Summary Purpose: A multicenter, prospective, long-term, open-label study to evaluate the effects of levetiracetam on electroencephalogram (EEG) abnormalities and photoparoxysmal response (PPR) of patients affected by juvenile myoclonic epilepsy (JME). Methods: Forty-eight patients with newly diagnosed JME (10) or resistant/intolerant (38) to previous antiepileptic drugs (AEDs) were enrolled. After an 8-week baseline period, levetiracetam was titrated in 2 weeks to 500 mg b.i.d. and then increased to up to 3,000 mg/day. Efficacy parameters were based on the comparison and analysis of EEG interictal abnormalities classified as spikes-and-waves, polyspikes-and-waves, and presence of PPR. Secondary end point was evaluation of EEG and PPR changes as predictive factors of 12-month seizure freedom. Results: Overall, mean dose of levetiracetam was 2,208 mg/day. Mean study period was 19.3 ± 11.5 months (range 0.3–38). During the baseline period, interictal EEG abnormalities were detected in 44/48 patients (91.6%) and PPR was determined in 17/48 (35.4%) of patients. After levetiracetam treatment, 27/48 (56.2%) of patients compared to 4/48 (8.3%) in the baseline period (p < 0.0001) had a normal EEG. Thirteen of 17 (76.4%) (p < 0.0003) patients showed suppression of PPR. Cumulative probability of days with myoclonia (DWM) 12-month remission was significantly higher (p < 0.05) in patients with a normal (normalized) EEG after levetiracetam treatment compared to those with an unchanged EEG. Conclusions: Levetiracetam appeared to be effective in decreasing epileptiform EEG abnormalities, and suppressing the PPR in JME patients. This effect, along with a good efficacy and tolerability profile in this population further supports a first-line role for levetiracetam in the treatment of JME
