Seizure overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
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.
The treatment of epilepsy is a subspecialty of neurology; the study of seizures is part of neuroscience.
Classification
The numerous epileptic seizure types are most commonly defined and grouped according to a scheme proposed by the International League Against Epilepsy (ILAE) in 1981.[1] Distinguishing between seizure types is important since different types of seizure may have different causes, prognosis and treatments.
Epidemiology and Demographics
About 4% of people will have an unprovoked seizure by the age of 80 and yet the chance of experiencing a second seizure is between 30% and 50%.
Diagnosis
Electroencephalogram
An isolated abnormal electrical activity recorded by an electroencephalography examination without a clinical presentation is called subclinical seizure. They may identify background epileptogenic activity, as well as help identify particular causes of seizures.
CT
These may show structural lesions within the brain, but the majority of those with epilepsy show nothing unusual.
References
- ↑ "Proposal for revised clinical and electroencephalographic classification of epileptic seizures. From the Commission on Classification and Terminology of the International League Against Epilepsy". Epilepsia. 22 (4): 489–501. 1981. PMID 6790275.