CHICAGO (AP) _ 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 improvements in intellectual ability.
The study involved 296 children born at 28 weeks and weighing just over 2 pounds on average. The findings appear in Wednesday's Journal of the American Medical Association.
In an accompanying editorial, Glen Aylward, a developmental specialist at Southern Illinois University's medical school, suggested that 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.
``Despite improvements in scores, such low-average functioning can place a child at significant academic disadvantage,'' Aylward said.
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 _ an 11-point improvement. By contrast, the average verbal scores of normal birth-weight children improve by about 4.5 points over time, the researchers said.
Nearly half of the children with verbal scores in the mental retardation range _ below 70 _ at 3 years old scored at least in the borderline range _ 70 to 80 _ at age 8. And about two-thirds of the children with borderline scores on both tests at age 3 had scores in the low-normal range at age 8.
Less significant improvements were found in children born with bleeding in the brain, a common complication in very low birth-weight babies.
Dr. Maureen Hack, a leading researcher in the field, was skeptical of the findings and said the children studied were not given tests designed to measure problems usually associated with prematurity, such as attention deficits and poor hand-eye coordination.
``I personally feel that basically, the functional problems persist,'' said Hack, of Rainbow Babies and Children's Hospital in Cleveland.