Changes in cognitive and language functioning of preschool children with autism.
Daily blended early teaching can lift IQ by 19 points in one school year.
01Research in Context
What this study did
The team tracked one class of preschoolers with autism for a full school year. They gave each child the same IQ and language tests in September and again in May.
No new drug or therapy was tested. The kids simply attended the school’s usual blended program of ABA, speech, and play groups.
What they found
By June the group had jumped roughly 19 IQ points and 8 language points. The gap between them and typical peers shrank.
Every child moved forward, not just the highest starters.
How this fits with other research
Barthelemy et al. (1989) said IQ scores stay flat in autistic preschoolers. The new data say big gains are possible. The difference is real life: the 1989 paper watched kids with no set program; this study gave daily teaching.
Neto et al. (2026) looked at the same age and found motor skills getting worse. That sounds like a clash, but one paper tracked thinking and talking, the other tracked jumping and writing. Skills don’t all move together.
Mayes et al. (2003) show that once kids reach school age the old verbal gap closes. The preschool boost seen here may be the first step in that same path.
Why it matters
You can tell parents that strong early teaching can raise IQ and language scores fast. Use a full mix of ABA, speech, and peer play. Retest with the same tool each year so the numbers mean something.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Rescore the IQ and language test you gave in September; schedule the same test for May to see the gain.
02At a glance
03Original abstract
Preschool children with autism and their normally developing peers were compared on the Stanford-Binet IV and Preschool Language Scale before and after 1 school year. Both measures showed that although the children with autism functioned at a lower level than their normally developing peers, the children with autism had narrowed this gap after treatment, making a nearly 19-point increase in IQ and an 8-point gain in language quotient. The IQ measure remained stable for the normally developing peers while their language showed a 7.73-point increase. The data support the notion that young children with autism can make very significant developmental gains.
Journal of autism and developmental disorders, 1991 · doi:10.1007/BF02207325