Neuroimaging Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1440, USA.
Proton MRS was performed in a patient with developmental acalculia. The results indicated a focal, wedge-shaped defect in the left temporoparietal brain region near the angular gyrus, with differential decreases in N-acetyl-aspartate, creatine, and choline. These results support the hypothesis that developmental acalculia, like acquired acalculia, is associated with left posterior hemisphere lesions.