Classifying the type of seizure a patient has helps the healthcare team choose the right therapy for that patient.
Seizure types are divided into two major groups:
- Generalized: Seizures produced by widespread abnormal electrical impulses present throughout the entire brain.
- Partial (sometimes referred to as focal or localized): Seizures produced by electrical impulses that generate from a relatively small or “localized” part of the brain (referred to as the focus).
Generalized epilepsy classifications
Generalized tonic-clonic (Grand Mal). Symptoms: The patient loses consciousness and usually collapses. The loss of consciousness is followed by generalized body stiffening (called the "tonic" phase of the seizure), then by violent jerking (called the "clonic" phase of the seizure), after which the patient goes into a deep sleep (called the "postictal" or “after-seizure” phase). During grand-mal seizures, injuries and accidents may occur, such as tongue biting and urinary incontinence.
Absence. Symptoms: Brief loss of consciousness (just a few seconds) with few or no symptoms. The patient typically interrupts an activity and stares blankly. These seizures begin and end abruptly and might occur several times a day. Patients are usually not aware that they are having a seizure, but may have a feeling of "losing time.”
Myoclonic. Symptoms: Sporadic and brief jerking movements, usually on both sides of the body. Patients sometimes describe the jerks as brief electrical shocks. When violent, these seizures might result in dropping or involuntarily throwing objects.
Clonic. Symptoms: Repetitive, rhythmic jerking movements that involve both sides of the body at the same time.
Tonic. Symptoms: Muscle stiffness and rigidity.
Atonic. Symptoms: Consist of a sudden and general loss of muscle tone, particularly in the arms and legs, which often results in a fall.
Partial epilepsy classifications
Simple partial (awareness maintained). __Symptoms: Simple partial seizures are further divided into four groups according to the nature of their symptoms:
- Motor. Motor symptoms include movements such as jerking, stiffening, muscle rigidity, spasms, and head-turning.
- Sensory. Sensory symptoms involve unusual sensations affecting any of the five senses (vision, hearing, smell, taste, or touch). The term “aura” is used to describe sensory symptoms that are present only (and not motor symptoms).
- Autonomic. Autonomic symptoms most often involve an unusual sensation in the stomach termed “gastric uprising”.
- Psychological. Psychological symptoms are characterized by various experiences involving memory (the sensation of déjà vu), emotions (such as fear or pleasure), or other complex psychological phenomena.
Complex partial (awareness impaired). Symptoms: Includes impairment of awareness. Patients seem to be "out of touch," "out of it," or "staring into space" during these seizures. Symptoms may also involve some complex symptoms called automatisms. Automatisms consist of involuntary but coordinated movements that tend to be purposeless and repetitive. Common automatisms include lip smacking, chewing, fidgeting, and walking around.
Partial seizure with secondary generalization. Symptoms: A partial seizure that evolves into a generalized seizure (typically a generalized tonic-clonic seizure).
Approximately 70% of patients with partial seizures can be controlled with medication. Partial seizures that cannot be controlled with medication can often be treated surgically.