Long-term clinical and EEG changes in patients with epilepsy
J. R. Hughes
I studied changes during a 15- to 40-year period in EEG paroxysms and
clinical seizures on 1,645 EEG tracings. The most common paroxysm before
other patterns was the frontal focus and after other patterns was the
temporal focus. Most patterns changed in six to eight years and these EEG
changes accurately predicted the type of later clinical attacks. The
majority of our patients manifested a temporal spike. The incidence of
bilateral foci, as opposed to unilateral temporal foci, increased with age
at a rate of almost 1% per year; the clinical expression of developing
bilateral temporal foci was seen in 34% of the patients. Right-sided foci
usually required more than twice as much time to manifest bilaterality than
did left-sided foci; all changes from temporal areas required shorter
development times than those from parasagittal areas. The most common
intrahemispheric change was lateral; anterior migration was not
statistically more common than posterior migration.
