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

Effect of Early-Life Lipid-Based Nutrient Supplement and Home Environment on Autonomic Nervous System Regulation at 9-11 Years: A Follow-Up of a Randomized Controlled Trial

Nutrition and the home environment contribute to the development of the autonomic nervous system (ANS). However, no study has examined the long-term effects of prenatal and postnatal small-quantity lipid-based nutrient supplements (SQ-LNS) and home environment on ANS regulation. We investigated the effect of early-life SQ-LNS and home environment on ANS regulation at 9-11 years. Participants were children born to women who participated in a randomized controlled trial in Ghana from 2009 to 2014. Women were randomized to receive daily, from pregnancy until delivery, either SQ-LNS, multiple micronutrients (MMN) or iron and folic acid (IFA) followed by SQ-LNS, MMN or placebo, respectively, until 6 months postpartum. Infants in the SQ-LNS group received SQ-LNS from 6 to 18 months. Quality of home environment was observed at 4-6 and 9-11 years. At 9-11 years, 965 children had their respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP) measured at baseline and during two inhibitory control tasks, the RACER Simon and Emotion Go/No-Go (EGNG) tasks. PEP reactivity to the RACER Simon task was greater in the MMN (-2.54 ± 4.45, p = 0.016) and SQ-LNS (-2.31 ± 4.94, p = 0.093) groups than in the IFA group (-1.57 ± 3.51). A better home environment at 4-6 predicted longer baseline PEP (β = 0.13, 95% CI: 0.02, 0.23, p = 0.016) and more PEP reactivity during the EGNG task (β = -0.06, 95% CI: -0.00, -0.02, p = 0.001). Prenatal micronutrient supplementation appears to increase SNS reactivity. Children raised in disadvantaged early home environments had more tonic SNS activation and less SNS reactivity, suggesting a predisposition for stronger fight-or-flight activation and less likelihood to modulate arousal in response to acute situations. Trial Registration: ClinicalTrials.gov identifier: NCT00970866.

Parental sensitivity modifies the associations between maternal prenatal stress exposure, autonomic nervous system functioning and infant temperament in a diverse, low-income sample

Evidence suggests that adversity experienced during fetal development may shape infant physiologic functioning and temperament. Parental sensitivity is associated with child stress regulation and may act as a buffer against risk for intergenerational health effects of pre- or postnatal adversity. Building upon prior evidence in a racially and ethnically diverse sample of infants (M infant age = 6.5 months) and women of low socioeconomic status, this study examined whether coded parenting sensitivity moderated the association between an objective measure of prenatal stress exposures (Stressful Life Events (SLE)) and infant parasympathetic (respiratory sinus arrhythmia; RSA) or sympathetic (pre-ejection period; PEP) nervous system functioning assessed during administration of the Still-Face-Paradigm (SFP) (n = 66), as well as maternal report of temperament (n = 154). Results showed that parental sensitivity moderated the associations between prenatal stress exposures and infant RSA reactivity, RSA recovery, PEP recovery, and temperamental negativity. Findings indicate that greater parental sensitivity is associated with lower infant autonomic nervous system reactivity and greater recovery from challenge. Results support the hypothesis that parental sensitivity buffers infants from the risk of prenatal stress exposure associations with offspring cross-system physiologic reactivity and regulation, potentially shaping trajectories of health and development and promoting resilience.

Dynamics of mother-infant parasympathetic regulation during face-to-face interaction: The role of maternal emotion dysregulation

The dynamics of parent-infant physiology are essential for understanding how biological substrates of emotion regulation are organized during infancy. Although parent-infant physiological processes are dyadic in nature, research is limited in understanding how one person's physiological responses predict one's own and as well as the other person's responses in the subsequent moment. In this study, we examined mother-infant respiratory sinus arrhythmia (RSA) dynamics during the Still-Face Paradigm (SFP) among 106 mothers (M_age  = 29.54) and their 7-month-old infants (55 males). Given mothers' role in shaping dyadic interactions with their infant, we also tested how mothers' self-reported emotion dysregulation (measured via the Difficulties in Emotion Regulation Scale) associated with these dynamics. Results showed that both mothers' and infants' RSA tended to return to their respective homeostatic points (i.e., exhibited return strength) during each SFP episode, indicating stability in RSA for mother-infant dyads. Significant shifts in mother and infant RSA return strength were observed across SFP episodes, highlighting the role of contextual demands on each individual's physiological dynamics. Mother-infant RSA dynamics varied as a function of maternal self-reported emotion dysregulation. Specifically, RSA levels of infants with more dysregulated mothers had a weaker tendency to return to homeostasis during the Reunion episode and were less affected by their mothers' RSA during the Still-Face and Reunion episodes of the SFP, suggesting a less effective coregulatory influence. Our findings have implications for the intergenerational transmission of emotion dysregulation via mother-infant physiological dynamics.

Autonomic profiles and self-regulation outcomes in early childhood

This study examined autonomic profiles in preschoolers (N = 278, age = 4.7 years) and their relations to self-regulation outcomes concurrently and one year later, in kindergarten. Children's sympathetic (preejection period [PEP]) and parasympathetic activity (respiratory sinus arrythmia [RSA]) were measured at rest and during cognitive and emotional tasks. Three self-regulatory competencies were assessed: executive functions, emotion regulation and behavioral regulation. Executive functioning was measured at ages 4 and 5 using laboratory tasks designed to assess updating/working memory, inhibitory control, and cognitive flexibility. Emotion regulation was observed during emotionally distressing tasks in the laboratory, both at ages 4 and 5. Behavioral regulation and emotional reactivity were assessed via teacher ratings in kindergarten, at age 5. Latent profile analysis yielded four autonomic profiles: moderate parasympathetic inhibition (45%), reciprocal sympathetic activation (26%), coinhibition (25%), and high sympathetic activation (7%). The reciprocal sympathetic activation group showed better executive functioning in preschool and kindergarten, particularly compared to the high sympathetic activation group. The moderate parasympathetic inhibition group showed lower emotional reactivity and better behavioral regulation in kindergarten, compared to the other three groups. Findings suggest that autonomic profiles meaningfully associate with self-regulation outcomes in early childhood, such that certain profiles relate to better self-regulation than others.

Maternal Sensitivity Modulates Child's Parasympathetic Mode and Buffers Sympathetic Activity in a Free Play Situation

Background

Behavioral and physiological (self-)regulation in early life is crucial for the understanding of childhood development and adjustment. The autonomic nervous system (ANS) is a main player in the regulative system and should therefore be modulated by the quality of interactive behavior of the caregiver. We experimentally investigated the ANS response of 18–36-month-old children in response to the quality of maternal behavior during a mother–child-interacting paradigm.

Method

Eighty mothers and their children came to our laboratory and took part in an experimental paradigm, consisting of three episodes: a resting phase (E1), a structured play phase (E2), and a free play situation (E3) between mothers and their child. Children’s and mother’s heart rate (HR), the sympathetic nervous system (SNS) activity via the pre-ejection period (PEP) and the left ventricular ejection time (LVET), and the parasympathetic nervous system (PNS) activity via the respiratory sinus arrhythmia (RSA) were continuously measured by an electrocardiogram. Maternal sensitivity of interactive behavior was assessed by using the Emotional Availability (EA) Scales.

Results

Children of mothers with insensitive behavior had a significantly lower RSA at baseline, showed a lack of RSA withdrawal during structured and free play, and had shorter LVET across all episodes compared to children of sensitive mothers.

Conclusion

Our findings depict the influence of low-quality maternal interaction on the child’s ANS regulation, in calm and more stressful play situations. The overall higher SNS mode with impaired PNS reactivity may negatively influence child’s ANS homoeostasis, which may result in a long-term impact on mental and physical wellbeing. Further, the maternal sensitivity may function as a buffer for the stress response of their child. These results could serve as a basis for the development of appropriate psychoeducational programs for mothers of low sensitivity in their interaction with the child.

Infant weight-for-length gain associated with autonomic nervous system reactivity

BACKGROUND

Research suggests that children's health and well-being are supported by core adaptive systems, including the autonomic nervous system (ANS). Despite evidence for the importance of adulthood ANS regulation in the development of disease, few studies have examined how early development may influence emerging ANS function. Therefore, we examined how infant adiposity gain during early infancy related to ANS regulation at 6 months.

METHODS

Infant weight and length were abstracted from birth records and measured during the 6-month assessment in a low-income, racially/ethnically diverse sample (N = 60). WHO-standardized weight-for-length-gain change was calculated across the first 6 months of life. ANS reactivity was measured as the combined sympathetic (i.e., pre-ejection period) and parasympathetic (i.e., respiratory sinus arrhythmia) nervous system responses during the developmentally challenging Still Face Paradigm (SFP). ANS "classic reactivity" response was characterized by paired sympathetic activation and parasympathetic withdrawal.

RESULTS

Lower weight-for-length gain in the first 6 months predicted classic reactivity during still face. However, greater weight-for-length gain predicted "classic reactivity" during the reunion, when infants were expected to recover, suggesting autonomic dysregulation.

CONCLUSIONS

These findings suggest an association between early life adiposity gain and the development of infant ANS regulation.

IMPACT

Adiposity gain during early infancy was associated with autonomic nervous system regulation at 6 months. This study identifies early adiposity gain (greater than average infant weight-for-length gain) as a risk for ANS dysregulation. This research focuses on a critical developmental period of ANS plasticity. If confirmed, findings can be used to inform early intervention programs targeting obesity prevention and to promote self-regulation.

Identifying profiles of multisystem physiological activity across early childhood: Examining developmental shifts and associations with stress and internalizing problems

Physiological regulation is an important predictor of health across the lifespan. Regulation occurs across multiple collaborative systems, yet few empirical studies explore multisystem activity and how this collaborative regulation develops early in life. The current study used latent profile analysis to evaluate multisystem regulation in the autonomic nervous system and hypothalamic pituitary adrenal (HPA) axis in 150 racially/ethnically diverse, low-income children at 18- and 36-months. At both timepoints, profiles of generally moderate activity (Moderate Arousal) and heightened baseline activity (Anticipatory Arousal) emerged. A profile of typically adaptive patterns across all systems (Active Copers) emerged at 18-months and a profile of heightened HPA Axis activity (HPA-axis Responders) emerged at 36-months. Persistent membership in the Anticipatory Arousal profile across time was associated with exposure to greater maternal stress at 18-months and child internalizing problems at 36-months. These findings highlight early multisystem profile development and suggest associations with stress and later behavior problems.

Distribution, Stability, and Continuity of Autonomic Nervous System Responsivity at 18- and 36-Months of Age

OBJECTIVE

Cardiac autonomic nervous system (ANS) measures, respiratory sinus arrhythmia (RSA) and preejection period (PEP), are valid and reliable indicators of children's sensitivity to their environment; however, there are few studies of ANS measures in children less than three years of age. This study's aim was to summarize the distributions, stability, and continuity of RSA and PEP measures during resting, challenge, and reactivity for children at 18- and 36-months.

METHODS

This was a cohort study of racially- and ethnically-diverse, low-income children who completed a developmentally challenging protocol while we simultaneously assessed their RSA and PEP at 18-months (N = 134) and 36-months (N = 102).

RESULTS

The ANS resting, challenge, and reactivity measures at 18- and 36-months of age were normally distributed. The RSA resting (r = 0.29), RSA challenge (r = 0.44), PEP resting (r = 0.55) and PEP challenge (r = 0.58) measures were moderately stable but RSA (r = 0.01) and PEP reactivity (r = 0.02) were not stable from 18- to 36-months of age. There was no continuity in the ANS measures from 18- to 36-months of age with statistically significant changes in sample means for all of the ANS measures.

DISCUSSION

These developmental changes in ANS are shown at the sample level but there are individual differences in ANS responses from 18- to 36-months that may be affected by adversity or protective factors experienced early in life.

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

Prediabetes in the form of impaired fasting glucose, impaired glucose tolerance, or both is considered as a preliminary stage for the onset of diabetes and diabetic complications. Hormonal fluctuations in adolescence are accompanied by body composition modifications, which are associated with insulin resistance and subclinical inflammation. Bioimpedance (BIA) accurately evaluates body composition, and heart rate variability (HRV) assesses cardiac autonomic function, which are frequently afflicted by insulin resistance. We aimed at evaluating the effect of glycemic status on mental stress, anxiety, and depression status in adolescents with impaired fasting glucose, body composition, and HRV parameters. This is a case-control study to evaluate the effect of the hyperglycemia on depression, anxiety, and stress levels (DASS21 questionnaire), body composition (BIA-ACC-BIOTEKNA©), and HRV (PPG Stress Flow-BIOTEKNA©), between euglycemic adolescents (euglycemic group) and adolescents with impaired fasting glucose (prediabetic group), aged 12-20 years. No differences were found between the prediabetic (n = 13) and the euglycemic (n = 16) groups in the outcome measures, possibly due to the number of participants. Interestingly, females, irrespective of their glycemic status, exhibited altered sympathovagal function as revealed by impaired HRV. In the euglycemic group, HRV parameters were significantly correlated and in line with the DASS21 scores, but in the prediabetic group, similarities to those of adults were observed. Impaired fasting glucose had no impact on mental health, body composition, or HRV parameters in adolescents. HRV parameters were impaired in females, irrespective of their glycemic status. This finding implies that females seem to be more prone to stress disorders, even from a young age. Future studies are needed to confirm these findings.

Diverse Autonomic Nervous System Stress Response Patterns in Childhood Sensory Modulation

The specific role of the autonomic nervous system (ANS) in emotional and behavioral regulation—particularly in relation to automatic processes—has gained increased attention in the sensory modulation literature. This mini-review article summarizes current knowledge about the role of the ANS in sensory modulation, with a focus on the integrated functions of the ANS and the hypothalamic-pituitary-adrenal (HPA) axis and their measurement. Research from the past decade illustrates that sympathetic and parasympathetic interactions are more complex than previously assumed. Patterns of ANS activation vary across individuals, with distinct physiological response profiles influencing the reactivity underlying automatic behavioral responses. This review article advances a deeper understanding of stress and the complex stress patterns within the ANS and HPA axis that contribute to allostatic load (AL). We argue that using multiple physiological measurements to capture individual ANS response variation is critical for effectively treating children with sensory modulation disorder (SMD) and sensory differences. We consider the relative contributions of automatic vs. deliberately controlled processes across large-scale neural networks in the development of sensorimotor function and their associated links with arousal patterns and sensory over- and under-responsivity.

Reduced caregiving quality measured during the strange situation procedure increases child's autonomic nervous system stress response

BACKGROUND

Dysfunctional maternal behavior has been shown to lead to disturbances in infant's regulatory capacities and alterations in vagal reactivity. We aim to investigate the autonomic nervous system (ANS) response of the child during the strange situation procedure (SSP) in relation to the quality of maternal behavior.

METHODS

Twelve month after birth, 163 mother-child-dyads were investigated during the SSP. Heart rate (HR) and both, the parasympathetic branch (PNS) via the respiratory sinus arrhythmia (RSA) and the sympathetic branch (SNS) via the left ventricular ejection time (LVET) of the ANS were continuously determined during the SSP using electrocardiogram (ECG) and impedance cardiogram (ICG) measures. Maternal behavior was assessed by using the AMBIANCE measure.

RESULTS

The ANS response in infants of mothers with disruptive behavior compared to infants of non-disruptive mothers was significantly altered during the SSP: HR increased especially when infants of disruptive mothers were alone with the stranger (F (1, 161) = 4.15, p = .04) with a significant vagal withdrawal when being in contact with the stranger despite of presence of the mother (F (1, 161) = 5.11, p = .03) and a significant increase in vagal tone during final reunion (F (1, 161) = 3.76, p = .05). HR increase was mainly based on a decrease in LVET (F (1, 161) = 4.08, p = .05) with a maximum infant's HR when the stranger came into the room instead of the mother.

CONCLUSION

Both, SNS and PNS branches of the child are significantly altered in terms of an ANS imbalance, especially during contract to a stranger, in relation to dysfunctional maternal behavior. Our findings suggest the importance of supporting high quality caregiving that enables the infant to adapt adequately to stressful interpersonal situations which is likely to promote later health.

Autonomic nervous system functioning in early childhood: Responses to cognitive and negatively valenced emotional challenges

Although autonomic nervous system (ANS) functioning is "context-dependent," few studies examined children's normative sympathetic and parasympathetic autonomic responses to distinct challenges in early childhood years. Examining children's ANS responsivity to distinct challenges is important for understanding normative autonomic responses toward everyday life stressors and identifying paradigms that effectively elicit a "stress response." We examined children's (N = 278) sympathetic (preejection period [PEP]) and parasympathetic (respiratory sinus arrhythmia [RSA]) responses to cognitive (i.e., problem-solving and cognitive control) and negatively valenced emotional (i.e., blocked goal and unfairness) challenges in preschool, kindergarten, and grade 1. Children, on average, demonstrated parasympathetic inhibition (RSA withdrawal) in response to all challenges but the magnitude of these responses depended on the task. Children showed sympathetic activation (PEP shortening) toward the problem-solving task at each assessment and there was no sample-level change in the magnitude of this response over time. Children showed greater sympathetic responsivity toward the cognitive control task over time, with evidence for a sympathetic activation response only in grade 1. Children experienced sympathetic inhibition (PEP lengthening) toward the unfairness tasks but did not experience significant sympathetic responsivity toward the blocked goal tasks. Parasympathetic responsivity to most challenges were modestly stable but there was no stability in sympathetic responsivity across time.

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

We examined the prospective associations of objective and subjective measures of stress during pregnancy with infant stress reactivity and regulation, an early-life predictor of psychopathology. In a racially and ethnically diverse low-income sample of 151 mother-infant dyads, maternal reports of stressful life events (SLE) and perceived stress (PS) were collected serially over gestation and the early postpartum period. Infant reactivity and regulation at 6 months of age was assessed via maternal report of temperament (negativity, surgency, and regulation) and infant parasympathetic nervous system physiology (respiratory sinus arrhythmia [RSA]) during the Still Face Paradigm. Regression models predicting infant temperament showed higher maternal prenatal PS predicted lower surgency and self-regulation but not negativity. Regression models predicting infant physiology showed higher numbers of SLE during gestation predicted greater RSA reactivity and weaker recovery. Tests of interactions revealed SLE predicted RSA reactivity only at moderate to high levels of PS. Thus, findings suggest objective and subjective measures of maternal prenatal stress uniquely predict infant behavior and physiology, adjusting for key pre- and postnatal covariates, and advance the limited evidence for such prenatal programming within high-risk populations. Assessing multiple levels of maternal stress and offspring stress reactivity and regulation provides a richer picture of intergenerational transmission of adversity.