Repetitive interests, behaviours and activities in autism: Their relationship to social-communication impairments, and to cognitive inflexibility

Autism is currently conceptualised as a unitary syndrome, in which social- communication impairments are found alongside repetitive interests, behaviours and activities (RIBAs). This relies upon the validity of the assumption that social- communication impairments and RIBAs co-occur at an above chance level as a result of sharing underlying causes. In the current review it is argued that the evidence for this assumption is scarce: the very great majority of RIBA research has not been intended for or suited to its examination. In fact only three studies are fit to address directly the question of the relationship between social-communication impairment and RIBA, and these contradict each other. In consequence, further relevant evidence was sought in the behavioural and molecular genetic literature. This approach suggested that the correlation between social-communication impairments and RIBAs has been exaggerated in the current consensus about the autism syndrome, and that these aspects of autism may well share largely independent underlying causes. Some clinical and research implications are discussed

What Is the Male-to-Female Ratio in Autism Spectrum Disorder? A Systematic Review and Meta-Analysis

OBJECTIVE: To derive the first systematically calculated estimate of the relative proportion of boys and girls with autism spectrum disorder (ASD) through a meta-analysis of prevalence studies conducted since the introduction of the DSM-IV and the International Classification of Diseases, Tenth Revision. METHOD: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The Medline, Embase, and PsycINFO databases were searched, and study quality was rated using a risk-of-bias tool. Random-effects meta-analysis was used. The pooled outcome measurement was the male-to-female odds ratio (MFOR), namely the odds of being male in the group with ASD compared with the non-ASD group. In effect, this is the ASD male-to-female ratio, controlling for the male-to-female ratio among participants without ASD. RESULTS: Fifty-four studies were analyzed, with 13,784,284 participants, of whom 53,712 had ASD (43,972 boys and 9,740 girls). The overall pooled MFOR was 4.20 (95% CI 3.84-4.60), but there was very substantial between-study variability (I(2) = 90.9%). High-quality studies had a lower MFOR (3.32; 95% CI 2.88-3.84). Studies that screened the general population to identify participants regardless of whether they already had an ASD diagnosis showed a lower MFOR (3.25; 95% CI 2.93-3.62) than studies that only ascertained participants with a pre-existing ASD diagnosis (MFOR 4.56; 95% CI 4.10-5.07). CONCLUSION: Of children meeting criteria for ASD, the true male-to-female ratio is not 4:1, as is often assumed; rather, it is closer to 3:1. There appears to be a diagnostic gender bias, meaning that girls who meet criteria for ASD are at disproportionate risk of not receiving a clinical diagnosis

Traits Contributing to the Autistic Spectrum

It is increasingly recognised that traits associated with autism reflect a spectrum with no clear boundary between typical and atypical behaviour. Dimensional traits are needed to investigate the broader autism phenotype.Ninety-three individual measures reflecting components of social, communication and repetitive behaviours characterising autistic spectrum disorder (ASD) were identified between the ages of 6 months and 9 years from the ALSPAC database. Using missing value imputation, data for 13,138 children were analysed. Factor analysis suggested the existence of 7 factors explaining 85% of the variance. The factors were labelled: verbal ability, language acquisition, social understanding, semantic-pragmatic skills, repetitive-stereotyped behaviour, articulation and social inhibition. Four factors (1, 3, 5 and 7) were specific to ASD being more strongly associated with this phenotype than other co-morbid conditions while other factors were more associated with learning difficulties and specific language impairment. Nevertheless, all 7 factors contributed independently to the explanation of ASD (p<0.001). Exploration of putative genetic causal factors such as variants in the CNTNAP2 gene showed a varying pattern of associations with these traits. An alternative predictive model of ASD was derived using four individual measures: the coherence subscale of the Children's Communication Checklist (9y), the Social and Communication Disorders Checklist (91 m), repetitive behaviour (69 m) and the sociability subscale of the Emotionality Activity and Sociability measure (38 m). Although univarably these traits performed better than some factors, their combined explanations of ASD were similar (R(2) =  0.48).These results support the fractional nature of ASD with different aetiological origins for these components despite pleiotropic genetic effects being observed. These traits are likely to be useful in the exploration of ASD

Neuropsychiatric comorbidities in Duchenne Muscular Dystrophy

info:eu-repo/semantics/nonPublishe

Relationship between symptom domains in autism spectrum disorders: a population based twin study

Factor structure and relationship between core features of autism (social impairments, communication difficulties, and restricted, repetitive behaviours or interests (RRBIs)) were explored in 189 children from the Twins Early Development Study, diagnosed with autistic spectrum disorders (ASDs) using the Development and Wellbeing Assessment (DAWBA; Goodman et al. in J Child Psychol Psyc 41:645–655, 2000). A bottom-up approach (analysis 1) used principal component factor analysis of DAWBA items indicating five factors, the first three mapping on the triad. In analysis 2, applying top-down DSM-IV criteria, correlations between domains were modest, strongest between social and communication difficulties. Cross-twin cross-trait correlations suggested small shared genetic effects between RRBIs and other symptoms. These findings from a clinical sample of twins indicate a fractionation of social/communicative and RRBI symptoms in ASD