Eyelid movements and mental activity at sleep onset.
The nature and time course of sleep onset (hypnagogic) mentation was studied in the home environment using the Nightcap, a reliable, cost-effective, and relatively noninvasive sleep monitor. The Nightcap, linked to a personal computer, reliably identified sleep onset according to changes in perceived sleepiness and the appearance of hypnagogic dream features. Awakenings were performed by the computer after 15 s to 5 min of sleep as defined by eyelid quiescence. Awakenings from longer periods of sleep were associated with (1) an increase in reported sleepiness, (2) a decrease in the length of mentation reports, (3) a decrease in the frequency of reports of normal, wake-like thoughts, (4) an increase in the frequency of "unusual thoughts," and (5) increased frequencies of formal dream features, including visual hallucination, self-representation, fictive movement, narrative plot, and bizarreness. While sleep-onset reports can include all features of rapid eye movement (REM) dream reports, the number of such features is markedly reduced at sleep onset, suggesting that this mentation is a greatly diminished version of REM dreaming.
Rowley
J T
JT
Laboratory of Neurophysiology, Harvard Medical School, 74 Fenwood Road, Boston, Massachusetts 02115, USA.
Stickgold
R
R
Hobson
J A
JA
D000328:Adult; D000704:Analysis of Variance; D003071:Cognition; D004325:Dreams; D005143:Eyelids / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D017286:Polysomnography; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D014851:Wakefulness