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Dyscalculia appears to cloud number images.
13 November 2003
HELEN PEARSON


Up to 6% of children suffer from dyscalculia.


Scientists have homed in on a brain region that leaves some people struggling with mathematics. Their research might point up better ways to teach numbers1.

The study looked at people with dyscalculia - the mathematical equivalent of dyslexia. Up to 6% of children are thought to suffer from the condition; they toil with times tables and can find it tough to add small numbers even as adults.

Dyscalculics have abnormal pulses of activity in a brain furrow called the right intraparietal sulcus, find Nicolas Molko of INSERM, the French Institute of Health and Medical Research in Paris, and his colleagues. The fissure helps the mind to conjure spatial images.

It was also unusually shallow and short in the 14 women that Molko's team scanned with functional magnetic resonance imaging. The women had a genetic condition called Turner's syndrome, which is linked with dyscalculia.

The finding supports the idea that dyscalculics have difficulty conceiving arrangements of numbers, such as a line stretching from one to 100. "It goes very well with what has been found before," says neuropsychologist Monica Rosselli of Florida Atlantic University in Boca Raton.

Molko hopes that brain imaging could eventually diagnose dyscalculics better than today's cognitive tests. The finding might also inform educational schemes that encourage affected children to use different strategies to number lines, say.

But dyscalculia is probably part of a wide spectrum of maths learning difficulties. Some people may have trouble keeping track of tens and units columns, others in recalling rote-learnt sums. "It's unlikely that one brain area can explain all of the problems," says developmental psychologist David Geary of the University of Missouri, Columbia.

Counting cost

Many studies attempt to get to the roots of dyslexia, but dyscalculia is an uncharted condition. This is partly because it is hard to tease apart from word, memory or attention disorders, with which it is often associated.

Diagnosis is further complicated because many people simply dislike maths. This might be due to mediocre teaching or low motivation. Some people almost have "a phobia for mathematics", says Rosselli.

It's unlikely that one brain area can explain all of the problems
David Geary
University of Missouri



More attention is now being focused on children's maths learning and disabilities following pressure from concerned parents and teachers. This year, for example, the US National Institutes of Health and Department of Education committed $18 million over five years to related research projects.

The intraparietal sulcus specifically has not been implicated in the abilities of maths prodigies. But areas of the cortex associated with spatial imagery, such as the parietal lobe - where the intraparietal sulcus is found - were unusually large in Albert Einstein's brain.


References
Molko, N. et al. Functional and structural alterations of the intraparietal sulcus in a developmental dyscalulia of genetic origin. Neuron, 40, 847 - 858, (2003). |Homepage|


© Nature News Service / Macmillan Magazines Ltd 2003