Abstract
OT practitioners can play a role in identifying children at risk for ASD. Early signs of ASD have been proposed across multiple developmental domains. The purpose of this study was to compare clinical data across domains for high-risk premature infants who were later diagnosed with ASD to those who were not. Results indicate that early development between these two groups is similar, but there are clinically and statistically significant differences seen at two years.
Primary Author and Speaker: Kelly Tanner
Additional Authors and Speakers: Maria Baldino
Contributing Authors: Helen Carey, Nicholas Kelly, Karen Ratliff-Schaub
Occupational therapy practitioners can play a role in identifying children at risk for autism spectrum disorder (ASD). Early signs of ASD have been proposed across multiple developmental domains (Zwaigenbaum, Bryson, & Garon, 2013). However, the age of first diagnosis for ASD remains around 3 years (Barbaro & Dissanayake, 2009). The purpose of this study was to compare high-risk premature infants who were later diagnosed with ASD to those who were not diagnosed with ASD across domains of development. In addition, we sought to determine whether clinical data can be used to detect early signs of ASD.
This retrospective study included 144 infants (gestational age <37 weeks) identified through a neonatal follow-up clinic. Seventy-two participants who were later diagnosed with ASD were included, as well as 72 controls who were matched for sex and gestational age. Exclusion criteria included comorbid developmental conditions such as Down syndrome and cerebral palsy.
Instruments for this study were two measures collected at regular intervals as part of standard clinical care: the Test of Infant Motor Performance (TIMP; 3-4 months) and Bayley Scales of Infant and Toddler Development, 3rd ed. (Bayley-3; 8-14 months and 20-26 months). Summary statistics were calculated for gestational age, Bayley-3 subscales, and TIMP scores. Between-group comparisons (ASD vs control) were conducted using two-sample t-tests for comparing Bayley-3 subscales and raw TIMP scores. Fisher’s exact test was used to compare TIMP categories between the groups. A two-sample t-test was used to compare change in Bayley-3 subscales across time points between the groups. Finally, paired t-tests were conducted to compare mean Bayley-3 scores at each time point within each group.
Between-group comparisons indicated no significant group difference in TIMP scores or gestational age. The ASD group had significantly lower scaled and raw Bayley-3 scores for all subscales at both time points (p<.05), with the exception of expressive communication raw score at 8-14 months (p=0.08). However, mean scaled scores were within the average clinical range for both groups at this time point. Results of the within-group comparisons indicated that the ASD group had significantly lower Bayley-3 scaled scores at 20-26 months (as compared to 8-14 months) for all subscales (p<.05); mean scores were in the below average clinical range for all subscales at 20-26 months. The control group also had significantly lower Bayley-3 scaled scores at 20-26 months (as compared to 8-14 months) for all subscales (p<.05). However, the decrease in Bayley-3 scaled scores for the cognitive, receptive communication, and expressive communication subscales between time points was significantly larger for the ASD group (p<.05).
The results of this study indicate that while early development for high-risk neonates who were later diagnosed with ASD and those who were not is clinically similar, there are clinically and statistically significant differences seen at 2 years. Children who are later diagnosed with ASD may exhibit a more precipitous drop in Bayley-3 scaled scores across time periods in comparison to those without ASD. The impact of this study is that it highlights the importance of long-term follow-up for high-risk neonates at risk of ASD, and the need to consider multiple domains of development when assessing early signs of ASD. Further research is needed to develop early clinical screening tools for ASD.
Barbaro, J. & Dissanayake, C. (2009). Autism spectrum disorders in infancy and toddlerhood: a review of the evidence on early signs, early identification tools, and early diagnosis. J Dev Behav Pediatr, 30(5), 447-59. doi: 10.1097/DBP.0b013e3181ba0f9f.
Zwaigenbaum, L., Bryson, S., & Garon, N. (2013). Early identification of autism spectrum disorders. Behavioural Brain Research, 251, 133–146. https://doi.org/10.1016/j.bbr.2013.04.004