Previous research has examined autism spectrum disorders (ASD) in extremely preterm infants (23-30 weeks gestational age) and has indicated increased screen positive rates (Limperopoulos et al., 2008) and elevated SCQ and SRS scores (Movsas & Paneth, 2012) indicating higher likelihood of meeting criteria for an ASD. Additional prospective research has found that extremely preterm infants have higher SCQ scores than term birth peers, regardless of diagnostic status (Johnson et al., 2010). Less is known however about late preterm infants (34-36 weeks gestational age) and its implications for ASD.
Objectives:
This study examined profiles of preterm and term toddlers with a diagnosis of autism. We aimed to further previous research by examining a cohort of children considered at greater risk for developmental delays due to shortened gestational age, however not typically followed as closely as their extremely preterm counterparts. Of greatest interest was the difference in diagnostic profiles of these cohorts before the age of 3.
Methods:
This study included 34 male toddlers, 10 late preterm (mean age 25.36 months) and 24 term (38-41 weeks gestational age, mean age 23.71 months), all diagnosed with Autistic Disorder. All participants were referred based on parent concerns for a first time comprehensive diagnostic evaluation that included the Mullen Scales of Early Learning, the ADOS, Module 1, and the Vineland Adaptive Behavior Scales II.
Results:
ANOVAS were used to compare differences between groups. On the developmental assessments, significant differences were found on the domain of Visual Reception (VR) [F (1, 32) = 4.717, p < .05], with preterm toddlers achieving higher scores than term toddlers. With regards to adaptive behavior, significant differences were found on the Daily Living Skills [F (1, 32) = 11.845, p < .01], Communication [F (1, 32) = 7.993, p < .01], and Socialization [F (1, 32) = 4.462 p < .05] domains. All standard scores were higher for late preterm infants. With regard to diagnostic differences, on the ADOS, significant differences were found on social affect domain totals [F (1, 32) = 5.847, p < .05], with preterm toddlers receiving lower social affect totals. No significant differences were found with respect to repetitive behaviors (p =.90). When VR is covaried, significant differences still remain.
Conclusions:
This study found that in contrast to previous research supporting elevated symptomatology in extremely preterm children, late preterm toddlers have lower levels of symptomatology as measured by the ADOS social affect total. A point of interest is that restrictive and repetitive behavior (RRB) totals are not significantly different between the two groups, suggesting that for preterm toddlers, their ADOS total scores are more substantially impacted by RRBs, than term toddlers. Additionally, late preterm toddlers have higher visual reception scores, though still below average. Late preterm toddlers are also showing greater adaptive functioning in all domains, with the exception of gross motor. Important future directions include obtaining a larger sample size, and following these toddlers into adolescence to investigate the impact of these early predictors on outcome and level of functioning.
See more of: Clinical Phenotype
See more of: Symptoms, Diagnosis & Phenotype