This study will asses the safety and efficacy of BGG492 in reducing the seizure rate in therapy-refractory partial seizures.

Inclusion Criteria:

1. A diagnosis of partial seizures (with or without secondary generalization) and undergoing an evaluation for epilepsy surgery, based on the classification of the International League Against Epilepsy (ILAE), as modified in 1981.
2. Absence of evolving space-occupying lesions or progressive neurological diseases.
3. Have normal vital signs (systolic and diastolic blood pressure and pulse rate)
4. All female subjects must have negative pregnancy test results
5. Subjects must weigh at least 50 kg to participate in this study and must have a body mass index (BMI) within the range of 18 to 35.

Exclusion Criteria:

1. A history of frequent and/or severe status epilepticus (i.e. requiring intensive care unit treatment).
2. Current treatment with phenobarbital, primidone or zonisamide (these drugs would have to be completely washed out before study start)
3. Having discontinued chronic benzodiazepine and barbiturate therapy within 30 days prior to the study start
4. Having electrodes implanted in the brain.
5. Having evidence on physical examination, or a history of any medically significant thyroid, cardiac, respiratory, hepatic, gastrointestinal, renal, hematologic, oncologic, psychiatric or progressive neurological disorder, requiring current medical intervention/therapy likely to have a significant impact on the outcome of this study.
6. With any surgical or medical condition which might significantly alter the absorption, distribution, metabolism or excretion of drugs, e.g. GI surgery and/or pancreatic or liver disease
7. Having a significant illness other than epilepsy within two (2) weeks prior to initial dosing.
8. Having recent (within the last three (3) years) and/or recurrent history of autonomic dysfunction (e.g., recurrent episodes of fainting, palpitations, etc).

Other protocol-defined inclusion/exclusion criteria may apply