1. Representative polysomnographic recordings from adults in the awake state and various stages of sleep. Recordings are made at conventional sleep laboratory speed of 10 mm/s (i.e., at the paper speed of one-third standard clinical EEG recordings). A. Upper tracings: Awake state (with eyes closed). Alpha rhythms are prominent in EEG. Normally active chin EMG. B. Middle tracings: Stage 1 (N1) sleep. Onset of sleep is defined by the diminished amplitude of alpha waves in the occipital EEG channel ("flat" appearance). C. Lower tracings: Stage 2 (N2) sleep, characterized by appearance of high-amplitude single-complex (K) waves and bursts of 13- to 16-Hz waves (sleep spindles) on a background of low frequency. D. Upper tracings: Stage 3 (N3) sleep. Appearance of high-voltage slow (delta) waves. E. Middle tracings: Deepest stage of N3 sleep, with predominant delta-wave activity occupying 50 percent of a 30-s tracing. F. Lower tracings: Rapid eye movement (REM) sleep, characterized by episodes of REM and occasional muscle twitches in an otherwise flat chin EMG. Technical Note: Four sites from the same montage are illustrated in each recording: C3/A2, left central to right mastoid; O2/A1, right occipital to left mastoid; ROC/A1, right outer canthus to left mastoid; LOC/A2, left outer canthus to right mastoid. A chin EMG tracing is added to each recording. (Adapted with permission from Butkov N. Atlas of Clinical Polysomnography. Vol 1. Synapse Media, Medford, OR, 1996.)
Source: Chapter 19. Sleep and Its Abnormalities, Adams and Victor's Principles of Neurology, 10e
Citation: Ropper AH, Samuels MA, Klein JP. Adams and Victor's Principles of Neurology, 10e; 2014 Available at: Accessed: January 03, 2018
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