Epilepsy is a neurological condition that causes a sudden spurt of electrical activity in the brain resulting in a seizure. The abnormal signals that the brain then sends to the entire nervous system cause unusual behaviors and sometimes convulsions or loss of consciousness. More than 2.5 million people in the United States have epilepsy. Most have been diagnosed with it either in childhood or as older adults.

In most cases, the origin of epilepsy remains unknown. Sometimes epilepsy runs in families indicating a possible hereditary factor. Epilepsy has also been linked as a possible result of alcoholism, Alzheimer's disease, brain tumor, stroke or head trauma.

There are many different types of epilepsy, each characterized by a specific set of symptoms and a history of seizures. A range of factors, including infection, alcohol consumption, stress, hormonal changes, certain medications and sleep deprivation, can trigger seizures.

Epilepsy is sometimes curable -- in some cases, symptoms have largely been eliminated through surgical intervention. Less commonly, the condition can resolve itself over a period of time. However, medical management and other interventions are used to control the majority of people. And, even with good epilepsy care, 25 percent of people with epilepsy struggle to gain and maintain good seizure control. Their condition is called intractable epilepsy.

Whatever kind of epilepsy you have, or whatever its origin, the Epilepsy Program at Beth Israel Medical Center will work with you to understand how the disease has manifested itself and how best to approach management. One of the first things the epilepsy team will do is pinpoint the types of seizures you experience.

Different Kinds of Seizures
There are more than 20 different types of seizures, but experts generally classify them into two broad categories: Partial or generalized.

Partial Seizures
Partial seizures occur in just one part of the brain and they can be simple, complex, or partial seizures secondarily generalized. Here is an overview of each kind.

• A simple partial seizure or aura involves just a small area of the brain. It is brief and usually does not cause loss of consciousness. While you may remain aware of the experience, you probably will not be able to control it. You may sense a strange smell or have visions from your remembered past. You may have a rush of an emotion like fear or joy for no apparent reason. Your experiences will depend on what area of the brain is being affected by the abnormal electrical activity. A simple partial seizure can occur alone, but if a simple partial seizure progresses to a complex partial seizure, it might serve as a warning to you.

• Complex partial seizures involve a larger, but still specific part of the brain. You may be aware of the beginning of these seizures during the aura stage, but you may also not experience that aura. During the middle of this seizure you will probably be unconscious. While you may be able to speak or appear conscious, you might be in a trancelike state and may not remember the experience. You may move in random, uncontrolled ways, chewing, walking, making grasping motions or pulling at clothing. These uncontrollable movements are called automatisms. A complex partial seizure usually last one to two minutes and is often followed by a recovery period that can be marked by disorientation.

• Partial seizures secondarily generalized are seizures that begin as partial and then evolve to become generalized.

Generalized Seizures
Generalized seizures affect the whole brain and can develop from a complex partial seizure. Here is an overview of the most common kinds of generalized seizures:

• Absence seizures or petit mal seizures: You may have a brief episode of staring with a lessening of awareness and responsiveness, only lasting a few seconds.

• Myoclonic seizures: You may experience a sudden and brief jerk of a muscle or group of muscles in a single part of the body, such as in one leg or arm.

• Atonic seizures or drop attacks. You may suddenly and briefly lose muscle strength and either drop something you are holding or even fall to the ground yourself.

• Tonic-clonic seizures or convulsive seizures or grand mal seizures: You will probably lose control of your muscle strength and fall to the ground. Your body might stiffen, jerk, twitch and shake in convulsions. You probably will not be conscious. Your breathing may be irregular. Sometimes there is a loss of bowel or bladder control. These seizures can last for several minutes and can be followed by a period of quiet unconsciousness, followed then by a post-seizure period often characterized by gradual wakening, fatigue, confusion and/or severe headache.