IF THE electroencephalographic and clinical features of epilepsy are viewed over a period long enough to allow maturational changes to become evident, certain phenomena appear that are as regular, predictable, and important as are more obvious short-time manifestations. This and previous studies1 show that the type of seizure and the location of the focus (when one is present) are largely determined by the age of the patient and the maturational state of his brain.
In order to obtain correlations and consistent relationships such as are reported here, it is necessary that electroencephalographic recordings be made in the waking and sleeping states. This statement may sound dogmatic, but it is supported by comparison of recordings awake and asleep in many thousands of cases1 and it is basic to the present discussion. To put the matter figuratively, sleep takes the blanket off the brain and reveals seizure discharges and underlying