Jim Kling

May 05, 2015

SAN DIEGO — The effect of socioeconomic status on language development can be seen in infants as young as 7 months, according to an American study of black girls.

The differences in preverbal behavior, preliteracy skills, and language skills weren't enough to be considered a deficit, but they were statistically significant and the trend toward a true deficit is clear, said Laura Betancourt, PhD, from the Children's Hospital of Philadelphia, who presented the results here at the Pediatric Academic Societies 2015 Annual Meeting.

"Based on other data that are available and our own observations of other cohorts, we, unfortunately, think a deficit is going to happen," she told Medscape Medical News.

Many other studies have looked at language in infants in the 7-month age range, but in those, socioeconomic status was considered a variable that had to be controlled for. "They are never designed just to look at that effect. And the variation of socioeconomic status within samples may be too limited to see an effect if you don't design the study for that purpose," said Dr Betancourt.

The researchers used the income-to-needs ratio for their analysis. If family income was at or below the poverty line and the mother had no more than a high-school education, socioeconomic status was considered low. If family income was above the poverty line and the mother had at least a high-school education, socioeconomic status was considered higher.

I was surprised at the size of the effect that early. I thought it would be more subtle.

Healthy infants delivered at term were enrolled in the study at birth and were evaluated at 7 months with the Preschool Language Scale 5. Mothers were evaluated with Wechsler Adult Intelligence Scale IV vocabulary and matrix reasoning subtests.

Vocabulary scores were lower in mothers of low socioeconomic status than in those of higher socioeconomic status. This correlated with infant auditory comprehension, but on hierarchical linear regression, maternal vocabulary did not mediate the relation between socioeconomic status and infant language scores. Specific data have been withheld at the request of Dr Betancourt.

She speculated that parents of low socioeconomic status are likely at a disadvantage because they have less education and less developed parenting skills.

Dr Betancourt said she has seen some parents of low socioeconomic status respond harshly when an older child is exploring. But even at earlier stages, differences in parenting styles can be evident.

One parent, fearful that his child would be exposed to germs, refused to let his infant mouth objects, she said. Some parents do not "understand why the infant is exploring the way they're exploring. Because they're worried about being a good parent — making sure the infants don't get germs, making sure they're well behaved — they sometimes hold children back from their play," she explained.

This research provides evidence that early intervention could alter a child's developmental trajectory, said session comoderator Alan Mendelsohn, MD, from the New York University School of Medicine in New York City.

It makes a very strong case for the role of parenting and long-term impacts.

"It makes a very strong case for the role of parenting and long-term impacts," he told Medscape Medical News.

Although the study's sample was small and the work needs to be confirmed in a larger cohort, the results are "fascinating, and on the face of it make some sense," said session comoderator Susan Berger, MD, from the Northwestern University Medical School in Evanston, Illinois.

If the results are confirmed, "I actually think it's good news," she added, pointing out that mounting evidence of the influence of parenting style on long-term outcomes could have implications for state intervention programs.

"Parenting style is a secondary outcome for them at this point. I think a lot of what was said at this session bodes well for the idea that it should be a primary place to intervene," said Dr Berger.

Dr Betancourt, Dr Mendelsohn, and Dr Berger have disclosed no relevant financial relationships.

Pediatric Academic Societies (PAS) 2015 Annual Meeting: Abstract 1655.4. Presented April 28, 2015.


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