Respiratory sinus arrhythmia (RSA) and heart period were evaluated in 5-month-old infants (N = 40) during interaction challenges requiring affective adjustment. The paradigm consisted of four 2-min experimental conditions designed to elicit behavioral and autonomic responses to object-mediated (Picture Attention and Toy Attention) and person-mediated (Still Face and Social Interaction) engagement. The data demonstrated that autonomic state systematically changed during engagement and disengagement with the environment. During the object-mediated challenge, increases in RSA were uniquely related to positive engagement. During the person-mediated challenge, there was a more complex integration of autonomic and behavioral responses characterized by concordant increases and decreases in RSA, heart period, positive engagement, negative affect, and motor activity. When participants were partitioned into two groups, based on their RSA response pattern during the person-mediated challenge, only participants who exhibited a pattern of RSA decrease from Toy Attention to Still Face followed by a rapid recovery during Social Interaction demonstrated regulation of behavioral activity, including concordant recovery from stress. These findings provide additional empirical support for the role of vagal regulation of the heart in the modulation of affective adjustment and engagement behavior.

Few studies have examined whether familiarity of partner affects social responses in children with autism. This study investigated heart rate regulation (respiratory sinus arrhythmia [RSA]: The myelinated vagus nerve's regulation of heart rate) and temporal-parietal electroencephalogram (EEG) activity while nineteen 8- to 12-year-old children with autism and 14 controls viewed videos of a familiar and an unfamiliar person reading a story. Children with autism had lower overall RSA levels and exhibited decreased RSA to the unfamiliar person, versus control children. Both groups decreased temporal-parietal EEG activity to the unfamiliar person. Higher RSA was related to higher social skill ratings and fewer problem behaviors. Thus, the social difficulties of children with autism may be characterized by specific mobilization to unfamiliar people.

The nature of mother–child interaction in autism and the maternal approach characteristics that elicit social response in children with autism were examined in two studies. Mother–child play sessions of 24 preschool children with autism and 24 typically developing preschoolers were compared in Study 1, and play sessions of 9 mothers with their autistic child and with their nonautistic child were compared in Study 2. Mother–child interactions were coded using the Approach Withdrawal Interaction Coding System to quantify maternal approach behaviors and child responses. Results of Study 1 indicate that, although the quantity of approaches did not differ between mothers with their autistic children and mothers with their nonautistic children, there were qualitative differences. Mothers used more physical contact, more high-intensity behaviors, and fewer social verbal approaches with autistic children. Results of Study 2 replicated these findings with mothers showing a similar pattern of approach toward their autistic children but not their nonautistic children. Although autistic children displayed lower contingency to maternal approaches in general, they showed greater responsiveness to approaches involving increased physical proximity and/or containing nonverbal object use. Mothers socially engaged both autistic and nonautistic children. The implications for parent training and intervention are discussed.

The current study evaluated processes underlying two common symptoms (i.e., state regulation problems and deficits in auditory processing) associated with a diagnosis of autism spectrum disorders. Although these symptoms have been treated in the literature as unrelated, when informed by the Polyvagal Theory, these symptoms may be viewed as the predictable consequences of depressed neural regulation of an integrated social engagement system, in which there is down regulation of neural influences to the heart (i.e., via the vagus) and to the middle ear muscles (i.e., via the facial and trigeminal cranial nerves). Respiratory sinus arrhythmia (RSA) and heart period were monitored to evaluate state regulation during a baseline and two auditory processing tasks (i.e., the SCAN tests for Filtered Words and Competing Words), which were used to evaluate auditory processing performance. Children with a diagnosis of autism spectrum disorders (ASD) were contrasted with aged matched typically developing children. The current study identified three features that distinguished the ASD group from a group of typical developing children: 1) baseline RSA, 2) direction of RSA reactivity, and 3) auditory processing performance. In the ASD group, the pattern of change in RSA during the attention demanding SCAN tests moderated the relation between performance on the Competing Words test and IQ. In addition, in a subset of ASD participants, auditory processing performance improved and RSA increased following an intervention designed to improve auditory processing.

Respiratory sinus arrhythmia (RSA), heart period, and motor activity were monitored in preschoolers during a variety of tasks varying in required movement. The data analyses indicate: (1) that when activity increases during tasks, there are synchronous decreases in heart period and RSA; (2) that correlations between changes in RSA and heart period are related to activity only during exercise when there is a major demand for increased metabolic resources; and (3) that the covariation among the variables within each condition is low except during exercise. These findings suggest that the slight increases in motor activity (i.e., hand movements) often required in attention demanding psychophysiological protocols are not related to RSA and heart period responses. However, when tasks necessitate large increases in motor activity (e.g., exercise), the decreases in heart period and RSA are related to the change in motor activity.