Editing Epilepsy (section)

==== Focal seizures ====
[[Focal seizure|Focal seizures]] originate in one [[Cerebral hemisphere|hemisphere]] of the brain and may involve localized or distributed networks.<ref name="Berg2010">{{Cite journal |last1=Berg |first1=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 |pmid=20196795 |issn=1528-1167|url-access=subscription }}</ref> 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).<ref name="Beniczky2025" />

They are further classified based on the state of consciousness during the episode:<ref name="Beniczky2025" />

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

Certain experiences, known as [[Aura (symptom)|auras]] often precede focal seizures.<ref name="EB06">{{cite web |title=Seizures and Status Epilepticus: Diagnosis and Management in the Emergency Department |url=http://www.ebmedicine.net/topics.php?paction=showTopic&topic_id=77 |url-status=live |archive-url=https://web.archive.org/web/20101230141114/https://www.ebmedicine.net/topics.php?paction=showTopic&topic_id=77 |archive-date=30 December 2010 |work=Emergency Medicine Practice |vauthors=Shearer P}}</ref> The seizures can include sensory (visual, hearing, or smell), psychic, autonomic, and motor phenomena depending on which part of the brain is involved.<ref name="Ham2010" /> Muscle jerks may start in a specific muscle group and spread to surrounding muscle groups in which case it is known as a [[Jacksonian march]].<ref name="Brad2012">{{cite book |title=Bradley's neurology in clinical practice. |vauthors=Bradley WG |publisher=Elsevier/Saunders |year=2012 |isbn=978-1-4377-0434-1 |edition=6th |location=Philadelphia, PA |chapter=67}}</ref>[[Automatism (medicine)|Automatisms]] may occur, which are non-consciously generated activities and mostly simple repetitive movements like smacking the lips or more complex activities such as attempts to pick up something.<ref name="Brad2012" /> Some focal seizures can evolve into focal-to-bilateral [[Generalized tonic–clonic seizure|tonic-clonic seizures]], where abnormal brain activity spreads to both hemispheres.<ref name="Beniczky2025" />