Cardiac adaptivity to attention-demanding tasks in children with a pervasive developmental disorder not otherwise specified (PDD-NOS)

Evidence for decreased parasympathetic response to a novel peer interaction in older children with autism spectrum disorder: a case-control study

Background

Individuals with autism spectrum disorder (ASD) often experience elevated stress during social interactions and may have difficulty forming and maintaining peer relationships. The autonomic nervous system (ANS) directs physiological changes in the body in response to a number of environmental stimuli, including social encounters. Evidence suggests the flexibility of the ANS response is an important driving factor in shaping social behavior. For youth with ASD, increased stress response and/or atypical ANS regulation to benign social encounters may therefore influence social behaviors, and, along with developmental and experiential factors, shape psychological outcomes.

Methods

The current study measured ANS response to a peer-based social interaction paradigm in 50 typically developing (TD) children and 50 children with ASD (ages 10–13). Respiratory sinus arrhythmia (RSA), a cardiac measure of parasympathetic influence on the heart, and pre-ejection period (PEP), a sympathetic indicator, were collected. Participants engaged in a friendly, face-to-face conversation with a novel, same-aged peer, and physiological data were collected continuously before and during the interaction. Participants also reported on state anxiety following the interaction, while parents reported on the child’s social functioning and number of social difficulties.

Results

Linear mixed models revealed that, while there were no diagnostic effects for RSA or PEP, older youth with ASD appeared to demonstrate a blunted parasympathetic (RSA) response. Further, increased severity of parent-reported social symptoms was associated with lower RSA. Youth with ASD reported more anxiety following the interaction; however, symptoms were not related to RSA or PEP response based on linear mixed modeling.

Conclusions

Physiological regulation, age, and social functioning likely influence stress responses to peer interactions for youth with ASD. Parasympathetic functioning, as opposed to sympathetic arousal, may be especially important in behavioral regulation, as older youth with ASD demonstrated atypical regulation and response to the social interaction paradigm. Future studies should help to further elucidate the developmental factors contributing to stress responses in ASD, the impact of physiological response on observable social behavior, and potential long-term consequences of chronic social stress in youth with ASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-020-09354-x.

Exploring Key Physiological System Profiles at Rest and the Association with Depressive Symptoms in Autism Spectrum Disorder

Depression is often associated with dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). Individuals with autism spectrum disorder (ASD) may experience physiological dysregulation and psychological comorbidities; however, the extent to which the interactions between these systems predict internalizing symptoms in ASD has not been investigated. The study examined interactions with the HPA axis and ANS in 10-13-year-old children with ASD (n = 41) and typical development (TD; n = 46). The interrelated systems uniquely contributed to depressive symptoms in ASD above and beyond any system in isolation. A reciprocal, parasympathetic-dominant ANS was related to fewer affective symptoms in ASD. Findings highlight the importance of examining arousal across multiple systems to more precisely identify profiles associated with maladaptive psychiatric outcomes in ASD.

Emotional Arousal During Social Stress in Young Adults With Autism: Insights From Heart Rate, Heart Rate Variability and Self-Report

In order to better understand which factors play a role in non-adaptive social behavior in autism spectrum disorder (ASD) we looked into physiological arousal and awareness of one's own emotions. Heart rate (HR) and heart rate variability (HRV) were measured during a public speaking task in 51 young adults with ASD and 28 typically developing (TD) controls. The results showed no significant group differences in baseline HR/HRV, HR reactivity (change from baseline to the speaking task) or self-reported emotional awareness. However, adults with ASD showed significantly lower HRV reactivity (p = .023, d = 0.6) compared to TD adults. These results suggest a mismatch between arousal regulation and emotional awareness, which may be related to problems in social adaptation in ASD.

Reduced heart rate variability in adults with autism spectrum disorder

A growing body of research has suggested heart rate variability (HRV) may be reduced in autism spectrum disorder (ASD) in comparison to neurotypical cohorts. While there have been several studies investigating HRV in children diagnosed with ASD, few studies have been conducted in adults. The objective of the current study was to investigate autonomic nervous system activity as assessed by HRV in adults diagnosed with ASD. We hypothesized that adults with ASD would show a reduction in HRV compared to neurotypical participants. Participants diagnosed with ASD (n = 55) were recruited from the Autism Clinic for Translational Research at the Brain and Mind Centre (University of Sydney) between 2013 and 2017. Neurotypical participants were recruited from advertisements and online media. Resting state heart rate was measured for 5 min while participants sat in an upright position. Results showed there was an overall significant difference in resting-state HRV between adults diagnosed with ASD compared to the neurotypical control group. Logarithmically transformed high frequency (HF) and root mean square of successive differences were particularly decreased in the ASD group, suggesting lower parasympathetic activity. The use of psychotropic medications and comorbidities were associated with reductions in low frequency of HRV. Our data suggest an overall dysregulation in resting autonomic activity in adults with ASD. This may represent an important physiological mechanism leading to potential cardiovascular risk in ASD, which warrants further investigation. Autism Res 2019, 12: 922-930. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: ASD is commonly associated with a range of physical and mental health comorbidities. Autonomic disruptions underlying reductions in heart rate variability (HRV) have been linked to a range of mental and physical health conditions. We assessed resting-state HRV in adults diagnosed with ASD in comparison to healthy individuals. Our results showed reduced heart rate variability in people diagnosed with ASD compared to adults without ASD. These findings implicate a role for autonomic activity as a potentially modifiable risk factor for ASD.

Comparing stress and arousal systems in response to different social contexts in children with ASD

Response to psychological stress can vary based on the extent to which the context is perceived as stressful, especially under different social conditions. The purpose of this preliminary study was to compare physiological stress (cortisol) and regulation (respiratory sinus arrhythmia, RSA) of 10-12 year old children with autism spectrum disorder (ASD, n = 31) or typical development (TD, n = 25) when exposed to two social stress protocols. The extent to which perceived emotion (affect recognition) and anxiety (state and trait) mediate the stress response was also explored. Results revealed different patterns of stress responses dependent on the type of stressor. During a friendly social interaction, both groups generally showed an adaptive, synergistic response between cortisol and RSA. In response to social evaluation, however, the ASD group did not show correlating responses between physiological systems, which was likely due to a blunted stress response to the social evaluative stressor. The ability to recognize neutral faces mediated the relationship between diagnostic group and physiological response to social evaluation, indicating that perception of threat is essential to triggering a stress response. The current study emphasizes the need to consider the important role of social context, social perception, and perceived anxiety when examining social interaction and stress.

Heart rate-defined sustained attention in infants at risk for autism

Background

Although aberrant visual attention has been identified in infants at high familial risk for autism, the developmental emergence of atypical attention remains unclear. Integrating biological measures of attention into prospective high-risk infant studies may inform more nuanced developmental trajectories, clarifying the onset and course of atypical attention and potentially advancing early screening or treatment protocols. Heart rate-defined sustained attention (HRDSA) is a well-validated biological measure of attentional engagement that, in non-clinical infant populations, provides incremental information about attentional engagement beyond looking behaviors alone. The present study aimed to examine the characteristics and clinical correlates of HRDSA in high-risk infants, informing whether HRDSA may operate as a promising biological measure of attention and clinical symptoms in this population.

Methods

We examined age-related patterns of HRDSA during a passive looking task in 5- to 14-month-old high-risk infant siblings of children with autism (n = 21) compared to low-risk controls (n = 21), with most participants contributing multiple assessments. Emergent autism features were measured using the Autism Diagnostic Observation Schedule at 24 months. Primary dependent variables included the proportion of time in behavioral attention, proportion of time in HRDSA, and average heart rate deceleration during HRDSA. For each variable, we used nested multilevel models to examine whether attention differed by group, as well as whether attention predicted emergent autism features among high-risk infant siblings.

Results

As expected, HRDSA served as a global biological measure of attention in high-risk infants, predicting greater variability in group risk status than behavioral looking alone. Among high-risk infants, more severe ASD features were also associated with increasingly shallow heart rate deceleration during HRDSA across development, suggesting abnormal qualities of HRDSA may inform individual differences within this population.

Conclusions

These preliminary findings provide initial evidence that HRDSA may offer a sensitive, affordable, and portable biological measure of attention that may enhance understanding of atypical attention in high-risk infants. Using this method, we also provide initial evidence that atypical patterns of heart activity previously reported in children and adults with autism may emerge in the first year of life, warranting further study of how HRDSA may specifically inform attention profiles in ASD.

Physiological Response to Social Evaluative Threat in Adolescents with Autism Spectrum Disorder

The Trier Social Stress Test (TSST) was employed to study response to social evaluative threat in male adolescents with Autism Spectrum Disorder (ASD, n = 21) and typical development (n = 13). Participants wore a mobile electrocardiogram to collect heart rate data. There were significant group effects on respiratory sinus arrhythmia (RSA), a measure of parasympathetic nervous system function, with lower values in ASD (F = 4.97). Bivariate correlations also showed a significant relationship between parent reports of social problems and RSA response to the TSST (r = -0.586). These findings suggest that autonomic dysregulation may contribute to social deficits in adolescents with ASD.

Heart Rate Variability and Skin Conductance During Repetitive TMS Course in Children with Autism

Autism spectrum disorder (ASD) is a developmental disorder marked by difficulty in social interactions and communication. ASD also often present symptoms of autonomic nervous system (ANS) functioning abnormalities. In individuals with autism the sympathetic branch of the ANS presents an over-activation on a background of the parasympathetic activity deficits, creating an autonomic imbalance, evidenced by a faster heart rate with little variation and increased tonic electrodermal activity. The objective of this study was to explore the effect of 12 sessions of 0.5 Hz repetitive transcranial magnetic stimulation (rTMS) over dorsolateral prefrontal cortex (DLPFC) on autonomic activity in children with ASD. Electrocardiogram and skin conductance level (SCL) were recorded and analyzed during each session of rTMS. The measures of interest were time domain (i.e., R-R intervals, standard deviation of cardiac intervals, NN50-cardio-intervals >50 ms different from preceding interval) and frequency domain heart rate variability (HRV) indices [i.e., power of high frequency (HF) and low frequency (LF) components of HRV spectrum, LF/HF ratio]. Based on our prior pilot studies it was proposed that the course of 12 weekly inhibitory low-frequency rTMS bilaterally applied to the DLPFC will improve autonomic balance probably through improved frontal inhibition of the ANS activity, and will be manifested in an increased length of cardiointervals and their variability, and in higher frequency-domain HRV in a form of increased HF power, decreased LF power, resulting in decreased LF/HF ratio, and in decreased SCL. Our post-12 TMS results showed significant increases in cardiac intervals variability measures and decrease of tonic SCL indicative of increased cardiac vagal control and reduced sympathetic arousal. Behavioral evaluations showed decreased irritability, hyperactivity, stereotype behavior and compulsive behavior ratings that correlated with several autonomic variables.

Heart rate variability during sleep in children with autism spectrum disorder

PURPOSE

Autonomic dysfunction has been reported in autism spectrum disorders (ASD). Less is known about autonomic function during sleep in ASD. The objective of this study is to provide insight into the autonomic cardiovascular control during different sleep stages in ASD. We hypothesized that patients with ASD have lower vagal and higher sympathetic modulation with elevated heart rate, as compared to typical developing children (TD).

METHODS

We studied 21 children with ASD and 23 TD children during overnight polysomnography. Heart rate and spectral parameters were calculated for each vigilance stage during sleep. Data from the first four sleep cycles were used to avoid possible effects of different individual sleep lengths and sleep cycle structures. Linear regression models were applied to study the effects of age and diagnosis (ASD and TD).

RESULTS

In both groups, HR decreased during non-REM sleep and increased during REM sleep. However, HR was significantly higher in stages N2, N3 and REM sleep in the ASD group. Children with ASD showed less high frequency (HF) modulation during N3 and REM sleep. LF/HF ratio was higher during REM. Heart rate decreases with age at the same level in ASD and in TD. We found an age effect in LF in REM different in ASD and TD.

CONCLUSION

Our findings suggest possible deficits in vagal influence to the heart during sleep, especially during REM sleep. Children with ASD may have higher sympathetic dominance during sleep but rather due to decreased vagal influence.

An Integrated Approach for the Monitoring of Brain and Autonomic Response of Children with Autism Spectrum Disorders during Treatment by Wearable Technologies

Autism Spectrum Disorders (ASD) are associated with physiological abnormalities, which are likely to contribute to the core symptoms of the condition. Wearable technologies can provide data in a semi-naturalistic setting, overcoming the limitations given by the constrained situations in which physiological signals are usually acquired. In this study an integrated system based on wearable technologies for the acquisition and analysis of neurophysiological and autonomic parameters during treatment is proposed and an application on five children with ASD is presented. Signals were acquired during a therapeutic session based on an imitation protocol in ASD children. Data were analyzed with the aim of extracting quantitative EEG (QEEG) features from EEG signals as well as heart rate and heart rate variability (HRV) from ECG. The system allowed evidencing changes in neurophysiological and autonomic response from the state of disengagement to the state of engagement of the children, evidencing a cognitive involvement in the children in the tasks proposed. The high grade of acceptability of the monitoring platform is promising for further development and implementation of the tool. In particular if the results of this feasibility study would be confirmed in a larger sample of subjects, the system proposed could be adopted in more naturalistic paradigms that allow real world stimuli to be incorporated into EEG/psychophysiological studies for the monitoring of the effect of the treatment and for the implementation of more individualized therapeutic programs.

Monitoring of autonomic response to sociocognitive tasks during treatment in children with Autism Spectrum Disorders by wearable technologies: A feasibility study

BACKGROUND

Autism Spectrum Disorders (ASD) represent a heterogeneous set of neurodevelopmental disorders characterized by impairments in social domain, where the autonomic nervous system (ANS) plays an important role. Several researchers have studied the ANS in ASD, during specific cognitive or sensory stimuli while few studies have examined response during social interactions. Wearable technologies can be very helpful in monitoring autonomic response in children with ASD in semi-naturalistic setting. The novelty of this study is to use such technologies to acquire physiological signals during therapeutic sessions supported by interactive "serious games" and to correlate the ANS response to the engagement of the child during sociocognitive tasks for an evaluation of the treatment effect and for the personalization of the therapy.

METHOD

A wearable chest belt for electrocardiographic (ECG) signal recording was used and specific algorithms for the extraction of clinically relevant features (Heart Rate - HR, Root Mean Square of the Successive Differences - RMSSD and Respiratory Sinus Arrhythmia - RSA) were developed. Sociocognitive tasks were mediated by "serious games" implemented on two tablets, which allowed a precise coding of the behaviors of the children. A longitudinal assessment of the physiological response of the children during six months of treatment was performed.

RESULTS

A link between physiological response, i.e. decrease in RMSSD and RSA, and engagement of the children during sociocognitive tasks was found. Longitudinal changes in the children's autonomic response, including a decrease of RSA during the engagement throughout the therapeutic sessions, were found.

CONCLUSIONS

These results foster the feasibility of this methodology to be applied in a clinical setting for the monitoring of the ANS response of children with ASD during treatment. A larger sample of patients is needed to confirm these preliminary findings.

Age differences in high frequency phasic heart rate variability and performance response to increased executive function load in three executive function tasks

The current study examines similarity or disparity of a frontally mediated physiological response of mental effort among multiple executive functioning tasks between children and adults. Task performance and phasic heart rate variability (HRV) were recorded in children (6 to 10 years old) and adults in an examination of age differences in executive functioning skills during periods of increased demand. Executive load levels were varied by increasing the difficulty levels of three executive functioning tasks: inhibition (IN), working memory (WM), and planning/problem solving (PL). Behavioral performance decreased in all tasks with increased executive demand in both children and adults. Adults' phasic high frequency HRV was suppressed during the management of increased IN and WM load. Children's phasic HRV was suppressed during the management of moderate WM load. HRV was not suppressed during either children's or adults' increasing load during the PL task. High frequency phasic HRV may be most sensitive to executive function tasks that have a time-response pressure, and simply requiring performance on a self-paced task requiring frontal lobe activation may not be enough to generate HRV responsitivity to increasing demand.

'Do Well B.': Design Of WELL Being monitoring systems. A study protocol for the application in autism

INTRODUCTION

Individuals with autism spectrum disorder (ASD) have difficulties in communication and social interaction resulting from atypical perceptual and cognitive information processing, leading to an accumulation of anxiety. Extreme overloading experienced internally may not be externally visible. Identifying stressful situations at an early stage may avoid socially problematic behaviour from occurring, such as self-injurious behaviour. Activation of the autonomous nervous system (ANS) is involved in the response to anxiety, which can be measured through heart rate variability and skin conductance with the use of portable devices, non-intrusively and pain-free. Thus, developing innovative analysis of signal perception and reaction is necessary, mainly for non-communicative individuals with autism.

METHODS AND ANALYSIS

The protocol will take place in real life (home and social environments). We aim to associate modifications of the ANS with external events that will be recorded in a synchronous manner through a specific design (spy glasses with video/audio recording). Four phases will be carried out on ASD participants and aged-matched controls: (1) 24-hour baseline pre-experiment (physical activity, sleep), (2) 2 h in a real life situation, (3) 30 min in a quiet environment, interrupted by a few seconds of stressful sound, (4) an interview to record feelings about events triggering anxiety. ASD and control participants will be together for phases 2 and 3, revealing different physiological responses to the same situations, and thus identifying potentially problematic events. The novelty will be to apply time-series analyses (which led to several Nobel Prizes in quantitative finance) on ANS series (heart rate, heart rate variability, skin conductance) and wrist motion.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from Ethics Committee of Clermont-Ferrand (South-East I), France (2014-A00611-46). Trial findings will be disseminated via open-access peer-reviewed publications, conferences, clinical networks, public lectures and our websites.

TRIAL REGISTRATION NUMBER

ClinicalTrials identifier NCT02275455.

Cardiac autonomic regulation in autism and Fragile X syndrome: a review

Despite the significance of efforts to understand the biological basis of autism, progress in this area has been hindered, in part, by the considerable heterogeneity in the disorder. Fragile X syndrome (FXS), a monogenic condition associated with high risk for autism, may pave the way for the dissection of biological heterogeneity within idiopathic autism. This article adopts a cross-syndrome biomarker approach to evaluate potentially overlapping profiles of cardiac arousal dysregulation (and broader autonomic dysfunction) in autism and FXS. Approaches such as this, aimed at delineating shared mechanisms across genetic syndromes, hold great potential for improving diagnostic precision, promoting earlier identification, and uncovering key systems that can be targeted in pharmaceutical/behavioral interventions. Biomarker approaches may be vital to deconstructing complex psychiatric disorders and are currently promoted as such by major research initiatives such as the NIMH Research Domain Criteria (RDoC). Evidence reviewed here supports physiological dysregulation in a subset of individuals with autism, as evidenced by patterns of hyperarousal and dampened parasympathetic vagal tone that overlap with the well-documented physiological profile of FXS. Moreover, there is growing support for a link between aberrant cardiac activity and core deficits associated with autism, such as communication and social impairment. The delineation of physiological mechanisms common to autism and FXS could lend insight into relationships between genetic etiology and behavioral endstates, highlighting FMR1 as a potential candidate gene. Research gaps and potential pitfalls are discussed to inform timely, well-controlled biomarker research that will ultimately promote better diagnosis and treatment of autism and associated conditions.

Effects of weekly low-frequency rTMS on autonomic measures in children with autism spectrum disorder

The term autism spectrum disorder (ASD) describes a range of conditions characterized by impairments in social interactions, communication, and by restricted and repetitive behaviors. Autism spectrum disorder may also present with symptoms suggestive of autonomic nervous system (ANS) dysfunction. The objective of this study was to determine the effect of 18 sessions of low frequency (LF) repetitive transcranial magnetic stimulation (rTMS) on autonomic function in children with ASD by recording electrocardiogram (ECG) and electrodermal activity (EDA) pre- post- and during each rTMS session. The autonomic measures of interest in this study were R-R cardiointervals in EKG (R-R), time and frequency domain measures of heart rate variability (HRV) and skin conductance level (SCL). Heart rate variability measures such as R-R intervals, standard deviation of cardiac intervals, pNN50 (percentage of cardiointervals >50 ms different from preceding interval), power of high frequency (HF) and LF components of HRV spectrum, LF/HF ratio, were then derived from the recorded EKG. We expected that the course of 18 weekly inhibitory LF rTMS applied to the dorsolateral prefrontal cortex (DLPFC) would enhance autonomic balance by facilitating frontal inhibition of limbic activity thus resulting in decreased overall heart rate (HR), increased HRV (in a form of increased HF power), decreased LF power (resulting in decreased LF/HF ratio), and decreased SCL. Behavioral evaluations post-18 TMS showed decreased irritability, hyperactivity, stereotype behavior and compulsive behavior ratings while autonomic measures indicated a significant increase in cardiac interval variability and a decrease of tonic SCL. The results suggest that 18 sessions of LF rTMS in ASD results in increased cardiac vagal control and reduced sympathetic arousal.

Physiological arousal in autism and fragile X syndrome: group comparisons and links with pragmatic language

This study tested the hypothesis that pragmatic (i.e., social) language impairment is linked to arousal dysregulation in autism spectrum disorder (ASD) and fragile X syndrome (FXS). Forty boys with ASD, 39 with FXS, and 27 with typical development (TD), aged 4-15 years, participated. Boys with FXS were hyperaroused compared to boys with TD but did not differ from boys with ASD. Dampened vagal tone predicted pragmatic impairment in ASD, and associations emerged between cardiac activity and receptive/expressive vocabulary across groups. Findings support autonomic dysfunction as a mechanism underlying pragmatic impairment in ASD and suggest that biophysiological profiles are shared in ASD and FXS, which has implications for understanding the role of fragile X mental retardation-1 (FMR1, the FXS gene) in the pathophysiology of ASD.

Psychophysiological responses to emotional stimuli in children and adolescents with autism and fragile X syndrome

Individuals with autism demonstrate atypical and variable responses to social and emotional stimuli, perhaps reflecting heterogeneity of the disorder. The goal of this study was to determine whether unique profiles of psychophysiological responses to such stimuli could be identified in individuals diagnosed with autism spectrum disorder (ASD), with fragile X syndrome (FXS), and with comorbid autism and fragile X syndrome (ASD + FXS), and in typically developing (TYP) individuals. This study included 52 boys (ages 10-17): idiopathic ASD (n = 12), FXS (n = 12), comorbid ASD + FXS (n = 17), and TYP (n = 11). Physiological responses, including potentiated startle, electrodermal response, heart rate variability, and vagal tone, were collected concurrently while participants viewed emotionally evocative pictures of human faces or nonsocial images. Although some of these measures have been utilized separately for investigations on these diagnostic groups, they have not been considered together. Results using Kruskal-Wallis one-way analysis of variance by ranks indicate statistically significant differences in distributions of autonomic regulation responses between groups. The most notable differences were between the ASD group and both the FXS groups on measures of sympathetic activity, with FXS groups evincing increased activity. Also, both the ASD and ASD + FXS groups showed significantly decreased parasympathetic activity compared with FXS and TYP groups. In addition, the ASD + FXS group demonstrated a unique distribution of startle potentiation and arousal modulation. This study provides evidence that autonomic arousal and regulation profiles could be useful for distinguishing subgroups of autism and shed light on the variability underlying emotional responsivity.

Parasympathetic response profiles related to social functioning in young children with autistic disorder

Psychophysiology studies of heart rate and heart rate variability can be employed to study regulatory processes in children with autism. The objective of this study was to test for differences in respiratory sinus arrhythmia (RSA; a measure of heart rate variability) and to examine the relationship between physiologic responses and measures of social behavior. Participants included 2- to 6-year-old children with Autistic Disorder and children without autism. Heart rate and RSA were derived from ECG recordings made during a baseline period and then a stranger approach paradigm. Social and adaptive behavior was assessed by parent report. Groups did not differ in mean heart rate or RSA at baseline or in response to social challenge. However, children with autism were more likely to show a physiologic response to intrusive portions of the stranger approach than to less intrusive portions of this procedure. Nonautistic children were equally likely to respond to intrusive and less intrusive social events. Within the autistic group, physiologic response to the intrusive stranger approach corresponded to higher ratings of social adaptive behaviors. These results suggest that physiologic responses to social challenge may help understand differences in social behavioral outcomes in children with autism.

Atypical attentional networks and the emergence of autism

The sociocommunicative impairments that define autism spectrum disorder (ASD) are not present at birth but emerge gradually over the first two years of life. In typical development, basic attentional processes may provide a critical foundation for sociocommunicative abilities. Therefore early attentional dysfunction in ASD may result in atypical development of social communication. Prior research has demonstrated that persons with ASD exhibit early and lifelong impairments in attention. The primary aim of this paper is to provide a review of the extant research on attention in ASD using a framework of functionally independent attentional networks as conceptualized by Posner and colleagues: the alerting, orienting and executive control networks (Posner and Petersen, 1990; Petersen and Posner, 2012). The neural substrates and typical development of each attentional network are briefly discussed, a review of the ASD attention literature is presented, and a hypothesis is proposed that links aberrant attentional mechanisms, specifically impaired disengagement of attention, with the emergence of core ASD symptoms.

ERP correlates of selective attention and working memory capacities in children with ADHD and/or PDD-NOS

OBJECTIVE

We examined whether children (8-11 years) diagnosed with Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) or Attention-Deficit/Hyperactivity Disorder (ADHD) showing primarily hyperactive behavior, differed in selective attention and working memory (WM) abilities.

METHODS

Healthy controls and children with ADHD, PDD-NOS or symptoms of both disorders (PDD/HD) (n=15 in each group) carried out a visual selective memory search task while their EEG was recorded from which event-related potentials were derived.

RESULTS

Compared to the control group, all patient groups made more omissions while hyperactive children also exhibited more false alarms. Regarding the process of WM-controlled search, significant group differences in ERP data were found between the control group and each of the clinical groups.

CONCLUSIONS

The results point to less efficient WM-functioning in all patient groups. Whereas the clinical groups differed from each other at the behavioral level as measured by questionnaires, no distinction between the clinical groups could be made with respect to performance or ERP measures of WM capacity and selective attention.

SIGNIFICANCE

The results suggest that a possible differentiation in selectivity and working memory capacities between PDD-NOS and ADHD is hard to find. This may agree with clinical practice, where differential diagnosis is a subject of discussion.

Cardiovascular and eye activity measures as indices for momentary changes in mental effort during simulated flight

This study examines effects of momentary changes in mental effort on cardiovascular and eye activity measures. A total of 19 male pilots performed an instrument flight task. Task load was manipulated by having the pilots perform flight manoeuvres of varying complexity. Multilevel analyses demonstrated clear effects of momentary changes in mental effort on both the cardiovascular and the eye activity measures. An increase in task load resulted in an increase of heart rate and a decrease in heart rate variability, mean dwell time and fixation duration. Heart rate differentiated between resting period and task execution. Heart rate variability from short data segments provided more insight in intermediate levels of mental effort. The eye activity measures were sensitive to intermediate levels of mental effort as well. Attitude changes resulted in an increase of mean dwell time and mean fixation duration. Task analysis is required to use eye measures as valid indices of mental effort. Having indications of the effects of changing mental demands during daily work of operators is of great importance nowadays. This paper presents an approach to estimate such effects on the basis of heart rate and eye activity measures. In particular, the use of averaged short-term heart rate variability measures is a relatively new aspect.

Swimming training program for children with cerebral palsy: body perceptions, problem behaviour, and competence

The aim of this study was to assess the effects of a 14-week swimming training program on the competence, problem behaviour, and body awareness in 13 children with cerebral palsy aged 5 to 10 years, compared with 10 subjects in a comparison group. Both of the groups continued a traditional rehabilitation program. The outcome measures were Child Behaviour Check List (CBCL) and Body Awareness. The parent forms were evaluated before and after training and also at 6 months followup. Teacher forms and body awareness were evaluated before and after training. The results showed that swimming training produced significant gain on body awareness in the Swimming Group, whereas no significant group differences were evident in competence and problem behaviours on parent or teacher forms of the CBCL.

Arousal modulation in females with fragile X or Turner syndrome

The present study was carried out to examine physiological arousal modulation (heart activity and skin conductance, across baseline and cognitive tasks, in females with fragile X or Turner syndrome and a comparison group of females with neither syndrome. Relative to the comparison group, for whom a greater increase in skin conductance was associated with poor arithmetic performance and less risk taking behavior, females with fragile X displayed a minimal increase in heart activity that was nevertheless associated with poor performance on mental arithmetic. In contrast, no arousal-cognitive performance relationship emerged for the group with Turner syndrome. Taken together, our findings suggest that distinct profiles of arousal modulation might be associated with cognitive deficits in these syndrome populations.

Neuropsychological effects of risperidone in children with pervasive developmental disorders: a blinded discontinuation study

OBJECTIVE

Little is known about the neuropsychological effects of risperidone in children with pervasive developmental disorders.

METHOD

Twenty-four children (aged 5-17 years) with pervasive developmental disorders and co-morbid disruptive behavior who responded favorably to open-label treatment with risperidone as part of a previously described controlled discontinuation study completed two different computerized attention tasks at baseline, weeks 4, 8, and 24 of open-label treatment, and, at 8 weeks after random assignment to either placebo or risperidone. The primary efficacy measures were response latencies to visually presented stimuli requiring two different types of attention-controlled processing, i.e., focused and divided attention.

RESULTS

About half of the clinical responders did not produce valid performance measures. These could be shown to be of younger mental age and less adaptive as measured by the Vineland Behavior Scales. For the valid task performers divided attention (serial search in working memory) was shown to regress in the placebo group (n = 7), while in the risperidone group (n = 7) there was further improvement. No such group difference was found for focused attention.

CONCLUSIONS

The study suggests a beneficial effect of risperidone after several months of treatment, enhancing divided attention in children with pervasive developmental disorders.

State regulation in adult ADHD: an event-related potential study

The state regulation hypothesis postulates that poor task performance of children with ADHD is related to poor energetical state control. The current study aimed to investigate whether such a deficit persists in adult ADHD. Event-related potentials (ERPs) were recorded during administration of a Go/No-Go task that incorporated the stressor presentation rate of stimuli. It was found that males with ADHD responded slower than control males in the slow condition, which was accompanied by smaller parietal P3s, suggesting less effort allocation. No group differences were found with respect to the response inhibition measures (errors of commission and the N2 effect). In conclusion, problems in state regulation seem to persist in male adults with ADHD.

Autonomic and Neuroendocrine Responses to a Psychosocial Stressor in Adults with Autistic Spectrum Disorder

Objective of the study was to replicate in adults our previous findings of decreased heart rate and normal endocrine responses to stress in autistic children and to elucidate the discrepancy between autonomic and endocrine stress responses by including epinephrine, norepinephrine, oxytocin and vasopressin measurements. Ten autistic spectrum disorder (ASD) adults were compared to 14 healthy controls in their response to a psychosocial stressor (public speaking). ASD patients showed decreased heart rate, but normal cortisol responses, consistent with our prior findings in children. No differences in norepinephrine, epinephrine, oxytocin or vasopressin responses to stress were found. However, in contrast to previous findings in low functioning autistic children, ASD adults showed increased basal oxytocin levels, which may be related to developmental factors.

Varieties of attention-deficit/hyperactivity disorder-related intra-individual variability

Intra-individual variability in behavior and functioning is ubiquitous among children with attention-deficit/hyperactivity disorder (ADHD), but it has not been systematically examined or integrated within causal models. This article seeks to provide a conceptual, methodologic, and analytic framework as a foundation for future research. We first identify five key research questions and methodologic issues. For illustration, we examine the periodic structure of Eriksen Flanker task reaction time (RT) data obtained from 24 boys with ADHD and 18 age-matched comparison boys. Reaction time variability in ADHD differed quantitatively from control subjects, particularly at a modal frequency around .05 Hz (cycle length approximately 20 sec). These oscillations in RT were unaffected by double-blind placebo and were suppressed by double-blind methylphenidate. Together with converging lines of basic and clinical evidence, these secondary data analyses support the speculative hypothesis that the increased power of multisecond oscillations in ADHD RT data, and by inference, in attentional performance, represents a catecholaminergic deficit in the ability to appropriately modulate such oscillations in neuronal activity. These results highlight the importance of retaining time-series data and quantitatively examining intra-subject measures of variability as a putative endophenotype for ADHD.

Autonomic response patterns observed during the performance of an attention-demanding task in two groups of children with autistic-type difficulties in social adjustment

Two groups of children with autistic-type behavior problems were compared to a group of normal children with respect to their autonomic response patterns observed during the performance of an attention-demanding task. Heart rate, blood pressure, and respiratory activity were measured during periods of rest and of task performance. Applying a quantitative model of the baroreflex, we were able to demonstrate qualitative differences among the groups with respect to their vagally controlled response patterns, whereas sympathetic responsiveness did not differ. In terms of our model, the groups with autistic-type behavior showed a decrease in central vagal tone during task performance, while vagal gain appeared to be unaffected or even increased. In contrast, the children in the control group showed the expected pattern of a decrease in vagal gain while vagal tone appeared to be increased. Implications of our findings are discussed in the light of Damasio's somatic marking hypothesis.

Cortical and Autonomic Correlates of Visual Selective Attention in Introverted and Extraverted Children

Abstract. We investigated the performance on a selective attention task in two groups of 8- to 12-year-old healthy children being characterized as extraverted and introverted, respectively. During task performance EEG-activity was recorded to investigate differential effects on a specific selection-related potential, the N2b. Cardiac activity was recorded continuously before, during and after task performance. Spectral energy was computed for three distinguishable frequency bands corresponding with a low (LF), mid- (MF), and high-frequency (HF) component in heart rate variability (HRV). The extraverted children were found to show greater perceptual sensitivity in response to irrelevant information. They also exhibited a greater N2b-component while showing significantly greater decreases in, particularly, the LF- and MF-power of HRV during task performance as compared to baseline periods. The magnitude of the N2b and the task-related decreases in LF-power of HRV were found to correlate significantly with the degree of extraversion and task performance, as well as with each other. The findings are discussed in the light of how selective attention and changes in physiological state may be related to the children's temperament.

Introducing a baroreflex model for studying cardiovascular effects of mental workload

A quantitative baroreflex control model is presented aimed at estimating differences in autonomic activation due to mental task performance. The model, which builds on earlier work of Wesseling and colleagues, is strongly supported by well-established knowledge of physiological control processes. Spectral measures of heart rate and blood pressure variability provide the information to estimate autonomic gain and tone parameters. The article gives a detailed model description as well as an evaluation in terms of spectral variability distributions, respiratory sinus arrhythmia, and vagal control mechanisms. The estimation procedure is outlined while presenting two studies that describe the effects of mental workload and vagal blockade, respectively. It is concluded that, using the model approach, cardiovascular effects of mental task performance can be interpreted in terms of specific changes in autonomic state. The model is implemented in a Matlab/Simulink environment and is available for other researchers in the field.

What the rodent prefrontal cortex can teach us about attention-deficit/hyperactivity disorder: the critical role of early developmental events on prefrontal function

The present review surveys a broad range of findings on the functions of the rodent prefrontal cortex (PFC) in the context of the known pathophysiology of attention-deficit/hyperactivity disorder (ADHD). An overview of clinical findings concludes that dysfunction of the right PFC plays a critical role in ADHD and that a number of early developmental factors conspire to increase the risk of the disorder. Rodent studies are described which go far in explaining how the core processes which are deficient in ADHD are mediated by the PFC and that the mesocortical dopamine (DA) system plays a central role in modulating these functions. These studies also demonstrate a surprising degree of cerebral lateralization of prefrontal function in the rat. Importantly, the PFC is highly vulnerable to a wide variety of early developmental insults, which parallel the known risk factors for ADHD. It is suggested that the regulation of physiological and behavioral arousal is a fundamental role of the PFC, upon which many "higher" prefrontal functions are dependent or at least influenced. These right hemispheric arousal systems, of which the mesocortical DA system is a component, are greatly affected by early adverse events, both peri- and postnatally. Abnormal development, particularly of the right PFC and its DAergic afferents, is suggested to contribute directly to the core deficits of ADHD through dysregulation of the right frontostriatal system.

The Polyvagal Theory: phylogenetic contributions to social behavior

The scientific legacy of Paul MacLean provides important insights into the neural substrate of adaptive social behavior in mammals. Through his research and visionary conceptualizations, current investigators can legitimately study social behavior from a neurobiological perspective. His research and writings provided three important contributions. First, he emphasized the importance of evolution as an organizing principle that shaped both the structure of the nervous system and the adaptive social behavior. Second, by defining the limbic system, he legitimized the biological perspective in the study of emotion. Third, he recognized the important role of the vagal afferents in the regulation of higher brain structures. The paper will focus on the Polyvagal Theory. The Polyvagal Theory is a new conceptualization of the role of vagus and employs several features that MacLean emphasized including the importance of evolution, limbic structures and vagal afferents. The Polyvagal Theory builds on these early findings by MacLean and focuses on the link between phylogenetic changes in the autonomic nervous system and social behavior. By focusing on the phylogenetic changes in the structure of the vagus and the role that the vagus plays in the neural regulation of visceral state, new insights regarding social behavior emerge. Moreover, by articulating the phylogenetically organized hierarchy of neural circuits, insights into benefits of social behavior become evident as do an understanding of the behavioral and physiological features associated with stress and psychiatric disorders.

Face recognition in children with a pervasive developmental disorder not otherwise specified

This study investigates the accuracy and speed of face recognition in children with a Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS; DSM-IV, American Psychiatric Association [APA], 1994). The study includes a clinical group of 26 nonretarded 7- to 10-year-old children with PDDNOS and a control group of 65 normally developing children of the same age. Two computerized reaction time tasks were administered: a face recognition task and a control task designed to measure the recognition of abstract visuospatial patterns. The latter were either easy or difficult to distinguish from a set of alternative patterns. The normally developing children recognized the faces much faster than the hardly distinguishable abstract patterns. The children in the PDDNOS group needed an amount of time to recognize the faces that almost equalled the time they needed to recognize the abstract patterns that were difficult to distinguish. The results suggest that, when processing faces, children with PDDNOS use a strategy that is more attention-demanding and, hence, less automatic or "Gestalt-like" than the one used by the control children. The results are discussed in the light of a theory that explains the development of coherent mental representations.