Neurophysiological responses to faces and gaze direction differentiate children with ASD,ADHD and ASD + ADHD

Children with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) demonstrate face processing abnormalities that may underlie social impairment. Despite substantial overlap between ASD and ADHD, ERP markers of face and gaze processing have not been directly compared across pure and comorbid cases. Children with ASD (n = 19), ADHD (n = 18), comorbid ASD + ADHD (n = 29) and typically developing (TD) controls (n = 26) were presented with upright/inverted faces with direct/averted gaze, with concurrent recording of the P1 and N170 components. While the N170 was predominant in the right hemisphere in TD and ADHD, children with ASD (ASD/ASD + ADHD) showed a bilateral distribution. In addition, children with ASD demonstrated altered response to gaze direction on P1 latency and no sensitivity to gaze direction on midline-N170 amplitude compared to TD and ADHD. In contrast, children with ADHD (ADHD/ASD + ADHD) exhibited a reduced face inversion effect on P1 latency compared to TD and ASD. These findings suggest children with ASD have specific abnormalities in gaze processing and altered neural specialisation, whereas children with ADHD show abnormalities at early visual attention stages. Children with ASD + ADHD are an additive co-occurrence with deficits of both disorders. Elucidating the neural basis of the overlap between ASD and ADHD is likely to inform aetiological investigation and clinical assessment.     

Health care access and treatment for children with co-morbid autism and psychiatric conditions

Purpose

To characterize the rate of comorbid psychiatric conditions (CPC) among children with autism spectrum disorders (ASD), to examine their treatment utilization, and to investigate treatment delay or non-delivery.

Methods

Lifetime ASD and CPC in children, aged 2–17, were investigated using data from the 2007–2008 National Survey of Children’s Health (NSCH). The NSCH surveyed parents and guardians regarding the health and well being, including treatment, of their child(ren) under age 18 (n?=?91,642). Children with health conditions were defined by parent report that a doctor or other health professional had ever said their child had that condition. Factors related to overall health, treatment utilization, and barriers to access variables were investigated among this group.

Results

Children with ASD/CPC had poorer overall health outcomes than children with ASD alone. They more often were dissatisfied with their between-provider communication and less often had insurance cover needed services. Nonetheless, they did tend to use care coordination and mental health services to a greater degree. Families were more likely to report the delay or non-receipt of needed services when they perceived a lack of communication and partnership with providers, when they lacked insurance coverage, and when they felt that health care costs were unreasonable.

Conclusions

The presence of a CPC seems to shape the treatment utilization and health outcomes of children with ASD. Because of this, health professionals working with children with autism should give special attention to treatment of those with comorbid diagnoses.     

The effect of gaze direction on the processing of facial expressions in children with autism spectrum disorder: An ERP study

This study investigated the neural basis of the effect of gaze direction on facial expression processing in children with and without ASD, using event-related potential (ERP). Children with ASD (10-17-year olds) and typically developing (TD) children (9-16-year olds) were asked to determine the emotional expressions (anger or fearful) of a facial stimulus with a direct or averted gaze, and the ERPs were recorded concurrently. In TD children, faces with a congruent expression and gaze direction in approach-avoidance motivation, such as an angry face with a direct gaze (i.e., approaching motivation) and a fearful face with an averted gaze (i.e., avoidant motivation), were recognized more accurately and elicited larger N170 amplitudes than motivationally incongruent facial stimuli (an angry face with an averted gaze and a fearful face with a direct gaze). These results demonstrated the neural basis and time course of integration of facial expression and gaze direction in TD children and its impairment in children with ASD.     

Stranger Fear and Early Risk for Social Anxiety in Preschoolers with Fragile X Syndrome Contrasted to Autism Spectrum Disorder

This study investigated behavioral indicators of social fear in preschool boys with fragile X syndrome (FXS) with a low degree of autism spectrum disorder (ASD) symptoms (FXS-Low; n?=?29), FXS with elevated ASD symptoms (FXS-High; n?=?25), idiopathic ASD (iASD; n?=?11), and typical development (TD; n?=?36). Gaze avoidance, escape behaviors, and facial fear during a stranger approach were coded. Boys with elevated ASD symptoms displayed more avoidant gaze, looking less at the stranger and parent than those with low ASD symptoms across etiologies. The iASD group displayed more facial fear than the other groups. Results suggest etiologically distinct behavioral patterns of social fear in preschoolers with elevated ASD symptoms.     

Effects of eye gaze directions of facial images on looking behaviour and autonomic responses in adolescents with autism spectrum disorders

It has been suggested that atypical eye contact of individuals with autism spectrum disorders (ASDs) arises from an unusually high level of autonomic activity elicited by another person's gaze. The present study investigated visual fixation duration and autonomic reactivity (heart rate, skin conductance response) simultaneously, while adolescents looked towards photographs of neutral faces, with either direct eye gaze, averted eye gaze or closed eyes. Both cognitively able adolescents with ASD (n = 31, mean age = 16 years, mean IQ = 104) and typically developing (TD) adolescents (n = 34, mean age = 16 years, mean IQ = 108) looked significantly longer towards the eye region of faces with direct eye gaze compared with faces with averted eye gaze or closed eyes. The adolescents with ASD did not show higher levels of autonomic activity than TD adolescents while they were instructed to look at the eye region. This suggests that looking at the eye region of static faces does not particularly trigger high autonomic arousal in adolescents with ASD.     

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.

     

Comparing oxytocin and cortisol regulation in a double-blind,placebo-controlled,hydrocortisone challenge pilot study in children with autism and typical development

Background

Children with autism spectrum disorder (ASD) show marked impairment in social functioning and poor adaptation to new and changing contexts, which may be influenced by underlying regulatory processes. Oxytocin (OT) and cortisol are key neuromodulators of biological and behavioral responses, show a synergistic effect, and have been implicated in the neuropathological profile in ASD. However, they are rarely investigated together. The purpose of the pilot study was to evaluate the relationship between cortisol and OT in children with ASD under baseline and physiological stress (hydrocortisone challenge) conditions. Arginine vasopressin (AVP), structurally similar to OT, was also examined.

Methods

A double-blind, placebo-controlled, randomly assigned, crossover design was employed in 25 children 8-to-12 years with ASD (N?=?14) or typical development (TD, N?=?11). A low dose of hydrocortisone and placebo were administered via liquid suspension. Analysis of variance (ANOVA) was used to examine the within-subject factor “Condition” (hydrocortisone/placebo) and “Time” (pre and post) and the between-subject factor “Group” (ASD vs. TD). Pearson correlations examined the relationship between hormone levels and clinical profile.

Results

There was a significant Time × Condition × Group interaction F (1.23)?=?4.18, p?=?0.05 showing a rise in OT during the experimental condition (hydrocortisone) and a drop during the placebo condition for the TD group but not the ASD group. There were no group differences for AVP. Hormone levels were associated with social profiles.

Conclusions

For the TD group, an inverse relationship was observed. OT increased during physiological challenge suggesting that OT played a stress-buffering role during cortisol administration. In contrast for the ASD group, OT remained unchanged or decreased during both the physiological challenge and the placebo condition, suggesting that OT failed to serve as a stress buffer under conditions of physiological stress.While OT has been tied to the social ability of children with ASD, the diminished moderating effect of OT on cortisol may also play a contributory role in the heightened stress often observed in children with ASD. These results contribute to our understanding of the growing complexity of the effects of OT on social behavior as well as the functional interplay and differential regulation OT may have on stress modulation.

     

Abnormal Activation of the Social Brain Network in Children with Autism Spectrum Disorder: An fMRI Study

Objective

The aim of this study is to investigate abnormal findings of social brain network in Korean children with autism spectrum disorder (ASD) compared with typically developing children (TDC).

Methods

Functional magnetic resonance imaging (fMRI) was performed to examine brain activations during the processing of emotional faces (happy, fearful, and neutral) in 17 children with ASD, 24 TDC.

Results

When emotional face stimuli were given to children with ASD, various areas of the social brain relevant to social cognition showed reduced activation. Specifically, ASD children exhibited less activation in the right amygdala (AMY), right superior temporal sulcus (STS) and right inferior frontal gyrus (IFG) than TDC group when fearful faces were shown. Activation of left insular cortex and right IFG in response to happy faces was less in the ASD group. Similar findings were also found in left superior insular gyrus and right insula in case of neutral stimulation.

Conclusion

These findings suggest that children with ASD have different processing of social and emotional experience at the neural level. In other words, the deficit of social cognition in ASD could be explained by the deterioration of the capacity for visual analysis of emotional faces, the subsequent inner imitation through mirror neuron system (MNS), and the ability to transmit it to the limbic system and to process the transmitted emotion.     

The growth of the foramen magnum in Crouzon syndrome

Background

Though the craniovertebral junction is often abnormal in children with Crouzon’s syndrome, no study had measured accurately the size of their foramen magnum (FM).

Patients and methods

We compared the FM size (area, diameters) on computed tomography examination in 21 children with a genetically confirmed Crouzon’s syndrome prior to any surgery and in 23 control children without craniofacial abnormalities. We extrapolated the growth pattern in both groups.

Results

We found a statistically significant smaller FM area (p?=?0.0228), FM sagittal diameter (p?=?0.0287), and FM sagittal posterior diameter (p?=?0.0023) in children with Crouzon’s syndrome. No differences were detected with regard to the transversal diameter. Hydrocephalus in children with Crouzon’s syndrome was associated with a small FM area (p?=?0.05), small sagittal diameter (p?=?0.023), small sagittal posterior diameter (p?=?0.0173), and reduced transversal diameter (p?=?0.03985). No association of the aforementioned findings was found with the position of the cerebellar tonsils or the lambdoid suture functional state (open or fused). Comparable results were observed among the two genetic forms (exon 8 or 10 mutations). Concerning the growth pattern, a first phase of rapid increase and a second phase of slow increase could be recognized in all the measurements in both populations, though with some significant differences.

Discussion and conclusions

The growth of FM follows a biphasic pattern in both Crouzon’s and control children. The sagittal diameter and the global size of the FM are mostly affected in children with Crouzon’s syndrome. The small FM, especially its posterior part, is likely to play a key role in the physiopathology of hydrocephalus.     

Inhibition, flexibility, working memory and planning in autism spectrum disorders with and without comorbid ADHD-symptoms

Background

Recent studies have not paid a great deal of attention to comorbid attention-deficit/hyperactivity disorder (ADHD) symptoms in autistic children even though it is well known that almost half of children with autism spectrum disorder (ASD) suffer from hyperactivity, inattention and impulsivity. The goal of this study was to evaluate and compare executive functioning (EF) profiles in children with ADHD and in children with ASD with and without comorbid ADHD.

Methods

Children aged 6 to 18 years old with ADHD (n = 20) or ASD (High-Functioning autism or Asperger syndrome) with (n = 20) and without (n = 20) comorbid ADHD and a typically developing group (n = 20) were compared on a battery of EF tasks comprising inhibition, flexibility, working memory and planning tasks. A MANOVA, effect sizes as well as correlations between ADHD-symptomatology and EF performance were calculated. Age- and IQ-corrected z scores were used.

Results

There was a significant effect for the factor group (F = 1.55; dF = 42; p = .02). Post-hoc analysis revealed significant differences between the ADHD and the TD group on the inhibition task for false alarms (p = .01) and between the ADHD group, the ASD+ group (p = .03), the ASD- group (p = .02) and the TD group (p = .01) for omissions. Effect sizes showed clear deficits of ADHD children in inhibition and working memory tasks. Participants with ASD were impaired in planning and flexibility abilities. The ASD+ group showed compared to the ASD- group more problems in inhibitory performance but not in the working memory task.

Conclusion

Our findings replicate previous results reporting impairment of ADHD children in inhibition and working memory tasks and of ASD children in planning and flexibility abilities. The ASD + group showed similarities to the ADHD group with regard to inhibitory but not to working memory deficits. Nevertheless the heterogeneity of these and previous results shows that EF assessment is not useful for differential diagnosis between ADHD and ASD. It might be useful for evaluating strengths and weaknesses in individual children.     

Amélioration de l’exploration visuelle d’un visage par des enfants avec autisme grâce au ralentissement de la dynamique faciale : une étude préliminaire en oculométrie

Objective

Face and gaze avoidance are among the most characteristic and salient symptoms of autism spectrum disorders (ASD). Studies using eye tracking highlighted early and lifelong ASD-specific abnormalities in attention to face such as decreased attention to internal facial features. These specificities could be partly explained by disorders in the perception and integration of rapid and complex information such as that conveyed by facial movements and more broadly by biological and physical environment. Therefore, we wish to test whether slowing down facial dynamics may improve the way children with ASD attend to a face.

Neural synchrony examined with magnetoencephalography (MEG) during eye gaze processing in autism spectrum disorders: preliminary findings

Background

Gaze processing deficits are a seminal, early, and enduring behavioral deficit in autism spectrum disorder (ASD); however, a comprehensive characterization of the neural processes mediating abnormal gaze processing in ASD has yet to be conducted.

Methods

This study investigated whole-brain patterns of neural synchrony during passive viewing of direct and averted eye gaze in ASD adolescents and young adults (M _Age  = 16.6) compared to neurotypicals (NT) (M _Age  = 17.5) while undergoing magnetoencephalography. Coherence between each pair of 54 brain regions within each of three frequency bands (low frequency (0 to 15 Hz), beta (15 to 30 Hz), and low gamma (30 to 45 Hz)) was calculated.

Results

Significantly higher coherence and synchronization in posterior brain regions (temporo-parietal-occipital) across all frequencies was evident in ASD, particularly within the low 0 to 15 Hz frequency range. Higher coherence in fronto-temporo-parietal regions was noted in NT. A significantly higher number of low frequency cross-hemispheric synchronous connections and a near absence of right intra-hemispheric coherence in the beta frequency band were noted in ASD. Significantly higher low frequency coherent activity in bilateral temporo-parieto-occipital cortical regions and higher gamma band coherence in right temporo-parieto-occipital brain regions during averted gaze was related to more severe symptomology as reported on the Autism Diagnostic Interview-Revised (ADI-R).

Conclusions

The preliminary results suggest a pattern of aberrant connectivity that includes higher low frequency synchronization in posterior cortical regions, lack of long-range right hemispheric beta and gamma coherence, and decreased coherence in fronto-temporo-parietal regions necessary for orienting to shifts in eye gaze in ASD; a critical behavior essential for social communication.     

The role of nonverbal working memory in morphosyntactic processing by children with specific language impairment and autism spectrum disorders

Background

Both children with autism spectrum disorders (ASD) and children with specific language impairment (SLI) have been shown to have difficulties with grammatical processing. A comparison of these two populations with neurodevelopmental disorders was undertaken to examine similarities and differences in the mechanisms that may underlie grammatical processing. Research has shown that working memory (WM) is recruited during grammatical processing. The goal of this study was to examine morphosyntactic processing on a grammatical judgment task in children who varied in clinical diagnosis and language abilities and to assess the extent to which performance is predicted by nonverbal working memory (WM). Two theoretical perspectives were evaluated relative to performance on the grammatical judgment task—the “working memory” account and the “wrap-up” account. These accounts make contrasting predictions about the detection of grammatical errors occurring early versus late in the sentence.

Methods

Participants were 84 school-age children with SLI (n?=?21), ASD (n?=?27), and typical development (TD, n?=?36). Performance was analyzed based on diagnostic group as well as language status (normal language, NL, n?=?54, and language impairment, LI, n?=?30). A grammatical judgment task was used in which the position of the error in the sentence (early versus late) was manipulated. A visual WM task (N-back) was administered and the ability of WM to predict morphosyntactic processing was assessed.

Results

Groups differed significantly in their sensitivity to grammatical errors (TD?>?SLI and NL?>?LI) but did not differ in nonverbal WM. Overall, children in all groups were more sensitive and quicker at detecting errors occurring late in the sentence than early in the sentence. Nonverbal WM predicted morphosyntactic processing across groups, but the specific profile of association between WM and early versus late error detection was reversed for children with and without language impairment.

Conclusions

Findings primarily support a “wrap up” account whereby the accumulating sentence context for errors positioned late in the sentence (rather than early) appeared to facilitate morphosyntactic processing. Although none of the groups displayed deficits in visual WM, individual differences in these nonverbal WM resources predicted proficiency in morphosyntactic processing.

     

Altered sensitivity to social gaze in the <Emphasis Type="Italic">FMR1</Emphasis> premutation and pragmatic language competence

Background

The FMR1 premutation affects 1:291 women and is associated with a range of cognitive, affective, and physical health complications, including deficits in pragmatic language (i.e., social language). This study investigated attention to eye gaze as a fundamental social-cognitive skill that may be impaired in the FMR1 premutation and could underlie pragmatic deficits. Given the high prevalence of the FMR1 premutation, efforts to define its phenotype and mechanistic underpinnings have significant public health implications.

Methods

Thirty-five women with the FMR1 premutation and 20 control women completed an eye-tracking paradigm that recorded time spent dwelling within the eye region in response to a face displaying either direct or averted gaze. Pragmatic language ability was coded from a conversational sample using the Pragmatic Rating Scale.

Results

Women with the FMR1 premutation failed to show attentional preference to direct gaze and spent more time dwelling on the averted eyes relative to controls. While dwelling on the eyes was associated with better pragmatic language performance in controls, these variables were unrelated in the women with the FMR1 premutation.

Conclusions

Altered sensitivity to social gaze, characterized by increased salience of averted gaze, was observed among women with the FMR1 premutation. Furthermore, women with the FMR1 premutation were unable to capitalize on information conveyed through the eyes to enhance social-communicative engagement, which differed from patterns seen in controls. These findings contribute to the growing characterization of social and communication phenotypes associated with the FMR1 premutation.

     

Victimisation in a French population of children and youths with autism spectrum disorder: a case control study

Background

Children and youths with autism spectrum disorder (ASD) have behavioural characteristics and severe social disabilities that make them vulnerable to victimisation. The current study explores the prevalence of peer victimisation in this population in France.

Methods

We used the Juvenile Victimization Questionnaire—Screener Sum Version in a French sample of 39 children and youths with ASD and 53 typically developing (TD) children and youths and tested the association of the victimisation with socio-demographic factors and clinical factors of anxiety and post-traumatic stress.

Results

The results indicate that 72% of the subjects with ASD had been victimised during the previous year and 94.9% during their entire lifetime. Of all students victimised at least once over the course of their lives, 75% had been victimised at school. Their peer victimisation score was significantly higher than in the TD group and was correlated to clinical factors such as a deficit in social skills and the severity of post-traumatic symptoms. Symptoms of anxiety were reported by parents of children and youths with ASD in 80% of cases.

Conclusions

Children and youths with ASD are particularly vulnerable to victimisation at school. Discussion focuses on the importance of considering the impacts and needs of school integration of this population in France in order to prevent these phenomena and their consequences.

     

Load matters: neural correlates of verbal working memory in children with autism spectrum disorder

Background

Autism spectrum disorder (ASD) is a pervasive neurodevelopmental disorder characterised by diminished social reciprocity and communication skills and the presence of stereotyped and restricted behaviours. Executive functioning deficits, such as working memory, are associated with core ASD symptoms. Working memory allows for temporary storage and manipulation of information and relies heavily on frontal-parietal networks of the brain. There are few reports on the neural correlates of working memory in youth with ASD. The current study identified the neural systems underlying verbal working memory capacity in youth with and without ASD using functional magnetic resonance imaging (fMRI).

Methods

Fifty-seven youth, 27 with ASD and 30 sex- and age-matched typically developing (TD) controls (9–16 years), completed a one-back letter matching task (LMT) with four levels of difficulty (i.e. cognitive load) while fMRI data were recorded. Linear trend analyses were conducted to examine brain regions that were recruited as a function of increasing cognitive load.

Results

We found similar behavioural performance on the LMT in terms of reaction times, but in the two higher load conditions, the ASD youth had lower accuracy than the TD group. Neural patterns of activations differed significantly between TD and ASD groups. In TD youth, areas classically used for working memory, including the lateral and medial frontal, as well as superior parietal brain regions, increased in activation with increasing task difficulty, while areas related to the default mode network (DMN) showed decreasing activation (i.e., deactivation). The youth with ASD did not appear to use this opposing cognitive processing system; they showed little recruitment of frontal and parietal regions across the load but did show similar modulation of the DMN.

Conclusions

In a working memory task, where the load was manipulated without changing executive demands, TD youth showed increasing recruitment with increasing load of the classic fronto-parietal brain areas and decreasing involvement in default mode regions. In contrast, although they modulated the default mode network, youth with ASD did not show the modulation of increasing brain activation with increasing load, suggesting that they may be unable to manage increasing verbal information. Impaired verbal working memory in ASD would interfere with the youths’ success academically and socially. Thus, determining the nature of atypical neural processing could help establish or monitor working memory interventions for ASD.

     

Parental Misperceptions of Children’s Underweight Status: A Meta-analysis

Background

Accurate parental perceptions of their children’s underweight status are needed to prevent overlooking potential disordered eating patterns or health conditions affecting growth.

Purpose

The aim of this study is to determine overall proportion of parents who misperceive children’s underweight status and correlates of such misperceptions.

Methods

Original studies published to January 2013 were chosen through a literature search in established databases. Studies included assessed parental perceptions of their children’s underweight and then compared perceptions to recognized standards for defining underweight based on anthropometric measures. Random- and mixed-effects models were used.

Results

Thirty-seven articles (representing 39 studies; N?=?4,039) were included. Pooled effect sizes indicated that 46.58 % (95 % CI 40.90–52.35 %) of parents misperceive their children’s underweight status, though the extent of misperceptions depended on a number of moderators.

Conclusions

Nearly half of parents perceive their underweight children as weighing more than they actually do. Health care professionals are well positioned to take steps to remedy misperceptions and encourage healthy behaviors.     

Broad Autism Phenotypic Traits and the Relationship to Sexual Orientation and Sexual Behavior

Individuals with higher levels of the broad autism phenotype (BAP) have some symptoms of autism spectrum disorder (ASD). Like individuals with ASD, people with higher-BAP may have fewer sexual experiences and may experience more same-sex attraction. This study measured BAP traits, sexual experiences, and sexual orientation in typically developing (TD) individuals to see if patterns of sexual behavior and sexual orientation in higher-BAP resemble those in ASD. Although BAP characteristics did not predict sexual experiences, one BAP measure significantly predicted sexual orientation, β?=?0.22, t?=?2.72, p?=?.007, controlling for demographic variables (R² change?=?.04, F?=?7.41, p?=?.007), showing individuals with higher-BAP also reported increased same-sex attraction. This finding supports the hypothesis that individuals with higher-BAP resemble ASD individuals in being more likely than TD individuals to experience same-sex attraction.     

Postural orientation and equilibrium processes associated with increased postural sway in autism spectrum disorder (ASD)

Background

Increased postural sway has been repeatedly documented in children with autism spectrum disorder (ASD). Characterizing the control processes underlying this deficit, including postural orientation and equilibrium, may provide key insights into neurophysiological mechanisms associated with ASD. Postural orientation refers to children’s ability to actively align their trunk and head with respect to their base of support, while postural equilibrium is an active process whereby children coordinate ankle dorsi-/plantar-flexion and hip abduction/adduction movements to stabilize their upper body. Dynamic engagement of each of these control processes is important for maintaining postural stability, though neither postural orientation nor equilibrium has been studied in ASD.

Methods

Twenty-two children with ASD and 21 age and performance IQ-matched typically developing (TD) controls completed three standing tests. During static stance, participants were instructed to stand as still as possible. During dynamic stances, participants swayed at a comfortable speed and magnitude in either anterior-posterior (AP) or mediolateral (ML) directions. The center of pressure (COP) standard deviation and trajectory length were examined to determine if children with ASD showed increased postural sway. Postural orientation was assessed using a novel virtual time-to-contact (VTC) approach that characterized spatiotemporal dimensions of children’s postural sway (i.e., body alignment) relative to their postural limitation boundary, defined as the maximum extent to which each child could sway in each direction. Postural equilibrium was quantified by evaluating the amount of shared or mutual information of COP time series measured along the AP and ML directions.

Results

Consistent with prior studies, children with ASD showed increased postural sway during both static and dynamic stances relative to TD children. In regard to postural orientation processes, children with ASD demonstrated reduced spatial perception of their postural limitation boundary towards target directions and reduced time to correct this error during dynamic postural sways but not during static stance. Regarding postural equilibrium, they showed a compromised ability to decouple ankle dorsi-/plantar-flexion and hip abduction/adduction processes during dynamic stances.

Conclusions

These results suggest that deficits in both postural orientation and equilibrium processes contribute to reduced postural stability in ASD. Specifically, increased postural sway in ASD appears to reflect patients’ impaired perception of their body movement relative to their own postural limitation boundary as well as a reduced ability to decouple distinct ankle and hip movements to align their body during standing. Our findings that deficits in postural orientation and equilibrium are more pronounced during dynamic compared to static stances suggests that the increased demands of everyday activities in which children must dynamically shift their COP involve more severe postural control deficits in ASD relative to static stance conditions that often are studied. Systematic assessment of dynamic postural control processes in ASD may provide important insights into new treatment targets and neurodevelopmental mechanisms.

     

Attentional bias for emotional faces in paediatric anxiety disorders: An investigation using the emotional go/no go task

Background

The present study examined contextual modulation of attentional control processes in paediatric anxiety disorders.

Method

Anxious children (N = 20) and non-anxious controls (N = 20) completed an emotional Go/No Go task in which they responded on some trials (i.e., Go trials) when neutral faces were presented amongst either angry or happy faces to which children avoided responding (i.e., No Go trials) or when angry and happy faces were presented as Go trials and children avoided responding to neutral faces.

Results

Anxious girls were slower responding to neutral faces with embedded angry compared with happy face No Go trials whereas non-anxious girls were slower responding to neutral faces with embedded happy versus angry face No Go trials. Anxious and non-anxious boys showed the same basic pattern as non-anxious girls. There were no significant group differences on No Go trials or when the emotional faces were presented as Go trials.

Conclusions

Results are discussed in terms of selective interference by angry faces in the control of attention in anxious girls.