The only symptom of epilepsy is the recurrence of seizures, but not all epileptic seizures are the same. Some seizures cause obvious physical movements or loss of consciousness, but in other cases a seizure might not be visible to a bystander — not even a health professional. Some people with undiagnosed epilepsy may not even realize that the strange sensations or emotions they’re experiencing are due to a seizure.
Epileptic seizures can vary by the type of epilepsy causing them. Partial epilepsy (also known as focal epilepsy) causes local seizures that originate in a very specific part of the brain (the focus of the seizure), but these seizures can spread across the brain to become generalized seizures.
Focal epilepsy causes two types of seizures:
- Simple partial seizures do not cause loss of consciousness. The individual having the seizure may experience flashes of light or a buzzing noise, and outward symptoms may be limited to jerky motions in the face or hands.
- Complex partial seizures (also called psychomotor attacks) often begin with the individual experiencing an “aura.” The aura varies and may be experienced as a smell, a feeling of anxiety, an odd sensation in the stomach, or other perceptions that are not outwardly visible to anyone else. The aura may be followed by a change in consciousness — not necessarily a collapse into unconsciousness but a brief period of “blankness” in which others will notice lack of responsiveness or inability to speak. The individual experiencing the attack may exhibit small repetitive movements such as picking at clothing or moving his or her mouth silently. After the attack, the individual rarely remembers the seizure or the moments leading up to it.
Generalized epilepsy can cause several different types of seizures.
- Petit mal seizures, also known as absence seizures, are most common in children. They last only a few seconds and have only mild outward signs, such as twitching facial muscles. Some children may have these seizures hundreds of times a day (see Epilepsy in Children).
- Grand mal seizures are the most severe, and most dangerous, type of seizures. Grand mal seizures have two phases. In the first phase, called the tonic phase, the individual loses consciousness and becomes stiff; in the next phase, called the clonic phase, the individual begins to jerk, sometimes violently. Grand mal seizures usually stop on their own, but when the seizing continues uncontrollably the condition is known as status epilepticus. Status epilepticus is an emergency that requires immediate treatment to prevent brain damage or even death.
Some seizures consist only of the tonic phase of a grand mal seizure. These tonic seizures cause a loss of consciousness but don’t involve the jerking motion. Myoclonic seizures don’t cause loss of consciousness but do cause brief periods of jerking. Atonic seizures (also called drop seizures, akinetic seizures, or drop attacks) are characterized by a sudden loss of muscle tone that causes an individual to collapse.
Although some seizures are mild, anyone with a seizure disorder should be treated to control them. Repeated seizures can cause brain damage over time, and there is a risk of sudden death in patients with epilepsy. Medications can be effective in treating most cases of epilepsy, but surgery is the only known cure (see Surgery for Epilepsy).
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- Vice Chair for Clinical Research
- David and Ursel Barnes Professor in Minimally Invasive Surgery
- Professor of Neurosurgery, Neurology, and Otolaryngology
- Director, Center for Epilepsy and Pituitary Surgery
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- Associate Professor of Neuropsychology in Neurological Surgery
- Director of Neuropsychology Services
- Victor and Tara Menezes Clinical Scholar in Neuroscience
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Reviewed by Theodore Schwartz, MD
Last reviewed/last updated: September 2023