Epilepsy Happens

Why Epilepsy Happens

As one of the first brain disorders described in ancient Babylon more than 3,000 years ago, epilepsy has been associated with many misconceptions over the years. Epilepsy is a disorder in which the normal pattern of brain activity becomes disturbed. During a seizure, neurons fire as many as 500 times a second, far exceeding the normal rate of about 80 times a second. The resulting seizure can occur at any time of the day or night with little to no warning. Some people have frequent attacks, but others seldom have them.

Genetic abnormalities may be the most significant factors that contribute to epilepsy. The condition may run in some families, and some researchers say that more than 500 genes could be linked to the disorder.

For many people, epilepsy is the result of brain injury from other conditions or disorders. Heart attacks and strokes, for example, deprive the brain of oxygen and can cause damage that can produce epilepsy. Conditions that affect the brain's normal workings, such as brain tumors, Alzheimer's disease and alcoholism, also may trigger it. Metabolic disorders such as pyruvate deficiency and other brain disorders such as cerebral palsy, neurofibromatosis and autism are all associated with an increased risk of epilepsy, as well.

Virtually any sort of injury to the brain, from head trauma to poisoning (such as from carbon monoxide or even illegal drug use) to infections can lead to seizures and epilepsy.

Other cases that involve neither brain damage, injury nor known genetic factors, and which have no known cause, are known as idiopathic epilepsy. The cause of epilepsy remains an active area of research.

Types of Seizure and Epilepsy: Many and Varied

To date, researchers have identified more than 20 different kinds of seizures and dozens of syndromes and other conditions that include recurring seizures. People can have one or more than one type of seizure. In general, there are two kinds of seizures:

Partial seizures. About 60 percent of people with epilepsy have partial seizures, which occur in just one part of the brain and affect the physical and mental activity controlled by that area of the brain. Partial seizures may also originate in multiple parts of the brain or start in one part of the brain and spread to the entire brain.

During a simple partial seizure, a woman can remain conscious and experience unexplained feelings or sensations. In a complex partial seizure (formerly called a psychomotor or temporal lobe seizure, a woman can experience an altered consciousness, display repetitious behavior or movements and not be able to interact with others until the seizure subsides. Emotional changes may also occur during the seizure. Complex partial seizures are the most common type of seizures in adults, although the condition typically begins in childhood. Repeated seizures in the temporal lobe of the brain can, over a long period of time, affect memory and learning.

Generalized seizures. There are many types of generalized seizures. Primary generalized seizures involve bursts of electrical energy that sweep through the whole brain at once, causing loss of consciousness for seconds or minutes, falls, convulsions or muscle spasms.

Absence seizures (formerly called petit mal seizures) are a common type of generalized seizure that typically start in childhood and typically stop when the child reaches puberty. During an absence seizure, a child may experience temporary lapses of consciousness that look like blank staring.

When seizures occur, a health care professional will determine if they are associated with epilepsy or another condition that can cause seizures. Determining the underlying cause is critical to effective and appropriate treatment. (See the Treatment section for more information.)

The many types of epilepsy are usually described by a specific group of symptoms. Some of the more common types include:

• Frontal lobe epilepsy: Sudden onset and termination of a cluster of very short seizures are the hallmarks of this type of epilepsy.
• Occipital lobe epilepsy: This type usually begins with visual hallucinations, rapid eye blinking or other eye-related symptoms: After that, it resembles temporal or frontal lobe epilepsy.
• Temporal lobe epilepsy: This type may typically have a "warning" or aura of altered perceptions (déjà-vu, jamais vu) followed by altered awareness, confusion and responsiveness.