Marsha Munroe was 29 weeks pregnant with twins when a doctor felt a tiny foot in her birth canal. There was no question the baby girls were on their way.
It would be 11 more weeks before she finally brought Kennedy and Kieran home, thrilled they were healthy but worried their early birth would affect the development of their brains.
One to 2 per cent of Canadian infants are extremely premature, born at 32 weeks gestation or earlier. By the time they start school, more than half have learning disabilities or behavioural problems. Margot Taylor and her colleagues at the Hospital for Sick Children in Toronto want to know why.
The twins, now 2, are part of an ambitious, long-term research project to track the brain development of very premature infants. The goal: to find a way to predict which youngsters are most likely to struggle in the classroom. A second study, this one with school-age children, is yielding intriguing clues about brain differences that may help explain why school is so challenging for former preemies. Dr. Taylor and her colleagues hope to find effective strategies to help toddlers and preschoolers at high risk of experiencing difficulties.
"We want to be able to help them before they get to school."
The number of children born at 32 weeks gestation or earlier has increased dramatically since the 1980s and continues to rise, Dr. Taylor said. Most seem to have largely normal development until Grade 1, she said; the problems often don't show up until they are challenged cognitively.
She and her colleagues are tracking the twins and 100 other preemies and toddlers. They scan their brains shortly after birth with a number of magnetic resonance imaging techniques, including some never before used with infants so small.
In the final months and weeks in the womb, the brain undergoes radical growth and dramatic changes. In preemies, this process occurs after birth.
More scans are done around the time the babies were expected to be born and again once they turn 2. In addition, the children undergo two in-depth assessments of their development at 2 and 4. Dr. Taylor and her colleagues hope to follow them until they are in second grade.
The second project, with older children, currently involves 26 school children, age 7 to 10. They were born at 32 weeks or earlier. Preliminary evidence suggests they tend to have weaker working memories than children in the control group, who were born at term, at 37 weeks or later.
Work memory is the ability to use information, to manipulate or work with facts using short-term memory. You need working memory to understand instructions and to solve math problems. When we read, it allows us to relate later facts to what came earlier.
The researchers asked the children to look at images that appeared on a computer monitor and press a button when one was repeated. The children in the control group had a distinctive pattern of activation in their frontal lobes when they did this. Those who were born prematurely did not.
The frontal lobes are involved in paying attention, storing and retrieving memories, reasoning, problem-solving and using language.
"These very preterm children had almost no frontal-lobe activity while doing this task," Dr. Taylor said.
As children's brains develop, particular regions become more specialized for different kinds of jobs, but this doesn't appear to be happening as much in the children who were born prematurely.
Unlike the children in the control group, they had relatively low levels of activity dispersed throughout the brain.
"Their brains are doing it differently," Dr. Taylor said.
As long as the working memory task was easy, they performed as well as children in the control group. But when the researchers made the test more difficult - the repeated images appeared after a longer interval - they were less adept.
The findings will be presented at a conference in June. But Dr. Taylor said it might be a good idea for parents of children born prematurely to exercise their youngsters' working memory with games like Go Fish, or Concentration.
"There are ways to improve working memory and attention. Attention is a big part of it,'' said Dr. Taylor, whose work is funded by the Canadian Institutes of Health Research.
She and her colleagues have also found structural differences in the brains of children who were born very prematurely. Parts of the cerebral cortex, or grey matter, were thinner than seen in children who were born at term.
"We are now in the process of putting all of these together," Dr. Taylor said.
For Ms. Munroe, who works for the Ontario government, it is comforting to know that researchers are closely following the brain development of Kennedy and Kieran. So far, the news has been encouraging and fits with what she sees when she compares the girls' development to that of their older sister, Kalen, now 5.
"The feeling we have about our kids is that they are doing well."