What is epilepsy?
Epilepsy is a disease of the central nervous system (CNS) that can cause excess electrical activity in the brain. This excess activity can lead to sudden loss of consciousness, often accompanied by abnormal sensations or movements. These episodes are usually referred to as seizures . In the U.S., around 3 million people are thought to suffer from epilepsy. The disease affects people of all ages; many develop epilepsy in childhood and people over the age of 60 are also more likely to develop the condition. Although epilepsy is often thought of as a single condition, there are in fact as many as 40 different types of seizures. Seizures are individual and affect everyone differently. Recovery time after a seizure will also vary from person to person.
There are two different categories of epilepsy: idiopathic epilepsy, where there is no clear cause for the epilepsy; and symptomatic epilepsy, which results from some abnormality in the brain that is present at birth or occurs later.
What are the symptoms of epilepsy?
The occurrence of a single seizure does not necessarily indicate that a person has epilepsy. However, if a person has a tendency to experience regular seizures, then this may be epilepsy. Tests can be carried out to confirm whether or not this is the case. There are many different types of seizures; some of the more common are listed here:
Tonic-clonic seizures. These used to be called “grand-mal” and are the most common type. These are generalized seizures and involve the whole brain and can last a few minutes, although the person may sleep for several hours afterwards. Typically, during a tonic-clonic seizure, the person will go stiff, fall to the ground, and then remain still before slowly coming round. In most cases, there is no warning that a seizure is about to occur.
Absence seizures. Previously known as “petit-mal” fits, these seizures occur commonly in children. As the name suggests, these seizures cause a momentary lapse or absence of awareness, and the child may appear as if he or she is daydreaming. Girls are more often affected than boys. Often the child will grow out of this type of epilepsy, although in some cases they will go on to develop tonic-clonic seizures later in life.
Partial seizures. During a simple partial seizure the person remains conscious. This type of seizure affects a particular part of the brain and can cause different symptoms depending on which area of the brain is affected. Symptoms can include twitching, numbness and disturbances of hearing, vision, smell or taste. During a complex partial seizure (also known as temporal lobe epilepsy), the person’s consciousness is impaired and they may not be aware of their actions. They may not remember the seizure, or their memory of it may be confused. Complex partial seizures can cause symptoms such as chewing and swallowing, repeatedly scratching the head or searching for an object. Occasionally, a person may wander off, recovering full awareness minutes or even hours later, unable to remember anything. Partial complex seizures can spread to the rest of the brain, becoming a secondary generalized tonic-clonic seizure.
Sleep seizures. These are often missed as they occur while the person is asleep and are not witnessed by others.
Status epilepticus. While fairly rare, it is a medical emergency. This is a prolonged seizure or a series of seizures occurring without any recovery in between. Immediate medical treatment is necessary to stop the seizures.