Premature babies don’t appear to have learning difficulties, says two studies

Two independent, but complementary, studies on premature births, indicated that pre-term babies are not necessarily disadvantaged mentally, says New Scientist (26 January, 2013).

Stephen Back at the Oregon Health & Science University in Portland, America, studied brains of sheep fetuses because they are similar to the brains of human fetuses. His team studied the cerebral cortex to determine the number of neurons. A small cerebral cortex in premature babies was assumed to reflect a lack of neurons, because some of the cells die when there is a reduced blood flow to the brain tissue (called ischemia) that often happens to premature babies.

Back’s team compared neuron numbers in sheep brains that had experienced ischemic injury with non-injured sheep brains. The numbers were the same, indicating that the neurons were intact and not damaged. However, the team noted that the cells were “all squished together” and differed in shape in the injured brains of the premature sheep. They lacked the branches (called dendrites) that radiate from healthy neurons. “Instead of oak trees [in shape], we saw saplings,” Back said.

In a similar study, Steven Miller at the Hospital for Sick Children in Toronto, Canada, studied the links between neonatal care and brain development in 95 pre-term babies. Miller’s team noted that the whole brain was not influenced, only the cerebral cortex. The team took MRI scans on babies 32-40 weeks old, which showed the same situation as Back’s team: the neurons were damaged, but not dead.  

The two research teams think they are witnessing the same results. They show that premature babies do not have dead brain cells, just damaged ones – which means that they have a “disorder of maturation, not loss.”

Miller’s study indicated that the damaged cells might be nurtured back to health with the right nutrition or cognitive stimulation that could stimulate brain growth. Zoltan Molnar of the University of Oxford in England thinks the work is groundbreaking, but the studies could have assessed other brain regions too, or a more complete picture, reports New Scientist. David Edwards at the University College London says it might be premature to get too excited – although the damaged cells appear to be repairable, he wonders by how much.