New Findings Validate the Accuracy of Autism Diagnosis in Children with Down Syndrome

New findings from a 16-year study confirm that the Diagnostic and Statistic Manual of Mental Disorders (DSM), the gold-standard for the classification of mental health conditions, can be used to accurately identify autism spectrum disorders (ASD) in children with Down syndrome, according to research from Kennedy Krieger Institute.

The DSM is used by a wide range of health professionals across clinical and research settings. Previously, the diagnosis of autism in children with Down syndrome has been questioned because of the presence of cognitive impairments in these individuals, despite estimates that 10 to 15 percent of children with Down syndrome are affected by both disorders. Autism-like behaviors are often difficult to differentiate from repetitive behaviors, communication difficulties and other cognitive delays associated with intellectual disability. Because of these challenges, physicians often hesitate to diagnose ASD in children with Down syndrome, leaving them unable to receive important therapy and educational services.

“Based on our findings, I encourage parents of children with Down syndrome who display difficulty with social interaction to ask their providers about the presence of autism or other intellectual disabilities,” says Dr. Walter E. Kaufmann, senior study author and director of Kennedy Krieger’s Center for Genetic Disorders of Cognition and Behavior. “Our results will significantly help clinicians in categorizing co-morbidities and support them in developing more targeted educational and intervention services for children with Down syndrome.”

Published in the Journal of Intellectual Disability Research [Epub ahead of print], the study confirmed the unbiased validity of the DSM for identifying autism in children with Down syndrome by comparing diagnoses based on its criteria with scores from a separate tool, the Aberrant Behavior Checklist – Community (ABC-C).

The ABC-C is one the most commonly used tools for evaluating behavioral problems in individuals with intellectual disabilities and has no relation to the DSM. The 58-item, parent-completed, clinician-interpreted checklist assesses the severity of non-productive behaviors.

“The behavioral diagnosis of autism will probably always be more complicated than a simple blood test,” says Dr. Kaufmann. “However, with this study, we’re able to use objective analytical methods to support the accurate diagnosis of autism in children with Down syndrome so that they can receive proper treatment and care.”

Researchers used the ABC-C scores to confirm or deny initial DSM-based autism diagnoses in 293 patients from the Institute’s Down Syndrome Clinic. The researchers were able to accurately distinguish three diagnostic groups:

* Down syndrome (DS): children with DS, but no significant behavioral problems that would warrant the diagnosis of a coexisting mental health condition
* DS + ASD: children with DS and autism spectrum disorders* DS + Disruptive behavior disorder (DBD): children with DS and DBD, characterized by temper tantrums, physical aggression, excessive argumentativeness, stealing and other forms of defiance or resistance to authority