Epilepsy is a blanket term that refers to a group of neurological disorders characterized by recurring seizures. All people with epilepsy have one feature in common, a disturbance in the normal pattern of the electrical activity of the brain -- like periodic electrical storms in the brain. When the brain's circuits misfire fast enough, a seizure results. It can range from a short vacant stare to automatic jerking movements or severe convulsions and loss of consciousness. Such disturbance is sudden and episodic, and frequently recurrent.
Focal seizures affect one area of the brain and were once called partial seizures. A person can have a focal seizure with or without loss of consciousness. During a simple focal seizure, the area of the brain that is affected by the dysfunctional electrical impulses will exhibit symptoms. Usually, these affect muscle movement limited to one or two muscle groups in close proximity.
During complex focal seizures, a person loses consciousness, but they appear to look aware and awake. The person may not pass out, but they are not aware of what's going on around them. People having a complex focal seizure will generally have some unusual behaviors, like lip smacking, crying, laughing or screaming.
Seizures may also appear to involve most areas of the brain, and these are called generalized seizures. There are several types of generalized seizures, but the most well-known are tonic-clonic seizures, which were once called grand mal seizures. The symptoms of tonic-clonic seizures are dramatic, but they are not the most common type of seizure. Tonic-clonic seizures cause a sudden loss of consciousness with a loss of bladder control and a combination of muscle stiffening and repeated jerking.
Two other types of generalized seizures also involve muscle groups. An atonic seizure causes a person to lose muscle control and drop suddenly to the ground. Dropping or falling can cause other significant injuries, especially if the person hits their head or strikes something sharp or hard. Myoclonic seizures trigger brief jerks or twitches in the arms and legs but usually no loss of consciousness.
Finally, are absence seizures, which were once called petit mal seizures. These seizures happen most often in children; the person is staring into space or making subtle body movements. These types of seizures can last up to 10 seconds and a person may have several hundred each day.
People can be diagnosed with epilepsy as children or adults, and while the exact cause is not entirely known, in general, it results from abnormal neurological signaling in the brain. Epilepsy is of unexpectedly high frequency and severity in many parts of the world. About six out of every 1,000 people worldwide have epilepsy and about 30% of epileptics are not helped by medication. Up to 50% of people in the world with epilepsy have idiopathic epilepsy, which means the exact cause cannot be identified. Every year, more than 150,000 people are diagnosed with epilepsy.
Epilepsy presents an important mental health and public health problem, not only because of its serious economic implications but also through its social impact on the family and the community. For example, the economic cost of epilepsy in the USA in 1975 is estimated to be over 3 billion dollars, including unemployment, underemployment, excessive mortality, treatment costs, care for the severely disabled, drug costs, vocational rehabilitation, special education and research in epilepsy. Furthermore, severe epilepsy causes serious disability and has a high mortality. For various reasons, including superstition, many patients are not brought for treatment. In one study nearly three quarters of the people studied had intellectual, behavioural or neurological handicaps. Children with epilepsy only have a few problems at school and those with additional problems have many difficulties. A higher percentage of people with epilepsy are unemployed, in part because of the additional risk of injury on the job and transportation to and from work. Approximately 50% of persons with epilepsy die directly or indirectly because of the condition. With modern methods the condition can probably be controlled in 75% of patients. An unnecessary burden of disability therefore exists.
Epilepsy of the temporal lobes (where memory and feelings reside) has been associated with artistic creation. Seizures, possibly undetected to observers, can prompt symptoms like hallucinations, powerful religious sensations, fury, fear, and a profound desire to write or draw, even after the seizure is over.