Scientists May Have Located the Source of Dyscalculia

April 2, 2007

Scientists, led by researchers from University College, London, have induced dyscalculia in normal people — but without the longterm mathematical learning difficulty commonly associated with it.

The major finding was that malfunctions in the brain's right parietal lobe are responsible for dyscalculia. This has implications for the diagnosis and management of the disability.

Dyscalculia is as prevalent in the population as are dyslexia and attention deficit hyperactivity disorder — around 5% of the population is affected. However, dyscalculia has not received the same attention as the other disorders. In addition, the underlying brain dysfunction causing dyscalculia is a mystery.

Applying what is called neuronavigated transcranial magnetic stimulation (TMS) to subjects' brains, scientists induced dyscalculia in normal people while they were asked to complete a mathematical task that involved comparing two digits. One digit was physically larger than the other while the second was numerically larger. For example, the subjects compared a larger-font 2 against a 4.

The researchers found that non-dyscalculic participants displayed dyscalculic-like behavior in number processing only during TMS-induced neuronal activity disruptions to the brain. This finding was validated by testing participants who suffer from developmental dyscalculia.

By comparing healthy participants with TMS-induced virtual dyscalculia to those suffering from developmental dyscalculia research has uncovered a direct causal relationship between malfunctions along the right intraparietal sulcus and development dyscalculia.

Source: UCL Media Relations Office