They occur when a focal point of abnormal electrical brain activity produces symptoms in a specific part of the body. Simple partial seizures are not associated with an impairment of consciousness. They can be manifested as a focal motor, focal sensory, somatosensory, psychic, or autonomic seizures. A complex partial seizure is associated with impairment in consciousness. A partial seizure, both simple and complex, can spread rapidly to other parts of the brain to become a secondarily generalized tonic clonic seizure.
Absence seizures begin in childhood and involve a brief loss of awareness.
They typically last five to 15 seconds and may be associated with fluttering of the eyelids. They begin without warning and end abruptly. Absence seizures may occur as often as 100 times a day. A generalized tonic-clonic seizure begins with little or no warning. During the tonic stage, the body stiffens, and during the clonic phase, the extremities contract and relax.