Genetic studies of autism spectrum disorders (ASD), as well as other disorders, rely on gold standard diagnostic criteria that are assessed at one time point. In autism research, the ADI-R and/or ADOS are used to confirm a diagnosis of ASD. While empirical results suggest that the diagnosis of autism spectrum disorders is stable over time in children who are diagnosed at a young age (Lord, et al., 2006), symptom levels and, therefore, specific DSM criteria may be less stable over time.
Objectives:
Change in diagnostic symptom level may be an important variable to consider in long-term genetic studies of autism. The objective of this project is to assess changes in parent report of diagnostic symptom levels in children with ASD who participated in two studies at the University of Washington.
Methods:
The Family Study of Autism (1998 – 2006) enrolled families with two or more children with diagnosed or suspected autism aged 3 to17 years. Diagnoses of ASD were confirmed using the gold standard diagnostic criteria of the ADOS and ADI-R. Families are presently being re-contacted to participate in the Family Traits Research Project (2010 – present; data collection is ongoing) in which current functioning of children diagnosed with ASD is being measured using the Social Communication Questionnaire (SCQ), a questionnaire based on the ADI-R. Descriptive data about these children includes their sex, IQ, age at diagnosis, specific DSM diagnosis, and SCQ-current score. We are analyzing differences in those who continue to (or do not continue to) meet ASD phenotype cutoffs on the SCQ. Also, parent report of item scores on the SCQ are being compared to their corresponding items on the ADI-R to determine trends of growth in specific domains (social interaction, communication, and restricted/repetitive interests/behaviors) for these children.
Results:
The average time between assessments was 8 years (range 5-12 years). Preliminary data from a subset of the sample suggest that approximately 52% of children diagnosed with ASD scored at or above the cutoff (greater than 15) on the SCQ, confirming symptom levels corresponding to the autism phenotype. Of the 42% of children who did not meet the SCQ cutoff, scores were evenly distributed from 3-13, indicating that many parents perceive significant changes in their children’s ASD symptoms over time.
Conclusions:
As our sample size increases, we predict significant stability in symptom level for children who at time of diagnosis were: (1) older and (2) had more severe symptoms. Preliminary analyses suggest that parent’s perception of autism symptoms may significantly change during childhood, adolescence, and early adulthood. While presented samples sizes are small, additional investigation of parent report and observational evaluations are warranted for children in multiplex families. Quantifiable change in autism traits may be an important variable for analysis.
See more of: Clinical Phenotype
See more of: Symptoms, Diagnosis & Phenotype