Early Red Flags of Autism Spectrum Disorders

There is now mounting evidence demonstrating the effectiveness of intensive early intervention with a substantial proportion of young children with autism spectrum disorders (ASD).

Research indicates that intervention provided before age 3½ has a much greater impact than if it begins after age 5, which underscores the importance of improving early identification. In spite of the severity of the behavioral characteristics of most children with ASD, the median age for diagnosis of ASD in the United States is 4½ years1. Although there have been significant advances in genetic and biomedical research on ASD, there is currently no biological marker for either autism or ASD, therefore screening and diagnosis must be based on behavioral features.

The American Academy of Pediatrics (AAP) recently published a policy statement for the identification and evaluation of children with ASD that recommended that all children be screened with a standardized broadband screening tool at the 9-, 18-, 24- and 30-month visits, and an ASD-specific screening tool at the 18- and 24-month visits2. The new AAP practice guidelines make the need for validated screening tools more pressing. The ongoing research of the FIRST WORDS Project is contributing important findings on screening tools for early identification of children with ASD at the ages recommended by the AAP. Following is a brief summary of our research findings.

FIRST WORDS® Project
Prospective Longitudinal Research Study of ASD

We are conducting an ongoing prospective, longitudinal study to identify precise early indicators of ASD by examining videotaped communication samples collected during the second year of life. Participants were recruited from a pool of 5,385 children screened by having parents complete the Infant-Toddler Checklist (ITC) when their children were under two years of age. Children were later assigned to groups based on the results of a follow-up diagnostic evaluation at 3 to 5 years of age, which included the Autism Diagnostic Observation Schedule, the Social Communication Questionnaire, the Vineland Adaptive Behavior Scales, and the Mullen Scales of Early Learning. The ASD and DD groups did not differ on their nonverbal or verbal developmental quotient. To date, we have identified 60 children later diagnosed with ASD and comparison groups of 30 children with developmental delays in which ASD is ruled out (DD), and 60 children with typical development (TD)3-7.

Accuracy of the ITC as a
Broadband Screener of Communication Delay

The ITC is one component of the Communication and Symbolic Behavior Scale Devlopmental Profile (CSBS DP) and consists of 24 questions about typical social communication milestones and a question about parent concern. To examine the accuracy of the ITC for early identification of communication delays, the agreement between children’s screening outcomes on the ITC was compared with their developmental outcomes on the CSBS DP Behavior Sample5. Following are the results for the ITC screen and parent report of concern:

The findings of this study suggest that parents of children 9-24 months are fairly accurate at reporting current developmental milestones but are not very accurate in reporting concern about their child’s development relative to what should be expected at their child’s age. This finding is important to consider because parent concern can influence whether parents seek out or agree to participate in screening and evaluation. The majority of parents of children under 21 months with delayed communication do not report concern. In contrast, a substantial percentage of parents of children 21-24 months report concern whether their child is typical or delayed.

Accuracy of the ITC to Detect Children with ASD

The ITC identified 56 of the 60 children with ASD in this general population sample which is 93% sensitivity5. However, it is important to point out that a positive screen on the ITC does not distinguish children with ASD from children with other communication delays. Children with ASD who had a positive screen on the ITC were most likely to perform in the bottom 10th percentile on the Social composite. Therefore, an ASD-specific screen should be considered particularly for children showing this pattern on the ITC. For the children with ASD screened one or more times with the ITC, the percentage of positive screens and parents with concern reported on the ITC are presented below.

The percentage of positive screens on the ITC increased with age and is above 90% at 12-14 months through 21-24 months. The proportion of parents with concern is less than half under 15 months and increases to more than two-thirds at 18-20 months and approaches three-fourths at 21-24 months. The results of this study support the validity of the ITC as a broadband screener of communication delays including ASD in children 9-24 months of age.

Red Flags of ASD from Structured Observations in the Second Year of Life

To identify early red flags of ASD, the videotaped communication samples from the second year of life were analyzed to examine differences between the children later diagnosed with ASD and the comparison groups3-7. The videotapes were analyzed for typical social communication milestones and atypical behaviors that may be associated with ASD. The results indicated that 9 red flags distinguished the children with ASD from the children with DD and TD and 4 red flags distinguished children with ASD and DD from children with TD:

These findings are on one of the largest samples of children with ASD identified prospectively at this young age and contribute to understanding the early phenotypic features of ASD. They offer more precise early red flags of ASD in the second year of life than previously available.

Conclusions

The combination of 1st stage screening for developmental delay with the ITC and 2nd stage screening for ASD with the 13 Red Flags identified from the CSBS DP Behavior Sample was effective for early identification. Children with ASD can be distinguished from those with DD and TD through systematic observation in the second year of life. The 13 red flags identified in our research include a combination of lack of typical behaviors and presence of atypical behaviors. These findings have important implications for improving early identification so that families can access intervention sooner.

References

1. Centers for Disease Control and Prevention (2007). Prevalence of autism spectrum disorders- Autism and developmental disabilities monitoring network, Six sites, Unites States, 2000-2002. In Surveillance Summaries, February 9, MMWR 2007; 56 (No. SS-1): 1-40.
2. Johnson, C.P. & Scott, M.M. (2007). Identification and evaluation of children with autism spectrum disorders. Pediatrics, 120, 1183-1215.
3. Morgan, L., Wetherby, A., & Barber, A. (accepted for publication). Repetitive and stereotyped movements in children with autism spectrum disorders late in the second year of life. Journal of Child Psychology and Psychiatry.
4. Watt, N., Wetherby, A., Barber, A., & Morgan, L. (accepted for publication) Repetitive and stereotyped behaviors in children with autism spectrum disorders in the second year of life. Journal of Autism and Developmental Disorders.
5. Wetherby, A., Brosnan-Maddox, S., Peace, V., & Newton, L. (invited article under review). Validation of the Infant-Toddler Checklist as a broadband screener for autism spectrum disorders from 9 to 24 months of age.
6. Wetherby, A., Watt, N., Morgan, L., & Shumway, S. (2007). Social communication profiles of children with autism spectrum disorders in the second year of life. Journal of Autism and Developmental Disorders, 37, 960-975.
7. Wetherby, A., Woods, J., Allen, L., Cleary, J., Dickinson, H., & Lord, C. (2004). Early indicators of autism spectrum disorders in the second year of life. Journal of Autism and Developmental Disorders, 34, 473-493.

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