A problem with numbers may add up to dyscalculia
The Times: 11th September, 2003.
Children who struggle with arithmetic may be suffering from the
mathematical form of dyslexia, a crippling inability to handle numbers.
Dyscalculia may affect as many as one in 20 people and make their lives a
misery, Brian Butterworth, professor of cognitive neuropsychology at
University College London, told the British Association for the
Advancement of Science yesterday. "They are misdiagnosed as stupid," he
"Their teachers think they are stupid; they think they are stupid. We have
done focus groups with nine year-olds and it is heartbreaking."
Children with the disability needed to be reassured that it was akin to
colour-blindness and they should be spared the daily humiliation of maths
lessons by being taught separately, he said.
The disability was innate and had nothing to do with the way children were
taught or their use of calculators. They simply lacked a proper sense of
number, tended to add using their fingers and could not do simple
arithmetic such as subtracting one two-digit number from another.
Entry to university was tricky because many could not pass the maths GCSE.
Those who did get in went on, however, to get good degrees.
Professor Butterworth cited the case of a woman with a First in Philosophy
who had serious dyscalculia. Elsewhere he has written about a man who had
a degree in philosophy but still could not add up. Shopping was a constant
embarrassment because he did not understand prices, had no idea how much
money to tender or what the right change ought to be.
At the association festival at Salford University experts in the
disability suggested that there was a link between dyscalculia and a
primitive number sense possessed by humans and animals that enabled them
to make instant assessments of the numbers of objects in a group without
having to count.
This process was called subitizing, Professor Butterworth said.
In what he described as the largest such study ever carried out, he
investigated visitors to the science exhibition Explore At Bristol.
A total of 18,000 visitors were shown a display of dots on a screen and
asked to say whether a number - two, say - corresponded to the dots.The
results showed that there did appear to be a distinct mechanism for the
instant recognition of small numbers and that women were slightly better
at it than men. Men and women were equally good when there were more than
four dots and they had to be counted.
The evidence is that dyscalculics are bad at the instant judgment of
numbers, possibly because of poor brain development in the parietal lobes
at the back of the brain that are involved in the process.
Stanislas Dehaene of the French National Institute of Health and Medical
Research said that he had used brainimaging methods to show that there
were specific cells in this part of the brain whose job it was to
represent numbers. His experiments showed that girls with Turner's
syndrome, a genetic disease, suffered dyscalculia and disorganisation of
this part of the brain.
Elizabeth Isaacs, of the Institute of Child Health in London, said that
very low birthweight babies who appeared quite normal but were poor at
arithmetic had a deficiency of a protein, taurine, in their blood soon
after birth. Brain scans showed that this group also had less grey matter
in the parietal lobes.
Sum of all fears
There is no simple test for dyscalculia, but children who suffer from it
often have problems:
understanding the arithmetical signs (plus, minus, etc)
adding or subtracting numbers
with the times tables
telling the time
They may also reverse numbers, eg 15 for 51
They may transpose numbers eg 364 to 634