Children with a regressive form of autism tend to have earlier first words and delayed phrase speech, compared with children with other patterns of autism symptom onset, a study showed.
They also have elevated autism symptom scores and are at greater risk for poorer outcomes, reported Luther G. Kalb and his associates at the center for autism and related disorders, Kennedy Krieger Institute, Baltimore.
The study, conducted with a sampling of data from the Interactive Autism Network (IAN), consisted of 2,720 participants aged 3-17 years. The data for each participant was extracted with IAN questionnaires, the Social Communications Questionnaire (SCQ), and the Social Responsiveness Scale (SRS). The children were classified into three groups: regression or skill loss (SL), plateau, and no loss and no plateau (NLNP).
First steps and words were reported later for the plateau group and NLNP group than for the skills loss group, and the SL group reported phrase speech 3 months later than the NLNP group. The first concerns about development occurred more than 2 months later for the SL and plateau groups than for the NLNP group. The mean age at onset of plateau was 24 months while the onset of regression was 19.5 months (J. Autism Dev. Disord. 2010 April 2 [doi: 10.1007/s10803-010-0998-7]).
Children in the skills loss group had higher Social Responsiveness Scale total raw scores than children in the other two groups, and regression severity also was associated with higher SRS scores. Children in the regression or skills loss group also had higher Social Communications Questionnaire scores than the plateau and no loss, no plateau groups. Children whose parents reported social and motor skills problems also reported higher Social Responsiveness Scale scores than did the language loss group.
These data indicate greater autism symptom severity for children with regression and with severe motor skill loss, the researchers said. When it came to diagnosis, children in the skills loss and plateau groups were more likely to be diagnosed with an autistic disorder than those in the NLNP group.
Thus, there appears to be a relationship between autism-onset pattern and developmental, diagnostic, and educational-behavioral outcomes, they said. There was less delayed early development in the skills loss group than in the NLNP and plateau groups. For parents who had reported a regression, first steps and words arrived within normal limits, and parental concerns came later, they said. Yet children with regression were more than two times more likely to be diagnosed with an autistic disorder.
Coinvestigator Dr. Paul Law, director of the Interactive Autism Network at the Kennedy Krieger Institute, said, "This study is important for several reasons. First, it is the largest to examine onset patterns of autism spectrum disorder and one of the first to investigate outcomes of children who experience developmental plateau. Second, the data provide further evidence that regression is an important onset pattern, an area of study that has conflicting findings.
"Lastly, this study provides additional insight for researchers and clinicians that may lay the groundwork for improved, tailored early intervention for onset types," he said in an interview.
Dr. Law also noted that parents, day care providers, and physicians should be aware of normal developmental patterns. "Whether the concern is delayed development or loss of skills, this understanding should point to appropriate evaluation, usually by their pediatrician, with referral to developmental specialists as needed." He suggested physicians tell parents about the Centers for Disease Control and Prevention Web site "Learn the Signs. Act Early" that describes appropriate developmental milestones starting at 3 months so that parents can tell if their children are lagging behind. ☐
Mr. Kalb said he had no conflicts of interests to disclose. Coauthor Dr. Paul A. Law received grants from Autism Speaks.