Objectives To evaluate the change in atonic or myoclonic seizures associated with the Lennox-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.
