The psychometric properties of the Greek version of the Social Communication Questionnaire

There is a scarcity of diagnostic assessments and screening tools for autism spectrum disorders (ASD) in Greek. In this study, we examined the psychometric properties of the recently developed Greek version of the Social Communication Questionnaire (SCQ). We used parental responses for 311 children (mean age: 7.54 years old, SD = 1.92), 122 with a diagnosis of ASD (93 boys, 29 girls) and 189 neurotypical children (104 boys, 85 girls), with 167 responses referring to the Lifetime and 144 to the Current form of the SCQ. Both forms presented adequate construct validity based on the four‐factor model, while in both forms, autistic children presented higher SCQ total and subscale scores (four factors) than typical children. The forms had excellent internal reliability. An item‐response‐theory analysis suggested that over 80% of test items fitted adequately a Rasch model, while a preliminary analysis of gender biases suggested that a small number of items (Lifetime: five; Current: six out of 39) were differentially sensitive to autistic symptomatology in boys and girls. A receiver‐operating‐characteristic analysis showed excellent diagnostic performance based on the SCQ total score (Lifetime: area‐under‐the‐curve/AUC = 0.937, Current: AUC = 0.963), and acceptable to excellent discrimination for the four subscales (AUCs between 0.737 and 0.955). Our preliminary results suggest that the Greek SCQ presents satisfactory psychometric properties and can be used for differentiating children with ASD from typical children in initial assessments within clinical and research settings. LAY SUMMARY: Autism spectrum disorder (ASD or autism) is a lifelong neurodevelopmental condition with a prevalence of ~1.5%–2% and characterized by difficulties in social interaction and communication and repetitive and restricted behaviors. There is increasing concern that research in ASD has focused on a small number of languages and cultural settings and that this bias challenges the identification and diagnosis of the condition in other languages and cultures, which are underrepresented in autism research. One such language is Greek (spoken by ~13.5 million), for which there is a scarcity of standardized instruments for the diagnosis of autism. This study examines the psychometric properties of the recently published Greek version of the Social Communication Questionnaire (SCQ), a widely used screening tool for ASD. We conduct an in‐depth psychometric analysis of the Greek SCQ, including both forms in which the instrument is available (Lifetime and Current). This analysis shows that the Greek SCQ can be used for differentiating children with ASD from typical children in initial assessments within clinical and research settings. The findings of this study have implications for clinicians, special educators and researchers working with Greek‐speaking individuals with ASD and, more broadly, for cross‐cultural autism research

Reprint of “Investigating ensemble perception of emotions in autistic and typical children and adolescents”

Ensemble perception, the ability to assess automatically the summary of large amounts of information presented in visual scenes, is available early in typical development. This ability might be compromised in autistic children, who are thought to present limitations in maintaining summary statistics representations for the recent history of sensory input. Here we examined ensemble perception of facial emotional expressions in 35 autistic children, 30 age- and ability-matched typical children and 25 typical adults. Participants received three tasks: a) an ‘ensemble’ emotion discrimination task; b) a baseline (single-face) emotion discrimination task; and c) a facial expression identification task. Children performed worse than adults on all three tasks. Unexpectedly, autistic and typical children were, on average, indistinguishable in their precision and accuracy on all three tasks. Computational modelling suggested that, on average, autistic and typical children used ensemble-encoding strategies to a similar extent; but ensemble perception was related to non-verbal reasoning abilities in autistic but not in typical children. Eye-movement data also showed no group differences in the way children attended to the stimuli. Our combined findings suggest that the abilities of autistic and typical children for ensemble perception of emotions are comparable on average. Keywords: Ensemble perception, Autism, Summary statistics, Facial expressions, Emotion

The light-from-above prior is intact in autistic children

Sensory information is inherently ambiguous. The brain disambiguates this information by anticipating or predicting the sensory environment based on prior knowledge. Pellicano and Burr (2012) proposed that this process may be atypical in autism and that internal assumptions, or “priors,” may be underweighted or less used than in typical individuals. A robust internal assumption used by adults is the “light-from-above” prior, a bias to interpret ambiguous shading patterns as if formed by a light source located above (and slightly to the left) of the scene. We investigated whether autistic children (n = 18) use this prior to the same degree as typical children of similar age and intellectual ability (n = 18). Children were asked to judge the shape (concave or convex) of a shaded hexagon stimulus presented in 24 rotations. We estimated the relation between the proportion of convex judgments and stimulus orientation for each child and calculated the light source location most consistent with those judgments. Children behaved similarly to adults in this task, preferring to assume that the light source was from above left, when other interpretations were compatible with the shading evidence. Autistic and typical children used prior assumptions to the same extent to make sense of shading patterns. Future research should examine whether this prior is as adaptable (i.e., modifiable with training) in autistic children as it is in typical adults

Recognizing the same face in different contexts : Testing within-person face recognition in typical development and in autism

Unfamiliar face recognition follows a particularly protracted developmental trajectory and is more likely to be atypical in children with autism than those without autism. There is a paucity of research, however, examining the ability to recognize the same face across multiple naturally varying images. Here, we investigated within-person face recognition in children with and without autism. In Experiment 1, typically developing 6- and 7-year-olds, 8- and 9-year-olds, 10- and 11-year-olds, 12- to 14-year-olds, and adults were given 40 grayscale photographs of two distinct male identities (20 of each face taken at different ages, from different angles, and in different lighting conditions) and were asked to sort them by identity. Children mistook images of the same person as images of different people, subdividing each individual into many perceived identities. Younger children divided images into more perceived identities than adults and also made more misidentification errors (placing two different identities together in the same group) than older children and adults. In Experiment 2, we used the same procedure with 32 cognitively able children with autism. Autistic children reported a similar number of identities and made similar numbers of misidentification errors to a group of typical children of similar age and ability. Fine-grained analysis using matrices revealed marginal group differences in overall performance. We suggest that the immature performance in typical and autistic children could arise from problems extracting the perceptual commonalities from different images of the same person and building stable representations of facial identity

Atypicalities in Perceptual Adaptation in Autism Do Not Extend to Perceptual Causality

A recent study showed that adaptation to causal events (collisions) in adults caused subsequent events to be less likely perceived as causal. In this study, we examined if a similar negative adaptation effect for perceptual causality occurs in children, both typically developing and with autism. Previous studies have reported diminished adaptation for face identity, facial configuration and gaze direction in children with autism. To test whether diminished adaptive coding extends beyond high-level social stimuli (such as faces) and could be a general property of autistic perception, we developed a child-friendly paradigm for adaptation of perceptual causality. We compared the performance of 22 children with autism with 22 typically developing children, individually matched on age and ability (IQ scores). We found significant and equally robust adaptation aftereffects for perceptual causality in both groups. There were also no differences between the two groups in their attention, as revealed by reaction times and accuracy in a change-detection task. These findings suggest that adaptation to perceptual causality in autism is largely similar to typical development and, further, that diminished adaptive coding might not be a general characteristic of autism at low levels of the perceptual hierarchy, constraining existing theories of adaptation in autism.16 page(s

The relationship between SLI in English and Modern Greek

We present a computational modelling approach to the study of SLI in two lan- guages with different typological characteristics, namely English and Modern Greek. Our modelling approach was based on the development of three neural network (connectionist) architectures, each assumed to underlie the acquisition of a core domain of language (inflectional morphology, syntax comprehension, and syntax production). The architectures were exposed to artificial linguistic environments reflecting the characteristics of their target domains in English and Greek. Computational simulations also considered conditions of atypical learning constraints, corresponding to different theoretical proposals for the type of deficit underlying SLI. The simulation results, combined with some shared properties of the three models, point to a unified explanation of the impairment under the connectionist framework

5 GHz 200 Mbit/s radio over polymer fibre link with envelope detection at 650 nm wavelength

Central tendency, the tendency of judgements of quantities (lengths, durations etc.) to gravitate towards their mean, is one of the most robust perceptual effects. A Bayesian account has recently suggested that central tendency reflects the integration of noisy sensory estimates with prior knowledge representations of a mean stimulus, serving to improve performance. The process is flexible, so prior knowledge is weighted more heavily when sensory estimates are imprecise, requiring more integration to reduce noise. In this study we measure central tendency in autism to evaluate a recent theoretical hypothesis suggesting that autistic perception relies less on prior knowledge representations than typical perception. If true, autistic children should show reduced central tendency than theoretically predicted from their temporal resolution. We tested autistic and age-and ability-matched typical children in two child-friendly tasks: (1) a time interval reproduction task, measuring central tendency in the temporal domain;and (2) a time discrimination task, assessing temporal resolution. Central tendency reduced with age in typical development, while temporal resolution improved. Autistic children performed far worse in temporal discrimination than the matched controls. Computational simulations suggested that central tendency was much less in autistic children than predicted by theoretical modelling, given their poor temporal resolution

Descriptive statistics for developmental variables for children with autism and typically developing children.

<p>^aVerbal, Performance and Full-Scale IQ were measured using the Wechsler Abbreviated Scales of Intelligence (WASI-II; [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120439#pone.0120439.ref027" target="_blank">27</a>])</p><p>^bSCQ: Social Communication Questionnaire (score out of 40; [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120439#pone.0120439.ref028" target="_blank">28</a>])</p><p>^cADOS-G: Autism Diagnosis Observation Schedule-Generic (score out of 28; [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120439#pone.0120439.ref029" target="_blank">29</a>])</p><p>Descriptive statistics for developmental variables for children with autism and typically developing children.</p