Hypnic tonic postural seizures in healthy children provide evidence for a partial epileptic syndrome of frontal lobe origin.
In the pediatric age period, three idiopathic partial epileptic syndromes are recognized: benign childhood epilepsy with centrotemporal spikes, childhood epilepsy with occipital paroxysms, and primary reading epilepsy. All other partial epilepsies are considered cryptogenic, and no other idiopathic partial epilepsies have been recognized. We observed 10 children with tonic partial postural seizures, mainly hypnic, coinciding with a recognizable ictal epileptiform EEG pattern. The children all had normal neuropsychological development before and after seizure onset. The seizures were tractable in all. Onset was in the early pediatric age period; no other type of seizure was recognized. The occurrence of a family history of epilepsy was high. The seizure pattern was typical of supplementary motor area origin. Because of the normal neuropsychological status, high familial incidence of epilepsy, and benign course of this partial epilepsy, we believe it should be considered idiopathic, using the criteria of the International Classification of Epilepsies and Epileptic Syndromes. We therefore suggest the existence of a partial idiopathic epileptic syndrome having onset with seizures of frontal lobe origin.