Transcoding and calculation in aphasia

Aphasia may have deteriorating effects on several numerical skills, such as counting, reading numerals aloud, or writing them to dictation, as these a bilities rely on intact language. However, aphasia also seems to have speci fic effects on the calculation system. Group studies, as well as single-cas e studies, point to the fact that language-impaired patients have particula r difficulties in completing multiplication tasks, while other operations a re less impaired. From a theoretical point of view, there is still a debate as to whether this association reflects a general psycholinguistic problem , the effect of aphasia on numerical cognition, or a deficit in non-specifi c resources underlying both number and language domains. In studies on numb er transcoding multi-route models have been proposed which parallel semanti c and asemantic routes in alphabetical processing. Yet, the review of the e mpirical evidence suggests that these models still lack relevant theoretica l specification.