You're probably so in tune with your baby's cry that you easily know the difference between an "I'm wet" wail and a whimper that tells you someone is getting very, very sleepy.
But can babies' cries also reveal important clues about their risk for autism? It's possible, according to a small study from researchers at Brown Medical School and Boston University that says that certain sounds and pitches infants make when they cry can identify which babies are most likely to be diagnosed with autism spectrum disorder as children.
And this has parents listening up.
What kind of sounds are we talking about? Researchers recorded cries from 39 6-month-old infants, 21 of whom were at risk for autism because they had an older sibling with the condition (having an older brother or sister with autism is a known risk factor for the disorder). The other 18 babies had no family history of autism.
After a computer analysis of the sounds, researchers found that babies in the high risk group tended to cry at higher pitches, and there was another subtle difference that had to do with a kind of self-generated "background noise" in their cry.
By the time the children in the study were 3 years old, three of them were diagnosed as having autism. As babies, these three children had cries that were the highest in pitch, say researchers. They also had cries that sounded more tense, with more "background noise" picked up by the computer analysis, reports Healthday.
Just a random coincidence? Researchers don't think so. Their decision to investigate babies' cries at six months was spurred by other studies that suggest 1-year-old children with autism make sounds and cries that are not typical. Vocal differences are also common in older children with autism.
"We know that older children with autism often produce sound in eccentric or unusual ways," study lead author Stephen Sheinkopf, an assistant professor of psychiatry and human behavior at Brown Medical School in Providence, Rhode Island, tells HealthDay. These atypical vocalizations appear to be related to certain changes in the central nervous system that are linked to the disorder.
If the new findings, published in the October issue of the journal Autism Research, hold up, it might pave the way for identifying children at risk for autism long before common symptoms are detected. Right now, the average age of autism diagnosis is around 6 years old, according to statistics gathered in 2009.
Early detection can mean more effective early intervention. "The earlier we can intervene, the more long-term changes we can make to the benefit of the child," says Sheinkopf.
Waiting for your baby to cry so you can check for pitch and background noise? Remember, researchers relied on a computer program to identify pitch and background noise, not the human ear. "We don't want parents to go home and listen anxiously to their babies cry. We think it's more subtle than that," notes Sheinkopf.
But that's exactly what new mom Maria Thornton, of Scottsdale, Arizona, did after hearing about this study. "I sat there listening to his cry for several minutes and then I snapped out of it," she says. "My goal is to hear him cry less, not more—I think I will just let researchers worry about this one!"