Developmental regression in children with an autism spectrum disorder identified by a population-based surveillance system.
Expect skill loss in roughly one in four to one in three young children with autism, usually near age two, and use that history to guide intensity of early intervention.
01Research in Context
What this study did
Casey et al. (2009) counted how many children with autism lose skills they once had. They used a state-wide tracking system that watches every child in the area. Doctors and schools had already reported each child’s details, so the team could look back for signs of regression.
What they found
About one in four children with autism had lost words, play, or social skills. Most losses happened around the second birthday. Boys showed this pattern more often than girls. Many of the children who regressed had shown slower development even before the loss began.
How this fits with other research
Later meta-analyses now include these same numbers. Prigge et al. (2013) and Tan et al. (2021) pooled many studies and bumped the estimate up to about one in three. The bigger samples moved the average age of loss a few months earlier, to roughly eighteen to twenty months.
Sharp et al. (2010) followed children past the toddler years and found that those with regression ended up with more severe symptoms. Boterberg et al. (2019) added that limited early communication can flag which toddlers are most likely to lose skills later.
The numbers look different at first glance, but they tell one story: surveillance counts are a floor, meta-analyses add parent-report studies, and the true figure sits near thirty percent.
Why it matters
When you screen a two-year-old, ask parents if words or gestures have vanished. If the answer is yes, plan closer follow-up and faster entry into intervention. Watch for epilepsy and intellectual disability red flags, because García-Villamisar et al. (2017) show these risks rise in the regression group. Document the timing; it helps set realistic language goals and keeps families prepared for a slower skill trajectory.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add one question to your intake: “Has your child lost any words, play skills, or social routines?” If yes, schedule a follow-up within four weeks.
02At a glance
03Original abstract
This study evaluated the phenomenon of autistic regression using population-based data. The sample comprised 285 children who met the autism spectrum disorder (ASD) case definition within an ongoing surveillance program. Results indicated that children with a previously documented ASD diagnosis had higher rates of autistic regression than children who met the ASD surveillance definition but did not have a clearly documented ASD diagnosis in their records (17-26 percent of surveillance cases). Most children regressed around 24 months of age and boys were more likely to have documented regression than girls. Half of the children with regression had developmental concerns noted prior to the loss of skills. Moreover, children with autistic regression were more likely to show certain associated features, including cognitive impairment.These data indicate that some children with ASD experience a loss of skills in the first few years of life and may have a unique symptom profile.
Autism : the international journal of research and practice, 2009 · doi:10.1177/1362361309105662