Name: Azetukalner (XEN1101) in Focal onset seizures: Definition and etiology
Published: 2026-09-21T21:41:53-04:00

Product information and disease description Place of product in therapy Disease description

Definition and etiology

7 evidence topics · 6 sources

Operational definition of epilepsy

“Seizures are defined as transient symptoms and signs due to abnormal excessive or simultaneous neuronal activity of a population of neuronal cells in the brain.” (opens the source at this quote in a new tab)
“The diagnosis of epilepsy requires at least two unprovoked seizures occurring greater than twenty-four hours apart.” (opens the source at this quote in a new tab)
“Therefore, the definition of epilepsy has been revised and expanded from having two or more unprovoked seizures more than twenty-four hours apart to including those with one seizure and a high likelihood (more than 60%) of having another” (opens the source at this quote in a new tab)
“More than 60% was taken because it is the lower limit of the confidence interval for the individual with two unprovoked seizures having another seizure” (opens the source at this quote in a new tab)

Resolved epilepsy

“It is said to be resolved after ten years of the seizure-free period with the last five years spent without medications, or the patient is no longer at risk for age-related epilepsy syndrome” (opens the source at this quote in a new tab)

Definition of focal seizures and the seizure classes

“Focal seizures are defined as originating within networks limited to one hemisphere.” (opens the source at this quote in a new tab)
“They may be discretely localized or more widely distributed and may originate in cortical or subcortical structures.” (opens the source at this quote in a new tab)
“The updated classification maintains four main seizure classes: Focal, Generalized, Unknown (whether focal or generalized), and Unclassified.” (opens the source at this quote in a new tab)
“This updated classification comprises four main classes and 21 seizure types.” (opens the source at this quote in a new tab)

Definition of drug-resistant epilepsy

“Failure of adequate trials of two tolerated and appropriately chosen and used antiseizure medication (ASM) schedules (whether as monotherapies or in combination) to achieve sustained seizure freedom” (opens the source at this quote in a new tab)
“The number of people for whom treatment fails to control their seizures remains at about 30%” (opens the source at this quote in a new tab)

Predictors of drug resistance and its association with focal epilepsy

“Some syndromes respond better to medication, e.g. the idiopathic generalized epilepsies or the childhood onset self-limited epilepsies which are less associated with resistance than the focal epilepsies or most of the DEEs.” (opens the source at this quote in a new tab)
“The two most robust epidemiological predictors of resistance are the number of previous ASMs tried (irrespective of the class of medication) and the number of seizures prior to starting medication, which is more likely a measure of disease severity rather than seizures influencing drug response.” (opens the source at this quote in a new tab)

Etiologic categories

“Etiology (structural, genetic, metabolic, infectious, immune, unknown)” (opens the source at this quote in a new tab)

Age distribution of etiologies

“Epilepsy incidence has a bimodal age distribution with the highest risk in infants (genetic, metabolic, and obstetrical causes) and older people (higher risk for stroke and neurodegenerative diseases)” (opens the source at this quote in a new tab)