Experts in epilepsy have developed a new way of organizing seizures and epilepsy that reflects more recent advances in the science and understanding of the brain and seizures. These terms don’t change what occurs during a seizure, or their treatment, but offer a different way of naming seizures. Here's a few questions to help you understand the differences.
What are the major changes made to terms used to describe seizures?
- Generalized seizures: These seizures are defined more clearly. The generalized seizures includes seizures that quickly involve both sides of the brain and different ‘networks’ or areas of the brain. The networks can be on the surface of the brain or involve deeper areas. Generalized seizures don’t need to involve the entire brain, just part of both sides. Sometimes seizures may look like they start on one side but spread so quickly to involve both sides of the brain.
- Focal seizures: The term ‘focal’ is similar to ‘partial’. These seizures start in an area or network on one side of the brain. They may start in surface areas of the brain, or in deeper areas and stay very localized or spread to larger areas. Sometimes more than one network is involved.
- The terms simple partial and complex partial seizures are not used to describe if a person’s awareness is affected.
- The new groupings describe focal seizures by the major types of symptoms involved in the seizure.
What is the new classification system?
Here is the new classification system that has been recommended. You’ll see many of the same names for seizures.
Revised Classifications of Seizures
(Report of the ILAE Commission 2005- 2009)
- Generalized seizures
- Focal seizures
- Epileptic Spasms
- (Events that are not clearly diagnosed into one of the categories above)
How are focal seizures described?
Focal seizures are now described mainly by the degree of impairment or change in consciousness or awareness and by other symptoms that occur.
- Without impairment of consciousness or awareness (similar to simple partial seizures)
- With observable motor or autonomic components (for example, movements of part of the body, nausea or upset stomach, changes in color, sweating, or other bodily symptoms)
- Involving subjective sensory or psychic phenomena only (similar to ‘aura’, for example numbness, tingling, pain, smell, sounds, déjà vu, jamais vu, or other changes in ‘experiences’)
- With impairment of consciousness or awareness or ‘dyscognitive seizure (similar to complex partial seizure, for example change in awareness, thinking, recall with or without other syptoms)
- Evolving to a bilateral or convulsive seizure (seizure that spreads to a tonic, clonic, or tonic-clonic seizure, previously called secondary generalized seizure)
Reference: Berg AT, Berkovic SF, Brodie MJ et al. Revised terminology and concepts for organization of seizures and epilepsies: Report of the ILAE Commission on Classification and Terminology, 2005-2009. Epilepsia, 51(4);676-685, 2010.