Premature Babies Intelligence

Most preemies' mental abilities improve with age

Last Updated: 2003-02-11 17:03:57 -0400 (Reuters Health)

By Alison McCook

NEW YORK (Reuters Health) - Very tiny premature babies may face a host of mental and physical problems, but new research released Tuesday suggests that most show significant improvements in word recognition and intelligence during the first years of life.

Researchers discovered that tiny preemies--weighing between 600 and 1,250 grams (about 1 to 3 pounds) at birth--improve their verbal skills and intelligence to the point where they score within normal range by age 8.

These findings suggest that, in some cases, a young child's early environment may help him overcome early developmental disadvantages from spending too little time in the womb, Dr. Glen P. Aylward, who wrote an accompanying editorial, told Reuters Health.

He noted that, if faced with the parents of a very tiny premature infant, he would counsel them to surround their growing baby with as engaging an environment as possible.

"A lot depends on the environment," Aylward said. "And that means you folks have to provide stimulation, so that Johnny can achieve all that he can achieve."

However, study author Dr. Laura R. Ment and her colleagues found that tiny preemies who developed bleeding in the brain--known as an intraventricular hemorrhage at birth--that injured their nervous systems scored lowest in test of word recognition, and those scores only decreased over time.

Aylward, of the Southern Illinois University School of Medicine in Springfield, cautioned that while these findings represent the general trend among pre-term babies, each individual baby can buck this trend.

"You can't predict an individual child. That's a critical idea here," he said.

Ment, of Yale University in New Haven, Connecticut, and her colleagues base their findings on a series of tests of word recognition and intelligence administered to very low birth weight pre-term infants when they reached 3, 4 1/2, 6, and 8 years of age.

The average score for the tests is 100. Ment and her team found that, in the tests of word recognition, half of the pre-term infants scored at least 88 when they were 3, and half reached a score of at least 99 by the time they turned 8.

Ment and her colleagues discovered that 45% of the children increased their scores by at least 10 points over the 5-year period. Another 12.5% experienced a jump in scores of between 5 and 9 points, the authors report in the February 12th issue of the Journal of the American Medical Association.

They note that they found similar improvements in children's scores on IQ tests.

These are significant improvements, Aylward said, which would likely be noticeable to people close to the children.

"Five points can make a big differences in the classroom," he said.

However, he cautioned that previous research has shown different results, with one study demonstrating that very premature infants may struggle in school through ages 9 and 10.

He added that the tests used in the current study are "gross measures" of a child's mental abilities, and pre-term infants may still have long-term, subtle problems that could surface as a child ages.

The current findings give cause for optimism, Aylward said, "but I think we need to be very cautious."

SOURCE: Journal of the American Medical Association 2003;289:705-711,752-753.

Copyright © 2003 Reuters Limited.