Pubmed du 06/07/15

Pubmed du jour

2015-07-06 12:03:50

1. Akechi H, Stein T, Kikuchi Y, Tojo Y, Osanai H, Hasegawa T. {{Preferential awareness of protofacial stimuli in autism}}. {Cognition};2015 (Jul 2);143:129-134.

It has been suggested that a subcortically mediated, innate sensitivity to protofacial stimuli leads to specialized face processing and to the development of the social brain. A dysfunction of this face-processing pathway has been associated with atypical social development in individuals with autism spectrum disorder (ASD). This study investigated whether individuals with ASD exhibit primary sensitivity to monochrome protoface stimuli using continuous flash suppression (CFS). Under CFS, visual stimuli are suppressed from awareness, and cortical processing is strongly reduced while subcortical regions continue to respond to invisible stimuli. We found that both adolescents with ASD and typically developing adolescents showed preferential detection of upright protoface stimuli under CFS but not in a non-CFS control condition. These results challenge the notion that a primitive sensitivity to protoface stimuli is essential for typical social development. Rather, our findings suggest such sensitivity is not a sufficient condition for typical social development and that the presence of other complementary factors is necessary for the development of the social brain.

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2. Bellando J, Fussell JJ, Lopez M. {{Autism Speaks Toolkits: Resources for Busy Physicians}}. {Clin Pediatr (Phila)};2015 (Jul 6)
Given the increased prevalence of autism spectrum disorders (ASD), it is likely that busy primary care providers (PCP) are providing care to individuals with ASD in their practice. Autism Speaks provides a wealth of educational, medical, and treatment/intervention information resources for PCPs and families, including at least 32 toolkits. This article serves to familiarize PCPs and families on the different toolkits that are available on the Autism Speaks website. This article is intended to increase physicians’ knowledge on the issues that families with children with ASD frequently encounter, to increase their ability to share evidence-based information to guide treatment and care for affected families in their practice.

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3. Demopoulos C, Brandes-Aitken AN, Desai SS, Hill SS, Antovich AD, Harris J, Marco EJ. {{Shared and Divergent Auditory and Tactile Processing in Children with Autism and Children with Sensory Processing Dysfunction Relative to Typically Developing Peers}}. {J Int Neuropsychol Soc};2015 (Jul 6):1-11.

The aim of this study was to compare sensory processing in typically developing children (TDC), children with Autism Spectrum Disorder (ASD), and those with sensory processing dysfunction (SPD) in the absence of an ASD. Performance-based measures of auditory and tactile processing were compared between male children ages 8-12 years assigned to an ASD (N=20), SPD (N=15), or TDC group (N=19). Both the SPD and ASD groups were impaired relative to the TDC group on a performance-based measure of tactile processing (right-handed graphesthesia). In contrast, only the ASD group showed significant impairment on an auditory processing index assessing dichotic listening, temporal patterning, and auditory discrimination. Furthermore, this impaired auditory processing was associated with parent-rated communication skills for both the ASD group and the combined study sample. No significant group differences were detected on measures of left-handed graphesthesia, tactile sensitivity, or form discrimination; however, more participants in the SPD group demonstrated a higher tactile detection threshold (60%) compared to the TDC (26.7%) and ASD groups (35%). This study provides support for use of performance-based measures in the assessment of children with ASD and SPD and highlights the need to better understand how sensory processing affects the higher order cognitive abilities associated with ASD, such as verbal and non-verbal communication, regardless of diagnostic classification. (JINS, 2015, 21, 1-11).

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4. Hurwitz S, Watson LR. {{Joint attention revisited: Finding strengths among children with autism}}. {Autism};2015 (Jul 6)
Differences in joint attention are prominent for some children with autism and are often used as an indicator of the disorder. This study examined the joint attention competencies of young children with autism who demonstrated joint attention ability and compared them to children with developmental delays. A total of 40 children with autism and developmental delays were matched pairwise based on mental and chronological age. Videos of children engaging in play were coded for the frequency and forms (eye contact, gestures, affect, etc.) of joint attention. Additionally, concurrent language was compared among children with autism (N = 32) by their joint attention ability. Children with autism spectrum disorder entered into joint attention significantly less often than children with developmental delays, but once engaged used the forms of joint attention similarly. For the matched pairs, there were no differences in language, but the children with autism who used joint attention had significantly better language than children with autism who did not (even after controlling for mental age). There is a group of young children with autism who can use joint attention but do so at lower frequencies than children with developmental delays. Possible reasons include difficulty disengaging attention and limited intrinsic social motivation to share. Adult persistence is recommended to encourage joint attention.

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5. Kuijper SJ, Hartman CA, Hendriks P. {{Who Is He? Children with ASD and ADHD Take the Listener into Account in Their Production of Ambiguous Pronouns}}. {PLoS One};2015;10(7):e0132408.

During conversation, speakers constantly make choices about how specific they wish to be in their use of referring expressions. In the present study we investigate whether speakers take the listener into account or whether they base their referential choices solely on their own representation of the discourse. We do this by examining the cognitive mechanisms that underlie the choice of referring expression at different discourse moments. Furthermore, we provide insights into how children with Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) use referring expressions and whether their use differs from that of typically developing (TD) children. Children between 6 and 12 years old (ASD: n=46; ADHD: n=37; TD: n=38) were tested on their production of referring expressions and on Theory of Mind, response inhibition and working memory. We found support for the view that speakers take the listener into account when choosing a referring expression: Theory of Mind was related to referential choice only at those moments when speakers could not solely base their choice on their own discourse representation to be understood. Working memory appeared to be involved in keeping track of the different referents in the discourse. Furthermore, we found that TD children as well as children with ASD and children with ADHD took the listener into account in their choice of referring expression. In addition, children with ADHD were less specific than TD children in contexts with more than one referent. The previously observed problems with referential choice in children with ASD may lie in difficulties in keeping track of longer and more complex discourses, rather than in problems with taking into account the listener.

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6. Peiker I, Schneider TR, Milne E, Schottle D, Vogeley K, Munchau A, Schunke O, Siegel M, Engel AK, David N. {{Stronger Neural Modulation by Visual Motion Intensity in Autism Spectrum Disorders}}. {PLoS One};2015;10(7):e0132531.

Theories of autism spectrum disorders (ASD) have focused on altered perceptual integration of sensory features as a possible core deficit. Yet, there is little understanding of the neuronal processing of elementary sensory features in ASD. For typically developed individuals, we previously established a direct link between frequency-specific neural activity and the intensity of a specific sensory feature: Gamma-band activity in the visual cortex increased approximately linearly with the strength of visual motion. Using magnetoencephalography (MEG), we investigated whether in individuals with ASD neural activity reflect the coherence, and thus intensity, of visual motion in a similar fashion. Thirteen adult participants with ASD and 14 control participants performed a motion direction discrimination task with increasing levels of motion coherence. A polynomial regression analysis revealed that gamma-band power increased significantly stronger with motion coherence in ASD compared to controls, suggesting excessive visual activation with increasing stimulus intensity originating from motion-responsive visual areas V3, V6 and hMT/V5. Enhanced neural responses with increasing stimulus intensity suggest an enhanced response gain in ASD. Response gain is controlled by excitatory-inhibitory interactions, which also drive high-frequency oscillations in the gamma-band. Thus, our data suggest that a disturbed excitatory-inhibitory balance underlies enhanced neural responses to coherent motion in ASD.

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