 1000 person-years, and the incidence of all suspected (probable and possible) SUDEP was 2.34 (95% CI 1.36-3.77) per 1000 person-years.

SIGNIFICANCE

The incidence of SUDEP was relatively high among Chinese people with epilepsy when compared with that in previous community-based studies from high-income countries. The burden of SUDEP in China requires further assessments.

Epilepsy as a systemic condition: Link with somatic comorbidities

BACKGROUND

People with epilepsy have more concomitant medical conditions than the general population; these comorbidities play an important role in premature mortality. We sought to generate explanatory hypotheses about the co-occurrence of somatic comorbidities and epilepsy, avoiding causal and treatment-resultant biases.

METHODS

We collected clinical, demographic and somatic comorbidity data for 2016 consecutive adults with epilepsy undergoing assessment at a tertiary centre and in 1278 people with epilepsy in the community. Underlying causes of epilepsy were not classed as comorbidities.

RESULTS

Somatic comorbidities were more frequent in the referral centre (49%) where people more frequently had active epilepsy than in the community (36%). Consistent risk factors for comorbidities were found in both cohorts. Using multivariable ordinal regression adjusted for age, longer epilepsy duration and an underlying brain lesion were independently associated with a smaller burden of somatic conditions. The treatment burden, measured by the number of drugs to which people were exposed, was not an independent predictor. Shorter epilepsy duration was a predictor for conditions that conceivably harbour significant mortality risks.

CONCLUSIONS

Somatic comorbidities do not occur randomly in relation to epilepsy; having more severe epilepsy seems to be a risk factor. Independently from age, the early period after epilepsy onset appears to be at particular risk, although it is not clear whether this relates to an early mortality or to a later decrease in the burden of comorbidities. These results suggest that, for some people, epilepsy should be considered a systemic condition not limited to the CNS.

Hamartia in hippocampal sclerosis-associated mesial temporal lobe epilepsy

Hamartia are small collections of rounded glioneuronal cells that are thought to be due to aberrant cell migration. Their presence has been recognized in association with mesial temporal lobe epilepsy; their prevalence among cases of hippocampal sclerosis (HS) and any potential association with patient demographics and outcomes is unknown. This study examines hamartia in a series of 292 patients with pathologically confirmed HS. Medical records were reviewed for pertinent patient clinical information (follow-up mean 5years). Hamartia were identified in 96 cases (33%) and were seen primarily in the amygdala (n=88) and less commonly in the hippocampus (n=10) and temporal lobe (n=4). A statistically significant relationship was found between the presence of hamartia and male gender, younger age of seizure onset, and history of childhood febrile seizures and developmental delay. It is unclear if these associations represent a real association or are a result of the underlying pathologies related to chronic epilepsy. At follow-up, there were no significant differences between patients who had hamartia and those who lacked this finding. Hamartia were observed in all subtypes of HS and there was a significant difference found in subtype distribution as well as proportion of cases between subtypes, but no association with any specific subtype overall. The presence of hamartia was not associated with the coexistence of focal cortical dysplasia or any specific histologic pattern of dysplasia. Hamartia are a common concomitant finding in HS and indicates evidence of aberrant cell migration in the hippocampal and parahippocampal regions in these patients.

Neurodegeneration and Pathology in Epilepsy: Clinical and Basic Perspectives

Epilepsy is commonly associated with a number of neurodegenerative and pathological alterations in those areas of the brain that are involved in repeated electrographic seizures. These most prominently include neuron loss and an increase in astrocyte number and size but may also include enhanced blood-brain barrier permeability, the formation of new capillaries, axonal sprouting, and central inflammation. In animal models in which seizures are either repeatedly elicited or are self-generated, a similar set of neurodegenerative and pathological alterations in brain anatomy are observed. The primary causal agent responsible for these alterations may be the cascade of events that follow a seizure and lead to an hypoperfusion/hypoxic episode. While epilepsy has long and correctly been considered an electrical disorder, the vascular system likely plays an important causal role in the neurodegeneration and pathology that occur as a consequence of repeated seizures.

Long-term outcome of medically treated epilepsy

PURPOSE

To review the long-term outcome of epilepsy in population-based studies.

METHOD

Analysis of population-based studies.

RESULTS

About two of three patients with new-onset epilepsy will, in the long run, enter five-year terminal remission. Chances for remission are best for those with idiopathic or cryptogenic epilepsy. It is unclear whether the seizure outcome has improved over the last several decades. Social outcome, however, may have become better because of the improved level of knowledge on and public attitudes toward people with epilepsy, and possibly fewer prejudices at home, daycare, school, military and labor market.

CONCLUSION

While we still do not have a cure for epilepsy for all patients, relief of the medical and social consequences is available for many and hope is on the horizon for people with epilepsy.

Sudden unexpected death in epilepsy genetics: Molecular diagnostics and prevention

Epidemiologic studies clearly document the public health burden of sudden unexpected death in epilepsy (SUDEP). Clinical and experimental studies have uncovered dynamic cardiorespiratory dysfunction, both interictally and at the time of sudden death due to epilepsy. Genetic analyses in humans and in model systems have facilitated our current molecular understanding of SUDEP. Many discoveries have been informed by progress in the field of sudden cardiac death and sudden infant death syndrome. It is becoming apparent that SUDEP genomic complexity parallels that of sudden cardiac death, and that there is a pauci1ty of analytically useful postmortem material. Because many challenges remain, future progress in SUDEP research, molecular diagnostics, and prevention rests in international, collaborative, and transdisciplinary dialogue in human and experimental translational research of sudden death.

Retinal nerve fibre layer thinning is associated with drug resistance in epilepsy

OBJECTIVE

Retinal nerve fibre layer (RNFL) thickness is related to the axonal anterior visual pathway and is considered a marker of overall white matter 'integrity'. We hypothesised that RNFL changes would occur in people with epilepsy, independently of vigabatrin exposure, and be related to clinical characteristics of epilepsy.

METHODS

Three hundred people with epilepsy attending specialist clinics and 90 healthy controls were included in this cross-sectional cohort study. RNFL imaging was performed using spectral-domain optical coherence tomography (OCT). Drug resistance was defined as failure of adequate trials of two antiepileptic drugs to achieve sustained seizure freedom.

RESULTS

The average RNFL thickness and the thickness of each of the 90° quadrants were significantly thinner in people with epilepsy than healthy controls (p<0.001, t test). In a multivariate logistic regression model, drug resistance was the only significant predictor of abnormal RNFL thinning (OR=2.09, 95% CI 1.09 to 4.01, p=0.03). Duration of epilepsy (coefficient -0.16, p=0.004) and presence of intellectual disability (coefficient -4.0, p=0.044) also showed a significant relationship with RNFL thinning in a multivariate linear regression model.

CONCLUSIONS

Our results suggest that people with epilepsy with no previous exposure to vigabatrin have a significantly thinner RNFL than healthy participants. Drug resistance emerged as a significant independent predictor of RNFL borderline attenuation or abnormal thinning in a logistic regression model. As this is easily assessed by OCT, RNFL thickness might be used to better understand the mechanisms underlying drug resistance, and possibly severity. Longitudinal studies are needed to confirm our findings.

Recognizing and preventing epilepsy-related mortality: A call for action

Epilepsy is associated with a high rate of premature mortality from direct and indirect effects of seizures, epilepsy, and antiseizure therapies. Sudden unexpected death in epilepsy (SUDEP) is the second leading neurologic cause of total lost potential life-years after stroke, yet SUDEP may account for less than half of all epilepsy-related deaths. Some epilepsy groups are especially vulnerable: individuals from low socioeconomic status groups and those with comorbid psychiatric illness die more often than controls. Despite clear evidence of an important public health problem, efforts to assess and prevent epilepsy-related deaths remain inadequate. We discuss factors contributing to the underestimation of SUDEP and other epilepsy-related causes of death. We suggest the need for a systematic classification of deaths directly due to epilepsy (e.g., SUDEP, drowning), due to acute symptomatic seizures, and indirectly due to epilepsy (e.g., suicide, chronic effects of antiseizure medications). Accurately estimating the frequency of epilepsy-related mortality is essential to support the development and assessment of preventive interventions. We propose that educational interventions and public health campaigns targeting medication adherence, psychiatric comorbidity, and other modifiable risk factors may reduce epilepsy-related mortality. Educational campaigns regarding sudden infant death syndrome and fires, which kill far fewer Americans than epilepsy, have been widely implemented. We have done too little to prevent epilepsy-related deaths. Everyone with epilepsy and everyone who treats people with epilepsy need to know that controlling seizures will save lives.

Epidemiology and long-term Turku outcome of childhood-onset epilepsy and mortality. Personal experiences. Part I

Introduction.Epidemiological studies on epilepsy were long based, with few exceptions, on hospital and institution patients with a subsequent bias toward more difficult cases and the reported prevalence and incidence rates were often obviously too low. Few data are available on the temporal changes in the incidence of epilepsy.

Aim.To study the prevalence and incidence in an unselected child population including all the children living either in the society or in the institution, temporal changes in the incidence and mortality through five decades.

Methods.The most important personal data were reviewed and compared with the relevant data of other investigators.

Results and discussion.The prevalence of epilepsy in our study was 3.2/1000, quite obviously true for the contemporary methodology and well comparable with 3.4–4.2/1000 of other relevant studies published about two decades later and using a more advanced methodology. Similarly, the incidence of 35/100 000, ascertained in two Finnish studies, was comparable with the relevant contemporary literature data. Another study of ours shows that, probably associated with the people “coming from the shadows” and an improved diagnostic methodology, the incidence of childhood epilepsy has increased and is now 60–70/100 000. However, the incidence of childhood epilepsy shows an obvious decreasing trend in the first two decades of the 2000s.

Conclusions.The incidence of childhood epilepsy, in all probability true for the contemporary methodology, was lower than it is now, but it now again shows a decreasing trend.

Audit of practice in sudden unexpected death in epilepsy (SUDEP) post mortems and neuropathological findings

AIMS

Sudden unexpected death in epilepsy (SUDEP) is one of the leading causes of death in people with epilepsy. For classification of definite SUDEP, a post mortem (PM), including anatomical and toxicological examination, is mandatory to exclude other causes of death. We audited PM practice as well as the value of brain examination in SUDEP.

METHODS

We reviewed 145 PM reports in SUDEP cases from four UK neuropathology centres. Data were extracted for clinical epilepsy details, circumstances of death and neuropathological findings.

RESULTS

Macroscopic brain abnormalities were identified in 52% of cases. Mild brain swelling was present in 28%, and microscopic pathologies relevant to cause or effect of seizures were seen in 89%. Examination based on whole fixed brains (76.6% of all PMs), and systematic regional sampling was associated with higher detection rates of underlying pathology (P < 0.01). Information was more frequently recorded regarding circumstances of death and body position/location than clinical epilepsy history and investigations.

CONCLUSION

Our findings support the contribution of examination of the whole fixed brain in SUDEP, with high rates of detection of relevant pathology. Availability of full clinical epilepsy-related information at the time of PM could potentially further improve detection through targeted tissue sampling. Apart from confirmation of SUDEP, complete neuropathological examination contributes to evaluation of risk factors as well as helping to direct future research into underlying causes.

Review: Hippocampal sclerosis in epilepsy: a neuropathology review

Hippocampal sclerosis (HS) is a common pathology encountered in mesial temporal lobe epilepsy (MTLE) as well as other epilepsy syndromes and in both surgical and post-mortem practice. The 2013 International League Against Epilepsy (ILAE) classification segregates HS into typical (type 1) and atypical (type 2 and 3) groups, based on the histological patterns of subfield neuronal loss and gliosis. In addition, granule cell reorganization and alterations of interneuronal populations, neuropeptide fibre networks and mossy fibre sprouting are distinctive features of HS associated with epilepsies; they can be useful diagnostic aids to discriminate from other causes of HS, as well as highlighting potential mechanisms of hippocampal epileptogenesis. The cause of HS remains elusive and may be multifactorial; the contribution of febrile seizures, genetic susceptibility, inflammatory and neurodevelopmental factors are discussed. Post-mortem based research in HS, as an addition to studies on surgical samples, has the added advantage of enabling the study of the wider network changes associated with HS, the long-term effects of epilepsy on the pathology and associated comorbidities. It is likely that HS is heterogeneous in aspects of its cause, epileptogenetic mechanisms, network alterations and response to medical and surgical treatments. Future neuropathological studies will contribute to better recognition and understanding of these clinical and patho-aetiological subtypes of HS.

The consequences of refractory epilepsy and its treatment

Seizures in some 30% to 40% of patients with epilepsy fail to respond to antiepileptic drugs or other treatments. While much has been made of the risks of new drug therapies, not enough attention has been given to the risks of uncontrolled and progressive epilepsy. This critical review summarizes known risks associated with refractory epilepsy, provides practical clinical recommendations, and indicates areas for future research. Eight international epilepsy experts from Europe, the United States, and South America met on May 4, 2013, to present, review, and discuss relevant concepts, data, and literature on the consequences of refractory epilepsy. While patients with refractory epilepsy represent the minority of the population with epilepsy, they require the overwhelming majority of time, effort, and focus from treating physicians. They also represent the greatest economic and psychosocial burdens. Diagnostic procedures and medical/surgical treatments are not without risks. Overlooked, however, is that these risks are usually smaller than the risks of long-term, uncontrolled seizures. Refractory epilepsy may be progressive, carrying risks of structural damage to the brain and nervous system, comorbidities (osteoporosis, fractures), and increased mortality (from suicide, accidents, sudden unexpected death in epilepsy, pneumonia, vascular disease), as well as psychological (depression, anxiety), educational, social (stigma, driving), and vocational consequences. Adding to this burden is neuropsychiatric impairment caused by underlying epileptogenic processes ("essential comorbidities"), which appears to be independent of the effects of ongoing seizures themselves. Tolerating persistent seizures or chronic medicinal adverse effects has risks and consequences that often outweigh risks of seemingly "more aggressive" treatments. Future research should focus not only on controlling seizures but also on preventing these consequences.