Absence seizure and Simple absence

Absence seizure noun - The occurrence of an abrupt, transient loss or impairment of consciousness (which is not subsequently remembered), sometimes with light twitching, fluttering eyelids, etc.; common in petit mal epilepsy.

Simple absence and absence seizure are semantically related. In some cases you can replace phrase "Simple absence" with "Absence seizure", this phrases are similar.

Simple absence noun - An absence seizure without other complications; followed by 3-per-sec brainwave spikes.

Absence seizure and simple absence are semantically related. You can use "Absence seizure" instead a noun phrase "Simple absence".