Epidemiology of Idiopathic Generalized Epilepsies

Abstract

Summary: Idiopathic generalized epilepsies (IGEs) are a relatively new category of disorders defined by strict clinical and electroencephalogram (EEG) features proposed by the International League Against Epilepsy (ILAE) classification of epileptic syndromes. IGEs are usually easy to diagnose when clinical and EEG data are collected, but epilepsy is not synonymous with epileptic syndrome. So far, IGEs are studied in the large group of epilepsies of undetermined or unknown etiology although the genetic origin is now largely accepted. ILAE-proposed criteria are helpful in the clinical and therapeutic management of IGEs, but many epidemiologic studies still confuse the cryptogenic and idiopathic groups. Some syndromes in childhood, which are completely described by strict electroclinical criteria such as the absence epilepsies, juvenile myoclonic epilepsies, are usually included and analyzed in epidemiologic studies; however, other epileptic syndromes observed in infancy, such as benign familial neonatal seizures and benign myoclonic epilepsy in infancy, are quite rare and are usually excluded from epidemiologic surveys because they are difficult to describe completely in electro-clinical terms. Another strong limitation in the study of epidemiology of IGEs is the lack of EEG data, either because EEG is not available or the routine EEG is normal. This is particularly relevant in the inclusion of patients with only tonic-clonic seizures. IGEs encompass several different syndromes, and a few patients shift from one phenotype to another. The overlapping of some syndromes during infancy and adolescence increased the difficulty to individualize strictly the correct syndrome. Many discrepancies can be observed in the distribution of the different syndromes included in the group of IGEs, because the strict criteria for classifying these syndromes proposed by the ILAE are often not respected. With this understanding, the general frequency of IGEs can be assessed at 15-20% of all epilepsies. The frequency and the distribution of incidence and prevalence of the different syndromes are tentatively reported and discussed. When the term idiopathic is used following the restrictive ILAE criteria, the mortality data concerning patients with idiopathic epilepsies do not show an increased standardized mortality ratio.

Generalized myoclonic epilepsy with photosensitivity in juvenile dogs caused by a defective DIRAS family GTPase 1

“…Generalized myoclonic epilepsy in RR dogs reveals important parallels to JME, which is one of the most common forms of epilepsy in humans (14,(20)(21)(22)(23). As in humans, jerks are bilateral, arrhythmic, at times asymmetric, and predominate upon the upper limbs and trunk (20,21), whereby additional nodding movements of the head were present in some RRs.…”

Mutation analysis of the hyperpolarization-activated cyclic nucleotide-gated channels HCN1 and HCN2 in idiopathic generalized epilepsy

“…Idiopathic generalized epilepsies (IGEs) account for 15-20% of all epilepsies and affect approximately 0.2% of the general population (Jallon and Latour, 2005). IGEs encompass several syndromes that are characterized by age-related, recurrent, unprovoked generalized seizures in the absence of detectable brain lesions or metabolic abnormalities (International League Against Epilepsy, 1989).…”

The Effect of Cognitive Functions on EEG in Patients with Juvenile Myoclonic Epilepsy

“…[1][2][3][4][5][6] Seizures are known to be triggered by conditions such as sleep deprivation, sudden awakening, fatigue, alcohol intake, flashing lights, menstruation and stres. [1][2][3][4] It has been also demonstrated that spesific or nonspecific complex cognitive activities such as calculations, constructive activities, drawing, playing strategic board games are able to precipitate seizures.…”