Autism Screening in Asymptomatic Kids: Jury Is Out

Nancy A. Melville

August 05, 2015

UPDATED August 6, 2015 // Evidence of the merits of autism screening for asymptomatic children when no concerns have been raised by the parent or healthcare provider is insufficient to recommend either for or against such screening, according to a draft recommendation on the matter issued this week by the United States Preventive Services Task Force (USPSTF), but at least one major organization, the American Academy of Pediatrics (AAP), disagrees.

In addition to possible grades of A through D, recommending for or against a service or action, the USPSTF can settle on "I," indicating that current evidence is insufficient to assess the balance of benefits and harms of a service, as was decided in this case.

"We want to get the message out that an 'I' doesn't mean not to screen or that there is no evidence on the issue but just that evidence is inadequate in terms of screening asymptomatic children under the age of 3 whose parents have not expressed concerns," USPSTF Vice-Chair David Grossman, MD, MPH, a pediatrician in Seattle, Washington, told Medscape Medical News.

"Clinicians should use their clinical judgement and remain aware of signs and symptoms of autism, and certainly if parents begin to express concerns, that's a different story," he said.

The recommendation was based on a review of 17 unique published studies that met the USPSTF's criteria for review and 42 studies involving interventions.

The task force found no randomized trials that looked directly at the issue of the efficacy of autism spectrum disorder screening in children aged 3 years and younger in terms of improving core symptoms, cognitive and intellectual functioning, and other factors, such as communication skills or quality of life for the child and family.

"Most of the literature involves older children with more severe symptoms," Dr Grossman said. "We really would like to see more trials of younger children."

The studies had significant heterogeneity. Three randomized clinical trials showed improvement in cognitive scores related to early intensive behavioral interventions, but a fourth trial showed no effect. Similar patterns were seen in language outcomes, but there were limitations in size and study design, and the applicability of the findings to a screen-detected population was unclear.

The review did, however, find adequate evidence that currently available tests can detect autism spectrum disorder in children between the ages of 18 to 30 months.

Although evidence was insufficient to recommend screening with any particular tool, Dr Grossman noted that "we did agree that the evidence supports the [commonly used] M-CHAT [Modified Checklist for Autism in Toddlers]."

Newer revisions of the M-CHAT include the Modified Checklist for Autism in Toddlers With Follow-up and the Modified Checklist for Autism in Toddlers, Revised With Follow-up (MCHAT-R/F).

For the parent-rated MCHAT-R/F, a positive finding triggers a follow-up interview, and if the interview is positive, a full diagnostic workup for autism spectrum disorder is indicated.

The review represents the first time the USPSTF has taken up the issue of autism screening in asymptomatic children, which was prompted by a nomination that the panel felt met its criteria for consideration, Dr Grossman said.

"Some of the things considered are the burden of the disease, and we feel autism places a very high burden on children, their families, and the public," he said.

"We also saw that there was a fair amount of research both on screening and on treatment, and we thought it might be an opportunity to make a statement about screening."

According to the Centers for Disease Control and Prevention, the prevalence of autism spectrum disorder in the United States in 2010 was 14.7 cases per 1000 children, or 1 in 68 children. The prevalence in 2010 represented a 23% increase from 2008, for reasons that are not fully understood, according to the USPSTF.

In terms of medical society guidelines on the matter, the AAP's Bright Futures Guidelines do call for universal screening for autistic spectrum disorder in all children at ages 18 and 24 months, and the group issued a statement expressing its disagreement with the task force's conclusion.

"Because early identification and referral for appropriate intervention are critical to ensuring that children with autism have access to effective therapies, the AAP recommends all children be screened for ASD at ages 18 and 24 months, along with regular developmental surveillance," the AAP's president, Sandra G Hassink, MD, wrote in the statement.

"The draft recommendation statement on autism screening released Aug. 3 by the US Preventive Services Task Force runs counter to AAP guidelines," she writes.

"The AAP remains committed to its recommendation for the timely screening and identification of children who would benefit from early intervention and treatment."

Contrary to the task force's review, "research shows that early intervention can considerably improve children's long-term development and social behaviors," Dr Hassink writes.

With the recommendation for the use of autism screening at 18 and 24 months having been in the AAP's guidelines since 2007, the task force's draft recommendation was therefore not expected, said Susan E. Levy, MD, MPH, of the Division of Developmental and Behavioral Pediatrics at the Children's Hospital of Philadelphia and chair of the AAP's Autism Subcommittee.

"We were surprised and a little dismayed," she told Medscape Medical News. "I know the AAP and other groups are planning to give feedback during the public comment period with the hopes that the wording of this can be modified to prevent a negative outcome."

Dr Levy noted that the lack of randomized controlled trials addressing the issue in young children is not a surprise ― and has more to do with the ethics of clinical trials than anything else.

"The problem is, you really can't do a randomized clinical trial in children with this issue ― it's not ethical to have one group of children who are screened and another who are not and then follow them over time," she said.

"We've shown there is evidence ― it may not be perfect, but it shows that screening can be effective in identifying kids with developmental delays or autism. We do need more data, though ― we do agree with that."

Furthermore, the draft recommendation applies to children who are asymptomatic, but it is important to consider that not all parents may be able to identify symptoms, Dr Levy added.

"Parents who, for instance, have their first child may not be as aware of some of the subtle characteristics of autism or autism spectrum disorder, so they may not be able to identify the children as having problems, so that's another important reason for screening."

Neurologist Ann Tilton, MD, a professor of neurology and pediatrics and section chair of child neurology at Louisiana State Health Science Center in New Orleans, Louisiana, agreed, noting that in such cases, the burden is placed on the physician to identify potential symptoms.

"If parents don't recognize abnormalities, then it can come down to the degree of surveillance on the physician's part, and it may very often be difficult for the physician to spend enough time to truly observe the child," she told Medscape Medical News.

"So it makes sense that the pediatricians and the AAP are the ones recommending the higher level of screening."

The MCHAT screening tool only involves 20 questions, Dr Levy noted. "Here at CHOP, it's electronic, and the family can do it either ahead of time or in the office at a routine checkup. It doesn't take much time at all and, importantly, can potentially help identify other developmental disorders early."

The American Academy of Neurology and the Child Neurology Society guidelines recommend developmental surveillance at all well-child visits from infancy through school age and at any older ages if concerns arise regarding social acceptance, learning, or behavior.

The American Academy of Child and Adolescent Psychiatry (AACAP) recommends routine questions about autism spectrum disorder and symptoms in the developmental assessment of young children and the psychiatric assessment of all children.

Dr Grossman underscored the fact that general awareness of parents and clinicians of signs of autism spectrum disorder is key to identifying the need for more screening.

"We agree with the recommendations that parents should be aware of what the developmental milestones should be and certainly alert to any symptoms. And clinicians should use their judgement on how to screen and when to screen."

In general, the USPSTF recommendations are consistent with the recommendations of the AACAP, Alice R Mao, MD, professor of psychiatry at the Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, in Houston, Texas, told Medscape Medical News.

"It is important that all children should be screened for developmental disorders, speech delays, and social and communication problems in their pediatric exams," said Dr Mao, who is a member of the AACAP.

"If no developmental problems or behavioral abnormalities are observed by parents, caretakers, or general healthcare providers, such as pediatricians or family practitioners, then there is no need to subject the child to genetic, neuroimaging, or laboratory screening."

"However, if on routine exam there is noted to be developmental disorders or speech and language impairment or communications disorders, then it may be necessary to do more thorough screening."

The draft recommendation for Screening for Autism Spectrum Disorder in Young Children is available for public comment on the USPSTF website and will remain so through August 31, 2015.

Dr Grossman, Dr Mao, Dr Levy, and Dr Tilton report no relevant financial relationships.

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