Doctors generally classify seizures as either focal or generalized, based on the abnormal brain activity.
Seizures that appear to result from abnormal activity in just one area of your brain are called focal (partial) seizures. Symptoms of focal seizures may be confused with other neurological disorders, such as migraine, narcolepsy or mental illness. A thorough examination and testing are needed to distinguish epilepsy from other disorders.
Types of focal seizures include:
- Focal seizures without loss of consciousness
Once called simple partial seizures, these seizures don't cause a loss of consciousness. They may alter emotions or change the way things look, smell, feel, taste or sound. They also may result in involuntary jerking of a body part, such as an arm or leg, and spontaneous sensory symptoms such as tingling, dizziness and flashing lights.
- Focal seizures with impaired awareness
Once called complex partial seizures, these seizures involve a change or loss of consciousness or awareness. During a complex partial seizure, you may stare into space and not respond normally to your environment or perform repetitive movements, such as hand rubbing, chewing, swallowing or walking in circles.
Seizures that appear to involve all areas of the brain are called generalized seizures, including:
- Absence seizures
Absence seizures, previously known as petit mal seizures, often occur in children and are characterized by staring into space or subtle body movements, such as eye blinking or lip smacking. These seizures may occur in clusters and cause a brief loss of awareness.
- Tonic seizures
Tonic seizures cause stiffening of your muscles. These seizures usually affect muscles in your back, arms and legs, and may cause you to fall to the ground.
- Atonic seizures
Atonic seizures, also known as drop seizures, cause a loss of muscle control, which may cause you to suddenly collapse or fall down.
- Clonic seizures
Clonic seizures are associated with repeated or rhythmic, jerking muscle movements. These seizures usually affect the neck, face and arms.
- Myoclonic seizures
Myoclonic seizures usually appear as sudden brief jerks or twitches of your arms and legs.
- Tonic-clonic seizures
Tonic-clonic seizures, previously known as grand mal seizures, are the most dramatic type of epileptic seizure and can cause an abrupt loss of consciousness, body stiffening and shaking, and sometimes loss of bladder control or biting your tongue.
- Juvenile myoclonic epilepsy
Juvenile myoclonic epilepsy is the most common type of generalized epilepsy syndrome and typically emerges in mid- to-late childhood. It is characterized by the presence of absence, myoclonic and tonic-clonic seizures.
Lennox-Gastaut syndrome (LGS) is a severe type of epilepsy with multiple types of seizures. It accounts for approximately 2 to 5% of all cases of childhood epilepsy. LGS seizures can be difficult to control and require lifelong treatment. Learning problems often, but not always, result from LGS. Children with LGS may develop normally before the onset of LGS but then lose their previously acquired skills, such as sitting, crawling or walking.