What is epilepsy?
Epilepsy is a brain disorder characterised by recurrent seizures -episodes of abnormal electrical activity in almost any part of the brain. The symptoms of a seizure can mimic any form of human behaviour, depending on which part(s) of the brain are affected. Generally, the term epilepsy (or seizure disorder) refers to relatively stereotyped attacks of involuntary behaviour. The exact symptoms and severity may vary, and the seizures may occur infrequently or in rapid succession.
While every case of epilepsy is distinct, a standardised classification scheme has been developed to describe seizures. The attacks are divided into two main types:
- Generalised (involving the entire brain)
- Partial (originating in one area of the brain).
Within these categories, seizures are further identified according to the pattern of the attack. The two most common forms of seizure are both of the generalised type:
- Absence (petit mal) seizures
- Tonic/clonic (grand mal) seizures.
Among the partial types are "simple" seizures (without impairment of consciousness), such as motor or Jacksonian seizures, and "complex" seizures (with impairment of consciousness), such as temporal lobe seizures.
The first signs of epilepsy are usually seen in childhood or adolescence. According to the NHS around one in 130 people in the UK has epilepsy. Epilepsy may also begin in the elderly and in that case often implies an old stroke or a tumour.
In most instances, the cause of epilepsy is unknown.
Sometimes, however, there may be a genetic cause. Other cases may be traceable to birth trauma, lead poisoning, brain infection during foetal development, head injury, alcohol or drug addiction, or the effects of organ disease. In someone with epilepsy, triggers for the attacks also vary widely. Among the factors that can bring on attacks are certain chemicals or foods, sleep deprivation, stress, flashing lights, menstruation, some prescription and over-the-counter medications, and possibly oral contraceptives.
How do I know if I have epilepsy?
Your doctor will take a detailed medical history (including a family history of seizures), gather information about your behaviour before, during, and after the episode, and do a physical examination. An electroencephalogram (EEG) -brain wave study - performed on a sleep-deprived individual can reveal abnormal brain waves characteristic of epilepsy, and imaging tests such as an MRI or CT scan can identify brain abnormalities that may be causing seizures.