Partial Seizures (Focal Seizures)

What Is It?

Nerve cells in the brain pass signals among themselves using both electrical current and chemicals. In a seizure, the brain's electricity is not passed in an organized way from one cell to the next, but spreads over a cluster of cells or the whole brain all at once. When only a portion of the brain is involved, the seizures are called partial seizures or focal seizures. These seizures vary tremendously in their effects on the person's movement, sensation or behavior depending on which area of brain is involved.

Some partial seizures are associated with a change in consciousness, even though the person might appear to be awake and his or her eyes may be open. In this type of seizure, called a complex partial seizure, the affected person is unaware of the people nearby during the event, is not aware of his or her own movements or behaviors during the seizure, and does not remember the seizure after it occurs. When the person having a partial seizure is aware of having a seizure, is aware of his or her surroundings and remembers the event afterward, the seizure is classified as a simple partial seizure.

Sometimes a seizure may begin as a partial seizure but change part way through the event to involve the whole brain in the seizure activity, ending with arm and leg movements on both sides and loss of consciousness. When this happens, it is called a generalized seizure. A person who has seizures repeatedly is said to have epilepsy. In 70 percent of cases, the cause of epilepsy cannot be found. Sometimes, epilepsy can be caused by scar tissue or a brain infection that can interfere with the brain's electrical signaling. Scar tissue in the brain can be caused by head injury, tumor, stroke or surgery.

Symptoms

A partial seizure can imitate any type of behavior or sensation that the brain can cause, depending on the part of the brain that the seizure activates. Seizures tend to occur in the same area of brain over and over, so symptoms in one person seem very similar from one time to the next. Examples of the symptoms of partial seizures include:

• Abrupt jerking muscle movements in an arm or leg
• Chewing or other mouth or tongue movements, or pulling or fumbling with clothing without a purpose
• A blank stare with no apparent awareness of one's surroundings
• A sudden feeling of fear, joy or rage that comes without reason
• Repeating a phrase or word
• A change in vision or a hallucination (seeing something that is not real)
• A sensation of smell or taste, usually unpleasant, that does not come from a real perfumed object or food
• Sudden loss of balance or dizziness

After a seizure a person may be disoriented for a few minutes.