PAROXYSMAL DISORDERS		      587

A jacksonian seizure begins as a localized motor seizure characterized by a spread of abnormal activity to adjacent areas of the brain. It typically produces a stiffening or jerking in one extremity, accopanied by a tingling sensation in the same area. For example, it may start in the thumb and spread to the entire hand and arm. the patient seldom loses consciousness. A jacksonian seizure may progress to a generalized tonic-clonic seizure.

The symptoms of a complex partial seizure are variable but ussually include purposeless behavior. The seizure may begin with an aura, a sensation the patient feels imediately before a seizure. An aura represents the beginning of abnormal electrical discharges within a focal area of the brain and may include a pungent smell, gastrointestinal distress (nausea or indigestion), a rising or sinking feeling in the stomach, a dreamy feeling, an unusual taste or visual disturbance. Overt signs of a complex partial seizure include a glassy stare, picking at one's clothes, aimless wandering, lip smacking or chewing motions, and unintelligible speech. Mental confusion may last several minutes after the seizure: as a result an observer may mistakenly suspect intoxication with alcohol or drugs, or psychosis.

Generalized seizures, as the term suggests, cause a generalized electrical abnormality within the brain and include several distinct types:

Absence (petit mal) seizures occur most often in children, although they may affect adults as well. They usually begin with a brief change in the level of consciousness, indicated by blinking or rolling of the eyes, a blank stare, and slight mouth movements. The patient retains his posture and continues pre-seizure activity without difficulty. Typically, each seizure lasts from 1 to 10 seconds. If not properly treated, seizures can recur as often as 100 times a day. An absence seizure my progress to generalized tonic-clonic seizures.