This study examined trajectories of repetitive sensorimotor (RSM), insistence on sameness (IS), and verbal RRBs from ages 2-19 in a well-characterized longitudinal cohort. We also tested the factor structure of the ADI-R restricted and repetitive behavior (RRB) domain at age 19 and the inclusion of a verbal RRBs factor, in addition to previously…

The processing speed index (PSI) of the Wechsler intelligence scale for children (WISC-IV) has been found to predict a child's level of academic functioning. The consistently reported PSI weakness in children with autism spectrum disorder (ASD) therefore warrants special assistance and attempts at compensation for the disadvantages associated with…

Previous studies measuring praxis abilities in young autistic children have only used praxis measures that were not optimised for autistic individuals. Hence, we used the FAB-R to measure praxis skills in autistic (n = 38) and typically developing (TD) children (n = 38) aged between four and 10 years. Praxis abilities were generally not different…

Studying anxiety in neurogenetic syndromes may inform the intersection of biological and developmental risks, facilitating effective and targeted interventions. We longitudinally examined stranger fear in infants and toddlers with fragile X syndrome (FXS; n = 46) and typical controls (n = 33), as well as associations between observed stranger fear…

A cross-sectional analysis was used to examine age-related differences in ASD symptoms and corresponding differences in disruptive behavior and social skills in 281 adult men with fragile X syndrome. Four age groups were created: 18-21, 22-29, 30-39, and 40-49 years. The 18-21 year-old group was reported to have more impairments in verbal…

This study investigated neurodevelopmental changes in sound processing by recording mismatch negativity (MMN) in response to various degrees of sound complexity in 18 mildly to moderately autistic versus 15 healthy boys aged between 6 and 15 years. Autistic boys presented with lower IQ and poor performance on a range of executive and social…

Canonical babbling is a critical milestone for speech development and is usually well in place by 10 months. The possibility that infants with autism spectrum disorder (ASD) show late onset of canonical babbling has so far eluded evaluation. Rate of vocalization or "volubility" has also been suggested as possibly aberrant in infants with…

This study examined the longitudinal associations between parent verbal responsiveness and language 3 years later in 34 toddlers with a diagnosis of an autism spectrum disorder. Parent-child play samples were coded for child engagement and communication acts and for parent verbal responsiveness. Measures of responsive verbal behaviors were used to…

Between 2006 and 2010, two research-validated instruments, Social Communication Questionnaire (SCQ) and Social Responsiveness Scale (SRS) were filled out online by 4,188 mothers of Autism Spectrum Disorder (ASD) children, aged 4-21, as part of voluntary parental participation in a large web-based registry. Univariate and multivariate linear…

The validity of the calibrated severity scores on the ADOS as reported by Gotham et al. (J Autism Dev Disord 39: 693-705, "2009"), was investigated in an independent sample of 1248 Dutch children with 1455 ADOS administrations (modules 1, 2 and 3). The greater comparability between ADOS administrations at different times, ages and in…

It was found that the autistic Ss' skills of comprehension and conversation improved significantly with age, and that speech improved somewhat as well, but that maladaptive behaviors other than hyperactivity did not change significantly with age. (Author/DLS)