(Reuters Health) - For decades, doctors have told parents to talk to kids as often as possible to help build speech and language skills. Now, a new study suggests that how parents talk to children may matter just as much as how much time they spend talking.

“We found that the most relevant component of children’s language exposure is not the sheer number of words they hear, but the amount of back-and-forth adult-child conversation they experience,” said lead study author Rachel Romeo of Boston Children’s Hospital and the Massachusetts Institute of Technology.

“These ‘conversational turns’ are strongly related to the physical strength of white-matter connections between the two key language regions in the left hemisphere of the brain,” Romeo said by email. “Most importantly, this relationship between conversational turns and brain structure held independent of family socioeconomic status, indicating the importance of turns across all sociodemographic backgrounds.”

Much of the advice parents get on the importance of talking to young kids dates to a landmark study in the early 1990s that found by the time children enter elementary school, kids from low-income families have typically been exposed to 30 million fewer words than kids from more affluent households. Since then, researchers and educators have been examining how increased language exposure in early childhood might help close income-based achievement gaps in school-age children.

For the current study, researchers examined data from recordings of all conversations between 40 children and their parents over two consecutive weekend days. Children ranged in age from 4 to 6 years old, and their parents came from diverse income and education levels.

From the recordings, researchers calculated how many words children heard adults speak and how many words the kids spoke. They also looked for conversational turns by measuring how many exchanges occurred with no more than five seconds passing between something said by the child and a response from the adult.

Then, researchers looked at brain scans of the children and found greater conversational turn-taking associated with stronger connections between two brain regions, known as Wernicke’s area and Broca’s area, that are central to the comprehension and production of speech.

Families’ socioeconomic backgrounds did not appear to influence the results, researchers report in The Journal of Neuroscience.

Beyond its small size, another limitation of the study is that many parents of girls failed to complete the home recordings, leaving 27 boys and only 13 girls in the analysis. It’s also possible that parents’ conversations with their kids on recording days differed from what they might sound like at other times.

Even so, the results add to a large and growing body of evidence suggesting that efforts to increase conversations in low-income households might help reduce the chance that these children will underperform relative to more affluent kids in school, the authors conclude.

“Previous studies have demonstrated that the quality of early language interactions have a significant impact on later language and cognitive skills,” said Natalie Brito a developmental psychologist at New York University in New York City who wasn’t involved in the study.

“But this is the first study to find associations connecting home language exposure, brain structure, and language skills,” Brito said by email.

While children in the current study did have better scores on tests of verbal skills when parents had higher income and education levels, conversation turns still independently influenced these scores, noted Dr. Caroline Kistin, a pediatrics researcher at Boston University School of Medicine and Boston Medical Center.

In the current study, higher parental income and education levels were associated with higher verbal scores. But when the authors statistically controlled for those factors in their analysis, conversational turns were still associated with higher verbal scores, indicating that the differences were not due solely to socioeconomic status.

“Back-and-forth adult-child conversation likely improves language development for all children,” Kistin, who wasn’t involved in the study, said by email. “Organizations that work with young children should recognize the importance of the caregiver-child bond and support families in caring for their children and forming supportive relationships that have been shown to positively influence child development.”

SOURCE: bit.ly/2OA9DDf The Journal of Neuroscience, online August 13, 2018.