Typically, this type of seizure lasts between 10 and 30 seconds. The person, most often a child aged 5 to 15, abruptly stops whatever he's doing (talking, walking) and appears to "stare into space." Absence seizures rarely cause a true convulsion in which the person falls down or collapses. Despite briefly losing consciousness, the person recovers fully with no lingering confusion or other ill effects. These "spells" may occur infrequently or several times per hour. In children, absence seizures may interfere with learning and are often misinterpreted as daydreaming or inattention. About a quarter of people who have absence seizures will develop another type of generalized seizure called tonic-clonic seizures (formerly called ''grand mal'' seizures). The vast majority of children, however, will outgrow them.
Approximately 20 to 30% of patients with epilepsy have intractable epilepsy and 10 to 50% of medically refractory patients may benefit from surgery. The surgically treatable disorders include mesial temporal sclerosis, benign neoplasms, developmental abnormalities and other focal lesions such as arteriovenous malformations.