SEIZURE DISORDER

A seizure is a temporary abnormal electro-physiologic phenomenon of the brain, resulting in abnormal synchronization of electrical neuronal activity. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms (such as déjà vu or jamais vu). It is caused by a temporary abnormal electrical activity of a group of brain cells. The medical syndrome of recurrent, unprovoked seizures is termed epilepsy, but some seizures may occur in people who do not have epilepsy.

Seizures can cause involuntary changes in body movement or function, sensation, awareness, or behavior. A seizure can last from a few seconds to status epilepticus, a continuous seizure that will not stop without intervention. Seizure is often associated with a sudden and involuntary contraction of a group of muscles. However, a seizure can also be as subtle as marching numbness of a part of the body, a brief loss of memory, sparkling or flashes, sensing an unpleasant odor, a strange epigastric sensation or a sensation of fear. Therefore seizures are typically classified as motor, sensory, autonomic, emotional or cognitive.

In some cases, the full onset of a seizure event is preceded by some of the sensations described above. These sensations can serve as a warning to the sufferer that a full tonic-clonic seizure is about to occur. These "warning sensations" are cumulatively called an aura.

Symptoms experienced by a person during a seizure depend on where in the brain the disturbance in electrical activity occurs. Recent studies show that seizures happen in sleep more often than was thought. A person having a tonic-clonic seizure may cry out, lose consciousness and fall to the ground, and convulse, often violently. A person having a complex partial seizure may appear confused or dazed and will not be able to respond to questions or direction. Some people have seizures that are not noticeable to others. Sometimes, the only clue that a person is having an absence seizure is rapid blinking or a few seconds of staring into space.

It is commonly thought among healthcare providers that many seizures, especially in children, are preceded by tachycardia that frequently persists throughout the seizure. This early increase in heart rate may supplement an aura as a physiological warning sign of an imminent seizure.