Strength of evidence for autism interventions: Updated research reviews

little boy playing instrument with teacher

Researchers at the Vanderbilt University Evidence-Based Practice Center and the Vanderbilt Kennedy Center reported findings from two systematic reviews of research studies to assess the strength of evidence for autism interventions that targeted sensory challenges, and nutritional and dietary interventions. Funded by the Agency for Healthcare Research and Quality (AHRQ), both reviews were published in Pediatrics in May.

Zachary Warren

Zachary Warren, Ph.D.

“Parents of children on the autism spectrum along with practitioners have to grapple constantly with deciding what types of interventions are best for individual children, which is especially challenging given how features of autism vary significantly from person to person,” said Zachary Warren, Ph.D., senior author of both reviews. “Interventions can be costly not only in dollars but also in effort and stress on families, so resources need to be directed to interventions where research supports positive effects.”

Warren is associate professor of Pediatrics, Psychiatry & Behavioral Sciences, and Special Education, and executive director of VKC TRIAD (Treatment and Research Institute for Autism Spectrum Disorders).

Both research reviews were updates of earlier AHRQ-funded reviews that covered studies from January 2000 to 2011. The current reviews covered studies from January 2010 to September 2016. (See articles linked at bottom for full authorship as well as details about methodology.)

Interventions targeting sensory challenges in autism spectrum disorders (ASD)

The review related to interventions targeting sensory challenges included 24 studies, including 20 randomized controlled trials (RCT). An RCT is study in which participants are assigned randomly to receive one of several clinical interventions, one of which may be standard practice, a placebo, or no intervention. This approach provides a way to determine if an intervention is effective, useless, or even harmful.

It is estimated that between 42% and 88% of individuals with ASD have difficulties with sensory processing. Symptoms can involve both strong interests and aversions that interfere with learning and social interactions. Even though sensory challenges are common, research investigating sensory challenges across the lifespan has been lacking, in part because of difficulty in diagnosing sensory challenges.

Interventions to target sensory challenges involve the incorporation of sensory experiences to affect a variety of outcomes. Interventions in the studies reviewed included those that were sensory integration-based, environmental enrichment-based, auditory integration-based, music therapy-based, massage-based, and others not fitting into these categories. Of the 24 studies, only 3 studies had a low risk of bias.

Photo of Amy Weitlauf, Ph.D.

Amy Weitlauf, Ph.D.

“Who took part, the specific interventions, and the outcomes varied considerably across the studies,” said first-author Amy Weitlauf, Ph.D., assistant professor of Pediatrics and VKC investigator. “Our conclusion was that some interventions may result in modest short-term improvements in sensory and other autism-related symptoms, but the evidence base is small and whether positive improvements would continue is unclear. These findings also show the need for more rigorous study design.”

Nutritional and dietary interventions for ASD

Many families adopt specific diets and/or nutritional supplements as part of intervention approaches for their children, even though research on the safety and benefits of such approaches are limited. This review included 19 randomized controlled trials, 4 with a low risk of bias. The majority of the studies involved small numbers of participants who were not well-characterized, were short-term, and other interventions being used along with nutritional and dietary interventions were not well-characterized.

Interventions in the studies reviewed included Omega-3 (fatty acid) supplementation, digestive enzyme supplementation, other dietary supplements, Gluten-Free Casein-Free (GFCF) diets, and other dietary approaches.

“Even though nutritional and dietary interventions are common, little research evidence supports effectiveness of nutritional supplement or the GFCF diet for improving behavioral symptoms in ASD,” Warren said. “Many, if not most, families of children with ASD try different diets and nutritional supplements at some point in time. Perceptions are that such interventions will be ‘safe’ and that they have fewer side effects than conventional medications. This isn’t always a safe assumption. Parents give these supplements or alter diets because they hope there will in fact be an active effect. If this is the case, it is smart to make sure part of that action doesn’t have a contraindication or risk of harm. For example, some nutritional supplements in high doses can actually cause harm. Ensuring that families talk to their pediatric providers is critical. There may be well thought through approaches that potentially help, but we don’t yet have compelling data that suggests such efficacy in controlled studies.”

Summary

Both systematic reviews highlight the need for families/caregivers and providers to carefully assess the possible benefits of intervention approaches for individual children.

“We all have a limited amount of time, energy, money, and resources to spend on our children,” Warren said. “We want to make sure we invest our resources in interventions with known efficacy and explore other interventions only as resources allow when there are no contraindications. I often recommend that pediatric providers try to openly discuss these concerns with families. Families are usually willing to do everything they possibly can to help their child and that’s why they pursue every possible intervention opportunity. Providers should join with families around this motivation, provide a transparent understanding of the evidence and harms, and link them with services of known benefit wherever possible.”

The authors also emphasize the need for research that follows the effects of specific interventions over longer periods of time to provide stronger evidence of benefits and harms.

About AHRQ

The two research review articles published in Pediatrics were authored by researchers at the Vanderbilt University Evidence-Based Practice Center. It is one of 13 AHRQ-funded research centers nationwide that provide comprehensive, science-based reviews of evidence related to common medical conditions and new health care technologies and strategies. The full evidence reviews are available to the public on the AHRQ website.

AHRQ is a research agency within the U.S. Department of Health and Human Services (HHS). In addition to studying topics on ways to make health care safer, higher quality, more accessible, equitable, and affordable, it works with HHS and other partners to make sure that the evidence is understood and used.

Weitlauf, A. S., Sathe, N., McPheeters, M. L., & Warren, Z. E. (2017). Interventions targeting sensory challenges in autism spectrum disorder: A systematic review. Pediatrics, May 26, 2017. [Epub ahead of print]

Sathe, N., Andrews, J. C., McPheeters, M. L., & Warren, Z. E. (2017). Nutritional and dietary interventions for autism spectrum disorder: A systematic review. Pediatrics, May 26, 2017. [Epub ahead of print]

Jan Rosemergy is VKC deputy director and director of Communications and Dissemination.

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