What are the Types of Seizures?
There are broad two types of seizures: generalized tonic clonic convulsions and partial seizures. Partial seizures may be simple or complex.
Generalized tonic clonic convulsions
In generalized seizures, abnormal excessive electricity occurs throughout the whole brain at once, with no apparent focal point of onset or warning beforehand. Generalized seizures alter consciousness. They can be convulsive or non-convulsive. This is the type of convulsive seizure that most people recognize as epilepsy. It used to be called a grand mal seizure, but now is more properly termed tonic clonic-tonic meaning stiffening, and clonic meaning jerking. It is a generalized seizure, meaning most of the nerve cells of the brain are firing at the same time so consciousness is lost. The person remains unconscious throughout the seizure.
This seizure begins with the tonic phase, in which the body's muscles stiffen. The person will typically let out a cry, which is really the sound of air being forced out through their contracted vocal cords. The stiffening of the body's muscles causes the person to fall to the ground. The back arches, the eyes roll back and the limbs extend. Breathing is difficult because of the stiffened chest muscles, and, with the change in available oxygen, the skin color turns bluish gray. Quickly the clonic phase begins, and the limbs, body and head begin to jerk rhythmically. Saliva builds up in the mouth and the tongue may be bitten. Control of the bladder or bowels may be lost. The person continues convulsing, usually for one to three minutes, before the jerking slows and the seizure ends. Often a sigh is emitted as normal breathing begins.
After a tonic clonic seizure, the body is limp. The nerve cells in the brain are reacting to their massive misfiring during the seizure. The person is usually confused, sleepy, headachy and irritable for a period of minutes or hours afterwards, and should be allowed to rest until they have fully recovered.
Partial seizures
Partial seizures begin in one place in the brain, called the seizure focus, and affect only part of the brain. Depending on where they start and which parts of the brain they involve, partial seizures may or may not alter consciousness or awareness.
Simple partial seizures
Partial seizures that do not alter consciousness are called "simple partial seizures." They used to be known as "focal" seizures because they occur in only a small part of the brain (the focus). The person having the seizure is aware of what is happening. A simple partial seizure usually lasts only a short time. This type of seizure is also known as an "aura" because it often serves as a warning that a bigger seizure will follow.
Simple partial seizures vary widely from person to person, depending on where in their brain an individual's seizure focus is located. These seizures consist of an unusual emotion, sensation, or movement.
For example, if the abnormal electrical burst occurs in a specific part of the brain responsible for vision, the simple partial seizure will consist of seeing flashing lights. If it is on the brain's sensory strip, the person will experience a tingling arm or leg; on the motor strip, their limb will jerk. Some people experience an overwhelming emotion like fear or dread from yet another part of their brain, or smell an unpleasant odor.
Complex partial seizures
Complex partial seizures involve deep, central structures of the brain controlling consciousness, so awareness is altered or lost. These used to be known as psychomotor or temporal lobe seizures, because they commonly occur in the brain's temporal or frontal lobes. The brain functions located in these lobes are as complex as the seizures beginning there.A complex partial seizure may begin as a simple partial seizure (like a funny feeling or emotion) before it spreads to areas of the brain controlling awareness, or it may begin without warning with an alteration in consciousness. With this loss of awareness, the person having a complex partial seizure typically stares blankly, and performs automatic, unconsciously repeated movements, such as lip smacking, picking at one's clothes, and wandering around, aimless and confused. These movements are called automatisms. During the seizure, the person's ability to speak, understand and respond is usually affected.This is a very common type of seizure, although the general public does often not recognize it as epilepsy. People having a complex partial seizure are sometimes treated as if they are drunk or high on drugs, and are often mishandled.