Lars Forsgren

Epileptic Seizures and Epilepsy: Definitions Proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE)

The International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE) have come to consensus definitions for the terms epileptic seizure and epilepsy. An epileptic seizure is a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Epilepsy is a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures and by the neurobiologic, cognitive, psychological, and social consequences of this condition. The definition of epilepsy requires the occurrence of at least one epileptic seizure.

ILAE Official Report: A practical clinical definition of epilepsy

Epilepsy was defined conceptually in 2005 as a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures. This definition is usually practically applied as having two unprovoked seizures >24 h apart. The International League Against Epilepsy (ILAE) accepted recommendations of a task force altering the practical definition for special circumstances that do not meet the two unprovoked seizures criteria. The task force proposed that epilepsy be considered to be a disease of the brain defined by any of the following conditions: (1) At least two unprovoked (or reflex) seizures occurring >24 h apart; (2) one unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years; (3) diagnosis of an epilepsy syndrome. Epilepsy is considered to be resolved for individuals who either had an age‐dependent epilepsy syndrome but are now past the applicable age or who have remained seizure‐free for the last 10 years and off antiseizure medicines for at least the last 5 years. “Resolved” is not necessarily identical to the conventional view of “remission or “cure.” Different practical definitions may be formed and used for various specific purposes. This revised definition of epilepsy brings the term in concordance with common use.

The epidemiology of epilepsy in Europe – a systematic review

Population‐based epidemiological studies on epilepsy are available mainly from the UK and the Nordic, Baltic and western Mediterranean countries. No studies were identified from large areas of Europe, especially from the former eastern Europe (except the Baltic countries) and the eastern Mediterranean countries. Based on the prevalence of epilepsy in different studies and accounting for incomplete case identification the estimated number of children and adolescents in Europe with active epilepsy is 0.9 million (prevalence 4.5–5.0 per 1000), 1.9 million in ages 20–64 years (prevalence six per 1000) and 0.6 million in ages 65 years and older (prevalence seven per 1000). Approximately 20–30% of the epilepsy population have more than one seizure per month. Based on the age‐specific incidence rates in European studies, the estimated number of new cases per year amongst European children and adolescents is 130 000 (incidence rate 70 per 100 000), 96 000 in adults 20–64 years (incidence rate 30 per 100 000) and 85 000 in the elderly 65 years and older (incidence 100 per 100 000). The proportion of both new and established cases with epilepsy in the young, adults and elderly in individual countries may differ substantially from total European distribution because of differences in age structure.

Incidence and Clinical Characterization of Unprovoked Seizures in Adults: A Prospective Population‐Based Study

In a population‐based prospective study of epileptic seizures in adults aged ≥17 years, we identified 563 patients with possible seizures in a period of 34 months. Seizures were unprovoked in 160 patients, an incidence of 56 in 100,000 person‐years. There was no difference in incidence between sexes. Age‐specific incidences of unprovoked seizures increased sharply in men from age 60 years and in women from age 70 years. The incidence of unprovoked seizures in those aged ≥65 years was 139 (men 166, women 116). The cumulative incidence of unprovoked seizures between the ages of 17 and 84 years was 4.6%. The proportion with an identified presumptive cause for unprovoked seizures increased with advancing age. A presumed etiology was identified in 77% of persons aged ≥60 years. Stroke was the most common etiology, detected in 30% (incidence 16) and in 45% at ages ≥60 years. Tumors were detected in 11% (incidence 6) and Alzheimers disease was detected in 7% (incidence 4). Eighteen percent of patients were demented. Unprovoked seizures were partial in 68% of cases (incidence 38), and generalized in 16% (incidence 9). Another 13% of patients had generalized seizures, but seizure onset was not witnessed (incidence 7). In 16%, there was a delay of ≥1 year from the first unprovoked seizure to initial diagnosis.

Recommendation for a definition of acute symptomatic seizure.

Purpose:  To consider the definition of acute symptomatic seizures for epidemiological studies, and to refine the criteria used to distinguish these seizures from unprovoked seizures for specific etiologies.

An altered immune response to Epstein-Barr virus in multiple sclerosis: A prospective study

Objective: To investigate the association between human herpesviruses and multiple sclerosis (MS), as well as between measles virus and MS. Methods: The authors identified prospectively collected serum samples from 73 MS cases and retrospective sera from 161 MS cases in two population-based serum bank registers. Analyses of IgG antibody responses in cases and matched referents were performed for Epstein-Barr virus (EBV [EBNA-1 and VCA]), human herpesvirus 6 (HHV-6), herpes simplex virus (HSV), varicella zoster virus (VZV), and measles. Results: All cases showed signs of past EBV infection. High activity to EBNA-1 and HHV-6 significantly (borderline significance for HHV-6) increased the risk for MS in prospective sera. A discrepancy between activities to EBNA-1 and VCA was striking in MS samples collected less than 5 years before relapsing-remitting MS onset, where high activity to EBNA-1 significantly increased, and high VCA activity significantly decreased the risk for MS. There was no support for major causal roles for HSV, VZV, or measles. Conclusion: Individuals who will develop MS exhibit an altered immune response against the EBV virus characterized by a high IgG activity to EBNA-1 in the absence of high activity to VCA, this being most pronounced in the 5-year period preceding MS onset.

Mortality of Epilepsy in Developed Countries: A Review

Summary:  Mortality in people with epilepsy has been studied in many different populations. In population‐based incidence cohorts of epilepsy with 7–29 years follow‐up, there was up to a threefold increase in mortality, compared to the general population (standardized mortality ratios [SMR] ranged from 1.6 to 3.0). When studies include selected epilepsy populations where patients with frequent and severe seizures are more common, the mortality is even greater. Relative survivorship (RS) following the diagnosis of epilepsy was 91%, 85%, and 83% after 5, 10, and 15 years, respectively. In a population with childhood‐onset epilepsy, RS was 94% and 88% after 10 and 20 years.

Cognitive function in early Parkinson's disease: a population-based study

Background and purpose:  The study aims to describe the frequency, pattern and determinants of cognitive function in patients with newly diagnosed Parkinson’s disease (PD); to compare patients with impaired cognition to patients with intact cognition; and to compare to matched healthy controls.

Estimating the cost of epilepsy in Europe: a review with economic modeling.

Purpose: Based on available epidemiologic, health economic, and international population statistics literature, the cost of epilepsy in Europe was estimated.

Prevalence and characteristics of epilepsy in children in Northern Sweden

Active epilepsy was assessed in all children aged 0-16 years in an area of northern Sweden with about 250,000 inhabitants and around 50,000 children in the age group. One hundred and fifty-five children fulfilled the criteria of active epilepsy giving a prevalence rate of 4.2/1000. The proportion of boys to girls was 1:1.1. This dominance of girls had also been seen in a prospective study of incidence of epilepsy in the same area. Partial seizures were more common than generalized. Among the syndromes benign childhood epilepsy with centrotemporal spikes occurred in 17.4%, absence epilepsy in 6.5% and Lennox-Gastaut syndrome in 5.8%. Children with neurodeficit (ND) more often had generalized epileptic syndromes while the non-ND groups more often had localisation related syndromes. The aetiology was regarded to be remote symptomatic in 42%, idiopathic in 28% and cryptogenic in 30% of the children. Almost all children were on antiepileptic treatment, three quarters of them on monotherapy. Neurodeficit was noted in 42%. The prevalence of epilepsy and mental retardation was 1.7/1000. Relatively few children with neurodeficit had been seizure free during the last year, 43% had more than one seizures per month compared to 19% in the non-ND group.