A twin case study of numerical impairment: the effectiveness of an intensive intervention for restoring number sense

Number sense is considered the start-up kit for learning mathematics and a lack of number sense causes serious numerical impairments. The present study describes two 9-years-old identical twins who experience severe difficulties with counting, comparing quantities and arithmetic. Test results showed that they had severe dyscalculia and that at least N probably suffers from the Gerstmann syndrome. The twins were given an intensive intervention to remediate their numerical problems. During 3 months, they played the Linear number board game and the Number Race twice a week during 15-20 minutes. Results showed little progress in the games for J, but almost no progress for N. No improvement was made on tasks concerning magnitude comparison, dots estimation, addition, subtraction, and number line estimation. The persistent number sense problem presumes brain damage. Possible candidates for brain lesions are the horizontal segment of the intraparietal sulcus (HIPS), the posterior superior...Show moreNumber sense is considered the start-up kit for learning mathematics and a lack of number sense causes serious numerical impairments. The present study describes two 9-years-old identical twins who experience severe difficulties with counting, comparing quantities and arithmetic. Test results showed that they had severe dyscalculia and that at least N probably suffers from the Gerstmann syndrome. The twins were given an intensive intervention to remediate their numerical problems. During 3 months, they played the Linear number board game and the Number Race twice a week during 15-20 minutes. Results showed little progress in the games for J, but almost no progress for N. No improvement was made on tasks concerning magnitude comparison, dots estimation, addition, subtraction, and number line estimation. The persistent number sense problem presumes brain damage. Possible candidates for brain lesions are the horizontal segment of the intraparietal sulcus (HIPS), the posterior superior parietal lobule (PSPL), or a small region of subcortical parietal white matter where fiber bundles related to symptoms of Gerstmann’s syndrome come together. Future research should indicate the exact location.Show less

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A twin case study of numerical impairment: the effectiveness of an intensive intervention for restoring number sense