EEG findings in Absense seizures/ Petit mal epilepsy

Electroencephalographic findings in typical absence seizures (petit mal epilepsy) are as follows:

1) Background activity is normal.
2) Frontally dominant bursts of 3-Hz spike-and-wave complexes are seen during the seizures.
3) In syndromes with less frequent absence seizures (juvenile absence epilepsy or juvenile myoclonic epilepsy), an awake recording may be normal; a sleep or sleep-deprived recording may show evidence of generalized 3-Hz spike-and-wave complexes.
4) There is abrupt onset and ending. No postictal EEG slowing is noted.
5) Video EEG may demonstrate that clinical seizures at times occur after the the start of ictal EEG activity by a few seconds.