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The study was led by Kristina Denisova, associate professor of psychology and neuroscience at Queens College.
By Forum Staff
Infants with very low IQ are at risk of developing childhood autism spectrum disorder (ASD), according to a new study in autism research released on Monday by Queens College.
Led by Kristina Denisova, associate professor of psychology and neuroscience at QC, “The importance of low IQ to early diagnosis of autism,” also establishes that both verbal and non-verbal delays suggest the need for early evaluation and intervention. While many researchers accept the importance of verbal delays, a breakthrough finding of Denisova’s study shows that any sign of lower cognitive ability—for example, not transferring toy blocks between two hands during play or not actively looking for a utensil such as a spoon when dropped–-is potentially important.
The study was supported by funding from the Simons Foundation Autism Research Initiative and the National Institute of Mental Health of the National Institutes of Health (NIMH).
Autism researchers already knew that many children with ASD also have low IQ scores and accept that verbal delays are reliable signs of ASD. About 35% of eight-year-olds with ASD in the United States have intellectual disability (ID), meaning an IQ below 70. However, low IQ was not believed to be a major feature of ASD, and no previous prospective study looked specifically at the cognitive abilities of infants from the general population in order to assess their risk for autism.
Denisova found that if an infant has low verbal or non-verbal early cognitive abilities, there is a 40% greater likelihood of developing ASD in childhood. Her findings should pave the way for parents and caregivers of infants to seek a medical evaluation at any sign of atypical cognitive development, and she hopes this will be especially helpful to underserved populations, in particular African American and Hispanic families. Rates of both ASD and ID are especially high in children in the African American community, and often there are delays in age of first diagnosis of their children.
“Low IQ can be considered an early sign of abnormal brain development that leads to autism,” Denisova suggested. “Early low IQ scores in early diagnosed children in this study may be an indicator of the impaired integrity of nascent neurodevelopmental function or structure. These children may differ in the cause of their condition from individuals who receive diagnoses in adolescence or adulthood and whose IQ scores are in the average range. The early-diagnosed individuals (versus later-diagnosed children) may need different clinical management and treatment.” She believes that future research may need to conduct magnetic resonance imaging (MRIs) scans of the brain structure and function of at-risk infants and to follow up as they grow.
In her new study, Denisova set out to ascertain specifically whether infants having low IQ were at risk of developing ASD by ages two to four, which would allow for earlier and therefore more effective intervention and supports for children and families.
“The average age at ASD diagnosis is relatively late, around four to five years, highlighting the importance of establishing early and reliable ASD markers,” she noted. “Earlier evaluation, diagnosis, and treatment could alleviate the burden for families and society associated with an ASD diagnosis, which is estimated to reach $276–1,011 billion by 2025 in the United States.”
