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Published on: February 25, 2016
Cardiac function and behavioral reactivity during infancy
N Snidman1, J Kagan, L Riordan
1Department of Psychology, Harvard University, Cambridge, MA 02138, USA.
Insights
Early cardiac function, including heart period and power, predicts infant temperament. These cardiac measures early in life may indicate temperamental qualities like reactivity and fear.
Area of Science:
- Developmental psychology
- Pediatric cardiology
- Infant behavior
Background:
- Cardiac function undergoes significant changes from the fetal period through infancy.
- Individual differences in cardiac measures stabilize later in infancy.
Purpose of the Study:
- To examine changes and stability in cardiac function from the fetal period to 21 months of age.
- To investigate the relationship between early cardiac function and temperamental characteristics (reactivity, fear) in infancy.
Main Methods:
- Longitudinal analysis of cardiac data (heart period, spectral power) from fetal stage to 21 months.
- Assessment of infant temperament (high/low reactivity at 4 months, fear of the unfamiliar in the second year).
Main Results:
- Heart period and cardiac power spectra changed significantly during the first two years of life.
- Individual cardiac differences were not stable until 9-14 months of age.
- Early cardiac measures (2-week sleep heart period, 2-month low-frequency power) predicted temperamental categories more effectively than later measures.
Conclusions:
- Cardiac function early in life is a sensitive indicator of temperamental qualities.
- Infant cardiac patterns may reflect underlying temperamental predispositions.
Abstract:
Longitudinal cardiac data from the end of the fetal period to 21 months of age were examined for change and stability over age and relations to the temperamental characteristics of high and low reactivity at 4 months of age and fear to the unfamiliar in the second year. Heart period and power in the cardiac spectra changed dramatically over the first 2 years, and individual differences were not preserved until 9-14 months of age. Sleep heart period at 2 weeks of age and low frequency power at 2 months of age were better predictors of the temperamental categories than later measures of the same variables, suggesting that cardiac function early in life may be an especially sensitive index of temperamental qualities.
