LAUSR

The current study examines the associations between low resting heart rate (HR), low electrodermal activity (EDA), and externalizing behavior (EB) in children 1–5 years old through the following measures: baseline 1 (B1) HR, startle period HR, and recovery-stage HR HR, EDA amplitude and skin conductance responses (SCR). We also investigate whether in-utero stress (exposure to Hurricane Sandy) moderates these relationships. A subsample of 206 children was drawn from a NIMH longitudinal study, the Stress in Pregnancy Study, that follows offspring from in-utero to 6 years of age. HR and EDA data was collected during a startle-probe paradigm. Mean age of the participants was 3.89 years. Approximately 52% were female and 50.5% were Hispanic. Participants’ EB was assessed by the Behavioral Assessment Screening for Children Version-2 parent rating scales. Externalizing symptoms were trichotomized (high, medium, and low). One-way ANOVA showed that three EB groups differed in baseline-HR (p = 0.034), startle-HR (p = 0.006), and recovery-stage HR (p = 0.008) in 4-year olds. EDA was not significantly different between EB groups. Furthermore, Hurricane Sandy exposure significantly and marginally significantly moderates the relationship between EB and amplitude (b = 3.0344, p = 0.044) and EB and SCR (b = 1.5629, p = 0.056), respectively. Hurricane Sandy exposure did not moderate the relationship between EB and HR. Externalizing problem symptom groups significantly differ in HR, but not EDA. Hurricane Sandy exposure moderates the relationship between EB and EDA, but not EB and HR. Results suggest that HR and EDA are differentially susceptible to environmental influence. Results can guide biologically informed treatments/screeners for EB in children.