Epileptic Seizures – 3 Major Groups of Seizures
There are 3 major groups of seizures: generalized onset, focal onset, and unknown onset. You may experience just one or more than one kind of seizure. The type of seizure you have and symptoms you show depend on what part of the brain the seizures come from.
Generalized onset seizures
These seizures affect both sides of the brain or groups of cells on both sides of the brain at the same time. This includes types of seizures like tonic-clonic, absence, and atonic to name a few.
Focal onset seizures
This term helps describe where seizures begin. Focal seizures can start in one area or group of cells in just one side of the brain. Focal seizures are broken down into two groups by how aware a person is of their surroundings.
- Focal Onset Aware Seizures: When a person is awake and aware during a seizure, it’s called a focal aware seizure. This used to be called a simple partial seizure.
- Focal Onset Impaired Awareness: When a person is confused or their awareness is affected in some way during a focal seizure, it’s called a focal impaired awareness seizure. This used to be called a complex partial seizure.
Unknown onset seizures
When we don’t know where a seizure begins, it is called an unknown onset seizure. A seizure could also be called an unknown onset if it’s not witnessed or seen by anyone. For example, when seizures happen at night or to a person who lives alone. Symptoms can be described as motor (muscles are involved) or non-motor (muscles are not involved). As doctors learn more about your seizures, an unknown onset seizure may later be diagnosed as a focal or generalized seizure.