Each stage of sleep from wakefulness through REM sleep is characterized by a predominant EEG brainwave pattern. Try the mnemonic BATS Drink Blood to help remember the order of brain waves through the stages of Non-REM and REM sleep. For more info about NREM & REM Sleep, check out this brief video.
BATS Drink Blood
Click on the video below for a quick breakdown of the mnemonic!