Diuranal rhythms in 2- and 8-week-old infants: sleep-waking state organization as a function of age and stress.
Time of day differences in sleep-waking state organization were studied in 2- and 8-week-old infants by means of videotape recordings. Observations were made prior to and following adaptation to standard laboratory conditions previously found to be stressful. Diurnal rhythms occurred for a number of component sleep-waking states under the nonstressful conditions only, and increased with age.
D000223:Adaptation, Psychological; D000367:Age Factors; D002940:Circadian Rhythm; D003448:Crying; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D012890:Sleep; D013312:Stress, Physiological / Q000150:complications*; D014851:Wakefulness