Protective Effects of Parasympathetic Activity in Violence-exposed Preschoolers: Sex-specific Associations with Behavior Problems

• In Event: 2-073 - Early Adversity, Biology, and Behavior: Examining Biological Consequences and Contingencies of Early Life Stress

Integrative Statement

BACKGROUND. Identifying biological markers of vulnerability to trauma exposure has the potential to inform our understanding of developmental psychopathology, as well as targeted clinical care. High baseline Respiratory Sinus Arrhythmia (RSA), an index of parasympathetic-mediated cardiac control associated with self-regulation, has been linked to lower mental health risk (Graziano & Derefinko, 2013). However, it is unclear whether these associations extend to high-risk or traumatized samples, as divergent associations between RSA and mental health outcomes are often observed among trauma-exposed samples, sometimes along sex-specific lines (Gray, Theall, Lipschutz & Drury, 2017). The current study extends the examination of the context-specific contribution of RSA to child behavior, examining patterns in a low-income sample of preschool-aged children oversampled for exposure to violence. We hypothesized that higher baseline RSA would be associated with lower behavior problems among children with low exposure to violence, but that divergent associations between RSA and behavior problems would be observed among children with higher exposure to violence (moderation); we additionally hypothesized sex differences.

METHODS. Preschool-aged children (3-5 years, M=51.62 months, SD=9.26 months; n=103; 54.2% girls; primarily African American) were recruited from Head Start centers and other service providers. All families were within 130% of the poverty level; children with exposure to violence were intentionally oversampled. Mothers reported on demographic information and on children’s behavior problems with the Child Behavior Checklist 1.5-5 (Achenbach & Resclora, 2001). Child exposure to violence was assessed using the Exposure to Violence Inventory parent interview (Selner-O’Hagan, Kindlon, Buka, Raudenbush, & Earls, 1998); a sum score was created for number of events that children experienced directly or witnessed (range: 0-4). Electrocardiogram (ECG) data were collected during a 2-minute, seated resting period using Mindware ambulatory mobile recorders; ECG signals were processed offline and RSA calculated via algorithm as the log transformation of high-frequency heart rate variability within an age-specified frequency bandwidth (.24-1.04). All models covaried child age and parent education.

RESULTS. Moderation was tested using Hayes’s PROCESS macro with bootstrapping. For externalizing behavior, a three-way interaction was observed between children’s exposure to violence, RSA, and sex (see Table 1, Figure 1). Among boys, higher RSA was only associated with lower behavior problems for boys with low violence exposure, suggesting that there may be a higher threshold level of violence exposure at which parasympathetic activity does not buffer against behavior problems for boys. Among girls with no violence exposure, lower baseline RSA was unexpectedly associated with lower externalizing behavior, but among girls with high exposure to violence, higher baseline RSA was associated with lower externalizing behavior, suggesting a protective effect. For internalizing behavior, the three-way interaction was trending, b = -2.52 [-5.07, 0.03], p = .053, with similar sex-differentiated associations.

DISCUSSION. Findings support a conceptualization of RSA as a sex-differentiated and context-specific protective factor, with buffering effects observed only among preschool-aged boys with low violence exposure, and among preschool-aged girls with high levels of violence exposure. Longitudinal studies are needed to unpack the developmental course of these associations, with implications for developmental psychopathology and targeted assessment.

Authors

• Sarah A Gray, Tulane University
  Presenting Author

• Erin Glackin, Tulane University
  Non-Presenting Author

• Virginia Hatch, Tulane University
  Non-Presenting Author

• Rebecca Lipschutz, University of Houston
  Non-Presenting Author