Pyknolepsy refers to a syndrome of typical absence seizures (both simple and complex) in otherwise normal, prepubertal children older than about 3 to 5 years. There is a strong genetic predisposition, and girls are more frequently affected. The absences are very frequent (occurring at least several times daily), and tend to cluster.
The absences may remit during adolescence, but generalized tonic-clonic seizures may develop.
The EEG reveals a bilateral, synchronous, symmetric 3-Hz spike-and-wave discharge with normal interictal background activity.
No distinct clinical or EEG features completely differentiate childhood absence epilepsy from juvenile absence epilepsy.