Photosensitivity Proof of Concept Trial

The purpose of this study is to determine whether patients who usually have abnormal
electrical EEG responses when shown flashing lights will show a reduction in abnormal
electrical activity when they take a single dose of 2 marketed drugs (carbamazepine and
levetiracetam). If so, a similar study in the future may be able to identify promising new
drugs for epilepsy.

Patients who successfully complete the screening visit, will return 4 additional times and
will receive either placebo (2 times) or a single oral dose of both carbamazepine 400mg and
levetiracetam 1000mg in random order.

During each of the study days, several procedures and intermittent photosensitivity (IPS)
assessments will be performed at 5 pre-determined times over the course of the day, one
pre-dose and 4 post-dose.