Mona El-Sheikh

Salivary α‐Amylase in Biobehavioral Research

Abstract:  In the history of science, technical advances often precede periods of rapid accumulation of knowledge. Within the past three decades, discoveries that enabled the noninvasive measurement of the psychobiology of stress (in saliva) have added new dimensions to the study of health and human development. This widespread enthusiasm has led to somewhat of a renaissance in behavioral science. At the cutting edge, the focus is on testing innovative theoretical models of individual differences in behavior as a function of multilevel biosocial processes in the context of everyday life. Several new studies have generated renewed interest in salivary α‐amylase (sAA) as a surrogate marker of the autonomic/sympathetic nervous system component of the psychobiology of stress. This article reviews sAAs properties and functions; presents illustrative findings relating sAA to stress and the physiology of stress, behavior, cognitive function, and health; and provides practical information regarding specimen collection and assay. The overarching intent is to accelerate the learning curve such that investigators avoid potential pitfalls associated with integrating this unique salivary analyte into the next generation of biobehavioral research.

Exposure to interparental conflict and children's adjustment and physical health: the moderating role of vagal tone.

Physiological regulation, as indexed by baseline vagal tone and delta vagal tone (the change in vagal tone during an attention-demanding or challenging task), was examined as a moderator in the relations between exposure to verbal and physical parental marital conflict and childrens adjustment and physical health. Higher vagal tone was posited to serve a protective function (i.e., buffer) for children exposed to higher levels of marital conflict. Seventy-five 8- to 12-year-olds and their mothers completed measures of parental conflict, and childrens adjustment and physical health. Childrens vagal tone was assessed during baseline conditions and during exposure to an audiotaped interadult argument. Results indicate that higher vagal tone buffered children against increased externalizing, internalizing, and health problems related to exposure to more frequent marital conflict, especially verbal conflict. Further, higher levels of delta vagal tone protected boys against externalizing problems associated with verbal conflict, and health problems associated with physical conflict.

Children's responses to different forms of expression of anger between adults.

Anger is not a homogeneous stimulus, but can vary on a variety of dimensions and domains. This study examined childrens responses to anger as a function of: (a) the mode of expression of anger (nonverbal, verbal, verbal-physical), and (b) whether or not anger between others was resolved. Children were presented with videotaped segments of angry and friendly interactions and asked questions concerning their responses. All angry interactions, including non-verbal anger, were perceived as negative events and elicited negative emotions. Unresolved anger was perceived as a far more negative event than resolved anger and induced greater feelings of anger and distress in children. Verbal-physical anger was perceived as the most negative form of expression of anger. Boys reported more angry feelings in response to anger than girls. Distress responding was greater in children from homes in which there was interparent physical aggression and in children with behavior problems. Finally, the utility of this methodology is supported by relatively high test-retest reliability and limited evidence of context effects.

Cortisol and Children’s Adjustment: The Moderating Role of Sympathetic Nervous System Activity

We examined relations among cortisol, markers of sympathetic nervous system (SNS) activity (including salivary alpha-amylase and skin conductance level), and children’s adjustment. We also tested the Bauer et al. (Journal of Developmental and Behavioral Pediatrics, 23(2), 102–113, 2002) hypothesis that interactions between the SNS and cortisol would be associated with internalizing and externalizing problems. Saliva samples were obtained from 8- to 9-year-olds before and after a laboratory assessment battery, and were assayed for cortisol and alpha-amylase (sAA). Basal skin conductance level (SCL) was measured during resting conditions. Parents reported on child adjustment. Interactions between basal SNS and cortisol levels explained moderate amounts of unique variance in children’s externalizing and internalizing problems. More specifically, higher basal cortisol levels were positively associated with higher internalizing and externalizing problems among children with higher SNS activity, as compared to children with lower SNS activity. Findings underscore the utility of including information about the coordination between hypothalamic–pituitary–adrenal (HPA) and SNS activity in biosocial models of atypical child development.

Integrating the measurement of salivary α-amylase into studies of child health, development, and social relationships

To advance our understanding of how biological and behavioral processes interact to determine risk or resilience, theorists suggest that social developmental models will need to include multiple measurements of stress-related biological processes. Identified in the early 1990s as a surrogate marker of the sympathetic nervous system component of the stress response, salivary-amylase has not been employed to test biosocial models of stress vulnerability in the context of child development until now. In this report, we describe a standard assay that behavioral scientists can use to improve the next generation of studies and specific recommendations about sample collection, preparation, and storage are presented. More importantly, four studies are presented with mother–infant dyads (N= 86), preschoolers (N= 54), children (N = 54), and adolescents (N = 29) to illustrate individual differences in stress-related change in α-amylase levels, that patterns of α-amylase stress reactivity distinctly differ from those measured by salivary cortisol, and associations between individual differences in α-amylase and social relationships, health, negative affectivity, cognitive/academic/behavior problems, and cardiovascular reactivity. We conclude that the integration of measurements of the adrenergic component of the locus ceruleus/autonomic (sympathetic) nervous system, as indexed by salivary α-amylase, into the study of biosocial relationships may extend our understanding of child health and development to new limits.

Longitudinal relations between marital conflict and child adjustment : Vagal regulation as a protective factor

Although associations between marital conflict and childrens adjustment problems are established, less is known about child individual differences that can have an impact on these relations. The authors examined longitudinal relations between marital conflict and childrens adjustment using a community sample of elementary school-age children and young adolescents and assessed the role of childrens vagal regulation in moderating the conflict-child problems link. Elevated marital conflict was predictive of negative child outcomes, and greater vagal suppression to a simulated argument was protective against internalizing problems associated with marital conflict. Findings are supportive of the value of a biopsychosocial perspective and illustrate that child vagal regulation can contribute to the aggregation or amelioration of risk for maladjustment in the context of exposure to marital conflict.

Family conflict, autonomic nervous system functioning, and child adaptation: state of the science and future directions.

The family is one of the primary contexts of child development. Marital and parent-child conflict (family conflict) are common and predict a wide range of negative behavioral and emotional outcomes in children. Thus, an important task for developmental researchers is to identify the processes through which family conflict contributes to childrens psychological maladjustment, as well as vulnerability and protective factors in the context of family conflict. In the current paper, we aim to advance a conceptual model that focuses on indices of childrens autonomic nervous system (ANS) functioning that increase vulnerability or provide protection against psychological maladjustment in the context of family conflict. In doing so, we provide a selective review that reflects the state of the science linking family conflict, childrens ANS activity, and child psychological adjustment, and offer directions and guidance for future research. Our hope is to accelerate research at the intersection of family conflict and ANS functioning to advance understanding of risk and resilience among children.

Considering sleep in a family context: introduction to the special issue.

The special issue addresses the importance of sleep considered within a family context in relation to a broad range of behavioral, emotional, and physical health issues. The collection of articles provides several excellent examples of studies that emphasize a family context for understanding various aspects of sleep in infants, children, adolescents, and adults. Taken together, these studies raise a set of compelling questions for future research in this area.

Concurrent and Longitudinal Relations between Children's Sleep and Cognitive Functioning: The Moderating Role of Parent Education.

Relations between childrens sleep and cognitive functioning were examined over 2 years, and race and socioeconomic status were assessed as moderators of effects. Third-grade African American and European American children (N = 166; M = 8.72 years) participated at Time 1 and again 2 years later (N = 132). At both Time 1 and Time 2, sleep was examined via self-report and actigraphy. Children were administered selected tests from the Woodcock-Johnson III Tests of Cognitive Abilities, and Stanford Achievement Test scores were obtained from schools. Childrens sleep was related to intellectual ability and academic achievement. Results build substantially on an emerging literature supportive of the importance of sleep in children.

Children’s Sleep and Adjustment Over Time: The Role of Socioeconomic Context

Relations were examined between childrens sleep and their externalizing and internalizing symptoms. Longitudinal relations were examined when children were in 3rd (T1) and 5th (T2) grades, and cross-sectional relations were assessed at T2. Participants included 176 children at T1 (M = 8.68 years) and 141 children at T2 (M = 10.70 years). Sleep was examined via subjective reports and actigraphy. Children reported on anxiety, self-esteem, and depression symptoms, and parents reported on childrens externalizing and internalizing symptoms. Cross-sectionally and longitudinally, sleep problems were associated with worse adjustment outcomes; African American children or those from lower socioeconomic status homes were at particular risk. Findings highlight the importance of adequate sleep for childrens optimal development, especially in the context of ecological risk.