Many new parents watch eagerly to see if their child is hitting developmental milestones, poring over parenting books and consulting doctors at the smallest hint of difficulty. Yet even if they start to notice signs that their child may be among the one in six who have a developmental disability, parents generally have to wait and watch to know for sure. In the case of autism, caregivers often notice differences in their child’s first one to two years, even as the average age of formal diagnosis remains at 4 to 5 years old.
What if we could recognize signs of developmental disorders much earlier, saving parents years of confusion and worry and helping address challenges sooner? At Brown University’s Hassenfeld Child Health Innovation Institute, we’re studying “biomarkers” that have the potential to identify a child’s risk for autism and other developmental disorders well before more obvious symptoms are apparent. Initial research, for example, suggests that characteristics in the cry of a 1-month old infant have the potential to predict whether they will later be diagnosed with autism.
Biomarkers measure the basic biological processes at the root of more visible, higher-order symptoms. They can inform us about what drives the development of autism from the earliest months of life. For instance, tracking a child’s eye movements can reveal their capacity for social attention — attention to socially relevant information — which plays a central role in the differences in communication and social interaction that are a hallmark of autism and related disorders.
When a caregiver points at or directs their gaze to a ball, most children turn their focus to the ball (what’s called joint attention). When someone is speaking, children typically direct their attention to the person’s face and mouth (a process known as face scanning). Yet many children with developmental disorders like autism deploy their social attention in very different ways.
In collaboration with our colleagues, we measure social attention using computerized technology to track infants’ eye movements as they watch videos. In a recent study, we examined how 12-month-olds pay attention to the mouth of a woman describing an object and then follow her gaze as it shifts to the object. The children’s gaze following and attention to the mouth predicted the development of their language skills at 18 and 24 months. (This particular work focused on children without autism, but studying typical developmental pathways helps to lay the groundwork for research on autism and other developmental disabilities.)
Other eye tracking research has shown that a reduced capacity for social attention in early infancy corresponds to a diagnosis of autism later in childhood. Scientists at Yale’s Child Study Center found that 6-month-olds later diagnosed with autism paid less attention to social scenes, the people within those scenes, and their faces than infants who did not go on to be diagnosed with autism.
Part of the power of biomarkers is that they allow us to get information from an infant or non-verbal individual who can’t tell us what’s going on inside their body and mind. For example, we can track heart rhythm as an indicator of stress in response to social situations. Two recent studies from our lab followed a unique group of infants from birth through a diagnosis with autism later in childhood. Those infants who would later be diagnosed with autism showed subtle changes in heart rhythm in response to social situations that differed from infants who had more typical developmental outcomes.
If we can effectively identify biomarkers like heart rhythm and eye movement that predict developmental issues, then we won’t have to wait until a child is struggling to know that there’s a challenge. Clinicians can use biomarkers to pinpoint difficulties earlier in the child’s life, and doctors and therapists can use them to track the response to interventions over time. Does the child’s cry sound less pained? Is their heart rate more stable when interacting with strangers?
By examining the biological processes at the root of a child’s symptoms, we can also do more to tailor treatment to a particular child. Autism is an umbrella diagnosis that covers varied symptoms with a wide range of causes. Scientists in Sweden have used face scanning to distinguish different types of social and communication issues in children with autism. Research like this might help us establish distinct autism pathways and determine what interventions are most effective for different etiologies.
Biomarkers can also help us identify which children are most at risk for certain health challenges. We know that preterm infants are a high-risk population, as around 30 to 40 percent of children born before 30 weeks will have developmental delays. Biomarkers could help determine which children are at greatest risk and why, so we can start treatment and intervention programs as soon as they leave the hospital.
In addition to transforming how we diagnose and treat developmental delays, biomarkers will advance our understanding of the mechanisms behind these disorders. For example, one of our latest studies found that in children with autism the autonomic nervous system that regulates heart rate and breathing may develop differently. We’re also studying how genes that regulate stress response are turned on and off in developmental disorders. This type of research can illuminate the pathways by which symptoms arise and lead to greater understanding of these disorders.
Perhaps the most exciting implication of biomarkers is that they might one day enable researchers and clinicians to develop new treatments and programs to ameliorate the long-term challenges associated with autism and other developmental disorders. Early interventions have already been shown to improve outcomes for children diagnosed with autism in the preschool years. Identifying children at risk for developmental challenges at ever younger ages will have an even greater clinical impact.
As children with developmental disorders grow, over time they diverge further and further from the typical developmental path. Researchers at Emory University found, for example, that children who are later diagnosed with autism have fairly typical patterns of eye contact in the first two months of life, but their tendency to look at people’s eyes diminishes between two and six months of age. This “narrow developmental window,” they write, might “offer a promising opportunity for early intervention.”
Moving research on biomarkers from the lab to clinical practice is a key step in what has come to be termed translational science. How such translations will be accomplished rests on the success of a coming generation of clinical research. If we can use biomarkers to understand when and how autism develops, we have a better chance of helping influence how it impacts children. We can thus move from remediating challenges to potentially preventing or reducing their onset, transforming how we address autism and other developmental disorders.
Stephen Sheinkopf and Barry Lester are both professors of psychiatry and human behavior and professors of pediatrics at Brown University, and are affiliated with the Hassenfeld Child Health Innovation Institute at the Brown School of Public Health and the Warren Alpert Medical School.