DRUG DISCONTINUATION IN EPILEPTIC CHILDREN: PREDICTIVE VALUE OF THE EEG

Background– Electroencephalography (EEG) is capable of determining the foci and intensity of epileptic discharges. The long-term use of antiepileptic drugs (AEDs) in children may be accompanied by side effects in 50% of cases; hence, drug therapy should be discontinued as early as possible. Before a decision is made to discontinue a drug, the recurrence of seizures could be predicted by interpreting the characteristics of the EEG. Methods– This study was conducted on 106 children who were without recurrent seizures for at least 1 year. They had been under AED therapy continuously. An EEG was taken while the child was awake, and the trace was assessed by a single neurologist with respect to background activity, focal slowing of waves, focal spike waves and generalized sharp spike waves. The children were monitored for signs of recurrent seizures every 3 months for at least 1 year. The results were assessed according to Kaplan-Meier survival analysis and the Log-Rank test. Results– The probability of recurrent seizures was 24.8 % (95% CI, 22.5–28.5 %) after 1 year of follow-up. A significant relationship existed between the state of the present EEG and previous EEGs (p < 0.05). Among the children with abnormal EEG results on drug discontinuation, seizure recurrence was more frequent in boys (p = 0.045). Comparing present and previous EEGs, the relative risk was calculated to be about 1.98 (95 % CI, 1.01– 3.91, p < 0.05). Conclusion– The risk of seizure recurrence was quite similar to the findings of other studies. Overall, there was no significant relationship between the presence of abnormal EEG findings and recurrence of the seizures. An important result of our study was the importance of comparing EEGs prior to drug withdrawal with primary EEGs (p < 0.05). Estimation of the probability of recurrent epileptic seizures must be only one part of the process of the physician’s decision. Attention must be paid to other factors such as the physical, social and economical consequences as well as the estimation of AED side effects.