You might hear a seizure called a convulsion, fit, or spell. Most people think of a seizure as shaking all over and losing control of your body. But there are different kinds of seizures, and all of them are caused by abnormal electrical activity in the brain. Your brain uses electrical signals and if those signals go a little haywire, a person can have a seizure. Some people may have only one seizure in their whole life or seizures may recur as part of a condition called epilepsy. People with epilepsy usually need medicine to control their seizures.