Sleep stages

Stages of Sleep

•          EEG (electroencephalogram) introduced by Berger in 1929 recorded brain activity and showed …

•          Clearly identifiable stages of brain activity during sleep (Dement, Aserinsky & Kleitman (1950’s).

•          Brain activity looks different when someone is awake or asleep.

•          When they are asleep 2 distinct types can be seen – NREM and REM.

NREM goes through different stages

Two Main Types of Sleep            

•          Slow-wave sleep (NREM)

•          Rapid eye movement (REM) sleep

Up and down the “sleep escalator”

•          Most people have 5 cycles of sleep a night that last approximately 90 minutes. Slow-wave sleep (SWS) occurs in only the first two cycles; REM sleep occurs in all of the cycles,…