A clinical and electroencephalographical follow-up study for more than 10 years in patients with epilepsy.

A clinical and electroencephalographical follow-up study of 10 to 18 years was conducted on 147 patients with epilepsy. Generalized epilepsy was prognostically favorable, but petit mal absence with grand mal was not always good clinically and electroencephalographically as generally accepted. Paroxysmal discharges found in the initial EEGs tended to become more localized in the final EEGs recorded at least more than 10 years later. The migration of spike foci and bilateral independent spikes were found in many patients. Prognostically the EEG background was more important. Fourteen and six-per-second positive spikes and 6Hz spike and wave phantoms had an age dependence as well as 3 Hz spike and wave complexes and these discharges were regarded as prognostically the favorable patterns.