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Autonomic response to auditory stimulation
S H Anderssen1, R B Nicolaisen, G W Gabrielsen
1Department of Pediatrics, University Hospital, Tromsø, Norway.
Acta Paediatrica (Oslo, Norway : 1992)
|November 1, 1993
Summary
Infants exhibit a passive defense response to sudden noise, characterized by apnea and bradycardia. This response, involving respiratory and heart rate changes, is more pronounced in younger infants and influenced by maternal smoking and sleep patterns.
Area of Science:
- Developmental Psychology
- Infant Physiology
- Behavioral Neuroscience
Background:
- The passive defense response, a conserved survival mechanism in animals, involves apnea and bradycardia.
- Its presence and characteristics in human infants are not well-established.
Purpose of the Study:
- To investigate the passive defense response in sleeping infants aged 8-50 weeks.
- To characterize autonomic and behavioral reactions to acute fear stimulation.
Main Methods:
- 12 infants aged 8-50 weeks were exposed to sudden loud noise (80 dB) during sleep.
- Respiratory and heart rate changes were monitored to assess autonomic and behavioral responses.
- Infant responses were analyzed in relation to age, sleep stage, and maternal smoking status.
Main Results:
- Apnea occurred in 58% of stimulations in younger infants (8-16 weeks) versus 14% in older infants (28-50 weeks).
- Apnea duration decreased with age, while preceding irregular respiration increased.
- Heart rate deceleration, associated with apnea, was more pronounced in younger infants.
Conclusions:
- The observed autonomic and behavioral changes in infants suggest a passive defense response.
- Factors such as maternal smoking, REM sleep, and postprandial sleep duration influence the infant's response.