Trial to Assess Optimized Dosage of Lacosamide as add-on Therapy in Patients With Partial Onset Seizure

Inclusion Criteria: * Patient has a diagnosis of partial-onset epilepsy with or without secondary generalization * Currently taking 1 to 3 concomitant marketed antiepileptic drugs * 18 years and older at study entry Exclusion Criteria: * Previous use of lacosamide * Hypersensitivity to any component of lacosamide * Patients with partial onset seizures not clearly identifiable * History of generalized epilepsy * History of status epilepticus within last 12 months * Uncountable seizures due to clustering within last 12 weeks * Non epileptic events, including pseudoseizures, conversion disorder that could be confused with seizures * History of drug or alcohol abuse * History of suicide attempt * Progressive cerebral disease * Concomitant treatment of felbamate * Prior or concomitant vigabatrin use * Under legal protection