- Published3 Apr 2023
- Author Karen Weintraub
- Source BrainFacts/SfN
Sometimes before a video begins to play, a message reads, “Warning: This video may potentially contain seizure triggers for those with photosensitive epilepsy.” Heeding this warning can help prevent seizures, or sudden, uncontrolled bursts of electrical activity in the brain, for people with certain types of epilepsy.
Epilepsy affects about 50 million people worldwide. People who have two or more seizures that cannot be explained by a temporary underlying medical condition, such as a high fever or low blood sugar, will receive a medical diagnosis of “epilepsy” — from the Greek word epilambanein, meaning “to be seized.”
Seizures result from irregular activities in brain cells lasting as long as five or more minutes at a time. Some seizures look like staring spells, while others cause people to collapse, shake, and become unaware of what is going on around them. The pattern of symptoms and after-seizure brain recordings using electroencephalograms (EEGs) are used to distinguish between different types of epilepsy and determine whether the true cause of the seizures is epilepsy or a different medical condition.
Seizures are classified by where they occur in the brain. Generalized seizures affect both sides of the brain. They include absence or petit mal seizures, which can cause rapid blinking or a few seconds of staring into space, and tonic-clonic or grand mal seizures, which can make someone fall, have muscle spasms, cry out, and/or lose consciousness. Focal or partial seizures are localized to one area of the brain. A simple focal seizure can cause twitching or a change in sensation, triggering strange smells or tastes. Complex focal seizures can leave a person confused and unable to answer questions or follow directions. A person can also have what’s known as secondary generalized seizures, which begin in one part of the brain but spread to become generalized seizures. In some patients with severe epilepsy, multiple types of seizure can occur at the same time.
Epilepsy has many possible causes and is thus considered a spectrum rather than a single disorder. Causes include premature birth, brain trauma, and abnormal development due to genetic factors. Attributes of epilepsy patients such as head size, movement disorders, and family history suggest that genetics is involved.
Seizures can also accompany or cause intellectual or psychiatric problems. For example, some seizures may suppress the growth of dendrites, leaving the person emotionally unsettled or less able to learn.
Treatments for epilepsy are directed toward controlling seizures with medication and/or diet. For most patients, a single medication is enough to control seizures, although a significant minority do not achieve adequate control from drugs. About half of epilepsy patients, particularly those with generalized epilepsy, can reduce their seizures by eating a ketogenic diet, which relies heavily on high-fat, low-carbohydrate foods, although it is unclear why this diet is effective. For severe cases that are not relieved by medication, doctors might recommend surgery to remove or inactivate the seizure-initiating part of the brain. In the most severe cases, if one side of the brain triggers seizures on the other side, surgeons may perform “split-brain surgery,” cutting the corpus callosum, a thick band of white matter that connects the two sides of the brain. Once their seizures are controlled, people with epilepsy can resume their normal lives.
Adapted from the 8th edition of Brain Facts by Karen Weintraub.
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