What will my child's future hold? phenotypes of intellectual development in 2-8-year-olds with autism spectrum disorder.
Autistic kids' IQ paths are highly uneven—plan for big gains or losses, not a single straight line.
01Research in Context
What this study did
The team tracked IQ scores in 129 autistic kids from . They tested each child every year with the same play-based IQ test.
Parents also filled out forms about services the kids got, like ABA or speech therapy.
What they found
Four clear paths showed up. One-third of the kids gained 30 or more IQ points. One-quarter lost points or stayed very low.
The other half stayed in the low range or reached average scores. No single therapy history matched any one path.
How this fits with other research
Tan et al. (2021) found that about 30 % of autistic toddlers lose skills around 20 months. Marjorie saw a similar 25 % who lost IQ points later, showing that regression can keep unfolding.
Waizbard-Bartov et al. (2022) tracked symptom severity in the same age band. Half of their kids got better, half got worse, just like the IQ paths in Marjorie's study. Together, the papers show that both IQ and autism features can swing up or down.
Brignell et al. (2024) looked at language growth and found that starting language level, not the autism label, predicted later progress. Marjorie's IQ paths line up with this: some kids with low early IQ still spurt ahead, reminding us that early scores are not destiny.
Why it matters
When you see a low IQ score at age 2, stay hopeful but watch closely. One in three kids may rocket ahead, while one in four may slide. Re-test yearly, adjust goals, and keep teaching new skills no matter the first score.
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02At a glance
03Original abstract
UNLABELLED: We examined phenotypes of autism spectrum disorder (ASD) based on trajectories of intellectual development from early (ages 2-3 ½) to middle (ages 5-8) childhood in a recent clinically ascertained cohort. Participants included 102 children (82 males) initially diagnosed with ASD from the Autism Phenome Project longitudinal sample. Latent class growth analysis was used to identify distinct IQ trajectories. Baseline and developmental course differences among groups were assessed using univariate techniques and repeated measures regression models, respectively. A four class model best represented the data. Using the highest posterior probability, participants were assigned to High Challenges (25.5%), Stable Low (17.6%), Changers (35.3%), and Lesser Challenges (21.6%) groups. The High Challenges and Stable Low groups exhibited persistently low IQ, although, the High Challenges group experienced declines while the Stable Low group's scores remained more constant. Changers showed IQ improvement of > 2 standard deviations. The Lesser Challenges group had IQs in the average range at both times that were about 1 standard deviation higher at T2. In summation, 75% of the participants experienced some relative improvements in intellectual and/or other areas of functioning between ages 2 and 8 years. The Changers group demonstrated the most significant IQ change that was accompanied by adaptive communication improvement and declining externalizing symptoms. Only the Lesser Challenges group showed a significant reduction in ASD symptom severity, such that by age 8, 14% of them no longer met ADOS-2 criteria for ASD. All groups showed reductions in internalizing symptoms. Intervention history was not associated with group status. Autism Res 2018, 11: 121-132. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We examined how the IQs of children with autism spectrum disorder change between ages 2 and 8, and identified four patterns. Two groups exhibited persistently lower IQs. One group showed IQ increases of greater than 30 points with improved communicate abilities and declining disruptive behaviors. The final group had IQs in the average or better range at both time points, and 14% of them lost their diagnoses. Over half of the children experienced improved intellectual functioning between ages 2 and 8, whereas about 25% showed declines. Findings were not associated with intervention history.
Autism research : official journal of the International Society for Autism Research, 2018 · doi:10.1016/j.jaac.2017.05.022