1. Addo RN, Wiens S, Nord M, Larsson M. {{Olfactory Functions in Adults With Autism Spectrum Disorders}}. {Perception}. 2017: 301006616686100.
Autism spectrum disorders (ASD) are often characterized by atypical sensory behavior (hyper- or hyporeactivity) although evidence is scarce regarding olfactory abilities in ASD; 16 adults with high-functioning ASD (mean age: 38.2, SD: 9.7) and 14 healthy control subjects (mean age: 42.0 years, SD: 12.5) were assessed in odor threshold, free and cued odor identification, and perceived pleasantness, intensity, and edibility of everyday odors. Although results showed no differences between groups, the Bayes Factors (close to 1) suggested that the evidence for no group differences on the threshold and identification tests was inconclusive. In contrast, there was some evidence for no group differences on perceived edibility (BF01 = 2.69) and perceived intensity (BF01 = 2.80). These results do not provide conclusive evidence for or against differences between ASD and healthy controls on olfactory abilities. However, they suggest that there are no apparent group differences in subjective ratings of odors.
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2. Andrews DS, Avino TA, Gudbrandsen M, Daly E, Marquand A, Murphy CM, Lai MC, Lombardo MV, Ruigrok AN, Williams SC, Bullmore ET, The Mrc Aims C, Suckling J, Baron-Cohen S, Craig MC, Murphy DG, Ecker C. {{In Vivo Evidence of Reduced Integrity of the Gray-White Matter Boundary in Autism Spectrum Disorder}}. {Cereb Cortex}. 2017.
Atypical cortical organization and reduced integrity of the gray-white matter boundary have been reported by postmortem studies in individuals with autism spectrum disorder (ASD). However, there are no in vivo studies that examine these particular features of cortical organization in ASD. Hence, we used structural magnetic resonance imaging to examine differences in tissue contrast between gray and white matter in 98 adults with ASD and 98 typically developing controls, to test the hypothesis that individuals with ASD have significantly reduced tissue contrast. More specifically, we examined contrast as a percentage between gray and white matter tissue signal intensities (GWPC) sampled at the gray-white matter boundary, and across different cortical layers. We found that individuals with ASD had significantly reduced GWPC in several clusters throughout the cortex (cluster, P < 0.05). As expected, these reductions were greatest when tissue intensities were sampled close to gray-white matter interface, which indicates a less distinct gray-white matter boundary in ASD. Our in vivo findings of reduced GWPC in ASD are therefore consistent with prior postmortem findings of a less well-defined gray-white matter boundary in ASD. Taken together, these results indicate that GWPC might be utilized as an in vivo proxy measure of atypical cortical microstructural organization in future studies. Lien vers le texte intégral (Open Access ou abonnement)
3. Ciaccio C, Di Pierro D, Sbardella D, Tundo GR, Curatolo P, Galasso C, Santarone ME, Casasco M, Cozza P, Cortelazzo A, Rossi M, De Felice C, Hayek J, Coletta M, Marini S. {{Oxygen exchange and energy metabolism in erythrocytes of Rett syndrome and their relationships with respiratory alterations}}. {Mol Cell Biochem}. 2017.
Rett syndrome (RTT) is a neurodevelopmental disorder, mainly affecting females, which is associated to a mutation on the methyl-CpG-binding protein 2 gene. In the pathogenesis and progression of classic RTT, red blood cell (RBC) morphology has been shown to be an important biosensor for redox imbalance and chronic hypoxemia. Here we have evaluated the impact of oxidation and redox imbalance on several functional properties of RTT erythrocytes. In particular, we report for the first time a stopped-flow measurement of the kinetics of oxygen release by RBCs and the analysis of the intrinsic affinity of the hemoglobin (Hb). According to our experimental approach, RBCs from RTT patients do not show any intrinsic difference with respect to those from healthy controls neither in Hb’s oxygen-binding affinity nor in O2 exchange processes at 37 degrees C. Therefore, these factors do not contribute to the observed alteration of the respiratory function in RTT patients. Moreover, the energy metabolism of RBCs, from both RTT patients and controls, was evaluated by ion-pairing HPLC method and related to the level of malondialdehyde and to the oxidative radical scavenging capacity of red cells. Results have clearly confirmed significant alterations in antioxidant defense capability, adding important informations concerning the high-energy compound levels in RBCs of RTT subjects, underlying possible correlations with inflammatory tissue alterations.
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4. Cooper RA, Richter FR, Bays PM, Plaisted-Grant KC, Baron-Cohen S, Simons JS. {{Reduced Hippocampal Functional Connectivity During Episodic Memory Retrieval in Autism}}. {Cereb Cortex}. 2017.
Increasing recent research has sought to understand the recollection impairments experienced by individuals with autism spectrum disorder (ASD). Here, we tested whether these memory deficits reflect a reduction in the probability of retrieval success or in the precision of memory representations. We also used functional magnetic resonance imaging (fMRI) to study the neural mechanisms underlying memory encoding and retrieval in ASD, focusing particularly on the functional connectivity of core episodic memory networks. Adults with ASD and typical control participants completed a memory task that involved studying visual displays and subsequently using a continuous dial to recreate their appearance. The ASD group exhibited reduced retrieval success, but there was no evidence of a difference in retrieval precision. fMRI data revealed similar patterns of brain activity and functional connectivity during memory encoding in the 2 groups, though encoding-related lateral frontal activity predicted subsequent retrieval success only in the control group. During memory retrieval, the ASD group exhibited attenuated lateral frontal activity and substantially reduced hippocampal connectivity, particularly between hippocampus and regions of the fronto-parietal control network. These findings demonstrate notable differences in brain function during episodic memory retrieval in ASD and highlight the importance of functional connectivity to understanding recollection-related retrieval deficits in this population.
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5. Guo X, Chen H, Long Z, Duan X, Zhang Y. {{Atypical developmental trajectory of local spontaneous brain activity in autism spectrum disorder}}. {Sci Rep}. 2017; 7: 39822.
Autism spectrum disorder (ASD) is marked by atypical trajectory of brain maturation, yet the developmental abnormalities in brain function remain unclear. The current study examined the effect of age on amplitude of low-frequency fluctuations (ALFF) in ASD and typical controls (TC) using a cross-sectional design. We classified all the participants into three age cohorts: child (<11 years, 18ASD/20TC), adolescent (11-18 years, 28ASD/26TC) and adult (>/=18 years, 18ASD/18TC). Two-way analysis of variance (ANOVA) was performed to ascertain main effects and interaction effects on whole brain ALFF maps. Results exhibited significant main effect of diagnosis in ASD with decreased ALFF in the right precuneus and left middle occipital gyrus during all developmental stages. Significant diagnosis-by-age interaction was observed in the medial prefrontal cortex (mPFC) with ALFF lowered in autistic children but highered in autistic adolescents and adults. Specifically, remarkable quadratic change of ALFF with increasing age in mPFC presented in TC group was absent in ASD. Additionally, abnormal ALFF values in diagnosis-related brain regions predicted the social deficits in ASD. Our findings indicated aberrant developmental patterns of spontaneous brain activity associated with social deficits in ASD and highlight the crucial role of the default mode network in the development of disease.
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6. Liberati A, Fadda R, Doneddu G, Congiu S, Javarone MA, Striano T, Chessa A. {{A Statistical Physics Perspective to Understand Social Visual Attention in Autism Spectrum Disorder}}. {Perception}. 2017: 301006616685976.
This study investigated social visual attention in children with Autism Spectrum Disorder (ASD) and with typical development (TD) in the light of Brockmann and Geisel’s model of visual attention. The probability distribution of gaze movements and clustering of gaze points, registered with eye-tracking technology, was studied during a free visual exploration of a gaze stimulus. A data-driven analysis of the distribution of eye movements was chosen to overcome any possible methodological problems related to the subjective expectations of the experimenters about the informative contents of the image in addition to a computational model to simulate group differences. Analysis of the eye-tracking data indicated that the scanpaths of children with TD and ASD were characterized by eye movements geometrically equivalent to Levy flights. Children with ASD showed a higher frequency of long saccadic amplitudes compared with controls. A clustering analysis revealed a greater dispersion of eye movements for these children. Modeling of the results indicated higher values of the model parameter modulating the dispersion of eye movements for children with ASD. Together, the experimental results and the model point to a greater dispersion of gaze points in ASD.
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7. Patten E, Labban JD, Casenhiser DM, Cotton CL. {{Synchrony Detection of Linguistic Stimuli in the Presence of Faces: Neuropsychological Implications for Language Development in ASD}}. {Dev Neuropsychol}. 2017: 1-13.
Children with autism spectrum disorders (ASD) may be impaired in their ability to detect audiovisual synchrony and their ability may be influenced by the nature of the stimuli. We investigated the possibility that synchrony detection is disrupted by the presence of human faces by testing children with ASD using a preferential looking language-based paradigm. Children with low language abilities were significantly worse at detecting synchrony when the stimuli include an unobscured face than when the face was obscured. Findings suggest that the presence of faces may make multisensory processing more difficult. Implications for interventions are discussed, particularly those targeting attention to faces.
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8. Schmitz Olin S, McFadden BA, Golem DL, Pellegrino JK, Walker AJ, Sanders DJ, Arent SM. {{The Effects of Exercise Dose on Stereotypical Behavior in Children with Autism}}. {Med Sci Sports Exerc}. 2017.
INTRODUCTION: Autism Spectrum Disorder (ASD) is a prevalent neurological disorder in children characterized by restrictive, repetitive patterns of behavior that place an added burden on everyday functions. Aerobic exercise has the propensity to reduce stereotypic behaviors in children with ASD. This study sought to quantify the acute effect of exercise and assess the influence of duration and intensity on frequency of stereotypic behaviors in children with ASD. METHODS: Participants in this study (N=7, Mage=13.0 +/- 1.4 yrs, Mheight=1.64 +/- 0.01m, Mweight=60.1 +/- 13.7kg) underwent five separate days of treatments including a control (C), low intensity 10 min (10L), high intensity 10 min (10H), low intensity 20 min (20L), and high intensity 20 min (20H) conditions in which intensity was quantified using HR as well as RPE. Prior to and for 60 min following exercise, frequency of stereotypic behaviors was recorded. RESULTS: Results indicated a reduction in behaviors in response to exercise compared to the C trial throughout all conditions except 20H. Interestingly, the most exhaustive exercise session led to increased stereotypic behaviors at all post time periods compared to the other exercise trials (p<.10). The 10L condition showed the greatest reduction at 60 min post compared to the 20H or the control trials' response (p<.05). Examining the behavioral responses to exercise using effect sizes indicated the 10L condition showed the greatest reduction in frequency throughout all 4 time points (ESrange= -.87 to -1.03) compared to baseline. CONCLUSION: While it appears high-intensity aerobic exercise may exacerbate stereotypic behaviors in children with ASD, low-to-moderate intensity exercise produces significant and large reductions in these behaviors. This provides an easily administered and cost-effective way to positively impact these individuals. Lien vers le texte intégral (Open Access ou abonnement)
9. Stewart CS, McEwen FS, Konstantellou A, Eisler I, Simic M. {{Impact of ASD Traits on Treatment Outcomes of Eating Disorders in Girls}}. {Eur Eat Disord Rev}. 2017.
Evidence links high levels of Autism Spectrum Disorder Traits in women with chronicity of anorexia nervosa. This study reports through clinical audit the impact of ASD traits on treatment outcomes of girls who were referred for treatment in a specialist eating disorder service. Presence of current, but not early childhood, ASD traits was elevated in comparison with previously reported community samples. Current ASD traits were correlated with emotional disorders and with need for treatment augmentation (psychiatric inpatient or day patient admission), but this relationship was not significant after the contribution of depression had been controlled for. There was no difference in Morgan Russell Outcomes at discharge for those with high and low current ASD traits. Parent-reported ASD-related developmental difficulties were associated with attenuated change in self-reported cognitive symptoms of AN. This study highlights the need for further understanding of the aetiology, diagnostic significance and predictive utility for future relapse of elevated ASD traits in childhood eating disorders. Copyright (c) 2017 John Wiley & Sons, Ltd and Eating Disorders Association.
