Childhood Absence Epilepsy- Electroclinical Profile and Prevalence of Attention-Deficit/Hyperactivity Disorder Among a Cohort of 47 Children.

Background: We aimed to find the proportion of attention-deficit/hyperactivity disorder (ADHD) among children with childhood absence epilepsy (CAE) and to describe their electroclinical features.

Methods: Video electroencephalography (EEG) was performed on 47 children who fulfilled International League Against Epilepsy criteria for CAE. These children were also assessed for the presence of ADHD.

Results: Of the 47 children, 27 (57%) met criteria for the diagnosis of ADHD. Majority (74%) of them had inattentive type of ADHD. Age at onset of absences ranged from three to 12 years (mean 7.2 ± 2.47). We analyzed 219 seizures (154 electroclinical and 65 electrographic). The average seizure duration was 7.1 seconds (range 1 to 38 [S.D. 5.81]). Of the 154 clinical absences, ictal discharges were less than or equal to two seconds in nine of 154 (5.8%); greater than two to less than or equal to four seconds in 33 of 154 (21.4%), and longer than 20 seconds in 11 of 154 (7%). The longest duration of ictal discharge recorded was 38 seconds, and the shortest duration was one second. The onset of ictal discharge had a "lead in" focus in 81% (177 of 219).

Conclusions: The proportion of ADHD among children with CAE is high. A "lead in" focus of the generalized ictal discharges was observed frequently, lending support to the theory that the origin of seizure discharges in CAE is indeed cortical. The shortest ictal discharge recorded was one second.