Spontaneous Arousals in Supine Infants While Swaddled and Unswaddled During
Rapid Eye Movement and Quiet Sleep
Claudia M. Gerard, MD, Kathleen A. Harris
and Bradley T. Thach, MD
From the Edward Mallinckrodt Department of Pediatrics, Washington University
School of Medicine, St Louis, Missouri
Objective. Supine sleep is recommended for infants to
decreasethe risk of sudden infant death syndrome, but many parents
reportthat their infants seem uncomfortable supine. Many culturesswaddle infants for sleep in the supine position. Swaddled infantsare said to "sleep better"; presumably they sleep longer or
with fewer arousals. However, there have been no studies ofthe
effect of swaddling on spontaneous arousals during sleep.Arousal is
initiated in brainstem centers and manifests as asequence of
reflexes: from sighs to startles and then to thrashingmovements.
Such "brainstem arousals" may progress to full arousal,but most do
not.
Methods. Twenty-six healthy infants, aged 80 ± 7 days,were
studied during normal nap times. Swaddled (cotton spandexswaddle)
and unswaddled trials were alternated for each infant.Sleep state
(rapid eye movement [REM] or quiet sleep [QS]) wasdetermined by
behavioral criteria (breathing pattern, eye movements)and
electroencephalogram/electrooculogram (10 infants). Respitrace,
submental and biceps electromyogram, and video recording wereused to
detect startles and sighs (augmented breaths). Fullarousals were
classified by eye opening and/or crying. Frequenciesof sighs,
startles, and full arousals per hour were calculated.Progression of
events was calculated as percentages in eachsleep state, as was
duration of sleep state.
Results. Swaddling decreased startles in QS and REM, full arousalin QS, and progression of startle to arousal in QS. It resulted
in shorter arousal duration during REM sleep and more REM sleep.
Conclusions. Swaddling has a significant inhibitory effect onprogression of arousals from brainstem to full arousals involvingthe cortex in QS. Swaddling decreases spontaneous arousals in
QS and increases the duration of REM sleep, perhaps by helping
infants return to sleep spontaneously, which may limit parental
intervention. For these reasons, a safe form of swaddling thatallows
hip flexion/abduction and chest wall excursion may helpparents keep
their infants in the supine sleep position andthereby prevent the
sudden infant death syndrome risks associatedwith the prone sleep
position.
Key Words: sudden infant death syndrome sighs startles
ALL INFORMATION, DATA, AND
MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS
OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR
LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"