What is normal sleep EEG?

Updated: May 15, 2018
  • Author: Selim R Benbadis, MD; Chief Editor: Helmi L Lutsep, MD  more...
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Answer

Loomis provided the earliest detailed description of various stages of sleep in the mid-1930s, and in the early 1950s, Aserinsky and Kleitman identified rapid eye movement (REM) sleep [1] . Sleep is generally divided into 2 broad types: nonrapid eye movement (NREM) sleep and REM sleep. Based on EEG changes, NREM is divided further into 4 stages (stage I, stage II, stage III, stage IV). NREM and REM occur in alternating cycles, each lasting approximately 90-100 minutes, with a total of 4-6 cycles. In general, in the healthy young adult NREM sleep accounts for 75-90% of sleep time (3-5% stage I, 50-60% stage II, and 10-20% stages III and IV). REM sleep accounts for 10-25% of sleep time.

According to the National Sleep Foundation, the appropriate sleep duration for newborns is between 14 and 17 hours, sleep cycles last approximately 60 minutes (50% NREM, 50% REM, alternating through a 3-4 hour interfeeding period); these numbers decline to a mean of 10 hours during childhood. Recommended sleep for infants is between 12 and 15 hours, toddlers between 11 and 14 hours, preschoolers between 10 and 13 hours, and school-aged children between 9 and 11 hours. For teenagers, 8 to 10 hours is considered appropriate, 7 to 9 hours for young adults and adults, and 7 to 8 hours of sleep for older adults. [2]


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