Number representation deficit: a bilingual case of failure to access written verbal numeral representations

Abstract

This study reports the case of a Greek–German bilingual patient (S.V.) with specific deficit in Arabic number production from written German number words. S.V. was able to successfully complete the reverse task, i.e. to convert Arabic numerals into written or oral German number words. She also showed preserved ability to produce both German and Greek numbers and to accurately make oral magnitude judgments in both languages. However, when transcoding two-digit numbers from German written numerals to Arabic numbers she consistently reversed the digits. A series of in-house tasks were used to test her general abilities of number processing, i.e. number synesthesia and calculation. Moreover, a number magnitude comparison task was developed specifically for pairs of numbers with reverse digits and we found that out of pairs of numbers with reverse digits with magnitude less than 100, there exist 19 pair combinations for which distance and relative distance are not concordant. The results suggest that S.V.’s performance was significantly worse as the absolute distance between the numbers in the number pairs increased. These investigations are discussed in analogy with a grammatical rule problem related to absolute and relative distance effects.