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Dissociation of exact and approximate calculation in severe global aphasia.

Urano M, Yoshino M, Yamamoto M, Mimura M - Open Neurol J (2009)

Bottom Line: Further analyses using specifically designed arithmetic and clock tasks demonstrated a clear dissociation of the patient's abilities between impaired exact calculation and well-preserved approximate calculation.The results support the notion that numerical and arithmetic abilities are heterogeneous in that rote verbal arithmetic facts and quantitative numerical knowledge can be separable.Implications of the present findings for neural correlates of numerical and arithmetic processing suggest that the right hemisphere plays a crucial role in approximate calculation.

View Article: PubMed Central - PubMed

Affiliation: 1Department of Rehabilitation Medicine, Yokohama Stroke and Brain Center, Kanagawa, Japan.

ABSTRACT
We report a 68-year-old patient with severe global aphasia secondary to a large left hemisphere infarction including the parietal lobe. In addition to language and neuroradiological evaluation, the patient was given specifically designed arithmetic and clock tasks requiring either exact calculation or approximate calculation. Despite severe language impairment, the patient showed relatively well-preserved abilities for numerical comprehension and arithmetic operations. Further analyses using specifically designed arithmetic and clock tasks demonstrated a clear dissociation of the patient's abilities between impaired exact calculation and well-preserved approximate calculation. The results support the notion that numerical and arithmetic abilities are heterogeneous in that rote verbal arithmetic facts and quantitative numerical knowledge can be separable. Implications of the present findings for neural correlates of numerical and arithmetic processing suggest that the right hemisphere plays a crucial role in approximate calculation.

No MeSH data available.


Related in: MedlinePlus

Results of the arithmetic task. Performance under the A condition (filled columns) was significantly better than under the E condition (open columns) for addition and subtraction tasks. In contrast, performance of multiplication was similarly poor under A and E conditions. A, approximate; E, exact.
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Figure 4: Results of the arithmetic task. Performance under the A condition (filled columns) was significantly better than under the E condition (open columns) for addition and subtraction tasks. In contrast, performance of multiplication was similarly poor under A and E conditions. A, approximate; E, exact.

Mentions: For addition, performance under E condition was significantly worse than under the A condition [E, 19/40 correct (47.5%) vs. A, 36/40 correct (90.0%), chi2=16.81, df=1, p<.0001]. Similar results were obtained for subtraction with performance under the E condition being significantly worse [E, 17/40 correct (42.5%) vs. A, 33/40 correct (82.5%), chi2=13.65, df=1, p<.0002]. For multiplication, however, correct responses were similarly limited to a chance rate of occurrence under E and A conditions [E, 20/40 correct (50.0%); A, 19/40 correct (47.5%) correct, chi2=0.05, df=1, p>.10] (Fig. 4).


Dissociation of exact and approximate calculation in severe global aphasia.

Urano M, Yoshino M, Yamamoto M, Mimura M - Open Neurol J (2009)

Results of the arithmetic task. Performance under the A condition (filled columns) was significantly better than under the E condition (open columns) for addition and subtraction tasks. In contrast, performance of multiplication was similarly poor under A and E conditions. A, approximate; E, exact.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2682839&req=5

Figure 4: Results of the arithmetic task. Performance under the A condition (filled columns) was significantly better than under the E condition (open columns) for addition and subtraction tasks. In contrast, performance of multiplication was similarly poor under A and E conditions. A, approximate; E, exact.
Mentions: For addition, performance under E condition was significantly worse than under the A condition [E, 19/40 correct (47.5%) vs. A, 36/40 correct (90.0%), chi2=16.81, df=1, p<.0001]. Similar results were obtained for subtraction with performance under the E condition being significantly worse [E, 17/40 correct (42.5%) vs. A, 33/40 correct (82.5%), chi2=13.65, df=1, p<.0002]. For multiplication, however, correct responses were similarly limited to a chance rate of occurrence under E and A conditions [E, 20/40 correct (50.0%); A, 19/40 correct (47.5%) correct, chi2=0.05, df=1, p>.10] (Fig. 4).

Bottom Line: Further analyses using specifically designed arithmetic and clock tasks demonstrated a clear dissociation of the patient's abilities between impaired exact calculation and well-preserved approximate calculation.The results support the notion that numerical and arithmetic abilities are heterogeneous in that rote verbal arithmetic facts and quantitative numerical knowledge can be separable.Implications of the present findings for neural correlates of numerical and arithmetic processing suggest that the right hemisphere plays a crucial role in approximate calculation.

View Article: PubMed Central - PubMed

Affiliation: 1Department of Rehabilitation Medicine, Yokohama Stroke and Brain Center, Kanagawa, Japan.

ABSTRACT
We report a 68-year-old patient with severe global aphasia secondary to a large left hemisphere infarction including the parietal lobe. In addition to language and neuroradiological evaluation, the patient was given specifically designed arithmetic and clock tasks requiring either exact calculation or approximate calculation. Despite severe language impairment, the patient showed relatively well-preserved abilities for numerical comprehension and arithmetic operations. Further analyses using specifically designed arithmetic and clock tasks demonstrated a clear dissociation of the patient's abilities between impaired exact calculation and well-preserved approximate calculation. The results support the notion that numerical and arithmetic abilities are heterogeneous in that rote verbal arithmetic facts and quantitative numerical knowledge can be separable. Implications of the present findings for neural correlates of numerical and arithmetic processing suggest that the right hemisphere plays a crucial role in approximate calculation.

No MeSH data available.


Related in: MedlinePlus