There are more than 30 specific types of epileptic seizures that fall into two general categoriespartial and generalized. In partial seizures, the abnormal electrical discharge is limited to one area of the brain. Many parts of the brain are involved in generalized seizures. Not all seizures are the result of epilepsy; when caused by other medical conditions, they are known as non-epileptic events.
Complex partial seizures (psychomotor or temporal lobe epilepsy) affect consciousness and originate from the temporal lobes of the brain. These seizures are characterized by automatisms, which are involuntary, repetitive behaviors such as head turning and random movement that is not remembered by the person after the seizure is over. The person may appear dazed during the seizure and be unresponsive to others.
Simple partial seizures generally do not affect consciousness and are the most common type of epilepsy. They may cause sudden, jerking motions of the body and affect vision or hearing.
Absence seizures (petit mal) typically occur in childhood and are distinguishable by short periods ( 5-15 seconds) of staring, blinking, rolling of the eyes, or arm movements. These brief lapses of consciousness are followed by a return to full awareness.
Tonic-clonic seizures (grand mal) are characterized by a stiffening of the body and jerking body movements. A person sometimes loses consciousness during a tonic-clonic seizure and may also have shallow breathing and a loss of bowel/bladder control.
Not every seizure is an epileptic seizure. An example is Psychogenic seizures.
Psychogenic seizures can look much like a true epileptic event, but no abnormal electrical activity occurs. These seizures are psychological in nature and can happen in people diagnosed with epilepsy and as well as those who are not.
There are some medical conditions that have symptoms similar to epileptic seizures, such as narcolepsy, heat stroke, cardiac arrhythmia, pre-eclampsia in pregnant women, and low blood sugar. Diagnostic tests such as continuous video EEG monitoring can help distinguish between epileptic seizures and non-epileptic events.
Triggers and Auras
Not all epileptic seizures occur out of the blue. After a while, some patients become aware of certain factors that seem to bring on or "trigger" a seizure. Among the most common triggers are: lack of sleep; flashing lights; alcohol; smoking; the hormonal changes brought on by the menstrual cycle; and stress.
Some people experience an unusual physical sensation before the onset of a seizure. This aura, which varies by individual, can be a strange taste or odor, a tense feeling, or even a sound.