Objectives: To evaluate the change in atonic or myoclonic seizures associated with the Lénnox-Gastaut syndrome during the initiation of the ketogenic diet, and to describe the development of a blinded crossover study of the efficacy of the ketogenic diet.
Design: A before-after trial.
Setting: The Johns Hopkins Hospital, Baltimore, Md.
Patients: Change in clinical seizure frequency was examined in 17 consecutively treated patients with atonic or myoclonic seizures. In a few patients, a 24-hour ambulatory electroencephalogram was obtained before and after diet initiation. We demonstrated the ability to manipulate the ketosis induced by fasting with the addition of glucose (dextrose) in 1 patient.
Interventions: Children fasted for 36 hours, and the diet was gradually introduced over 3 days. Parents were instructed to keep a baseline seizure frequency calendar for the month before the initiation of the diet. These calendars continued to be maintained as the diet was initiated.
Main outcome measure: Seizure decrease from baseline.
Results: The atonic or myoclonic seizures decreased in these children by more than 50% immediately. Using a 24-hour ambulatory electroencephalogram, we documented that the seizures reported by a parent represent only a fraction of the electroclinical events; the technique could be used to measure the profound decrease in electrically documented seizures. Ketosis was eliminated with glucose, 60 g/d.
Conclusions: It is feasible to evaluate the ketogenic diet's efficacy in atonic or myoclonic seizures in a blinded, crossover study. The diet can be manipulated on a short-term basis in a blinded manner, and ketosis can be achieved or eliminated.