There are many different types of seizures and epilepsies, all with different disease trajectories and outcomes. The goal of classification is to identify the type of seizure and epilepsy a person has, to help provide further information regarding treatment choices and seizure outcomes.
There are 2 main types of seizures/epilepsies: focal and generalized. Focal seizures arise from one hemisphere of the brain whereas generalized seizures originate from both sides of the brain. In some cases, the seizure cannot be immediately classified, and is referred to an unclassified seizure or seizure of unknown onset.
TYPES OF SEIZURES
Focal aware seizures
Formerly simple partial seizures or focal seizures
Focal seizures can evolve into bilateral tonic-clonic seizures.
Previously referred to as secondarily generalized seizures.
Focal seizures with impaired awareness
Formerly complex partial seizures, focal dyscognitive seizures, psychic seizures
These seizures can have any of the onset symptoms as described for focal seizures without loss of awareness. However, during these seizures, the individual loses contact with the environment and may stop responding to it, or have no idea that they had a seizure.
Seizures of unknown onset
Seizures with unknown onset are seizures where the onset of the seizure was not observed or noticed, and only later symptoms are noted. In this situation, clinicians are unable to accurately determine localization of the seizure (focal vs. generalized) based on the information available. These seizures can be sub-categorized into:
Only to be used if the clinician is certain the event is a seizure, but cannot classify it further because of incomplete information, or the unusual nature of the seizure.
Both modern MRI techniques and advances in genetics have increased our understanding of the causes of epilepsy. We now recognize a number of causes for epilepsy: