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Archive for Wednesday, February 12, 2003

Preemie intelligence not fixed at birth

February 12, 2003

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— Very small premature babies born with brain damage are not necessarily doomed to below-normal intelligence after all, according to a surprising new study that found that many youngsters' IQ scores improve over time.

Children born extremely prematurely run the risk of a variety of neurological problems, ranging from cerebral palsy, retardation and vision trouble to more subtle learning and behavior difficulties.

But the study found that many youngsters considered borderline retarded make up for lost ground and end up scoring in the nearly normal IQ range by age 8.

The findings are surprising because previous research has found long-term consequences in very small preemies and because the conventional wisdom says that IQ does not change -- at least in people born at normal weight.

"We were thrilled by the findings and surprised because previous reports suggested that there's an adverse outcome for very low birth-weight babies," said lead researcher Dr. Laura Ment, a Yale University pediatric neurologist. "We found children progressively getting better between 3 and 8 years of age."

Ment said the study results echo recent research in animals showing that the developing brain can repair itself.

In the study, children who received early attention such as speech therapy, those from two-parent families and those whose mothers had high levels of education showed the most improvement.

The study involved 296 children born at 28 weeks and weighing around 2 pounds. The findings are in today's Journal of the American Medical Assn.

In an accompanying editorial, Glen Aylward, a developmental specialist at Southern Illinois University's medical school, suggested broader tests of mental function would have had poorer results. And he noted that the IQ improvements were still in the average to low-average range.

The youngsters were given a test of verbal abilities and three different IQ tests starting at age 3. A score of 100 would be average on both the IQ and verbal tests for a normal birth-weight 8-year-old.

The premature youngsters' average IQ scores increased from 90 to 95.

Their average score on the verbal test increased from 88 points at age 3 to 99 points at age 8. By contrast, the average verbal scores of normal birth-weight children improve by about 4.5 points over time, the researchers said.

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