Measuring Cardiac Autonomic Nervous System (ANS) Activity in Toddlers - Resting and Developmental Challenges

Abstract

The autonomic nervous system (ANS) consists of two branches, the parasympathetic and sympathetic nervous systems, and controls the function of internal organs (e.g., heart rate, respiration, digestion) and responds to everyday and adverse experiences 1. ANS measures in children have been found to be related to behavior problems, emotion regulation, and health 2-7. Therefore, understanding the factors that affect ANS development during early childhood is important. Both branches of the ANS affect young children's cardiovascular responses to stimuli and have been measured noninvasively, via external monitoring equipment, using valid and reliable measures of physiological change 8-11. However, there are few studies of very young children with simultaneous measures of the parasympathetic and sympathetic nervous systems, which limits understanding of the integrated functioning of the two systems. In addition, the majority of existing studies of young children report on infants' resting ANS measures or their reactivity to commonly used mother-child interaction paradigms, and less is known about ANS reactivity to other challenging conditions. We present a study design and standardized protocol for a non-invasive and rapid assessment of cardiac autonomic control in 18 month old children. We describe methods for continuous monitoring of the parasympathetic and sympathetic branches of the ANS under resting and challenge conditions during a home or laboratory visit and provide descriptive findings from our sample of 140 ethnically diverse toddlers using validated equipment and scoring software. Results revealed that this protocol can produce a range of physiological responses to both resting and developmentally challenging conditions, as indicated by changes in heart rate and indices of parasympathetic and sympathetic activity. Individuals demonstrated variability in resting levels, responses to challenges, and challenge reactivity, which provides additional evidence that this protocol is useful for the examination of ANS individual differences for toddlers.

Effects of pre- and postnatal maternal stress on infant temperament and autonomic nervous system reactivity and regulation in a diverse, low-income population

“…After infants acclimated to the assessors, trained RAs attached cardiac monitoring equipment to the infant while he or she sat on the mother's lap. The RA placed four spot electrodes on the infant's neck and trunk to collect impedance and respiratory measures, and three spot electrodes were placed on the right clavicle, lower left rib, and right abdomen for ECG measures (Bush, Caron, Blackburn, & Alkon, 2016). Infants were then placed into a secure, stationary infant seat, surrounded by a trifold, white visual barrier obstructing his or her view of the environment behind and to the sides of the seat.…”

Biological sensitivity to context: A test of the hypothesized U-shaped relation between early adversity and stress responsivity

“…The correlations between the four PEP reactivity scores and between the four RSA reactivity scores were small (i.e., r < .15) and mostly nonsignificant across the tasks (see Bush, Alkon, et al, 2011, for details of the task-by-task intercorrelations among the RSA and SNS measures). Despite these low correlations, multidomain composites are fairly standard in child physiology literature, and our approach is consistent with that taken by a multitude of labs and studies (Alkon et al, 2003;Boyce et al, 2001;Bush, Alkon, et al, 2011;Bush, Caron, Blackburn, & Alkon, 2016;Gangel et al, 2017;Suurland, van der Heijden, Huijbregts, Van Goozen, & Swaab, 2018). High correlations among specific task reactivities are not required for such an approach and are not expected at a sample level, as the protocol was designed to capture reactivity across a variety of unrelated contexts.…”

Sexual Dimorphism of Heart Rate Variability in Adolescence: A Case-Control Study on Depression, Anxiety, Stress Levels, Body Composition, and Heart Rate Variability in Adolescents with Impaired Fasting Glucose

“…On a different note, interesting correlations between the HRV parameters and the psychometric subscales of DASS21 were revealed. HRV has been subject to criticism [52], since there are no clear boundaries between the two branches of the autonomic nervous system, due to their dynamic balance, especially in developing brains [53]. Normal, healthy adolescent brains give rise to odd results in the HRV tests.…”