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Abstract:
Abstract: We report on an eighteen year old male (JS) with a
diagnosis of developmental dyscalculia and dysgraphia. His
neurological history is negative and a recent MRI was read as
normal. MR spectroscopy, however, showed marked decreases in
N-acetyl-aspartate, creatine and choline in the left inferior
parietal lobe. Standard Neuropsychological tests and further pilot
testing of JS suggested intact simple numerical processing (i.e.,
numerical comparison) but deficits in higher level calculation
(i.e., single digit multiplication). In two experiments we
investigated which brain areas were being used for numerical
processing with functional MRI (Experiment 1) and the effects of
strategic practice on JS's multiplication performance (Experiment
2).Preliminary Experiment 1 results suggest that JS's simple
numerical processing is subserved by superior parietal regions
normally recruited during more complex calculations. Preliminary
Experiment 2 results further suggest that JS's higher level
multiplication deficits are due to his inability to construct
durable long-term representations. Despite his deficit in
representational storage, JS was able to learn a non-memorial,
spatial finger calculation strategy which he could use to solve
relatively complex arithmetic problems. These results suggest a
functional and neural dissociation between simple and complex
numerical processing in the parietal lobe and also support the use
of alternative, non-memorial strategies to help children with
developmental dyscalculia compensate for their deficit.
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