The Utility of the First Year Inventory in Evaluating Autism Symptoms at 12 Months in Infants at High Risk for ASD

Background:  Younger siblings of children with autism spectrum disorder (ASD) (high-risk siblings, HR) are at higher risk of developing ASD and other developmental problems than those in the general population. Research has suggested that some symptoms of ASD are present in HR siblings at 12 months of age. Screening at this age, however, is complicated by variable autism symptom onset patterns, and especially complex in HR populations because of the substantial numbers of HR infants who do not develop ASD but present with similar symptoms over the second year of life.

Objectives:  We examined the utility of information gathered at 12 months via parental questionnaire (First Year Inventory; FYI; Baranek et al., 2003) for predicting a later diagnosis of ASD in HR infants at the domain and construct level as well as at the item level.

Methods:  Participants included 96 families of 12-month-old infants: 71 at HR and 25 at low risk (LR) for ASD.  The 61 questions on the FYI comprise two domains (Social Communication and Sensory-Regulatory), each domain consisting of four constructs. At 36 months, the infants were extensively assessed (Mullen, ADOS, Reynell, Vineland) by a team of expert clinicians and classified as having ASD (n=16); other delays, subclinical autism symptoms, or a history of either (HR-ATYP; N=36); or typical development (HR-TYP, n=19; LR-TYP, n=25). Analysis consisted of between-group ANOVAs followed by post-hoc tests and classification tree (CART) analysis of FYI items.

Results:  The four groups differed on the Social Communication domain (F(3,92)=5.2, p=.002) and two of its four constructs: Social Orienting and Receptive Communication (F(3,92)=3.0, p=.021) and Imitation (F(3,92)=6.0, p=.001). Post-hoc analyses showed that infants with ASD had significantly higher (worse) scores on the Social Communication domain compared to HR-ATYP (p=.025, d=.75) and LR-TYP (p=.001, d=1.18) but not HR-TYP infants.  The ASD group had significantly higher scores on the Social Orienting/Receptive Communication construct than the LR-TYP (p=.021, d=.91) group, but not the other HR groups.  The ASD group had higher scores on the Imitation construct than the HR-ATYP (p=.004, d=.94), HR-TYP (p=.002, d=1.17), and LR-TYP (p=.002, d=1.10) groups, with large effect sizes for each comparison.  There were no between-group differences for the Sensory-Regulatory domain or any of its constructs.  The CART analysis revealed that a combination of questions related to recent declines in play and communication and to lack of imitation of vocal sounds correctly predicted almost 2/3 of the children with ASD and 93% of the children without ASD.

Conclusions:   Our results suggest that parent-reported information about social communication and imitation in 12-month-old infants helps identify infants at highest risk for an ASD among HR siblings. We will also discuss concordance between parent report and clinician observation as a critical issue in the development of screening tools.