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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

Examples of the E (exact) condition (panel a) and the A (approximate) condition (panel b) for arithmetic tasks.
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Figure 3: Examples of the E (exact) condition (panel a) and the A (approximate) condition (panel b) for arithmetic tasks.

Mentions: According to Stanescu-Cosson et al. [13], the patient was given 20 questions requiring use of one of three rules of arithmetic, i.e., addition, subtraction, or multiplication. Division was not tested because the patient refused solving the problems. The patient was asked to respond by pointing to one of two alternatives presented on a white card. Two conditions were set; exact calculation (E) and approximate calculation (A). Under the E condition (Fig. 3a), the wrong answer was close to the exact correct answer by 2-3 units. In contrast, under the A condition (Fig. 3b), the approximate correct answer was a number off by only one unit, and the wrong answer was remote from the correct one (Fig. 3b). E and A conditions for each arithmetic operation were tested twice on separate days. Operands ranged from 1 to 9. Questions re-using the same digit (e.g. 2+2, 6+6) were avoided.


Dissociation of exact and approximate calculation in severe global aphasia.

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

Examples of the E (exact) condition (panel a) and the A (approximate) condition (panel b) for arithmetic tasks.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Examples of the E (exact) condition (panel a) and the A (approximate) condition (panel b) for arithmetic tasks.
Mentions: According to Stanescu-Cosson et al. [13], the patient was given 20 questions requiring use of one of three rules of arithmetic, i.e., addition, subtraction, or multiplication. Division was not tested because the patient refused solving the problems. The patient was asked to respond by pointing to one of two alternatives presented on a white card. Two conditions were set; exact calculation (E) and approximate calculation (A). Under the E condition (Fig. 3a), the wrong answer was close to the exact correct answer by 2-3 units. In contrast, under the A condition (Fig. 3b), the approximate correct answer was a number off by only one unit, and the wrong answer was remote from the correct one (Fig. 3b). E and A conditions for each arithmetic operation were tested twice on separate days. Operands ranged from 1 to 9. Questions re-using the same digit (e.g. 2+2, 6+6) were avoided.

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