Long-term follow-up of adult patients with genetic generalized epilepsy with typical absence seizures and generalized paroxysmal fast activity in their EEG

Abstract

Purpose: Generalized paroxysmal fast activity (GPFA), an EEG pattern with variable frequency and duration, is usually noted in symptomatic/cryptogenic generalized epilepsies. However, GPFA has also been reported in a few patients with genetic generalized epilepsy (GGE) who presented with typical absence seizures (TAS). Our aim was to report the results of long-term follow-up and genetic findings in these patients.

Methods: We investigated all EEGs of adult GGE patients with TAS, and identified 12 patients with GPFA (8.3% of adult GGE patients with TAS). Ten of these patients were available for long-term follow up. Their clinical and electroencephalographic courses and genetic features were investigated. The control group was composed of 24 adult GGE patients who also had TAS, but lacking GPFA with a similar follow-up duration in the same epilepsy center.

Results: The mean age at GPFA detection was 33±16.6 (16-71 years) and 80% still had GPFA in their last EEG. The duration of epilepsy and persistence of TAS were both significantly longer in the GPFA group despite a similar follow-up duration. Sixty percent of the GPFA group had consanguineous parents, whereas this rate was only 4.17% in the control group. Seven relatives of the GPFA group also had epilepsy. We could not show any known mutations in two families. At the end of the follow-up, none of the patients with GPFA was dependent in self-care, despite continuing seizures.

Conclusion: Our study shows that GPFA is an ignored EEG pattern of adult GGE patients with TAS, indicating a long and non-remitting course in almost all of the patients.

Keywords: Absences; Fast activity; Idiopathic epilepsy; Prognosis.