Dyadic Stress Vulnerability in Mother-Infant Dyads: Sympathetic Nervous System and Adrenocortical Reactivity to Infant Challenge
Open Access
- Author:
- Kivlighan, Katie Therese
- Graduate Program:
- Biobehavioral Health
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 28, 2006
- Committee Members:
- Douglas A Granger, Committee Chair/Co-Chair
Elizabeth Susman, Committee Member
John Walter Graham, Committee Member
Laura Klein, Committee Member
Clancy Blair, Committee Member - Keywords:
- salivary alpha-amylase
salivary cortisol
stress reactivity
mother-infant relationship
maternal behavior
temperament - Abstract:
- The mother-infant relationship is bi-directional with implications for both infant and maternal health, behavior, and physiology. The current study examined the impact of the mother-infant relationship on infant and maternal stress physiology through examination of sympathetic and adrenocortical responses to infant challenge. A sample of 284 mother-infant dyads was selected from families participating in a large, multi-site study of child development under conditions of rural poverty. During a home visit, mothers and infants participated in a free-play session and a series of infant challenge tasks to elicit distress to novelty and frustration. Observational coding of maternal sensitivity, intrusiveness, and detachment were conducted from digital recordings of the free-play and infant behavioral reactivity and regulation were coded from DVDs of the challenge tasks. Saliva samples were collected before, 20-, and 40-minutes after the challenge tasks and assayed for salivary alpha-amylase (sAA) and cortisol. Symptoms of maternal depression and anxiety were assessed using the Brief Symptom Index (BSI). A growth mixture modeling technique was applied to sAA and cortisol data. Analyses were controlled for sampling time of day, demographic factors, health behaviors, and medication use. In general, there were more associations with infant and maternal behaviors for infant physiology than for maternal stress physiology. Infant reactivity and regulatory behaviors interacted to predict infant sAA and cortisol response to challenge. Infants displaying both high behavioral reactivity and regulatory behavior were more likely to have low, non-reactive sAA levels and cortisol reactivity with recovery. In contrast, low reactive infants (i.e., little fussing) displaying few regulatory behaviors tended to show sAA increases and were less likely to display cortisol reactivity. Infants of highly detached mothers tended to display low and non-reactive sAA levels, while infants of highly anxious mothers more often showed sAA increases. Mothers of boys were more likely to have higher baseline cortisol levels than mothers of girls. Physiological attunement in mother-infant dyads was found for baseline levels of sAA and cortisol, but not between profiles of reactivity to the challenge. The present study has implications for understanding how early mother-infant relationships in high-risk environments can influence the development of stress physiological systems.