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.
In population-based studies the most frequent causes of epilepsy are cryptogenic (presumed symptomatic) or idiopathic (presumed genetic), ranging from 44.5% 30 to 67%31, with the proportion of identified causes (symptomatic or localisation-related epilepsy – remote or progressive) increasing with age. The number of cases classified as cryptogenic has remained broadly similar over the past 20 years despite significant improvements in neuroimaging.