Tuesday, March 01, 2005

Dyscalculia & Two Brain Pathways for Math

Troubleshooting problem areas in mathematics can be difficult especially as the math problems become more complex. Recognizing the pattern of errors that a child is making can mean the difference between success and failure.

In upcoming posts, we'll try to tackle specific problems that can happen in math disabilities, but biggest recent news that can help students with dyscalculia is that there are 2 different pathways for math in the brain. The fact that these systems are located in different parts of the brain is important because it usually means if you've got problems in one route, the other is just fine.

The images below are excerpted from the Dehaene group's paper. They refer to an 'exact' mathematical pathway vs. 'approximate'. Based on work from other researchers, we prefer to call them the Rote math memory pathway (e.g. memorized math facts) and the Spatial math memory pathway (approximation, estimation, numbers related spatially or visually). What you can see in these fMRI views is that more brain activation is present for the Rote memory pathway on the left side of the brain(top brain facing left), whereas more activation is present on the right side of the brain (bottom brain facing right) for the Spatial pathway.


The distinction is an important one in the classroom, especially if a math disability might be present. Some children may seem to present with inexplicable difficulties memorizing math facts. There are tricks to compensate for this, but one alternative is to use the other route by adopting spatial strategies (including mental math and estimation). If the problems are spatial though, then estimation and mental math may seem impossible and rote memorization (e.g. through jingles or stories) may be the way to go. These kids may have more problem with subtraction (more spatial than multiplication), but there are additional tricks for this.

Interestingly, one of the studies below noted that 1st grade boys and girls differed in the strategies they adopted to solve math problems. The girls were more likely to adopt spatial strategies (with manipulatives and counting on fingers), whereas boys preferred math fact retrieval approaches, even if this resulted in more errors.
Boys and Girls Think Differently When It Comes to Problem Solving
Understanding dissociations in dyscalculia: A brain imaging study of the impact of number size on the cerebral networks for exact and approximate calculation -- Stanescu-Cosson et al. 123 (11): 2240 -- Brain
Different Strategies for Processing Math

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