Clinical and electroencephalographic follow-up after a first unprovoked seizure.

We studied the role of clinical and electroencephalographic factors in the follow-up of children and adolescents after a first unprovoked seizure, and their correlation with recurrence and risk for epilepsy. We conducted a 24-month follow-up of 109 patients aged 1 month to 16 years who had a first unprovoked seizure. We analyzed the characteristics of the first seizure, perinatal history, family history of seizures, electroencephalographic patterns and their influence on seizure recurrence, and calculated risk for subsequent epilepsy. Fifty-six patients (51.4%) had recurrent seizures. The bivariate statistical analysis revealed that maternal prenatal disease (relative risk = 2.02, P = 0.03) and an abnormal electroencephalogram (relative risk = 2.89, P = 0.0003) were significantly associated with seizure recurrence. Other factors (male sex, partial first seizure, vaginal delivery, family history of seizures, and sleep state) approached statistical significance. Logistic regression revealed that the only variable significantly associated with recurrence was an abnormal electroencephalographic pattern on the first examination (relative risk = 2.48, P = 0.003). Cumulative risk ranged from 50-68% at 24 months when the first electroencephalogram was abnormal, and from 26-36% when it was normal. We concluded that the electroencephalogram may have an important diagnostic value in the prognosis of epileptic seizure recurrence in children and adolescents.