Types of Epilepsy
There are many types of epilepsy. Each type of epilepsy has different behavioral effects and is treated with different methods. In some cases, people know they are about to have a seizure because they see or hear something, or feel dizzy, nauseous, or “strange.” This is called an aura. An aura can act as an “early warning system” telling a person that a seizure is about to happen. The person can therefore minimize a possible injury by taking precautions such as sitting down.
Generalized seizures – uncontrollable discharge of neurons on BOTH sides of the brain. This is the most common type of epilepsy. The seizure starts in one area of the brain and spreads across the brain. These seizures produce muscle twitches, convulsions and loss of consciousness. People with this type of epilepsy do not remember having a seizure.
There are several types of generalized seizures:
Tonic-clonic (“grand mal”) seizure – This seizure occurs when there is a massive discharge of neurons on both cerebral hemispheres. The body becomes rigid and there is also jerking of the body. “Tonic-clonic” means “stiffness-violent.” “Grand mal” means “great sickness.”
Absence (“petit mal”) seizure – This seizure is nonconvulsive. However, a person may become unaware of his or her surroundings and may stare off in space or freeze. This seizure lasts only 5-30 seconds.
Myoclonic seizure – This seizure involves the motor cortex and causes twitching or jerking of certain parts of the body.
Atonic seizure – This seizure is characterized by the loss of muscle tone and causes a person to fall down.
Status epilepticus – This seizure is characterized by frequent, long-lasting seizures without regaining consciousness between attacks. This condition requires immediate medical attention.
Partial Seizures – This type of seizure is characterized by abnormal electrical activity involving only a small part of the brain. Sometimes a partial seizure can spread to the whole brain.
Two types of partial seizures are:
Simple partial seizures (also called “Jacksonian” or “focal” seizures) – Short-lasting seizures without loss of consciousness. People with these kinds of seizures often see, hear or smell something strange. Also, only part of the body may jerk.
Complex partial (psychomotor) seizures – A seizure with a change, not a loss, in consciousness. People may hear or see things or memories may resurface. Feelings of deja vu may also occur.
Many (50-70%) cases of epilepsy have no known cause. For the remaining cases, there are many other events that may cause epileptic seizures:
Head injuries, such as a car accident or a fall.
Arteriosclerosis (fatty plaque build-up in arteries)
Brain injury before birth caused by infection or lack of oxygen to the brain
Infection, such as meningitis or encephalitis
Brain damage resulting from these events may cause a “scar” on the brain. This is where an epileptic seizure starts. At this time it is not known why a scar starts a seizure. There may be a genetic link for some types of epilepsy, but this is usually NOT the case. Sometimes a seizure will be started (“triggered”) by:
lack of sleep
flashing lights or sounds (like from a video game or TV)
low blood sugar
A doctor will want to find out several things before a diagnosis of epilepsy is made. The doctor may want to know the answers to the following questions:
How often do the seizures occur?
When was the first seizure?
Was there a head injury?
What are the seizures like?
Were there any unusual sensations (smells, sounds, lights)?
Is there any memory of the seizures?
An electroencephalogram (EEG) is often used to help in the diagnosis of epilepsy. The EEG of people with epilepsy often shows large spikes. Sometimes the EEG must be recorded for a whole day in the hospital or at home because a short test does not always pick up the abnormal activity. However, the EEG does not always work because about 5% of people without epilepsy have “abnormal” EEG activity and about 20% of people with epilepsy have normal EEG activity.
Brain imaging methods (magnetic resonance imaging [MRI] or computer tomography [CT] scanning) may also be used to find the location of a scar or damaged brain tissue. Sometimes positron emission tomography [PET] is used to examine brain blood flow.
Treatment for Epilepsy
Sometimes seizures stop without treatment. Many people take antiepileptic (also called “anticonvulsant”) drugs to control seizures. These drugs, however, do not cure the disorder. Rather, these drugs control the symptoms and are effective in 60-80% of the cases. Antiepileptic drugs work by reducing the abnormal firing of cortical neurons. These drugs may change the activity of neurotransmitters responsible for seizures or alter the way ions flow in and out of neurons. Unfortunately, many of these drugs have side effects such as drowsiness, dizziness and nausea so doctors must balance these undesirable effects with seizure control. It is also important to remember that different drugs are used to treat different types of seizures.
When medication fails and the area of the brain where the seizure occurs is known, surgery may be performed to treat epilepsy. There are several types of surgery that have been used:
Temporal Lobe Surgery – This is performed to remove brain tissue where the epileptic seizure starts. This type of surgery often removes part of the cortex of the temporal lobe, hippocampus and amygdala. [Brain mapping during surgery]
Corpus Callosotomy (“Split Brain” operation) – The corpus callosum is cut to separate the right and left cerebral hemispheres. This procedure is done to prevent the spread of the seizure from one side of the brain to the other.
Hemispherectomy – One cerebral hemisphere is removed. The procedure is not performed very often. Children who have this surgery CAN function quite well although they often have trouble using their arm on the side of the body opposite to the surgery. In some surgeries, only specific lobes of the brain are removed.
Several treatments for epilepsy are still under investigation. How and if they work is still controversial.
Ketogenic Diet – a high fat, low protein/carbohydrate diet
Biofeedback – people trained to control EEG patterns to shorten seizures
Vagus Nerve Stimulation – an electrical stimulator is implanted to stimulate the vagus nerve (cranial nerve X)
Vitamin and Mineral Supplements
Famous People with Epilepsy
Julius Caesar – Roman Statesman (100-44 B.C.) Napoleon Bonaparte – Emperor of France (1769-1821)
George Frederick Handel – Composer (1685-1759) Vincent van Gogh – Painter (1853-1890)
Fyodor Dostoevski – Writer (1821-1881) Pius IX – Pope (1792-1878)
Peter the Great – Russian Czar (1682-1725) Lord Byron – Poet (1788-182