focal seizure
Pronunciation: FOH-kal
A seizure that originates in a localized area of the brain, previously known as partial seizure.
Full Definition
Focal seizures arise from abnormal electrical activity in a specific, localized region of the brain rather than involving the entire brain simultaneously. The 2017 ILAE classification system replaced the older term 'partial seizure' with 'focal seizure' to better reflect current understanding of seizure mechanisms. Focal seizures are subdivided based on whether awareness is preserved (focal aware) or impaired (focal impaired awareness). They may remain localized or secondarily generalize to involve the whole brain. In pediatric patients, focal seizures can present with diverse symptoms including motor movements, sensory experiences, behavioral changes, or autonomic phenomena, depending on the brain region involved. Identification of focal seizures is crucial for determining treatment options and surgical candidacy.
Usage
Usage note: Preferred term over 'partial seizure' in current medical literature. Specify awareness level when possible.
In Context
- "The focal seizure originated in the right temporal lobe and remained localized throughout the event." — EEG interpretation
- "Focal seizures with impaired awareness were captured during video-EEG monitoring." — Epilepsy monitoring unit report