The cumulative impact of attention deficit hyperactivity disorder, autism and intellectual disability for young people.

BACKGROUND: Neurodevelopmental conditions frequently co-occur. The aim of this paper was to determine whether there is a cumulative association between (1) the number of neurodevelopmental conditions, specifically hyperkinetic disorder (hereafter referred to as attention deficit hyperactivity disorder), autism spectrum disorder (hereafter referred to as autism) and intellectual disability, and (2) behavioural and socio-emotional problems and the level of clinician-rated functioning for young males and females. METHODS: In this cross-sectional study, diagnostic information, caregiver-rated behavioural and socio-emotional data (as conceptualised by the Strengths and Difficulties Questionnaire) and clinician-rated functioning scores (as conceptualised by the Children's Global Assessment Scale) were extracted from electronic patient records for 2768 young people aged 3-17 years (mean = 11.55, SD = 3.46). All data were extracted at baseline, that is, at the time the young person was diagnosed with attention deficit hyperactivity disorder, autism and/or an intellectual disability. Ordinal regression analyses tested associations between the number of neurodevelopmental conditions met (i.e. 1, 2 or 3) and behavioural and socio-emotional outcomes and functioning. RESULTS: After controlling for age and biological sex, the number of neurodevelopmental conditions was associated with higher levels of inattention/hyperactivity and peer problems, lower levels of prosocial behaviour and poorer clinician-rated functioning. Although these findings were consistent for males, a cumulative association was not identified for females, except for clinician-rated functioning. CONCLUSIONS: For young people, the presence of multiple neurodevelopmental conditions may have a cumulative impact across domains, but this may differ between males and females.

A texture-processing model of the 'visual sense of number'.

It has been suggested that numerosity is an elementary quality of perception, similar to colour. If so (and despite considerable investigation), its mechanism remains unknown. Here, we show that observers require on average a massive difference of approximately 40% to detect a change in the number of objects that vary irrelevantly in blur, contrast and spatial separation, and that some naive observers require even more than this. We suggest that relative numerosity is a type of texture discrimination and that a simple model computing the contrast energy at fine spatial scales in the image can perform at least as well as human observers. Like some human observers, this mechanism finds it harder to discriminate relative numerosity in two patterns with different degrees of blur, but it still outpaces the human. We propose energy discrimination as a benchmark model against which more complex models and new data can be tested.