Maternal dynamic respiratory sinus arrhythmia during toddlers' interactions with novelty

Parents' Physiological Reactivity to Child Distress and Associations with Parenting Behaviour: A Systematic Review

This systematic review and narrative synthesis characterized parents' physiological stress responses to child distress and how parents' physiological and behavioural responses relate. The review was pre-registered with PROSPERO (#CRD42021252852). In total, 3,607 unique records were identified through Medline, Embase, PsycINFO, and CINAHL. Fifty-five studies reported on parents' physiological stress responses during their young child's (0-3 years) distress and were included in the review. Results were synthesized based on the biological outcome and distress context used and risk of bias was evaluated. Most studies examined cortisol or heart rate variability (HRV). Small to moderate decreases in parents' cortisol levels from baseline to post-stressor were reported across studies. Studies of salivary alpha amylase, electrodermal activity, HRV, and other cardiac outcomes reflected weak or inconsistent physiological responses or a paucity of relevant studies. Among the studies that examined associations between parents' physiological and behavioural responses, stronger associations emerged for insensitive parenting behaviours and during dyadic frustration tasks. Risk of bias was a significant limitation across studies and recommendations for future research are discussed.

Temperamental and physiological regulatory capacity in infancy: Links with toddler behavior problems

Although correlates of temperamental regulatory processes in childhood have been well established, there is considerably less work examining correlates and moderators of rudimentary forms of temperamental regulation in infancy. We examined whether infants' physiological regulation indexed via changes in respiratory sinus arrhythmia (RSA) across phases of the Still-Face Paradigm moderated the association between maternal-reported infant regulatory capacity at 8 months (N = 50, M_age = 8.51 months, SD_age = 0.28 months, 25 girls) and behavior problems at 14 months. We found that cardiac vagal regulation from baseline to still-face moderated the relation between infant regulatory capacity at 8 months and behavior problems at 14 months. Among infants who displayed relatively high cardiac vagal regulation from baseline to still-face, regulatory capacity was negatively associated with behavior problems. There was no relation between regulatory capacity and behavior problems among infants who displayed average or relatively low cardiac vagal regulation. We speculate that high levels of regulatory capacity and cardiac vagal regulation may allow infants to focus their attention outward and cope with emotionally evocative environmental demands as they arise even in the absence of external regulation provided by their caregivers.