Infants at high risk for autism spectrum disorder (ASD) are less attuned to differences in speech patterns compared to low-risk infants, according to a new study from Columbia University in New York.
The findings, published in the journal Brain and Language, suggest that interventions to improve language skills should begin during infancy for those at high risk for autism.
“Humans are born with an astonishing ability to distinguish basic sound units that make up all of the world’s languages,” said Kristina Denisova, Ph.D., assistant professor of clinical psychology at the Columbia University Vagelos College of Physicians and Surgeons.
“But why some infants at high familial risk for autism spectrum disorder are less likely to develop their language-specific competence in toddlerhood has remained a mystery.”
In a previous study, Denisova showed that high-risk infants (those who had a sibling with autism) were less likely to turn their heads in response to spoken language than typically developing infants.
Denisova says that “our team dissociated between head movements in infants at high vs. low familial risk for developing autism and detected the signal of future atypical development as early as 1-2 months after birth.”
A large body of research suggests that as an infant grows, future language development depends in part on the ability to distinguish sounds and elements of speech that are familiar versus those that are unfamiliar — including elements of pronunciation, such as stress patterns on different syllables. Sensitivity to specific stress patterns in one’s language serve as important cues for learning language.
In the new study, the researchers evaluated 52 infants (9 to 10 months old) who heard speech with familiar and unfamiliar stress patterns while undergoing MRI. Half of the infants were at high risk of autism. The research team recorded the infants’ head movements throughout the scan and studied whether features of head movements differed between the two groups.
The findings show that low-risk infants turned their heads more frequently while listening to speech with different syllabic patterns, while the high-risk infants did not. High-risk infants had significantly worse receptive language scores and the most atypical head-turning patterns on this task.
Infants who had more abnormal head-turning behavior during three types of exposure — listening to alternating stress speech, listening to language, and during sleep — were more likely to develop ASD by age three.
Denisova then looked at the findings of other studies in an attempt to understand what mechanisms might explain the differences in infant response. Her examination of studies of 774 infants confirmed that high-risk infants have lower receptive language scores compared to low-risk infants, further suggesting atypical processing of speech in the high-risk group.