You are in: eMedicine Specialties > Neurology > EEG Atlas: Normal Sleep EEG - Rapid Eye Movement SleepArticle Last Updated: *ba 0, 0AUTHOR AND EDITOR INFORMATIONSection 1 of 6
  Author: Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital Selim R Benbadis is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, and American Medical Association Coauthor(s): Diego Rielo, MD, Staff Physician, Department of Neurology, Memorial Hospital West, Memorial Hospital Pembroke, Memorial Healthcare Editors: Leslie Huszar, MD, Consulting Staff, Department of Neurology, Indian River Memorial Hospital; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Norberto Alvarez, MD, Assistant Professor, Department of Neurology, Harvard Medical School; Consulting Staff, Department of Neurology, Boston Children's Hospital; Matthew J Baker, MD, Consulting Staff, Collier Neurologic Specialists, Naples Community Hospital; Nicholas Y Lorenzo, MD, Chief Editor, eMedicine Neurology; Consulting Staff, Neurology Specialists and Consultants Author and Editor Disclosure Synonyms and related keywords: EEG atlas, normal sleep EEG, stage I sleep, stage II sleep, stage III sleep, stage IV sleep, EEG desynchronization, REM sleep, saw tooth wave, rapid eye movement sleep, non-REM sleep, nonrapid eye movement sleep, sleep stages, sleep-onset REM period, SOREMP, sleep waveforms INTRODUCTIONSection 2 of 6
  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. Sleep generally is divided in 2 broad types: nonrapid eye movement sleep (NREM) and REM sleep. On the basis of 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. REM sleep normally is not seen on routine EEGs, because the normal latency to REM sleep (100 min) is well beyond the duration of routine EEG recordings (approximately 20-30 min). The appearance of REM sleep during a routine EEG is referred to as sleep-onset REM period (SOREMP) and is considered an abnormality. While not observed on routine EEG, REM sleep commonly is seen during prolonged (>24 h) EEG monitoring. Representative examples of waveforms described here can be seen in Images 1-6. For excellent patient education resources, visit eMedicine's Procedures Center. Also, see eMedicine's patient education articles Sleep: Understanding the Basics, REM Sleep Behavior Disorder and Electroencephalography (EEG). WAVEFORM DESCRIPTIONSSection 3 of 6
By strict sleep staging criteria on polysomnography, REM sleep is defined by (1) rapid eye movements; (2) muscle atonia; and (3) EEG "desynchronization" (compared to slow wave sleep). Thus, 2 of the 3 defining characteristics are not cerebral waves and theoretically require monitoring of eye movements (electrooculogram [EOG]) and muscle tone (electromyelogram [EMG]). Fortunately, muscle activity and eye movements can be evaluated on EEG, thus REM sleep is usually not difficult to identify. In addition to the 3 features already named, "saw tooth" waves also are seen in REM sleep.
Despite the lack of a dedicated EMG channel, the muscle atonia that characterizes REM sleep is usually apparent as a general sense of "quiet" muscle artifacts compared to wakefulness. CLINICAL CORRELATIONSection 4 of 6
The duration of REM sleep increases progressively with each cycle and tends to predominate late in the sleep period into early morning. The occurrence of REM too soon after sleep onset, referred to as SOREMP, is considered pathological. However, newborns and infants enter REM more rapidly and spend a higher proportion of sleep in REM (this is true in most species and supports the theory that REM sleep is involved in brain development). MULTIMEDIASection 5 of 6
REFERENCESSection 6 of 6
EEG Atlas: Normal Sleep EEG - Rapid Eye Movement Sleep excerpt Article Last Updated: *ba 0, 0 | ||||||||||||||||||||||||||||||||||||||||||
