Comparison of Behavioral Development and Socio-Demographics Between Infants and Young Children At Higher or Lower Risk for ASD

Background: ASD is an inheritable condition and infants who have older siblings with ASD are at increased risk of ASD or autistic-like behaviors. Recent research has begun to identify early signs of ASD in at-risk infants. These studies have identified behavioural and developmental differences between at-risk infants subsequently diagnosed with ASD from at-risk infants not diagnosed, as well as between at-risk and low-risk infants. More research is needed on examining possible differences between at- and low-risk infants not just on core ASD symptoms, but also on collateral behaviors commonly seen in young children with ASD. There is also a need to determine if there are socio-demographic differences in at- and low-risk groups and if these demographic differences are related to early signs scores.

Objectives: (1) Determine if young children who have older siblings with ASD (at-risk group) have higher scores and more elevated items on a validated parent report measure of early signs of ASD than sex and age-matched children who have no family history of ASD (low-risk group); (2) determine if any socio-demographic differences exist between these two groups and (3) determine if socio-demographic differences are related to scores on the early markers scale.

Methods: This cross sectional study used the 61-item Parent Observation of Early Markers Scale (POEMS) to compare behavioral development of 69, 6-36 month old children at risk for ASD (older sibling diagnosed with ASD) to 69 sex and age-matched children with low risk (no family history of ASD). This parent-report, 4-point rating scale has been shown to have acceptable psychometric properties, sensitivity and specificity, when administered prospectively. It identified infant sibs who were subsequently diagnosed with ASD by 36 months from those who were not as early as 9 months of age.

Results: The at-risk children had significantly more elevated POEMS items (score of 3 or higher) than the low-risk children at 12, 18, 24, 30 and 36 months of age, even when seven subsequently diagnosed children (all in the at-risk group) were removed from the analyses. Differences were noted in core social-communication skills (e.g., imitation, interest in faces) as well as behavioral challenges commonly seen in older children with ASD (e.g., sleep issues, intolerance to waiting). POEMS total scores were not significantly different. Families of high risk children had older parents, lower family incomes and fewer mothers working out of home. These socio-demographic variables were not significantly correlated with POEMS scores.

Conclusions: The results support the use of the POEMS as a prospective parent report measure to monitor possible early signs of ASD and collateral behaviors associated with the broader phenotype. The study highlights the need to examine elevated items (as opposed to just total scores), and to include subsidiary behaviors and socio-demographic data in comparison studies. Future research will examine developmental trajectories of at-risk infants in longitudinal studies using the POEMS.