More common than you might realize, epilepsy affects one in every 26 Americans. Seizures are caused by an interruption to the brain’s normal electrical activity. While these interruptions are sometimes linked to a tumor or brain injury, there's no apparent cause for about 70 percent of epilepsy cases. Luckily, with proper treatment and prevention, most people with epilepsy can achieve the same quality of life they had before their diagnosis. Yale Medicine is home to some of the world's leading specialists in the treatment of epilepsy.