The aim of this study was to investigate numerical
difficulties in 50 patients with left hemispheric lesions.
Aphasic patients were grouped according to their type of
aphasia diagnosed by the Aachener Aphasia Test. The overall
error rate in various transcoding and calculation tasks
was clearly correlated with the severity of the language
deficit, global aphasics being the most impaired patients.
Broca's and Wernicke's aphasics scored similarly
at the quantitative level, and amnesic aphasics were less
impaired. Interestingly, qualitative analysis of the errors
indicated that each group presented with specific difficulties,
partially reflecting the nature of the language problems.
In simple calculation, multiplication was found to be the
most impaired operation, in particular in Broca's
aphasics. This result supports the hypothesis that the
retrieval of multiplication facts is preferentially mediated
by verbal processing. Calculation procedures were mainly
impaired in Wernicke's and global aphasics. (JINS,
1999, 5, 213–221.)