Search

Synaesthesia is a sensory phenomenon where external stimuli, such as sounds or letters, trigger additional sensations (e.g. colours). Synaesthesia aggregates in families but its heritability is unknown. The phenomenon is more common in people on the autism spectrum compared with the general population and associated with higher autistic traits. Using classical twin design, we assessed the heritability of individual differences in self-reported synaesthesia and the genetic and environmental contributions to their association with autistic traits within a population twin cohort (n = 4262, age = 18 years). We estimated individual differences in synaesthesia to be heritable and influenced by environmental factors not shared between twins. The association between individual differences in synaesthesia and autistic traits was estimated to be predominantly under genetic influence and seemed to be mainly driven by non-social autistic traits (repetitive behaviours, restricted interests and attention to detail). Our study suggests that the link between synaesthesia and autism might reside in shared genetic causes, related to non-social autistic traits such as alterations in perception. Future studies building on these findings may attempt to identify specific groups of genes that influence both autism, synaesthesia and perception. [ABSTRACT FROM AUTHOR]

Systematic reviews have traditionally focused on internal validity, while external validity often has been overlooked. In this study, we systematically reviewed determinants of external validity in the accumulated randomized controlled trials of social skills group interventions for children and adolescents with autism spectrum disorder. We extracted data clustered into six overarching themes: source population, included population, context, treatment provider, treatment intervention, and outcome. A total of 15 eligible randomized controlled trials were identified. The eligible population was typically limited to high-functioning school-aged children with autism spectrum disorder, and the included population was predominantly male and Caucasian. Scant information about the recruitment of participants was provided, and details about treatment providers and settings were sparse. It was not evident from the trials to what extent acquired social skills were enacted in everyday life and maintained over time. We conclude that the generalizability of the accumulated evidence is unclear and that the determinants of external validity are often inadequately reported. At this point, more effectiveness-oriented randomized controlled trials of equally high internal and external validity are needed. More attention to the determinants of external validity is warranted when this new generation of randomized controlled trials are planned and reported. We provide a tentative checklist for this purpose.

The possible effect of the DSM-5 impairment criterion on diagnosing autism spectrum disorder (ASD) in young children was examined in 127 children aged 20-47 months with a DSM-IV-TR clinical consensus diagnosis of ASD. The composite score of the Vineland Adaptive Behavior Scales (VABS) served as a proxy for the DSM-5 impairment criterion. When applying a "mild" level of impairment (cutoff: 1 SD below the mean on the VABS), 88% of the cases fulfilled the impairment criterion. Sixty-nine percent fulfilled the impairment criterion at a "moderate" level (1.5 SDs) and 33% at a "severe" level (2 SDs). Findings indicate that a strict application of the new DSM-5 impairment criterion might compromise early diagnosis of ASD.

Research on visual local and global perception in Autism Spectrum Disorder (ASD) is incomplete in young children. We investigated 35 three-year-old siblings of children with ASD, either diagnosed (n = 12) or not diagnosed (n = 23) with ASD as well as 14 controls with typical development and with no family history of ASD. Data from the local tasks Children's Embedded Figures Test, Hidden Pictures, Figure-Ground and the global tasks Closure and Fragmented Picture Test were collected. Enhanced performance on the local task Hidden Pictures differentiated children with ASD from the other groups. Implications of these results are discussed., Author(s): Elisabeth Nilsson Jobs [sup.1] [sup.2] [sup.3] , Terje Falck-Ytter [sup.1] [sup.2] [sup.3] , Sven Bölte [sup.2] [sup.3] [sup.4] Author Affiliations: (Aff1) 0000 0004 1936 9457, grid.8993.b, Uppsala Child and [...]

Autism spectrum disorder (ASD) and social anxiety disorder (SAD) have partly overlapping symptoms. Gaze avoidance has been linked to both SAD and ASD, but little is known about differences in social attention between the two conditions. We studied eye movements in a group of treatment-seeking adolescents with SAD (N = 25), assessing SAD and ASD dimensionally. The results indicated a double dissociation between two measures of social attention and the two symptom dimensions. Controlling for social anxiety, elevated autistic traits were associated with delayed orienting to eyes presented among distractors. In contrast, elevated social anxiety levels were associated with faster orienting away from the eyes, when controlling for autistic traits. This distinction deepens our understanding of ASD and SAD., Author(s): Johan Lundin Kleberg [sup.1] , Jens Högström [sup.2] [sup.3] , Martina Nord [sup.2] [sup.3] , Sven Bölte [sup.4] [sup.5] , Eva Serlachius [sup.2] [sup.3] , Terje Falck-Ytter [sup.1] [sup.4] [...]

Autism spectrum disorder (ASD) has been associated with gastrointestinal (GI) problems, but the nature of this association is unclear. Parents to siblings, concordant or discordant for ASD (N = 217), participated in a web survey covering mother's weight gain during pregnancy, maternal viral/bacterial infection and use of antibiotics, duration of breastfeeding, mode of delivery, birth weight and child GI problems. ASD was associated with GI problems and perinatal environmental risk, based on a summation of maternal infection and antibiotic use during pregnancy and/or the breastfeeding period. The association between GI problems and ASD remained within the sibling pairs ([beta] = 1.23; p < .001) in the adjusted model. Our results indicate non-shared environmental effects on the ASD/GI association, but none of the factors examined explained the link., Author(s): Johan Isaksson [sup.1] [sup.2] [sup.3] , Erik Pettersson [sup.4] , Elzbieta Kostrzewa [sup.1] , Rochellys Diaz Heijtz [sup.5] , Sven Bölte [sup.1] [sup.6] Author Affiliations: (1) Department of Women's [...]

Current evidence suggests the phenotype of autism spectrum disorder to be driven by a complex interaction of genetic and environmental factors impacting onto brain maturation, synaptic function, and cortical networks. However, findings are heterogeneous, and the exact neurobiological pathways of autism spectrum disorder still remain poorly understood. The co-twin control or twin-difference design is a potentially powerful tool to disentangle causal genetic and environmental contributions on neurodevelopment in autism spectrum disorder. To this end, monozygotic twins discordant for this condition provide unique means for the maximum control of potentially confounding factors. Unfortunately, only few studies of a rather narrow scope, and limited sample size, have been conducted. In an attempt to highlight the great potential of combining the brain connectome approach with monozygotic twin design, we first give an overview of the existing neurobiological evidence for autism spectrum disorder and its cognitive correlates. Then, a special focus is made onto the brain imaging findings reported within populations of monozygotic twins phenotypically discordant for autism spectrum disorder. Finally, we introduce the brain connectome model and describe an ongoing project using this approach among the largest cohort of monozygotic twins discordant for autism spectrum disorder ever recruited.

The current study aimed to investigate the Autism Diagnostic Interview-Revised (ADI-R) algorithms for toddlers and young preschoolers (Kim and Lord, "J Autism Dev Disord" 42(1):82-93, 2012) in a non-US sample from ten sites in nine countries (n = 1,104). The construct validity indicated a good fit of the algorithms. The diagnostic validity was lower, with satisfactorily high specificities but moderate sensitivities. Young children with clinical ASD and lower language ability were largely in the mild-to-moderate or moderate-to-severe concern ranges of the ADI-R, nearly half of the older and phrase speech ASD-group fell into the little-to-no concern range. Although broadly the findings support the toddler algorithms, further work is required to understand why they might have different properties in different samples to further inform research and clinical use.

Whether gaze following--a key component of joint attention--is impaired in children with autism spectrum disorder (ASD) is currently debated. Functional gaze following involves saccading towards the attended rather than unattended targets (accuracy) as well as a subsequent processing bias for attended objects. Using non-invasive eye tracking technology, we show that gaze following accuracy is intact in intellectually low-functioning 3-year-olds with ASD. However, analyses of the duration of first fixations at the objects in the scene revealed markedly weaker initial processing bias for attended objects in children with ASD compared to children with typical development and non-autistic children with developmental delays. Limited processing bias for the objects other people attend to may negatively affect learning opportunities in ASD.

The diagnostic validity of the new research algorithms of the Autism Diagnostic Interview-Revised and the revised algorithms of the Autism Diagnostic Observation Schedule was examined in a clinical sample of children aged 18-47 months. Validity was determined for each instrument separately and their combination against a clinical consensus diagnosis. A total of N = 268 children (n = 171 with autism spectrum disorder) were assessed. The new Autism Diagnostic Interview-Revised algorithms (research cutoff) gave excellent specificities (91%-96%) but low sensitivities (44%-52%). Applying adjusted cutoffs (lower than recommended based on receiver operating characteristics) yielded a better balance between sensitivity (77%-82%) and specificity (60%-62%). Findings for the Autism Diagnostic Observation Schedule were consistent with previous studies showing high sensitivity (94%-100%) and alongside lower specificity (52%-76%) when using the autism spectrum cutoff, but better balanced sensitivity (81%-94%) and specificity (81%-83%) when using the autism cutoff. A combination of both the Autism Diagnostic Interview-Revised (with adjusted cutoff) and the Autism Diagnostic Observation Schedule (autism spectrum cutoff) yielded balanced sensitivity (77%-80%) and specificity (87%-90%). Results favor a combined usage of the Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule in young children with unclear developmental problems, including suspicion of autism spectrum disorder. Evaluated separately, the Autism Diagnostic Observation Schedule (cutoff for autism) provides a better diagnostic accuracy than the Autism Diagnostic Interview-Revised.