A dissociation of number processing between arabic and korean numbers: A case study

ABSTRACT

The cognitive domain of number processing has been known to be separable from that of language. Further, the number processing consists of Arabic and verbal number systems which could be also separable from each other. We report a 49-year-old woman who showed a dissociation between Arabic and Korean verbal numbers. Her impairment in number processing was characterized by the defective comprehension and expression of Korean verbal umbers, without notable defects in those of Arabic numbers. A follow-up examination revealed a further dissociation within the processing of Korean numbers, showing persistent impairment of number comprehension with improvement of number expression. In dealing with numbers with more than two digits, she showed syntactic errors characterized by uttering a string of single digit numbers(I.e., 365) rather than stating them as a whole number(365). Furthermore, auditory comprehension was also more accurate when the numbers were presented as an array of single digit numbers than a whole number with units. However, these syntactic errors were not observed on an automatic counting task. The evidence of separable representation of Arabic and Korean number system could be drawn from these observations, and therefore we propose the possibility of dual number processing pathways, one for a simple numbering system without semantic mediation and the other for a complex, multidigit numbering with semantic mediation.