Changes in cognition after introduction or withdrawal of zonisamide versus topiramate in epilepsy patients: A retrospective study using Bayes statistics.

This is the first study to provide objective evidence for a considerable negative effect of ZNS treatment on executive function in a naturalistic treatment setting. Comparable to the well-known TPM effect, cognition worsens with adjunction and recovers with withdrawal of ZNS. However, the majority of patients do not show a significant negative effect, suggesting disparate susceptibilities to adverse events. The findings emphasize the need for routine monitoring of cognitive side effects to identify early on those patients who are negatively affected by new AED.