Rasmussen syndrome is a form of childhood epilepsy that causes frequent, severe seizures. The seizures damage one side (hemisphere) of the brain, often resulting in gradual loss of movement and sensation on one side of the body, problems with mental development, partial loss of vision in one eye, and speech and language problems.

Children with Rasmussen syndrome usually develop seizures before age 10. Infections such as meningitis and encephalitis may play some role in causing the condition.

Drug therapy is almost never successful in treating Rasmussen syndrome. For some children with the condition, though, a type of brain surgery called hemispherectomy can prevent seizures and improve some of the problems that may occur with the epilepsy.