In a study involving 15 young adults, a very small electrical current delivered to the scalp above the right anterior temporal lobe significantly improved their memory for the names of famous people (by 11%). Memory for famous landmarks was not affected. The findings support the idea that the anterior temporal lobes are critically involved in the retrieval of people's names.

A follow-up study is currently investigating whether transcranial direct current stimulation (tDCS) will likewise improve name memory in older adults — indeed, because their level of recall is likely to be lower, it is hoped that the procedure will have a greater effect. If so, the next question is whether repeating tDCS may lead to longer lasting improvement. The procedure may offer hope for rehabilitation for stroke or other neurological damage.

This idea receives support from another recent study, in which 15 students spent six days learning a series of unfamiliar symbols that corresponded to the numbers zero to nine, and also had daily sessions of (tDCS). Five students were given 20 minutes of stimulation above the right parietal lobe; five had 20 minutes of stimulation above the left parietal lobe, and five experienced only 30 seconds of stimulation — too short to induce any permanent changes.

The students were tested on the new number system at the end of each day. After four days, those who had experienced current to the right parietal lobe performed as well as they would be expected to do with normal numbers. However, those who had experienced the stimulation to the left parietal lobe performed significantly worse. The control students performed at a level between the two other groups.

Most excitingly, when the students were tested six months later, they performed at the same level, indicating the stimulation had a durable effect. However, it should be noted that the effects were small and highly variable, and were limited to the new number system. While it may be that one day this sort of approach will be of benefit to those with dyscalculia, more research is needed.

Older news items (pre-2010) brought over from the old website

Right parietal lobe implicated in dyscalculia

By temporarily knocking out an area in the right parietal lobe (the right intraparietal sulcus), researchers have induced dyscalculia in normal subjects, providing strong evidence that dyscalculia is caused by malfunction in this area. These findings were further validated by testing participants suffering from developmental dyscalculia. Although less well-known, dyscalculia is as prevalent as dyslexia and attention deficit hyperactivity disorder (around 5%).

Kadosh, R.C. et al. 2007. Virtual Dyscalculia Induced by Parietal-Lobe TMS Impairs Automatic Magnitude Processing. Current Biology, online ahead of print March 22


Scientists find brain function most important to math ability

A finding that an area of the brain widely thought to be involved in processing number information generally, in fact has two very separate functions, may be the key to diagnosing dyscalculia. One function is responsible for counting 'how many' things are present and the other is responsible for knowing 'how much'. The brain activity specific to estimating numbers of things is thought to be the brain network that underlies arithmetic and may be abnormal in dyscalculics.

[1336] Castelli, F., Glaser D. E., & Butterworth B.
(2006).  Discrete and analogue quantity processing in the parietal lobe: A functional MRI study.
Proceedings of the National Academy of Sciences of the United States of America. 103(12), 4693 - 4698.


Calculation difficulties in children of very low birthweight

Learning difficulties, including problems with numeracy, are common in Western populations. Many children with learning difficulty are survivors of preterm birth. Although some of these children have neurological disabilities, many are neurologically normal. A neuroimaging study of neurologically normal adolescent children who had been born preterm at 30 weeks gestation or less found an area in the left parietal lobe where children without a deficit in calculation ability have more grey matter than those who do have this deficit.

[1281] Isaacs, E. B., Edmonds C. J., Lucas A., & Gadian D. G.
(2001).  Calculation difficulties in children of very low birthweight: A neural correlate.
Brain. 124(9), 1701 - 1707.