PROJECT SUMMARY/ABSTRACT
Maternal-child synchrony describes the temporal associations between maternal and child social and
physiological states, often occurring within maternal-child interactions. Maternal-child synchrony is a critical
component of child development that emerges during pregnancy and is present throughout childhood. The
quality of maternal-child synchrony is associated with future social development, making it an important
construct to understand. Given its developmental importance, it is critical to characterize maternal-child
synchrony in specific subgroups vulnerable to weakened maternal-child synchrony. It is well established that
maternal-child physiological synchrony decreases in clinical samples, such as when mothers are experiencing
mental health challenges (e.g., anxiety, depression) and when children themselves belong to at-risk groups
(e.g., prematurity), but this association is poorly understood in neurodevelopmental disorders, like fragile X
syndrome (FXS). FXS is a rare, monogenetic disorder, characterized by deficits in attention, social
development, and emotional regulation. These deficits have been attributed to physiological hyperarousal. This
“hyperarousal hypothesis” of FXS has been demonstrated via cardiac activity, particularly when indexed by
respiratory sinus arrythmia (RSA), wherein individuals with FXS have shown depressed RSA (thereby
indicating physiological arousal) when neurotypically (NT) developing individuals have shown higher RSA. As
an inherited disorder, mothers of children with FXS typically have the fragile X premutation (FXp). Women with
FXp demonstrate atypical physiological arousal indexed by lower RSA as well, and they experience elevated
anxiety, depression, and stress. Collectively, in FXS, these child and maternal phenotypic factors (i.e., clinical
status, atypical RSA) coalesce into vulnerability to disrupted maternal-child RSA synchrony. Yet, no studies
have examined maternal-child RSA synchrony in FXS or focused on infancy. Just as maternal-child synchrony
is influenced by the phenotypes of the dyadic partners, mother-child interactions are influenced by contextual
factors that surround the child, such as parental stress and familial relationships; this important contextual
influence has also been absent from the FXS maternal-child synchrony literature. Therefore, the over-arching
aim of this F31 is to examine maternal-child RSA synchrony in 12-month-old males with FXS (nFXS = 25),
contrasted against male infants with neurotypical development (NT; nNT = 25) at baseline (Aim 1a) and during a
standardized mother-child free play interaction task (Aim 2b). I will identify how contextual variables (i.e.,
parental stress, family relationships) differentially impact both baseline maternal-child RSA synchrony (Aim 1b)
and maternal-child RSA synchrony during the mother-child free play task (Aim 2b) in both groups, as well as
how behavioral synchrony impacts maternal-child RSA synchrony during the mother-child free play task (Aim
2c) across groups.