title: Prevalence and etiology of epilepsy in a Norwegian county-A population based study.
abstract: OBJECTIVE
  Epilepsy represents a substantial personal and social burden worldwide. When addressing the multifaceted issues of epilepsy care, updated epidemiologic studies using recent guidelines are essential. The aim of this study was to find the prevalence and causes of epilepsy in a representative Norwegian county, implementing the new guidelines and terminology suggested by the International League Against Epilepsy (ILAE).
  
  
  METHODS
  Included in the study were all patients from Buskerud County in Norway with a diagnosis of epilepsy at Drammen Hospital and the National Center for Epilepsy at Oslo University Hospital. The study period was 1999-2014. Patients with active epilepsy were identified through a systematic review of medical records, containing information about case history, electroencephalography (EEG), cerebral magnetic resonance imaging (MRI), genetic tests, blood samples, treatment, and other investigations. Epilepsies were classified according to the revised terminology suggested by the ILAE in 2010.
  
  
  RESULTS
  In a population of 272,228 inhabitants, 1,771 persons had active epilepsy. Point prevalence on January 1, 2014 was 0.65%. Of the subjects registered with a diagnostic code of epilepsy, 20% did not fulfill the ILAE criteria of the diagnosis. Epilepsy etiology was structural-metabolic in 43%, genetic/presumed genetic in 20%, and unknown in 32%. Due to lack of information, etiology could not be determined in 4%.
  
  
  CONCLUSIONS
  Epilepsy is a common disorder, affecting 0.65% of the subjects in this cohort. Every fifth subject registered with a diagnosis of epilepsy was misdiagnosed. In those with a reliable epilepsy diagnosis, every third patient had an unknown etiology. Future advances in genetic research will probably lead to an increased identification of genetic and hopefully treatable causes of epilepsy.
authors: Department of Neurology, Drammen Hospital, Drammen, Norway.
authors: Marte
authors: M
authors: Syvertsen
authors: National Center for Epilepsy, Oslo University Hospital, Oslo, Norway.
authors: Karl Otto
authors: KO
authors: Nakken
authors: Department of Neurology, Drammen Hospital, Drammen, Norway.
authors: Astrid
authors: A
authors: Edland
authors: Department of Neurology, Drammen Hospital, Drammen, Norway.
authors: Gunnar
authors: G
authors: Hansen
authors: Department of Neurology, Drammen Hospital, Drammen, Norway.
authors: Morten Kristoffer
authors: MK
authors: Hellum
authors: Department of Neurology, Drammen Hospital, Drammen, Norway.
authors: Jeanette
authors: J
authors: Koht
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D018672:Community Health Planning; D004569:Electroencephalography; D004827:Epilepsy / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D005820:Genetic Testing; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D055815:Young Adult
keywords: Classification; Epidemiology; Epilepsy; Norway; Prevalence