Neuropsychological abilities before and after 5 years of stable antiepileptic drug therapy.

Detailed neuropsychological evaluations were conducted on 198 adults with epilepsy before and after a 5-year study period. Of these, three groups of 11 persons each were formed in which the patients did not change their medication: (a) phenytoin (PHT) monotherapy; (b) PHT and other drug(s); (c) drug regimens exclusive of PHT. The typical patient had few seizures during the study period. Examination of data from 20 neuropsychological and intellectual variables obtained at the beginning and end of the 5-year study period revealed few statistically significant changes in mental abilities and no losses. Thus, we were unable to find evidence for insidious cognitive losses with PHT and other drugs over time with normal therapeutic serum levels and in the absence of active seizure disorders.