Electroclinical features and incidence of GPFA in children with typical absence seizures

What is it about?

Objective: Generalized paroxysmal fast activity (GPFA) is a diffuse, paroxysmal, frontal predominant activity described in patients with generalized epilepsies. Studies specifically focusing on electro-clinical features of typical absence seizures (TAS) in children have not reported any GPFA like features. We sought to identify GPFA in children with TAS, study its incidence, characteristic electroclinical features, and effect on their epilepsy. Methods: We performed a retrospective review of EEGs of children with diagnosis of absence epilepsy. A total of 173 subjects were identified. In subjects with GPFA on their EEGs, GPFA characteristics were collected (i.e. predominant location, duration, amplitude, frequency, provocation factors and if GPFA was followed by spike-wave discharges). In GPFA positive subjects, further data sets were collected examining their demographics, duration of epilepsy, and pharmacoresponsiveness to epilepsy. Results: GPFA was identified in 10 subjects (5.78%) with female to male ratio of 9:1. Median age of subjects was 17 years and median duration of illness was 9.5 years. Mean maximum GPFA amplitude was 88.3 µV with posterior predominance in 9/10 subjects. GPFA frequency ranged between 11-20 Hz with duration of 1-4 seconds. GPFA was provoked with eye closure, hyperventilation, and photic stimulation. Anti-seizure medications had no effect on GPFA, and epilepsy was well controlled in most subjects. Conclusion: GPFA is uncommon in children with TAS and has medium voltage, posterior predominance and marked female preponderance. GPFA is seen during both pharmacoresponsive and drug-resistant epilepsy, and is not affected by anti-seizure medications. It may serve as an independent marker of lifelong epilepsy.

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Why is it important?

GPFA can help identify children at risk for lifelong epilepsy. Childhood absence epilepsy children with GPFA have a poor prognosis. It helps in their better management and prognosis.

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