Ved myoklone anfald blev antallet af anfald om ugen mere end halveret hos 58, 3% af de patienter, der fik Keppra, mod en mindskelse på 23, 3% hos dem, der fik placebo.
For myoclonic seizures, 58.3% of the patients who received Keppra had at least a halving of the number of seizure days per week, compared with 23.3% of the patients who received placebo.