Limits...
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

Diagram of information processing for numerals and arithmetics as proposed by Dehaene and Cohen [7], with apparent functional lesions shown for the present patient.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2682839&req=5

Figure 6: Diagram of information processing for numerals and arithmetics as proposed by Dehaene and Cohen [7], with apparent functional lesions shown for the present patient.

Mentions: In an analysis of numerical and arithmetic processing, Dehaene and Cohen [7] postulated two distinct pathways involving symbolic and magnitude representations (Fig. 6). The symbolic representation deals with arithmetical operations, transcoding (reading and writing) and memory for digits. Verbalization is essential for symbolic manipulation. In contrast, magnitude representation transfers information from digital to analog form without verbalization, and plays a major role in estimation or comparison of quantities, memory for magnitude, and approximate measurements.


Dissociation of exact and approximate calculation in severe global aphasia.

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

Diagram of information processing for numerals and arithmetics as proposed by Dehaene and Cohen [7], with apparent functional lesions shown for the present patient.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: Diagram of information processing for numerals and arithmetics as proposed by Dehaene and Cohen [7], with apparent functional lesions shown for the present patient.
Mentions: In an analysis of numerical and arithmetic processing, Dehaene and Cohen [7] postulated two distinct pathways involving symbolic and magnitude representations (Fig. 6). The symbolic representation deals with arithmetical operations, transcoding (reading and writing) and memory for digits. Verbalization is essential for symbolic manipulation. In contrast, magnitude representation transfers information from digital to analog form without verbalization, and plays a major role in estimation or comparison of quantities, memory for magnitude, and approximate measurements.

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