Seizure Disorder, Focal
BASICS
DESCRIPTION
- Seizures occur when abnormal synchronous neuronal discharges in the brain cause transient cortical dysfunction.
- Focal or localization-related seizures have previously been referred to as partial seizures and originate from a discrete focus limited to one cerebral hemisphere.
- Focal seizures are further divided into aware versus unaware and motor versus nonmotor:
- Focal seizures with impairment of awareness (formerly “complex partial seizures”)
- Focal seizures without impairment of awareness (formerly “simple partial seizures”)
EPIDEMIOLOGY
Prevalence
Focal seizures occur in 20/100,000 persons in the United States.
ETIOLOGY AND PATHOPHYSIOLOGY
- Focal seizures begin when a localized seizure focus produces an abnormal, synchronized depolarization within a neuronal network limited to one cerebral hemisphere; it may stay discretely localized or be widely distributed throughout that hemisphere.
- The area of cortex involved in the seizure determines the symptoms; for example, an epileptogenic focus in motor cortex produces contralateral motor symptoms.
- Most common etiologies vary by life stage:
- Early childhood: developmental/congenital malformation, trauma
- Young adults: developmental, infection, trauma
- Adults 40 to 60 years of age: cerebrovascular insult, infection, trauma
- Adults >60 years of age: cerebrovascular insult, trauma, neoplasm
Genetics
Benign rolandic epilepsy has an autosomal dominant inheritance pattern.
RISK FACTORS
- History of traumatic brain injury (TBI)
- Thiamine-deficient formula
COMMONLY ASSOCIATED CONDITIONS
Depression
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Citation
Domino, Frank J., et al., editors. "Seizure Disorder, Focal." 5-Minute Clinical Consult, 34th ed., Wolters Kluwer, 2026. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688257/all/Seizure_Disorder_Focal.
Seizure Disorder, Focal. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2026. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688257/all/Seizure_Disorder_Focal. Accessed July 20, 2025.
Seizure Disorder, Focal. (2026). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (34th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688257/all/Seizure_Disorder_Focal
Seizure Disorder, Focal [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2026. [cited 2025 July 20]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688257/all/Seizure_Disorder_Focal.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC
T1 - Seizure Disorder, Focal
ID - 1688257
ED - Domino,Frank J,
ED - Baldor,Robert A,
ED - Golding,Jeremy,
ED - Stephens,Mark B,
BT - 5-Minute Clinical Consult, Updating
UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688257/all/Seizure_Disorder_Focal
PB - Wolters Kluwer
ET - 34
DB - Medicine Central
DP - Unbound Medicine
ER -