Sleep studies of KLS show varying results based on the amount of time the patient is observed. Slow wave sleep is often reduced at the beginning of episodes, and REM sleep is reduced near the end. Conversely, REM sleep is often normal at the beginning, and slow wave sleep is often normal by the conclusion. Stage two non-rapid eye movement sleep is often interrupted during KLS. Studies also show that stage one and three non-rapid eye movement sleep become more efficient when the episodes end. The Multiple Sleep Latency Test has yielded inconsistent results when given to KLS patients. In many cases, hours are spent in a withdrawn sleep-like state while awake during episodes. Most sleep studies have been performed while subject is near the end of their episodes. Some patients experience brief insomnia and become very happy and talkative after the episode ends.
