Wednesday, November 14, 2012

Math Disorder: Brain Imaging Research

In previous posts, I have reviewed research related to the definition and prevalence of mathematics disorder.  Mathematics disorder was compared to reading disability and the role of genetic and environmental influences in math disorder was examined.

Advances in brain imaging technology provide additional tools to understand brain function including performing calculations and other math cognitive skills.

An early important brain imaging study in mathematics disorders has been published by Davis and colleagues at Vanderbilt University.  Using functional brain magnetic resonance imaging (fMRI), they compared the region brain activation patterns in solving calculation tasks in a group of children with math disorder compared to control children.  

The key elements of the design for this study included:

  • Cases: Third grade students without neuropsychiatric disorders with  normal IQ and math calculation skills below 25%tile for age
  • Controls: Third grade students without neuropsychiatric disorders and math calculation skills at the 50%tile or above
  • Scan tasks: all subjects completed math calculation tasks (an exact and an approximation task) in a 3T fMRI scanners as well as a non-mathematical task (matching Greek letters) interspersed with rest periods
  • Statistical analysis: Brain activation patterns were compared within subjects (math vs non-math, math vs rest) and between cases and controls

The fMRI brain regional activation patterns were similar between the math disorder subjects and controls.  However, the key finding from the study was that the math disorder children had significantly increased activation with math calculation tasks in:
  • brain frontal cortex regions
  • brain parietal cortex regions 
  • left brain cingulate cortex regions (anterior and posterior)

The figure presented here demonstrates the brain cingulate cortex, a region with hyperactivation in the math disorder group. 

The authors note their findings show that "the majority of our findings were found in anatomical regions associated with domain general cognitive resources that support higher level arithmetic skill but are not specific to mathematical processing".

This finding is noted to suggest that the hyperactivation of general cognitive processing brain areas is consistent with relatively immature brain development and a decreased efficiency in solving math calculations.  Math disorders appear to require more intense "revving up" of general brain regions used in executive function and working memory when doing math calculations.

In other words, children with math disorder use the right brain networks to solve calculation problems, but require increased cognitive effort to do so.  Although, the math disorder group correctly solved the presented math problems as accurately as control subjects, they did so more slowly and with more intense cognitive effort.

In a final post on this topic, I will take a look a brain imaging study related to math anxiety, a common concurrent problem in children with math disorder.

Photo of great blue heron in flight from the Venice, Florida rookery is from the author's files.

iPad creen shot of cingulate cortex is from the app 3D Brain. 

Davis N, Cannistraci CJ, Rogers BP, Gatenby JC, Fuchs LS, Anderson AW, & Gore JC (2009). Aberrant functional activation in school age children at-risk for mathematical disability: a functional imaging study of simple arithmetic skill. Neuropsychologia, 47 (12), 2470-9 PMID: 19410589

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