In this case study of an aphasic patient with difficulties in numerical processing, the patient responded to a series of linguistic and numerical tasks designed to assess efficiency levels in processing various linguistic components. In addition, the patient completed a series of transcoding tasks that were directed at isolating whether the problems were associated primarily with arabic numerals or with other modalities (spoken or written). Data were analyzed using chi-square goodness-of-fit tests. Statistically significant differences were obtained between spoken verbal and written verbal outputs and between arabic and spoken verbal outputs. Based upon an analysis of errors, it was tentatively concluded that the disorders were associated with two types of dissociation operating together, one between spoken verbal and written verbal outputs at the syntactical level and the other between lexical and syntactical components in the spoken verbal output. A revised model is proposed to provide a tentative explanation for these observations.

The aim of this study was to evaluate if children with Developmental Dyscalculia (DD) exhibit a general deficit in magnitude representations or a specific deficit in the connection of symbolic representations with the corresponding analogous magnitudes. DD was diagnosed using a timed arithmetic task. The experimental magnitude comparison tasks were presented in non-symbolic and symbolic formats. DD and typically developing (TD) children showed similar numerical distance and size congruity effects. However, DD children performed significantly slower in the symbolic task. These results are consistent with the access deficit hypothesis, according to which DD children's deficits are caused by difficulties accessing magnitude information from numerical symbols rather than in processing numerosities per se.