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Types of Epileptic Seizures

Focal Seizures (Partial Seizures)

Simple partial epileptic seizures are confined to a small part of the brain. During partial seizures, individuals have a normal awareness of their surroundings. They may experience the jerk of an arm or hand or other symptoms that correspond to the part of the brain having the seizure.

EEG indicating focal abnormality (right temporal).

Complex partial epileptic seizures are confined to a particular region but have spread enough that individuals have an impaired level awareness about their surroundings. This seizure is common, particularly involving the temporal lobe. Individuals having complex partial seizures may exhibit the following symptoms:

A glassy stare and lack of response
Inappropriate or confused responses to questions
Sitting, standing, or walking aimlessly
Lip smacking or chewing motions
Unusual vocal sounds
Fidgeting

Partial seizures with secondary generalization are focal seizures that spread to both sides of the brain causing a grand mal convulsion. Except for beginning locally and spreading, partial seizures look the same as the generalized tonic-clonic seizure, described below. Many families describe a complex partial seizure as the patient's "small seizure" and the convulsions that result from secondary generalization as "big seizures."

EEG indicating generalized seizure discharge.

Generalized Epileptic Seizures

Generalized epileptic seizures start on both sides of the brain at once. Many people with generalized seizures have a genetic or hereditary cause underlying their epilepsy. Types of generalized seizures include absence seizures, tonic-clonic seizures, myoclonic seizures, and atonic seizures (also called drop attacks).

Absence seizures, also known as petit mal seizures, are usually brief and often staring spells without motor movements. They are usually shorter than complex partial seizures; however, patients may have a look of confusion or of being "out of it." Normal functioning usually returns quickly. This type of seizure is most common in children.

Generalized tonic-clonic seizures, or grand mal seizures, are the most dramatic convulsions of any seizure type. They are often characterized by total body stiffening and a cry or vocalization, followed by rhythmic jerking of the body about 30 seconds later. After the seizure, the patient usually is confused or sleepy for minutes to hours. The tonic part of the seizure involves total stiffening of the body, while the clonic part of the seizure is associated with rhythmic jerking of the body without stiffening.

Myoclonic seizures are characterized by sudden, brief, almost instantaneous jerks of the body or parts of the body. Young children with infantile spasms have clusters of myoclonic jerks that tend to occur when they awaken.

Atonic seizures or drop attacks are brief seizures that cause an unexpected and rapid fall to the ground. They can result from tonic (stiffening) or atonic (sudden loss of tone) events and are difficult to treat. Because of the risk of injury, they can be a major problem.

Disorders That Mimic Epileptic Seizures

Neurologists must distinguish between spells that are epileptic seizures (and require treatment with anti-epilepsy medication or surgery) and spells from another cause (that require a completely different treatment plan). The possible causes tend to vary with age. In infancy, breath-holding spells, apnea, and gastroesophageal reflux (Sandifer's syndrome) are common types of spells. In later childhood, sleep disorders, tic disorders, behavioral inattention, migraines, hyperekplexia (startle attacks), and episodic dyskinesias or ataxias are seen. In teenagers and adults, the common types of spells are syncope (fainting), psychogenic seizures (stress-related seizures), sleep disturbances, sleep apnea, cardiac rhythm disturbances, and migraines.