Recent studies suggest that brain-wave data and hearing tests may help diagnose autism spectrum disorder (ASD) earlier. One study conducted by researchers at the University of Rochester Medical Center found that measuring auditory brainstem responses (ABR) in infants as young as six months old can help identify children who are at high risk for developing autism. The study found that children who later received an autism diagnosis had significantly different ABR patterns than children who did not develop autism.
According to a new Rutgers-led study, brain-wave data collected during a routine newborn hearing test could help clinicians detect neurodevelopmental disorders such as autism in early infancy.
Researchers discovered that newborns who were later diagnosed with autism spectrum disorder (ASD) had significant delays in their brainstem responses to sounds. When compared to neurotypical newborns, these babies had a 1.76-millisecond lag in a system that operates on a microsecond timescale.
Because of their limited access to sound frequency, these newborns may have difficulty integrating sound with other sensory streams such as vision, movement, and pain. They may also struggle with social communication and language learning.
Research shows that the so-called “repetitive, ritualistic behaviors” are an adaptation of a system operating on different hardware but still attempting to communicate with us. Our findings force us to reconsider what autism truly is.
Elizabeth Torres
The study, led by Rutgers psychology professor Elizabeth Torres and published in Proceedings of the National Academy of Sciences (PNAS Nexus), suggests a possible approach for developing a universal screening tool for neurodevelopmental disorders, as well as new avenues for targeted personalized treatments.
“We could build a universal screening test with very little effort and cost to eliminate disparities in infant neurodevelopment and establish normative scales of such a dynamic process,” said Torres, who is also the director of the New Jersey Autism Center of Excellence. “This will allow us to measure individual deviations from these neurotypical ranges as soon as possible, when the nervous system is rapidly changing and adapting to its environment and the brain-body circuitry is forming.”
In the study, the researchers examined fluctuations in waveforms – which are often discarded across repetitions – recorded by the Auditory Brainstem Response (ABR) test that assesses hearing. In this test, clinicians play clicks to sleeping babies, whose brain response is recorded using soft electrodes.
“At birth, the brainstem is already critical for survival functions like breathing, swallowing, and excreting,” Torres explained. “It also serves as a conduit to neocortex, subcortical regions, the cerebellum, and the spinal cord, where emergent control and coordination of actions give rise to basic building blocks of social behaviors.” “Because of an infant’s brain’s extreme plasticity, the earlier the therapeutic intervention, the more effective the treatment.”
The findings may explain differences in language acquisition, sensory processing, and motor control as the baby grows and matures, all of which are critical to social interactions and communication. It also explains why young autistic children’s movements are noisy, with repetitive actions, or “stimming,” and unexpected responses to various sensory stimuli.
The team first standardized the waveforms in the experiment to eliminate anatomical differences, such as head circumference, as a source of variability. They then compared waveforms from infants later diagnosed with autism spectrum disorder to a similar number of undiagnosed babies.
Babies who would later be diagnosed with ASD had consistently delayed responses to clicks and limited access to sound frequencies.
Torres, who leads the Sensory Motor Integration Lab and the New Jersey Autism Center of Excellence, said by the time those with ASD receive their diagnosis in the U.S. and even later abroad, their nervous systems developed compensatory coping mechanisms and circuitry different from neurotypical babies.
Researchers can catch these differences early enough to support the system to process sensory signals within the ranges and timescales that will coincide with those of neurotypical individuals, thus enabling information processing and communication between two systems.
“Research shows that the so-called “repetitive, ritualistic behaviors” are an adaptation of a system operating on different hardware but still attempting to communicate with us,” Torres said. “Our findings force us to reconsider what autism truly is.”
The study was co-authored by Rutgers doctoral student Joe Vero and Hannah Varkey, a premed research assistant at the Sensory-Motor Integration Lab. It was conducted in collaboration with the New York State Institute for Basic Research and the University of Miami.
