[1] Univ Montreal, Sch Publ Hlth, Montreal, PQ, Canada
[2] Univ Montreal, Dept Neurosci, Montreal, PQ, Canada
[3] Stichting Epilepsie Instellingen Nederland, Heemstede, Netherlands
[4] Leiden Univ, Med Ctr, Dept Neurol, Leiden, Netherlands
[5] UCL Queen Sq Inst Neurol, London WC1N 3BG, England
[6] Chalfont Ctr Epilepsy, Gerrards Cross, England