What Is Epilepsy?

Living reference work entry


Defining epilepsy is a dynamic and challenging process, constantly in evolution as our understanding of the brain and its underlying mechanisms expand. The International League Against Epilepsy (ILAE) has led the global effort over the last several decades, and the various definitions have gone through several revisions (Fisher et al. 2014; Fisher 2015). Most recently, the ILAE accepted a new practical clinical definition of epilepsy stated as:
A disease of the brain defined by any of the following conditions
  1. 1.

    At least two unprovoked (or reflex) seizures occurring > 24 h apart

  2. 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. 3.

    Diagnosis of an epilepsy syndrome


Epilepsy is considered to be resolved for individuals who had an age-dependent epilepsy syndrome but are now past the applicable age or those who have remained seizure-free for the last 10 years, with no seizure medicines for the last 5 years. (Fisher et al. 2014)


  1. Arzimanoglou A, French J, Blume WT, Cross JH, Ernst JP, Feucht M et al (2009) Lennox-Gastaut syndrome: a consensus approach on diagnosis, assessment, management, and trial methodology. Lancet Neurol 8(1):82–93CrossRefGoogle Scholar
  2. Atakli D, Senadim S, Baslo SA, Guveli BT, Daryan MD, Sari H (2016) Misdiagnosis in JME: still a problem after 17 years? Seizure 36:27–30CrossRefGoogle Scholar
  3. Auvin S, Cilio MR, Vezzani A (2016) Current understanding and neurobiology of epileptic encephalopathies. Neurobiol Dis 92(Pt A):72–89CrossRefGoogle Scholar
  4. Beal JC, Cherian K, Moshe SL (2012) Early-onset epileptic encephalopathies: Ohtahara syndrome and early myoclonic encephalopathy. Pediatr Neurol 47(5):317–323CrossRefGoogle Scholar
  5. Berg AT, Berkovic SF, Brodie MJ, Buchhalter J, Cross JH, van Emde Boas W et al (2010) Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005–2009. Epilepsia 51(4):676–685CrossRefGoogle Scholar
  6. Blumenfeld H (2005) Cellular and network mechanisms of spike-wave seizures. Epilepsia 46(Suppl 9):21–33CrossRefGoogle Scholar
  7. Brodie MJ (2016) Modern management of juvenile myoclonic epilepsy. Expert Rev Neurother 16(6):681–688CrossRefGoogle Scholar
  8. Broomfield E, Cavazos J, Sirven J (eds) (2006) An introduction to epilepsy [internet]. Chapter 1, Basic mechanisms underlying seizures and epilepsy. American Epilepsy Society, West HartfordGoogle Scholar
  9. Camfield PR (2011) Definition and natural history of Lennox-Gastaut syndrome. Epilepsia 52(Suppl 5):3–9CrossRefGoogle Scholar
  10. Camfield P, Camfield C (2015) Febrile seizures and genetic epilepsy with febrile seizures plus (GEFS+). Epileptic Disord 17(2):124–133PubMedGoogle Scholar
  11. Camfield CS, Striano P, Camfield PR (2013) Epidemiology of juvenile myoclonic epilepsy. Epilepsy Behav 28(Suppl 1):S15–S17CrossRefGoogle Scholar
  12. Caraballo R, Koutroumanidis M, Panayiotopoulos CP, Fejerman N (2009) Idiopathic childhood occipital epilepsy of Gastaut: a review and differentiation from migraine and other epilepsies. J Child Neurol 24(12):1536–1542CrossRefGoogle Scholar
  13. Caraballo RH, Flesler S, Pasteris MC, Lopez Avaria MF, Fortini S, Vilte C (2013) Myoclonic epilepsy in infancy: an electroclinical study and long-term follow-up of 38 patients. Epilepsia 54(9):1605–1612CrossRefGoogle Scholar
  14. Carmant L, Whiting S (2012) Lennox-Gastaut syndrome: an update on treatment. Can J Neurol Sci 39(6):702–711CrossRefGoogle Scholar
  15. Connolly MB (2016) Dravet syndrome: diagnosis and long-term course. Can J Neurol Sci 43(Suppl 3):S3–S8CrossRefGoogle Scholar
  16. Donner EJ, Snead OC 3rd (2006) New generation anticonvulsants for the treatment of epilepsy in children. NeuroRx 3(2):170–180CrossRefGoogle Scholar
  17. Dravet C (2011) The core Dravet syndrome phenotype. Epilepsia 52(Suppl 2):3–9CrossRefGoogle Scholar
  18. Ferrari-Marinho T, Macedo EF, Costa Neves RS, Costa LV, Tudesco IS, Carvalho KC et al (2013) Gastaut type idiopathic childhood occipital epilepsy. Epileptic Disord 15(1):80–83PubMedGoogle Scholar
  19. Fisher RS (2015) Redefining epilepsy. Curr Opin Neurol 28(2):130–135CrossRefGoogle Scholar
  20. Fisher RS, Acevedo C, Arzimanoglou A, Bogacz A, Cross JH, Elger CE et al (2014) ILAE official report: a practical clinical definition of epilepsy. Epilepsia 55(4):475–482CrossRefGoogle Scholar
  21. Genton P, Thomas P, Kasteleijn-Nolst Trenite DG, Medina MT, Salas-Puig J (2013) Clinical aspects of juvenile myoclonic epilepsy. Epilepsy Behav 28(Suppl 1):S8–14CrossRefGoogle Scholar
  22. Glauser TA, Loddenkemper T (2013) Management of childhood epilepsy. Continuum (Minneap Minn) 19(3 Epilepsy):656–681Google Scholar
  23. Go CY, Mackay MT, Weiss SK, Stephens D, Adams-Webber T, Ashwal S et al (2012) Evidence-based guideline update: medical treatment of infantile spasms. Report of the Guideline Development Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology 78(24):1974–1980CrossRefGoogle Scholar
  24. Gobbi G, Boni A, Filippini M (2006) The spectrum of idiopathic Rolandic epilepsy syndromes and idiopathic occipital epilepsies: from the benign to the disabling. Epilepsia 47(Suppl 2):62–66CrossRefGoogle Scholar
  25. Guerrini R, Pellacani S (2012) Benign childhood focal epilepsies. Epilepsia 53(Suppl 4):9–18CrossRefGoogle Scholar
  26. Hart AR, Pilling EL, Alix JJ (2015) Neonatal seizures-part 2: aetiology of acute symptomatic seizures, treatments and the neonatal epilepsy syndromes. Arch Dis Child Educ Pract Ed 100(5):226–232CrossRefGoogle Scholar
  27. Hawrylycz MJ, Lein ES, Guillozet-Bongaarts AL, Shen EH, Ng L, Miller JA et al (2012) An anatomically comprehensive atlas of the adult human brain transcriptome. Nature 489(7416):391–399CrossRefGoogle Scholar
  28. Kelley SA, Kossoff EH (2010) Doose syndrome (myoclonic-astatic epilepsy): 40 years of progress. Dev Med Child Neurol 52(11):988–993CrossRefGoogle Scholar
  29. Khan S, Al Baradie R (2012) Epileptic encephalopathies: an overview. Epilepsy Res Treat 2012:403592PubMedPubMedCentralGoogle Scholar
  30. Korff CM, Nordli DR Jr (2006) Epilepsy syndromes in infancy. Pediatr Neurol 34(4):253–263CrossRefGoogle Scholar
  31. Korff CM, Jallon P, Lascano A, Michel C, Seeck M, Haenggeli CA (2009) Is benign myoclonic epilepsy of infancy truly idiopathic and generalized? Epileptic Disord 11(2):132–135PubMedGoogle Scholar
  32. Kossoff EH, Zupec-Kania BA, Rho JM (2009) Ketogenic diets: an update for child neurologists. J Child Neurol 24(8):979–988CrossRefGoogle Scholar
  33. Koutroumanidis M (2007) Panayiotopoulos syndrome: an important electroclinical example of benign childhood system epilepsy. Epilepsia 48(6):1044–1053CrossRefGoogle Scholar
  34. Kwan P, Schachter SC, Brodie MJ (2011) Drug-resistant epilepsy. N Engl J Med 365(10):919–926CrossRefGoogle Scholar
  35. Lewis EC, Duchowny M (2015) Long-term seizure and antiepileptic drug outcomes after epilepsy surgery in children. In: Malmgren K, Baxendale S, Cross H (eds) Long-term outcomes of epilepsy surgery in adults and children, 1st edn. Springer, Switzerland, p 43CrossRefGoogle Scholar
  36. Matricardi S, Verrotti A, Chiarelli F, Cerminara C, Curatolo P (2014) Current advances in childhood absence epilepsy. Pediatr Neurol 50(3):205–212CrossRefGoogle Scholar
  37. McCormick DA, Contreras D (2001) On the cellular and network bases of epileptic seizures. Annu Rev Physiol 63:815–846CrossRefGoogle Scholar
  38. Montouris GD (2011) Rational approach to treatment options for Lennox-Gastaut syndrome. Epilepsia 52(Suppl 5):10–20CrossRefGoogle Scholar
  39. Muthugovindan D, Hartman AL (2010) Pediatric epilepsy syndromes. Neurologist 16(4):223–237CrossRefGoogle Scholar
  40. Nickels K (2015) Seizure and psychosocial outcomes of childhood and juvenile onset generalized epilepsies: wolf in sheep’s clothing, or well-dressed wolf? Epilepsy Curr 15(3):114–117CrossRefGoogle Scholar
  41. Ohtahara S, Yamatogi Y (2003) Epileptic encephalopathies in early infancy with suppression-burst. J Clin Neurophysiol 20(6):398–407CrossRefGoogle Scholar
  42. Ohtahara S, Yamatogi Y (2006) Ohtahara syndrome: with special reference to its developmental aspects for differentiating from early myoclonic encephalopathy. Epilepsy Res 70(Suppl 1):S58–S67CrossRefGoogle Scholar
  43. Ottman R (1993) Autosomal dominant partial epilepsy with auditory features. In: Pagon RA, Adam MP, Ardinger HH, Wallace SE, Amemiya A, Bean LJH et al (eds) GeneReviews®. University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reservedGoogle Scholar
  44. Panayiotopoulos CP, Michael M, Sanders S, Valeta T, Koutroumanidis M (2008) Benign childhood focal epilepsies: assessment of established and newly recognized syndromes. Brain 131(Pt 9):2264–2286CrossRefGoogle Scholar
  45. Pellock JM, Hrachovy R, Shinnar S, Baram TZ, Bettis D, Dlugos DJ et al (2010) Infantile spasms: a U.S. Consensus report. Epilepsia 51(10):2175–2189CrossRefGoogle Scholar
  46. Ramey WL, Martirosyan NL, Lieu CM, Hasham HA, Lemole GM Jr, Weinand ME (2013) Current management and surgical outcomes of medically intractable epilepsy. Clin Neurol Neurosurg 115(12):2411–2418CrossRefGoogle Scholar
  47. Scharfman HE (2007) The neurobiology of epilepsy. Curr Neurol Neurosci Rep 7(4):348–354CrossRefGoogle Scholar
  48. Scheffer IE (2012) Diagnosis and long-term course of Dravet syndrome. Eur J Paediatr Neurol 16(Suppl 1):S5–S8CrossRefGoogle Scholar
  49. Scheffer IE, Zhang YH, Jansen FE, Dibbens L (2009) Dravet syndrome or genetic (generalized) epilepsy with febrile seizures plus? Brain and Development 31(5):394–400CrossRefGoogle Scholar
  50. Scheffer IE, Berkovic SF, et al (2014) The organization of the epilepsies: report of the ILAE Commission on Classification and TerminologyGoogle Scholar
  51. Specchio N, Vigevano F (2006) The spectrum of benign infantile seizures. Epilepsy Res 70(Suppl 1):S156–S167CrossRefGoogle Scholar
  52. Stephani U (2006) The natural history of myoclonic astatic epilepsy (Doose syndrome) and Lennox-Gastaut syndrome. Epilepsia 47(Suppl 2):53–55CrossRefGoogle Scholar
  53. Tenney JR, Glauser TA (2013) The current state of absence epilepsy: can we have your attention? Epilepsy Curr 13(3):135–140CrossRefGoogle Scholar
  54. Tenney JR, Jain SV (2014) Absence epilepsy: older vs newer AEDs. Curr Treat Options Neurol 16(5):290. -014-0290-9CrossRefGoogle Scholar
  55. Turnbull J, Lohi H, Kearney JA, Rouleau GA, Delgado-Escueta AV, Meisler MH et al (2005) Sacred disease secrets revealed: the genetics of human epilepsy. Hum Mol Genet 14(2):2491–2500CrossRefGoogle Scholar
  56. Verrotti A, Loiacono G, Coppola G, Spalice A, Mohn A, Chiarelli F (2011) Pharmacotherapy for children and adolescents with epilepsy. Expert Opin Pharmacother 12(2):175–194CrossRefGoogle Scholar
  57. Widjaja E, Go C, McCoy B, Snead OC (2015) Neurodevelopmental outcome of infantile spasms: a systematic review and meta-analysis. Epilepsy Res 109:155–162CrossRefGoogle Scholar
  58. Wirrell E (2016) Infantile, childhood, and adolescent epilepsies. Continuum (Minneap Minn) 22(1 Epilepsy):60–93Google Scholar
  59. Yamamoto H, Okumura A, Fukuda M (2011) Epilepsies and epileptic syndromes starting in the neonatal period. Brain Dev 33(3):213–220CrossRefGoogle Scholar

Authors and Affiliations

  1. 1.SickKidsTorontoCanada
  2. 2.Neurology Centre of TorontoTorontoCanada
  3. 3.Division of Paediatric NeurologySickKidsTorontoCanada

Section editors and affiliations

  • James Thomas Rutka
    • 1
  1. 1.The Arthur and Sonia Labatt Brain Tumour Research CentreThe Hospital for Sick Children, The University of TorontoTorontoUSA

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