Editing Seizure (section)

== Classification ==
{{See also|Seizure types}}

Seizures are classified according to their site of onset in the brain, clinical features, and level of awareness during the episode. In 2025, the [[International League Against Epilepsy]] (ILAE) released an updated classification to improve clarity, clinical relevance, and global applicability. The system distinguishes four major types: focal, generalized, unknown onset, and unclassified seizures. Seizures are further characterized based on whether awareness is preserved or impaired, as determined by responsiveness during the event.<ref name="Beniczky2025">{{Cite journal |last=Beniczky |first=Sándor |last2=Trinka |first2=Eugen |last3=Wirrell |first3=Elaine |last4=Abdulla |first4=Fatema |last5=Al Baradie |first5=Raidah |last6=Alonso Vanegas |first6=Mario |last7=Auvin |first7=Stéphane |last8=Singh |first8=Mamta Bhushan |last9=Blumenfeld |first9=Hal |last10=Bogacz Fressola |first10=Alicia |last11=Caraballo |first11=Roberto |last12=Carreno |first12=Mar |last13=Cendes |first13=Fernando |last14=Charway |first14=Augustina |last15=Cook |first15=Mark |date=2025-04-23 |title=Updated classification of epileptic seizures: Position paper of the International League Against Epilepsy |url=https://onlinelibrary.wiley.com/doi/10.1111/epi.18338 |journal=Epilepsia |language=en |doi=10.1111/epi.18338 |issn=0013-9580|doi-access=free }}</ref>

===Focal seizures===
[[Focal seizure]]s originate within a network limited to one [[Cerebral hemisphere|hemisphere]] of the brain.<ref name="Berg2010">{{Cite journal |last=Berg |first=Anne T. |last2=Berkovic |first2=Samuel F. |last3=Brodie |first3=Martin J. |last4=Buchhalter |first4=Jeffrey |last5=Cross |first5=J. Helen |last6=Van Emde Boas |first6=Walter |last7=Engel |first7=Jerome |last8=French |first8=Jacqueline |last9=Glauser |first9=Tracy A. |last10=Mathern |first10=Gary W. |last11=Moshé |first11=Solomon L. |last12=Nordli |first12=Douglas |last13=Plouin |first13=Perrine |last14=Scheffer |first14=Ingrid E. |date=2010 |title=Revised terminology and concepts for organization of seizures and epilepsies: Report of the ILAE Commission on Classification and Terminology, 2005–2009 |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1528-1167.2010.02522.x |journal=Epilepsia |language=en |volume=51 |issue=4 |pages=676–685 |doi=10.1111/j.1528-1167.2010.02522.x |issn=1528-1167}}</ref> They may arise from the cerebral cortex or subcortical structures. For a given seizure type, the site of onset tends to be consistent across episodes. Once initiated, the seizure may remain localized or spread to adjacent areas, and in some cases, may propagate to the opposite hemisphere (contralateral spread). Despite this potential for spread, the initial focus remains consistent.

They are subdivided based on whether consciousness is preserved or impaired, a classifier defined by awareness and responsiveness during the event:<ref name="Beniczky2025" />

* Focal preserved consciousness seizure: the person remains aware and responsive.
* Focal impaired consciousness seizure: awareness and/or responsiveness are affected.

They can manifest with motor, sensory, autonomic, cognitive, or emotional symptoms, depending on the regions involved. Some focal seizures can evolve into focal-to-bilateral [[Generalized tonic–clonic seizure|tonic-clonic seizures]], where abnormal brain activity spreads to both hemispheres.

===Generalized seizures===
[[Generalized epilepsy|Generalized seizures]] originate at a specific point within, and quickly spread across both hemispheres through interconnected brain networks. Generalized seizures can present in several forms, including:<ref name="Beniczky2025" />

* [[Absence seizure]]s (brief lapses in awareness)
* [[Generalized tonic–clonic seizure]]s (stiffening followed by rhythmic jerking)
* Other generalized seizures (a grouping term encompassing various motor and non-motor types)

Generalized tonic–clonic seizures are associated with the highest morbidity and mortality, and are the primary risk factor for [[sudden unexpected death in epilepsy]] (SUDEP).<ref>{{Cite journal |last=Salas-Puig |first=Xavier |last2=Iniesta |first2=Marc |last3=Abraira |first3=Laura |last4=Puig |first4=Josep |last5=QUIN-GTC study group |date=2019 |title=Accidental injuries in patients with generalized tonic-clonic seizures. A multicenter, observational, cross-sectional study (QUIN-GTC study) |url=https://pubmed.ncbi.nlm.nih.gov/30658321 |journal=Epilepsy & Behavior |volume=92 |pages=135–139 |doi=10.1016/j.yebeh.2018.10.043 |issn=1525-5069 |pmid=30658321}}</ref>

=== Unknown (whether focal or generalized) seizures ===
When available information is insufficient to determine whether a seizure is focal or generalized, it is classified as unknown. These seizures may still be characterized based on consciousness and observable manifestations when possible.<ref name="Beniczky2025" />

=== Unclassified seizures ===
Seizures are designated as unclassified when they are recognized as epileptic events, but insufficient information is available to assign them to any specific class. This is typically a temporary designation pending further clinical evaluation.<ref name="Beniczky2025" />