Despite considerable progress in characterizing the early signs of autism spectrum disorder (ASD), more remains to be learned about how symptoms emerge in the first year of life. Parents with a new baby who already had at least one biological child diagnosed with ASD (high-risk) or no family history of ASD (low-risk) completed two measures when…

The objectives were to characterize behavioral signs of autism spectrum disorder (ASD) in younger siblings of diagnosed children (high-risk; HR) and examine classification features of the Autism Observation Scale for Infants (AOSI). Participants (501 HR and 180 low-risk [LR]) were assessed between 6 and 18 months using the AOSI and at age 3 for…

Research concerning temperament in children and adults with autism spectrum disorder (ASD) has suggested a consistent profile of low positive affect, high negative affect, and low regulation (Visser et al., 2016). One area receiving less attention is individual differences among children diagnosed with ASD. The primary objective of this study was…

This study examined the performance of the First Year Inventory (FYI; version 2.0), a community-normed parent-reported screening instrument, in a high-risk (HR) sample of 12-month-olds with older siblings diagnosed with autism spectrum disorder (ASD). The FYI 2.0 was completed by parents of 86 HR infants and 35 low-risk control infants at age…

This study examined the potential of the short form of the Quantitative Checklist for Autism in Toddlers (Q-CHAT-10) to identify autism spectrum disorder (ASD) in a high-risk sibling cohort. High-risk (HR; siblings of children diagnosed with ASD) and low-risk (LR; no family history of ASD) toddlers were assessed prospectively at 18 and 24 months…

This study examines the construct validity of the First-Year Inventory 2.0 with respect to other established instruments in a sample of high-risk infant siblings of children with Autism Spectrum Disorder. The First-Year Inventory 2.0 is a parent-report screening instrument designed to identify 12-month-old infants at risk for an eventual diagnosis…

Considerable evidence on autism spectrum disorder emergence comes from longitudinal high-risk samples (i.e. younger siblings of children with autism spectrum disorder). Diagnostic stability to age 3 is very good when diagnosed as early as 18-24 months, but sensitivity is weaker, and relatively little is known beyond toddlerhood. We examined…

This study assessed sensory processing differences between 24-month infants at high-risk of autism spectrum disorder (ASD), each with an older sibling with ASD, and low-risk infants with no family history of ASD. Sensory processing differences were assessed using the Infant/Toddler Sensory Profile, a parent-reported measure. Groups were compared…

This study examined whether a novel parent-report questionnaire, the Autism Parent Screen for Infants, could differentiate infants subsequently diagnosed with autism spectrum disorder from a high-risk cohort (siblings of children diagnosed with autism spectrum disorder (n = 66)) from high-risk and low-risk comparison infants (no family history of…

Background: Parental concerns persist that immunization increases the risk of autism spectrum disorder, resulting in the potential for reduced uptake by parents of younger siblings of children with autism spectrum disorder ("younger sibs"). Objective: To compare immunization uptake by parents for their younger child relative to their…

Sex differences were examined in 3-year-olds with autism spectrum disorders (ASD) ascertained from a high-risk cohort, and high- and low-risk comparison groups. Participants included 319 high-risk siblings and 129 low-risk controls. Eighty-five siblings were diagnosed with ASD, including 57 of 176 boys (32.4%) and 28 of 143 girls (19.6%), implying…

The Autism Observation Scale for Infants (AOSI) was developed to detect and monitor early signs of autism as they emerge in high-risk infants (all with an older sibling with an autistic spectrum disorder). Here we describe the scale and its development, and provide preliminary data on its reliability. Inter-rater reliability both for total scores…

The present study prospectively investigated early temperamental profiles and their associations with autistic symptoms in high-risk infants (N = 138) with an older sibling with autistic spectrum disorder (ASD) and low-risk infants (N = 73) with no family history of ASD. Children who were diagnosed with ASD at 36 months were distinguished from…

The present paper documents the development of autism/autistic spectrum disorder in a consecutive series of nine high-risk infants followed prospectively from 6 months of age. Evidence is provided for two broadly defined subgroups: the first subgroup (n = 6) showed a decrease in IQ between 12 and 24 or 36 months (from average/near average to…