Latent trajectories of adaptive behaviour in infants at high and low familial risk for autism spectrum disorder.
Giorgia Bussu, Emily J H Jones, Tony Charman and 2 others
PMID 30923608WHAT IT FOUND
Infants at high risk for autism split into three adaptive behaviour trajectories.
A small group with initially high scores declined significantly and had higher autism symptom severity. Most maintained stable average skills, while another group started low and recovered to average levels by age two.
Key findings
01A small class of infants (8.3%) showed decreasing adaptive behaviour trajectories starting from above-average scores, which was associated with higher autism symptom severity and a greater likelihood of an ASD diagnosis at 36 months.
02The majority of infants (73.8%) maintained stable adaptive behaviour around average levels, while a smaller group (17.9%) started with low scores but recovered to average levels by age two.
03Adaptive behaviour trajectories did not perfectly align with cognitive development; the group that recovered adaptive skills showed stable average cognitive scores, indicating a dissociation between the two domains.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
Trajectories were separated at the group level, but there was substantial overlap in individual variation. Adaptive behaviour was assessed via parent report, which may introduce bias compared to observational measures. The three-step analysis method might underestimate the association between class membership and external variables due to classification errors. Experimenters were aware of risk status, which could lead to ascertainment bias. The study did not include biological data (e.g., brain imaging) to explain the mechanisms behind the trajectories.
Declared interests
The study was funded by the H2020 Marie Skłodowska-Curie Actions, the Innovative Medicines Initiative, the UK Medical Research Council, and the Seventh Framework Programme. The authors declared no competing interests.
The easy way to misread this
Do not assume that high early adaptive scores are protective against ASD. The study found that a small group of infants with above-average initial skills experienced a significant decline in adaptive behaviour and had higher symptom severity later. A downward trajectory from a high baseline is a stronger indicator of risk than a stable low baseline.