Hispanic children often have undiagnosed developmental delays and large numbers of both Hispanic and non-Hispanic children who first were thought to have developmental delay actually had autism, researchers affiliated with the UC Davis MIND Institute have found.
The study, one of the largest to date to compare development in Hispanic and non-Hispanic children, is published in the journal Autism. The results lead the study authors to recommend increased public health efforts to improve awareness, especially among Hispanics, about the indicators of developmental delay and autism.
"Our study raises concerns about access to accurate, culturally relevant information regarding developmental milestones and the importance of early detection and treatment," said Virginia Chaidez, the lead author and a postdoctoral researcher in the UC Davis Department of Public Health Sciences when the study was conducted. "Autism and developmental delay tend to go undiagnosed when parents are not aware of the signs to look for, and the conditions are often misdiagnosed when parents don't have access to adequate developmental surveillance and screening."
Developmental delay is diagnosed in children who lag behind others in reaching important mental or physical milestones, while autism is characterized by deficits in social interactions and communication behaviors. The symptoms of both disorders can be improved with targeted interventions, with the greatest improvements seen when interventions begin early in life.
In conducting the study, the researchers used data from the Childhood Autism Risk from Genetics and the Environment (CHARGE) Study, a population-based study of factors that increase risk for autism or developmental delay. The current study included 1,061 children living in California who were between 24 and 60 months of age. They were divided into three groups: children with autism, children with developmental delay but not autism, and children with typical development. All diagnoses were confirmed or changed based on evaluations by MIND Institute clinicians.
The evaluations of Hispanic children were conducted by bicultural and bilingual clinicians in Spanish or English, depending on the primary language used at home. The results for children with at least one Hispanic parent of any race were compared to the results for children of non-Hispanic white parents.
"Our goal was to use the CHARGE Study to help fill the gaps in research on autism for Hispanics so we can better understand what autism is like for this growing U.S. population," said Irva Hertz-Picciotto, professor of public health sciences, researcher with the UC Davis MIND Institute and principal investigator of CHARGE. "No other study of autism has included such a large proportion of Hispanic children."
When the outcomes for Hispanic children were compared to non-Hispanic children, the results revealed more similarities than differences in terms of autism profiles, including diagnostic scores, language function, whether or not children lost acquired skills and overall intellectual, social and physical functioning.
A striking outcome, however, was that 6.3 percent of Hispanic children enrolled in the study who were selected randomly out of the general population met criteria for developmental delay, compared with only 2.4 percent of non-Hispanic participants, which is the expected percentage. This raised concerns among the researchers that many Hispanic children with developmental delays may not be getting the services they need.
For both Hispanic and non-Hispanic children, there was a high percentage (about 19 percent overall) of Hispanic and non-Hispanic children recruited for the study with developmental delay who actually met criteria for autism, raising concerns about adequate access to accurate developmental assessment.
When the analysis was restricted to bilingual children, a significant relationship also emerged between secondary language exposure (when a child was spoken to 25 to 50 percent of the time in a language other than English) and lower scores on standardized tests of receptive and expressive language. This resulted in lower overall cognitive scores for this group.
"Our results emphasize the importance of considering cultural and other family factors such as multiple language exposure that can affect development when interpreting clinical tests, even when they are conducted in the child's preferred language," said Robin Hansen, chief of developmental-behavioral pediatrics at UC Davis, director of clinical programs with the MIND Institute and a study co-author.
Hansen, the MIND Institute clinical team and the Center for Excellence in Developmental Disabilities at the MIND Institute have worked hard to provide accurate, current and evidence-based information about developmental disabilities to parents, educators, therapists and health-care specialists through an annual conference, website resources and community outreach.
"That so many children are slipping through the cracks is disheartening," Hansen said. "The differences between developmental disabilities can be subtle but important and involve distinct treatment pathways. We need to make sure that all children are getting routine developmental screening, early diagnosis and intervention so they can achieve their fullest potential."
For information on developmental milestones, visit the Centers for Disease Control and Prevention "Learn the Signs" website, which is available in English and Spanish at www.cdc.gov/ncbddd/actearly/index.html. Parents with concerns about their child's development should work with their health-care provider, school district and California Department of Developmental Services regional center to identify appropriate services.
The study, titled "Autism spectrum disorders in Hispanics and non-Hispanics," is available at http://aut.sagepub.com/content/16/4/381. The research was funded by the National Institute of Environmental Health Sciences (grants R01-ES015359 and P01-ES11269), the U.S. Environmental Protection Agency's STAR program (grants R-829388 and R-833292) and the UC Davis MIND Institute.
Based in Sacramento, Calif., the UC Davis MIND Institute is a collaborative international research center committed to the awareness, understanding, prevention, care and cure of neurodevelopmental disorders. Utilizing the advanced biomedical technology and research infrastructure of UC Davis, the institute's scientists and clinicians pursue investigations that will ensure better futures for the one in twenty Americans with neurodevelopmental disorders. For information, visit www.ucdmc.ucdavis.edu/mindinstitute.