TD Children Research Articles

Altered tactile processing in children with autism spectrum disorder.

Although tactile reactivity issues are commonly reported in children with autism spectrum disorder (ASD), the underlying mechanisms are poorly understood. Less feed-forward inhibition has been proposed as a potential mechanism for some symptoms of ASD. We tested static and dynamic tactile thresholds as a behavioral proxy of feed-forward inhibition in 42 children (21 children with ASD and 21 typically developing [TD] children). Subthreshold conditioning typically raises the dynamic detection threshold, thus comparison of the dynamic to the static threshold generates a metric that predicts gamma-aminobutyric acid (GABA) mediated feed-forward inhibition. Children with ASD had marginally higher static thresholds and a significantly lower ratio between thresholds as compared with TD children. The lower ratio, only seen in children with ASD, might be indicative of less inhibition. Static thresholds were correlated with autism spectrum quotient scores, indicating the higher the tactile threshold, the more ASD traits. The amount of feed-forward inhibition (ratio between dynamic/static) was negatively correlated with autism diagnostic observation schedule repetitive behavior scores, meaning the less inhibition the more ASD symptoms. In summary, children with ASD showed altered tactile processing compared with TD children; thus measuring static and dynamic thresholds could be a potential biomarker for ASD and might be useful for prediction of treatment response with therapeutics, including those that target the GABAergic system. Autism Res 2016, 9: 616-620. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

Children with Autism Understand Indirect Speech Acts: Evidence from a Semi-Structured Act-Out Task.

Children with Autism Spectrum Disorder are often said to present a global pragmatic impairment. However, there is some observational evidence that context-based comprehension of indirect requests may be preserved in autism. In order to provide experimental confirmation to this hypothesis, indirect speech act comprehension was tested in a group of 15 children with autism between 7 and 12 years and a group of 20 typically developing children between 2:7 and 3:6 years. The aim of the study was to determine whether children with autism can display genuinely contextual understanding of indirect requests. The experiment consisted of a three-pronged semi-structured task involving Mr Potato Head. In the first phase a declarative sentence was uttered by one adult as an instruction to put a garment on a Mr Potato Head toy; in the second the same sentence was uttered as a comment on a picture by another speaker; in the third phase the same sentence was uttered as a comment on a picture by the first speaker. Children with autism complied with the indirect request in the first phase and demonstrated the capacity to inhibit the directive interpretation in phases 2 and 3. TD children had some difficulty in understanding the indirect instruction in phase 1. These results call for a more nuanced view of pragmatic dysfunction in autism.

Gaze strategies while negotiating obstacles in a virtual environment with distractors

s / Gait & Posture 42S (2015) S1–S27 S3 Table 1 Morphological and structural features in CP and TD children. Age [years] Muscle volume [cm3] Muscle length [cm] MTU [cm] Average muscle area [cm2] Normalized Muscle volume [cm2] Mean EI of muscle CP 8.6±2.3 32.4±13.8 16.2±3.9 33.5±6.0 2.1±0.5 1.1±0.3 101.0±9.7 TD 9.2±2.3 52.2±19.0 17.3±2.7 34.0±4.9 2.9±0.7 1.5±0.4 129.2±20.3 t-Test (p-value) 0.740 0.103 0.331 0.566 0.018* 0.040* 0.006* volume (=volume/MTU length) were calculated. In addition, the mean EI value (expressed in a grey-scale of 256 values), was also evaluated. Comparisons were made using the Student t-test (unpaired). Statistical significance (*) was set to p 0.79, p>0.01), but with a lower slope in CP (5.2 vs. 7.8 cm3/years). In CP, a significant negative correlation was found between EI and average muscle area (R2 =0.60, p=0.04). Discussion: We found a smaller muscle volume in CP children, as previously reported [2]. Interestingly, as a CP child ages, slower muscle growth occurs than in the TD children. Averaged muscle area was found to be more sensitive to distinguish between TD and CP children. Furthermore, the MG was hyper-echoic in the CP group relative to the TD group, supporting our hypothesis. Combining EI and average muscle area shows potential in estimating the amount of fibrotic changes occurring within a muscle. Utilising the new approach for 3D reconstruction offers an objective and efficient manner to diagnose muscle and tendon morphological and structural changes in the clinical environment.

Effect of muscles’ activation on proximal femoral growth tendency

Discussion: The lack of correlation between level of cocontraction during MVIC and the two walking speeds might be causedbydifferences inmotor control during thesemeasurements. Contradictory to what Barber et al. reported [1], the CP children in this study did not have a higher level of co-contraction than the TD children duringMVIC’s. The TD children in this studywere younger than theCP,whichmightpartially explain these results [3].Walking at a higher walking speed and the MVIC’s are more strenuous than walking at self-selected speed and therefore require more movement control and/or stability, which may result in an increased muscle activity and level of co-contraction in both groups.

Differences in co-contraction level between cp and td children during a functional and isometric strength assessment

Accurate coordination of mediolateral foot placement, relative to the center of mass kinematic state, is one of the mechanisms which ensures mediolateral stability during human walking. Previously, we found that shoes constraining ankle moments decreased the degree of foot placement control with respect to the center of mass kinematic state. As such, ankle moment constraints can be seen as a perturbation of foot placement. Direct mechanical perturbations of the swing leg trajectory can improve the degree of foot placement control as an after-effect. Here, we asked whether constrained ankle moments could have a similar effect. If confirmed, this would offer a simple training tool for individuals with impaired foot placement control. Participants walked in three conditions; normal (baseline) while wearing shoes constraining ankle moments (training) and normal again (after-effects). The degree of foot placement control was calculated as the percentage of variance in foot placement that could be predicted based on the center of mass kinematic state in the preceding swing phase. During training, the degree of foot placement control decreased initially compared to baseline, but it gradually improved over time. In the after-effect condition, it was higher than during baseline, yet not significantly so. During training, we observed increased step width, decreased stride time and reduced local dynamic stability. In conclusion, constraining ankle moment control deteriorates the degree of foot placement control. A non-significant trend towards an improved degree of foot placement control after prolonged exposure to constrained ankle moments, allows for speculation on a training potential.

Echogenicity intensity of the medial gastrocnemius and tendon achilles in age matched CP and TD children

simultaneously track theUS probe, 4 rigidly attachedmarkerswere tracked by a motion analysis system, at 120Hz (Optitrack, USA). For both volume and distance, 3 acquisition repetitions were performed. An in-house developedPythonpackage [2,4] andMeVisLab (www.mevislab.de) were used to reconstruct the acquisition data, whereby volume [2] and lengths were then manually extracted from the resulting 3D voxel array reconstruction (VA). In addition, the US probe was also used as a spatial pointer (PaP) to visualize the cross-wire points, and measure the length. Each reconstructed volume and calculated length was compared to the known values, obtained with a weighing scale and tape measure. Each acquisition was processed 3 times by 2 raters. The acquisition and feature extraction comparisons were investigated by the intra-class correlation coefficients for intra-rater (3,1) and inter-rater (3,k), and the standard error of measurement (SEM). Results: The ICC and SEM reliability for all measures were greater than 0.99 and 0.98, and 2.2ml and 2.1mm, respectively (Table 1). For the validity, on average, 3DUS overestimates volumes by 1.6%, lengths by 1.3% (PAP) and 2.1% (VA). Discussion: This study demonstrates a high reliability for the 3DUS method to estimate volume and lengths. This efficient method can be translated into clinical practice, where the reported validity suggests adequate accuracy required for defining anatomically relevant structures, such as muscle and tendon.

Leisure Activity Enjoyment of Children with Autism Spectrum Disorders.

Enjoyment is a fundamental component of activity participation. This study compared leisure activity enjoyment experienced by typically developing children (TD; n = 64) and those with autism spectrum disorders (ASD; n = 67) from age 6 to 13. The TD children enjoyed formal and physical activities significantly more than the children with ASD. Symptom severity was negatively related to enjoyment of overall, formal, physical and social activities. Older children with ASD enjoyed overall, informal, recreational, and self-improvement activities significantly less than younger children, but no differences were seen across TD age groups. Children with ASD enjoyed swimming significantly more than TD children. Understanding patterns of activity enjoyment is useful for being better able to address a child's motivation to participate in various life activities.

Positively Biased Self-Perceptions in Children with ADHD: Unique Predictor of Future Maladjustment.

This study assessed children's overestimations of self-competence (positively biased self-perceptions or positive bias [PB]) relative to parent/teacher ratings of children's competence in predicting children's adjustment in a new setting. Eighty-five children (13 boys and 11 girls with Attention-Deficit/Hyperactivity Disorder [ADHD]; 30 boys and 31 girls who were typically developing [TD]), ages 6.8 to 9.8 years (M = 8.13; SD = 0.82), attended a 2-week summer day camp grouped into same-age, same-sex classrooms with previously unacquainted peers and counselors. Prior to camp, PB was assessed by creating standardized discrepancy scores between children's self-ratings relative to parent or teacher ratings of the children's social and behavioral competence. The relative ability of these discrepancy scores to predict peer preference and oppositionality at camp in relation to parent or teacher ratings alone was evaluated. For children with ADHD, both discrepancy scores and informant ratings of competence were uniquely predictive of peer preference and oppositionality assessed during camp. For TD children, only informant ratings of competence were predictive of outcomes at camp. These results suggest that PB may be a unique predictor of maladjustment within a novel environment for children with ADHD, but not TD children.

Selected vitamin D metabolic gene variants and risk for autism spectrum disorder in the CHARGE Study

BackgroundVitamin D is essential for proper neurodevelopment and cognitive and behavioral function. We examined associations between autism spectrum disorder (ASD) and common, functional polymorphisms in vitamin D pathways. MethodsChildren aged 24–60months enrolled from 2003 to 2009 in the population-based CHARGE case–control study were evaluated clinically and confirmed to have ASD (n=474) or typical development (TD, n=281). Maternal, paternal, and child DNA samples for 384 (81%) families of children with ASD and 234 (83%) families of TD children were genotyped for: TaqI, BsmI, FokI, and Cdx2 in the vitamin D receptor (VDR) gene, and CYP27B1 rs4646536, GC rs4588, and CYP2R1 rs10741657. Case–control logistic regression, family-based log-linear, and hybrid log-linear analyses were conducted to produce risk estimates and 95% confidence intervals (CI) for each allelic variant. ResultsPaternal VDR TaqI homozygous variant genotype was significantly associated with ASD in case–control analysis (odds ratio [OR] [CI]: 6.3 [1.9–20.7]) and there was a trend towards increased risk associated with VDR BsmI (OR [CI]: 4.7 [1.6–13.4]). Log-linear triad analyses detected parental imprinting, with greater effects of paternally-derived VDR alleles. Child GC AA-genotype/A-allele was associated with ASD in log-linear and ETDT analyses. A significant association between decreased ASD risk and child CYP2R1 AA-genotype was found in hybrid log-linear analysis. There were limitations of low statistical power for less common alleles due to missing paternal genotypes. ConclusionsThis study provides preliminary evidence that paternal and child vitamin D metabolism could play a role in the etiology of ASD; further research in larger study populations is warranted.

Morphonotactics in L1 acquisition of Lithuanian: TD vs. SLI

DOI: http://dx.doi.org/10.5128/ERYa11.06 The aim of the present study is to test the Strong Morphonotactic Hypothesis (SMH), according to which speakers use morphonotactic consonant clusters as morphological boundary signals (Korecky-Kroll et al. 2014). It is hypothesized that morphonotactic clusters will be better retained during production than phonotactic clusters due to the function fulfilled by a morpheme. The study is based on experimental data collected from 60 Lithuanian TD children and 11 Lithuanian SLI children. This study explores the impact of morphology on the acquisition of phonotactics. The findings suggest that TD children process morphonotactic clusters more accurately than phonotactic clusters because morphonotactic clusters have the function of co-signalling the existence of a morphological rule. In contrast to TD children, for SLI children prototypical morphonotactic clusters are the most difficult as SLI children are not sensitive to morphological information which is carried by morphonotactic clusters.

Grey matter volumes in treatment naïve vs. chronically treated children with attention deficit/hyperactivity disorder: a combined approach

Psychostimulants are the first-line treatment in attention deficit/hyperactivity disorder (ADHD), but their effects on brain development remain poorly understood. In particular, previous structural magnetic resonance imaging (sMRI) studies only investigated treatment effects on grey matter (GM) volumes in selected regions of interest (ROIs). In this study, voxel-based morphometry (VBM) was used to assess medication-related GM volume differences across the entire brain. Automated tracing measurements of selected ROIs were also obtained. Three groups (77 participants aged 7-to-13 year old) underwent MRI scans and were compared: never-medicated children with ADHD (n=33), medicated (methylphenidate) children with ADHD (n=20) and typically developing children (TD; n=24). Optimised VBM was used to investigate regional GM volumes, controlling for age and gender. Automated tracing procedures were also used to assess the average volume of the caudate nucleus, the amygdala and the nucleus accumbens. When compared to both medicated children with ADHD and TD children, never-medicated children with ADHD exhibited decreased GM volume in the insula and in the middle temporal gyrus. When compared to TD children, medicated children with ADHD had decreased GM volume in the middle frontal gyrus and in the precentral gyrus. Finally, ROI analyses revealed a significant association between duration of treatment and GM volume of the left nucleus accumbens in medicated children with ADHD. In conclusion, this study documents potential methylphenidate-related GM volume normalization and deviation in previously unexplored brain structures, and reports a positive association between treatment history and GM volume in the nucleus accumbens, a key region for reward-processing.

Hyperactivity in Attention-Deficit/Hyperactivity Disorder (ADHD): Impairing Deficit or Compensatory Behavior?

Excess gross motor activity (hyperactivity) is considered a core diagnostic feature of childhood ADHD that impedes learning. This view has been challenged, however, by recent models that conceptualize excess motor activity as a compensatory mechanism that facilitates neurocognitive functioning in children with ADHD. The current study investigated competing model predictions regarding activity level's relation with working memory (WM) performance and attention in boys aged 8-12years (M = 9.64, SD = 1.26) with ADHD (n = 29) and typically developing children (TD; n = 23). Children's phonological WM and attentive behavior were objectively assessed during four counterbalanced WM tasks administered across four separate sessions. These data were then sequenced hierarchically based on behavioral observations of each child's gross motor activity during each task. Analysis of the relations among intra-individual changes in observed activity level, attention, and performance revealed that higher rates of activity level predicted significantly better, but not normalized WM performance for children with ADHD. Conversely, higher rates of activity level predicted somewhat lower WM performance for TD children. Variations in movement did not predict changes in attention for either group. At the individual level, children with ADHD and TD children were more likely to be classified as reliably Improved and Deteriorated, respectively, when comparing their WM performance at their highest versus lowest observed activity level. These findings appear most consistent with models ascribing a functional role to hyperactivity in ADHD, with implications for selecting behavioral treatment targets to avoid overcorrecting gross motor activity during academic tasks that rely on phonological WM.

Reduced satellite cell number in situ in muscular contractures from children with cerebral palsy.

Satellite cells (SC) are quiescent adult muscle stem cells critical for postnatal development. Children with cerebral palsy have impaired muscular growth and develop contractures. While flow cytometry previously demonstrated a reduced SC population, extracellular matrix abnormalities may influence the cell isolation methods used, systematically isolating fewer cells from CP muscle and creating a biased result. Consequently, the purpose of this study was to use immunohistochemistry on serial muscle sections to quantify SC in situ. Serial cross-sections from human gracilis muscle biopsies (n = 11) were labeled with fluorescent antibodies for Pax7 (SC transcriptional marker), laminin (basal lamina), and 4',6-diamidino-2-phenylindole (nuclei). Fluorescence microscopy under high magnification was used to identify SC based on labeling and location. Mean SC/100 myofibers was reduced by ∼70% (p < 0.001) in children with CP (2.89 ± 0.39) compared to TD children (8.77 ± 0.79). Furthermore, SC distribution across fields was different (p < 0.05) with increased percentage of SC in fields being solitary cells (p < 0.01) in children with CP. Quantification of SC number in situ, without any other tissue manipulation confirms children with spastic CP have a reduced number. This stem cell loss may, in part, explain impaired muscle growth and apparent decreased responsiveness of CP muscle to exercise.

The Understanding of Intentions, Desires and Beliefs in Young Children with Autism Spectrum Disorder.

This study provides a comprehensive picture of three core elements (Intentions, Desires, Beliefs) of Theory of Mind (ToM) in young children with autism spectrum disorder (ASD, n = 63, Mage = 55 months) and typically developing children (TD, n = 69, Mage = 54 months). Outcomes showed that ASD and TD children understood intentional actions equally well. Yet, children with ASD lacked the social interest to share intentions. Additionally, children with ASD had more difficulties in understanding others’ desires and beliefs compared to their TD peers. It is discussed whether the ToM delay seen in children with ASD is a motivational or a conceptual problem.

Short-term motor learning of dynamic balance control in children with probable Developmental Coordination Disorder

PurposeTo explore the differences in learning a dynamic balance task between children with and without probable Developmental Coordination Disorder (p-DCD) from different cultural backgrounds. ParticipantsTwenty-eight Dutch children with DCD (p-DCD-NL), a similar group of 17 South African children (p-DCD-SA) and 21 Dutch typically developing children (TD-NL) participated in the study. MethodsAll children performed the Wii Fit protocol. The slope of the learning curve was used to estimate motor learning for each group. The protocol was repeated after six weeks. Level of motor skill was assessed with the Movement ABC-2. ResultsNo significant difference in motor learning rate was found between p-DCD-NL and p-DCD-SA, but the learning rate of children with p-DCD was slower than the learning rate of TD children. Speed–accuracy trade off, as a way to improve performance by slowing down in the beginning was only seen in the TD children, indicating that TD children and p-DCD children used different strategies. Retention of the level of learned control of the game after six weeks was found in all three groups after six weeks. The learning slope was associated with the level of balance skill for all children. This study provides evidence that children with p-DCD have limitations in motor learning on a complex balance task. In addition, the data do not support the contention that learning in DCD differs depending on cultural background.

Investigating distinct and related contributions of Weak Central Coherence, Executive Dysfunction, and Systemizing theories to the cognitive profiles of children with Autism Spectrum Disorders and typically developing children

Many attempts have been made to explain the cognitive profiles of children and adults with Autism Spectrum Disorders (ASD). The current study investigated three prominent theories of cognitive processing – Weak Central Coherence, Executive Dysfunction, and Systemizing – to determine how they could define the cognitive patterns of performance in children with ASD. Utilizing tasks that tapped into visuospatial and linguistic domains, and both parent-report and child performance, the present research found support for the Weak Central Coherence and Executive Dysfunction theories in accounting for distinct cognitive profiles in children with ASD. No differences were observed between children with ASD and TD children on Systemizing abilities or preferences. The results also indicate that cognitive profiles in ASD may manifest in different ways in children historically considered High-Functioning Autism and Asperger's Syndrome. Additionally, the present research demonstrated the importance of using comprehensive measures to assess cognition and behavior in children with ASD. These results provide support for the consideration of individual differences in cognitive profiles of children with HFA and children with AS when developing educational and therapeutic programming.

Neural and cortisol responses during play with human and computer partners in children with autism.

Children with autism spectrum disorder (ASD) exhibit impairment in reciprocal social interactions, including play, which can manifest as failure to show social preference or discrimination between social and nonsocial stimuli. To explore mechanisms underlying these deficits, we collected salivary cortisol from 42 children 8-12 years with ASD or typical development during a playground interaction with a confederate child. Participants underwent functional MRI during a prisoner's dilemma game requiring cooperation or defection with a human (confederate) or computer partner. Search region of interest analyses were based on previous research (e.g. insula, amygdala, temporal parietal junction-TPJ). There were significant group differences in neural activation based on partner and response pattern. When playing with a human partner, children with ASD showed limited engagement of a social salience brain circuit during defection. Reduced insula activation during defection in the ASD children relative to TD children, regardless of partner type, was also a prominent finding. Insula and TPJ BOLD during defection was also associated with stress responsivity and behavior in the ASD group under playground conditions. Children with ASD engage social salience networks less than TD children during conditions of social salience, supporting a fundamental disturbance of social engagement.

Information processing speed as a predictor of IQ in children with and without specific language impairment in grades 3 and 8

PurposeThis study investigated (1) whether nonlinguistic processing speed predicts nonverbal IQ in TD children and children with SLI and (2) if the proposed relationship is different at two time points. MethodThe participants consisted of a subset of a longitudinal dataset, 55 typically developing children and 55 children with SLI. Children completed four nonverbal speed tasks and four subtests of the WISC-III. The WISC-III subtests requiring timed and untimed responses were examined separately. ResultsLinear mixed model analyses indicated that in both groups, processing speed predicted nonverbal IQ subtests that reward speedy responses, but not IQ subtests that do not. The relationships between processing speed and IQ with speed bonuses did not differ at grades 3 and 8, and these relationships also were not significantly different in children with SLI and their TD peers. ConclusionsThe results suggest that the presence of processing speed limitations in many children with SLI raises questions about the utility of timed nonverbal IQ measures as tools for diagnosis of SLI. Future studies should investigate other cognitive assessments that could be used as inclusionary criteria for SLI.Learning outcomes: The reader will be able to (1) describe the relationship between processing speed and nonverbal IQ in children with TD and SLI and (2) discuss problems using an IQ criterion to diagnose children as having SLI.

Emotional prosody perception and its association with pragmatic language in school-aged children with high-function autism.

Emotional prosody perception is essential for social communication, but it is still an open issue whether children with high-function autism (HFA) exhibit any prosodic perception deficits or experience selective impairments in recognizing the prosody of positive emotions. Moreover, the associations between prosody perception, pragmatic language, and social adaptation in children with HFA have not been fully explored. This study investigated whether emotional prosody perception for words and sentences in children with HFA (n=25, 6-11 years of age) differed from age-matched, typically developing children (TD, n=25) when presented with an emotional prosody identification task. The Children's Communication Checklist and Vineland Adaptive Behavior Scale were used to assess pragmatic and social adaption abilities. Results show that children with HFA performed poorer than TD children in identifying happy prosody in both emotionally neutral and relevant utterances. In contrast, children with HFA did not exhibit any deficits in identifying sad and angry prosody. Results of correlation analyses revealed a positive association between happy prosody identification and pragmatic function. The findings indicate that school-aged children with HFA experience difficulties in recognizing happy prosody, and that this limitation in prosody perception is associated with their pragmatic and social adaption performances.

Anthropometric measures of Spanish children with autism spectrum disorder

We aimed to compare body mass index (BMI) and healthy eating index (HEI) in children with autism spectrum disorder (ASD, n=105) and typically developing (TD, n=495) children. They were aged 6–9 years, lived in Valencia (Spain) and came from similar cultural and socio-economic backgrounds. In this case–control study, the weight, height and BMI were measured for both groups. Three-day food records were used to assess dietary intake. Although the differences between children with ASD and TD children in raw BMI (p=0.44), BMI z-score (p=0.37), HEI (p=0.43) and total energy intake (p=0.86) were not significant, children with ASD and the boys subgroup were shorter (p=0.01), but not the girls subgroup, compared to TD children of the same gender. Using the controls values as a reference, the BMI distribution in children with ASD became distorted, with values below the 5th percentile (11% vs. 4%, p=0.03) and above the 95th percentile (8% vs. 5%, p=0.04). The gender- and age-adjusted odds ratios for being underweight in the groups of all children and boys with ASD were 3.03 and 2.39, respectively, vs. TD children. Our data suggest that routine monitoring of children with ASD should include anthropometric measurements and assessment of their dietary habits.