When infants see or hear something interesting to them, like the sound of a human voice, their heart rate tends to slow down ever so slightly, a sign they’re paying attention. But a recent small study suggests this may not be true for infants at risk for autism.
Researchers led by Katherine Perdue, PhD, of the Laboratories of Cognitive Neuroscience at Boston Children’s Hospital, studied 40 babies who had an older sibling with autism spectrum disorder (ASD). These “baby sibs” are at 20-fold risk for developing autism themselves. For comparison, Perdue and colleagues also studied 48 infants who did not have a sibling with ASD and were therefore at low risk for autism.
At 3, 6, 9 and 12 months of age, the at-risk infants had slower heartbeats than the low-risk infants. When the babies were presented with speech sounds, heart rates slowed less in the at-risk babies than in the low-risk infants.
While none of the at-risk infants, followed until age 2, were later diagnosed with ASD, the researchers believe they may still be at risk for problems such as delayed speech. This may be due to differences in auditory processing. “It might not be autism per se, but it could be something that’s related to communication in some way,” Perdue told Spectrum News.