Acoustic Properties of Cries in 12-Month Old Infants at High-Risk of Autism Spectrum Disorder.

There is preliminary evidence that infant siblings of children with Autism Spectrum Disorder (ASD) have an atypical pattern of cry, characterized by higher fundamental frequency and increased dysphonation. This prospective study collected multiple cry samples of 12-month old siblings of children with ASD (n = 22, 'high-risk' group) and 12-month olds with no family history of ASD (n = 27, 'low risk' group). While there was no difference between groups in the fundamental frequency or degree of phonation of the cry samples, the duration of each cry unit was significantly shorter in the high-risk siblings (p < .05). The six infant siblings who received a diagnosis of ASD at age two had amongst the shortest recorded cry durations.

A Prospective Ultrasound Study of Prenatal Growth in Infant Siblings of Children With Autism.

Numerous studies have observed that a proportion of infants later diagnosed with autism spectrum disorder (ASD) experience accelerated head growth during the first years of life. An emerging methodology for examining the developmental trajectory prior to a diagnosis of ASD is to investigate siblings of affected individuals. The current study is the first prospective investigation of fetal growth in siblings of children with ASD. Two groups of pregnant women were recruited as part of the PRegnancy Investigation of Siblings and Mothers of children with autism cohort in Perth, Western Australia. The "high risk" group (n = 23) comprised pregnant women who have an existing child with a diagnosis of ASD and the "low risk" group (n = 36) comprised pregnant mothers who have an existing child who has developed typically. Prenatal ultrasounds were procured at multiple time-points throughout the second- and third-trimesters, enabling an examination of growth trajectories. Growth measurements were then compared for the high- and low-risk fetuses. Mixed linear regression models identified no significant differences between the high- and low-risk fetuses in the rate of prenatal head and body growth throughout the second- and third-trimester (all P-values >0.05). Similarly, there were no significant differences observed when comparing high and low risk groups on a ratio of head circumference relative to body size (ß = -0.019, P = 0.75). Future studies may consider looking beyond the macro architecture of the prenatal brain and examine the growth of brain subregions that have been implicated in the presentation of ASD symptoms.

A "bottom-up" approach to aetiological research in autism spectrum disorders.

Autism spectrum disorders (ASD) are currently diagnosed in the presence of impairments in social interaction and communication, and a restricted range of activities and interests. However, there is considerable variability in the behaviors of different individuals with an ASD diagnosis. The heterogeneity spans the entire range of IQ and language abilities, as well as other behavioral, communicative, and social functions. While any psychiatric condition is likely to incorporate a degree of heterogeneity, the variability in the nature and severity of behaviors observed in ASD is thought to exceed that of other disorders. The current paper aims to provide a model for future research into ASD subgroups. In doing so, we examined whether two proposed risk factors - low birth weight (LBW), and in utero exposure to selective serotonin reuptake inhibitors (SSRIs) - are associated with greater behavioral homogeneity. Using data from the Western Australian Autism Biological Registry, this study found that LBW and maternal SSRI use during pregnancy were associated with greater sleep disturbances and a greater number of gastrointestinal complaints in children with ASD, respectively. The findings from this "proof of principle" paper provide support for this "bottom-up" approach as a feasible method for creating homogenous groups.