The photosensitivity model is not a model for partial (focal) seizures.

New, more effective and less toxic medications are desperately needed for patients with partial (focal) epilepsy. Many hurdles prevent the appropriate study of promising compounds. One of these hurdles is the difficult gap between Phase I and Phase II-the expensive proof of concept to suggest that human trials in partial seizure patients will be successful. A short-cut, the photoparoxysmal response (PPR) model has recently been used to increase confidence in moving a compound into Phase II and III (K-N Trenite et al., 2015). This shortcut has substantial limitations. This article outlines these limitations in an effort to create full disclosure to all involved with development of drugs for partial seizures.