Influence of swaddling on sleep and arousal characteristics of healthy infants.
OBJECTIVE
Swaddling is an old infant care practice. It was reported to favor sleep and to reduce crying among irritable infants. There are few data on the physiologic effects of swaddling on infants' sleep-wake characteristics. This study was conducted to evaluate whether swaddling influences infants' arousal thresholds for environmental auditory stress.


METHODS
Sixteen healthy infants, with a median age of 10 weeks (range: 6-16 weeks), underwent polygraphic recording in their usual supine position during one night. The infants were successively recorded swaddled and nonswaddled, or vice versa. In both conditions, the infants were exposed to white noise of increasing intensity, from 50 to 100 dB(A), during rapid eye movement sleep, to determine their arousal thresholds.


RESULTS
Swaddling was associated with increases in the infants' sleep efficiency and in the time spent in non-rapid eye movement sleep. When swaddled, the infants awakened spontaneously less often. However, significantly less-intense auditory stimuli were needed during rapid eye movement sleep to induce cortical arousals when swaddled than when not swaddled.


CONCLUSIONS
Swaddling promotes more-sustained sleep and reduces the frequency of spontaneous awakenings, whereas induced cortical arousals are elicited by less-intense stimuli. These findings could indicate that, although swaddling favors sleep continuity, it is associated with increased responsiveness to environmental auditory stress.
Franco
Patricia
P
Pediatric Sleep Unit, University Children's Hospital, Free University of Brussels, Brussels, Belgium. patricia.franco@ulb.ac.be
Seret
Nicole
N
Van Hees
Jean-Noël
JN
Scaillet
Sonia
S
Groswasser
José
J
Kahn
André
A
D000161:Acoustic Stimulation; D001143:Arousal; D003020:Clothing; D004569:Electroencephalography; D006339:Heart Rate; D006801:Humans; D007223:Infant; D012890:Sleep; D012894:Sleep Stages