Pre-term infants slower at processing information

Processing Speed Plays a Role in Intelligence and is Affected by Medical Risk Factors

WASHINGTON – Although individuals vary widely, on average, pre-term infants are markedly slower at processing information — including understanding what they see — than full-term infants. New research shows this deficit in processing speed is already present in the first year of life and the gap in performance does not narrow with age. The research is published in the November issue of Developmental Psychology, a journal of the American Psychological Association (APA).

Many of the tasks thought to depend on processing speed are the same ones in which many pre-term infants perform poorly when older, including measures of intelligence, language and academic achievement, such as reading, arithmetic and spelling. Among pre-terms, slower processing speed is also associated with greater medical risk, such as respiratory distress syndrome.

To explore whether individual differences in processing speed have their roots in infancy, Susan A. Rose, Ph.D., Judith F. Feldman, Ph.D., and Jeffery J. Jankowski, Ph.D., of Albert Einstein College of Medicine – Children’s Hospital at Montefiore studied 153 full-term and 59 pre-term infants (born weighing less than four pounds) to assess processing speed at five, seven and 12 months of age. The infants were presented with a series of pictures of paired faces, one that remained the same across the trials and one that changed. The trials continued until an infant showed a consistent preference for the new faces.

The researchers found that as early as five months of age, pre-terms were significantly slower at processing the paired faces than full-terms. Preterms took about 20 percent more trials and about 30 percent more time than full-terms to study the paired faces and reliably recognize the new faces. The differences were similar at all three ages with no evidence found that the performance gap narrowed with age or that the pre-terms caught up.

The results of the study are consistent with previous research by Rose and colleagues on pre-term/full-term differences in infant recognition memory with studies that show that pre-term infants need more time than full-terms to encode a stimulus well enough to recognize it. “It appears that although pre-terms are as quick as full-terms to orient to a change in their environment, they’re slower at encoding what they see,” said Dr. Rose.

Previous research has also indicated that a number of the medical risks suffered by pre-terms have an effect on processing speed. “The detrimental effect of respiratory distress syndrome and other conditions involving insufficient oxygen (hypoxic-ischemic events) on infant information processing speed is consistent with earlier data showing that these same medical risk factors adversely affect visual recognition memory in infancy,” according to the authors.

“It is not surprising to find that both processing speed and visual recognition memory are vulnerable to the same perinatal (around the time of birth) risk factors. There is evidence both that recognition memory is mediated by the hippocampus and that hypoxic-ischemic events selectively damage the hippocampus.” The findings raise the possibility that these factors affect areas of the hippocampus important to the encoding phase of recognition memory.

Article: “Processing Speed in the 1st Year of Life: A Longitudinal Study of Preterm and Full-Term Infants,” Susan A. Rose, Judith F. Feldman, and Jeffery J. Jankowski, Albert Einstein College of Medicine – Children’s Hospital at Montefiore; Developmental Psychology, Vol. 38, No. 6.