Natural history and prognosis of epilepsy: report of a multi-institutional study in Japan. The group for the study of prognosis of epilepsy in Japan.

A multi-institutional study on the prognosis of patients with epilepsy was performed in Japan from 1975 to 1977, including 20 institutions. The outcome of epileptic seizures and social adjustment 10, 5, and 3 years after the onset of the illness was studied in three different groups of epileptic patients, respectively. The number of successfully followed-up cases was 1,868 in total, follow-up rate being 42%. The data were analyzed statistically by use of analysis of variance. The rate of remission of seizures in all was 58.3% and the rate of normal social adjustment 62.6%. The remission rate showed no significant difference among the 10-, 5-, and 3-year outcome groups. The study on the outcome of seizure control indicated that the prognosis of seizure control is more favorable (a) in idiopathic than in residual or symptomatic epileptics; (b) in patients with onset before 10 years of age than in those with onset after 10 years; (c) in patients with less frequent seizures; (d) in sleep epilepsy than in waking and diffuse epilepsies; (e) in patients who started treatment within 1 year of onset of seizure; (f) in patients with single-type partial seizures than in those with partial seizures combined with tonic-clonic seizures; (g) in patients without high grade EEG background abnormality; and (h) in patients without neurological symptoms, intellectual deficits, personality disturbances, or psychotic symptoms. Factors that determine the prognosis of social adjustment were almost similar to those for remission of seizures. There was a close correlation between the outcome of seizure control and that of social adjustment. Correlation coefficient between follow-up rate and remission rate in 15 of the 20 collaborated institutions was 0.55 (p less than 0.05), showing a tendency that the remission rate becomes higher as the follow-up rate is raised.