Infants born prematurely take longer to process
information
But researchers suggest identifying problem early may help them
later in life.
"Premature infants as a group take longer to process information than full-term
infants, New York researchers have found.
While it's known that many babies born prematurely do experience academic difficulties
as they age, this study found that some components of the difficulties may present
themselves early, says Susan Rose of the Albert Einstein College of Medicine.
"We're not trying to stigmatize babies," Rose stresses of the findings. "We're trying
to find the roots of later problems and target interventions."
In the study, published in the November issue of Developmental Psychology, preemies
took 30 percent more time and 20 percent more trials to process faces of babies
they were shown, compared to infants who were born full-term.
This translates to a difference of about 10 seconds at 5 months of age, Rose says,
and although it sounds minute, "it's a significant difference."
The children were tested at 5 months, 7 months and 12 months, although the premature
infants were at their corrected age. Corrected age is the age the preemies would
be if they had been born full-term, so they averaged about 10 weeks older than the
full-term infants in the study. At their corrected age, their development is more
on par with their peers, Rose explains.
The premature infants all weighed less than 1,750 grams at birth, and almost 92
percent of them were considered to be very low birth weight, weighing less than
1,500 grams when born. The full-term babies all weighed more than 2,500 grams at
birth.
There were 153 full-term infants who started the study, of which 144 returned at
seven months, and 126 at the year mark. There were 50 preemies at five months, 59
at seven months, and 56 at 12 months; some of who returned from earlier visits.
The infants were shown series of pictures of paired babies, one face that remained
the same across trials and one that changed. The trials continued until an infant
showed a regular preference for the new faces.
"Babies have a predilection for detecting what's new in the environment," Rose explains.
Having trouble remembering a new face presents a real problem that could haunt the
child for life, she notes. "If you have to study a face for 30 seconds to remember
it, that limits you."
While the premature infants did poorly as a group, this was not true for every single
baby born early, she stresses, nor does it necessarily last. "The majority goes
on to do well. About 30 percent go on to have difficulties."
The researchers do not know what causes the preemies to have these problems, but
speculate that respiratory distress syndrome (RDS), a problem noted in about 50
percent of premature infants, is implicated. "Those that had RDS were the worst
off," Rose notes.
Dr. Saroj Saigal, a professor of pediatrics at McMaster University in Hamilton,
Ontario, doesn't think RDS is the reason premature infants take longer to encode
information.
Nowadays babies in distress at birth are ventilated, and "it's not a problem," she
says. "We can perhaps attribute it to problems with the brain" such as lesions,
she suggests, but there was no data on brain imaging, so she can only speculate.
Rose's study is interesting because it shows the problem exists early on, Saigal
says: "It really is there at the start of infancy and not related to environmental
factors."
"It's very solid research," adds John Hagen, executive officer of the Society for
Research in Child Development. He points out that while the 5-month-old infants
had a 10-second difference in encoding information compared to full-term children,
this gap decreased by 12 months of age, when the difference was five seconds. "The
kids show lags; they're not bottoming out."
Rose says that testing for the problem early may mean it can be corrected. "I'm
excited. We may be able to help these children," she says."