Children's maths linked to grey matter

Scientists have found that children who are poor at arithmetic are more likely to have less "grey matter" in a part of the brain associated with mathematical ability.

A study of children born prematurely has revealed that those with a pronounced inability to do simple sums have smaller amounts of grey matter in the left parietal lobe, a region on top of the head behind the ear.

Grey matter is composed of the densely packed central "bodies" of nerve cells. The researchers, however, do not know whether the findings mean that children with arithmetic problems have fewer brain cells in the grey matter. "The essential finding is that we provided an explanation for why there is a high incidence of numeracy problems within pre-term [premature] babies," said Elizabeth Isaacs, who led the study at the Institute of Child Health in London.

"What we need to find out is why it happens. It doesn't happen in all premature babies. However, there is an increased incidence of learning difficulties in pre-term babies generally and the risk increases as the birth weight goes down," Dr Isaacs said.

In a study published in the journal Brain, the scientists studied 80 low-birthweight children who were born prematurely. They compared brain scans of those with normal numeracy skills with those who had problems with simple arithmetic. The differences in the amount of grey matter within the left parietal lobe were too small to be seen with the naked eye, but did emerge when the scans were analysed by a computer.

"We cannot yet say that all children with calculation deficit will have the same parietal lobe anomaly. Imaging studies will be needed for a broader range of children," Dr Isaacs said.

"However, since the area identified has also been implicated in adult studies, it seems a fruitful area for further research," she said.

Adults who have brain strokes within the parietal lobe often suffer from the complete inability to use numbers in a condition known as acalculia but other areas of the brain are also believed to be involved in numeracy.

"Our results do not mean that the left parietal lobe is the only region of the brain that is important in arithmetic skills," Dr Isaacs said.

The average age of the pre-term children in the study was 15, but many of those with numeracy problems were tested at the age of seven and found to be normal.