Overview of Epilepsy & Seizures
Epilepsy is a recurrent seizure disorder caused by abnormal electrical discharges from brain cells, often in the cerebral cortex. It is not a distinct disease, it is a group of disorders for which recurrent seizures are the main symptom. Different forms of epilepsy are either secondary to a particular brain abnormality or neurological disorder, or are said to be "idiopathic," without any clear cause.
Normally, nerve transmission in the brain occurs in an orderly way, allowing a smooth flow of electrical activity. A seizure occurs when these neurons generate uncoordinated electrical discharges that spread throughout the brain. This can occur with both normal and abnormal nerve cells.
Seizure disorders are a common neurological problem. In the United States alone, it has been estimated that more than 4 million people have some form of epilepsy.
The incidence of epilepsy, that is the number of newly diagnosed cases over a specific period of time (e.g., one year), depends somewhat on the age of the individual. The risk of epilepsy from birth through age 20 is approximately 1 percent. Within this group, the risk is highest during the first year of life and increases somewhat at the onset of puberty. From age 20 to 55 it decreases again, but increases after age 55. The prevalence of epilepsy (defined as the total of the population suffering from a disorder at a particular time) has been estimated to be about 5 to 8 in every 1000 people.