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. 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.
Based on community-based studies 6,12,32 proportions (%) of presumed identified causes of epilepsy are the following: cerebrovascular disease 11−21%, trauma 2−6%, tumours 4−7%, infection 0−3%, and idiopathic 54−65%. A systematic review17 found that partial seizures occurred in 55% of patients compared to 45% with generalised seizures. In the Rochester study age-specific incidences of generalised and partial seizures were compared; generalised seizures were more common in the first five years of life.