An audit of the use of EEG in the ketogenic diet
Abstract The Ketogenic Diet (KD) is used in drug-resistant epilepsy. It mimics starvation, and has been shown to be effective at seizure reduction in recent trials. Limited evidence is available about the use of EEG in the KD, although an improvement has been shown whilst on the KD.
Aim Survey to determine the value of follow-up EEG's in patients who responded to the KD.
Method Patient details were recorded on the KD service database including baseline and follow-up treatment EEG results. Follow-up EEG's were arranged after 3 months if a clinical improvement in seizures was noted.
Results Thirty-four patients were available for analysis, of which four started as emergency inpatients (12%). The median (range) age was 7.1 (0.3-11) years, and 22 (65%) were male. From baseline EEG's 24 (70%), had generalised epilepsy; 9 (26%) had focal epilepsy; one had a normal EEG. Slow spike and wave was the most common finding (33%). Fourteen (43%) had a seizure during the EEG.
Twenty-four (71%) of children tolerated the diet for more than three months. The diet was most commonly discontinued due to lack of effect (47%). Eleven (46%) had a follow-up EEG with a median (range) time of 12 (3- 48) months. Twelve of the 13 (93%) patients did not have an EEG as there was no clinical improvement in seizures. One child clinically improved, but did not have a follow-up EEG. Four (57%) children had normal EEG's compared to 1 (3%) at baseline.
Conclusion Follow-up EEG's were done in 46% of the 24 patients who tolerated the diet for more than three months. Improvement in the follow-up EEG was seen, which may be reassuring for parents. Follow-up EEG's may not be necessary in all cases, as it did not alter management and cost could be saved. Those without a follow-up EEG usually stopped the diet shortly after due to lack of effect. Further research should be done to provide evidence about baseline EEG factors that may affect response.