Prognosis of epilepsy. Remission of seizures and relapse in 808 adult patients.

In a retrospective study of 808 adult epileptic patients undertaken at the Neurological Institute of Montevideo, Uruguay, the rate of remission of seizures (three seizure-free years) was 32%, and that of relapse 39%. Remission occurred mostly during the first years after onset, and relapse during the first years after remission. Patients with generalized or partial seizures alone had a better prognosis than when both types coexisted. Patients with Petit Mal absences persisting after 14 years of age, had the lowest rate of remission. Mental status, abnormal neurological examination and age of onset showed no significant prognosis value. Remission and relapse was similar in cryptogenetic and symptomatic epilepsy. Genetic predisposition did not change the prognosis. Withdrawal of drugs after a minimal seizure-free period of three years produced a higher rate of relapse than when medication was continued. In the first EEG, only the existence of a slow background rhythm had an unfavorable prognosis. These results are compared with those of other series. It is concluded that the differing results can be attributed to a different selection of population and different methods of study. Anyway, several factors showed a similar influence on prognosis in the different series. As to indication for method of drug withdrawal after remission, and its influence on relapse, no definite conclusion can be drawn and a large, multicentric, methodical study on this topic is suggested.