Table 1 Patients; inclusion and exclusion criteria

• Male and female patients aged ≥16 to ≤70 years with partial epilepsy (defined by the International League Against Epilepsy, 1981 [19]) and a medical history of seizures.

• Patients with only simple partial seizures without a motor component.

• Presence of generalized seizure syndromes.

• Absence of confounding factors (e.g. pseudoseizures, syncope).

• History of pseudoseizures.

• Documented electroencephalography recording consistent with partial-onset epilepsy and documented computerized tomography or magnetic resonance imaging scan showing absence of a progressive structural abnormality (within 10 years prior to screening).

• Current seizures relating to acute medical illness, or seizures secondary to metabolic, toxic or infectious disorder or drug abuse.

• ≥4 partial onset seizures 8 weeks prior to screening with no 4-week seizure-free period.

• Status epilepticus within 2 years prior to screening.

• Treatment with a stable dose of 1–2 AEDs in the 4 weeks prior to screening. In the situation where a patient was receiving two AEDs at screening, the patient was enrolled if:

• Seizures only occurring in a cluster pattern.

  - One of the two AEDs was not one of the following sodium channel blockers: phenytoin, carbamazepine, oxcarbazepine, or lamotrigine; and

• Psychiatric history, including major depressive episode within 6 months, active suicidal plan or intent within the past one month, history of suicide attempt, significant psychiatric disorder, or alcohol or substance abuse within 2 years.

  - The second of the 2 AEDs was not being dosed in the upper dose range (defined as greater than approximately two-thirds of the defined daily dose^*).

• In elderly patients (65–70 years), no additional/potential health complications.