Marie-Pascale Noël

Finger gnosia: a predictor of numerical abilities in children?

This paper aimed to test the specificity of predicting power of finger gnosia on later numerical abilities in school-age children and to contribute to the understanding of this effect. Forty-one children were tested in the beginning of Grade 1 on finger gnosia, left–right orientation (another sign of the Gerstmann “syndrome”), and global development. Fifteen months later, numerical and reading abilities were assessed. Analyses of the results indicated that, contrary to the general measures of cognitive development, performance in the finger gnosia test was a good predictor of numerical skills 1 year later but not of reading skills, which proves the specificity of that predictor. The same conclusion was also true for the left–right orientation. However, finger gnosia could equally predict performance in numerical tasks that do or do not rely heavily on finger representation or on magnitude representation. Results are discussed in terms of the localizationist and the functional hypotheses.

Arabic number reading deficit: A single case study or when 236 is read (2306) and judged superior to 1258

This paper presents a single-case study of a patient (NR) showing a very specific (though not isolated) disorder in Arabic number reading. The type of reading errors and the pattern of the results observed in tasks tapping different components of the number processing system support the hypothesis of a deficit in the syntactic module of the Arabic comprehension system (in McCloskey, Sokol, & Goodmans [1986] model). NRs deficit is also examined in the light of two other number reading models: Seron and Deloche (1984) and Cohen and Dehaene (1991). In addition, the opposition beween semantic and asemantic transcoding models is discussed. In tasks based on a representation of the quantity, NRs errors with Arabic forms seem to result from correct semantic processing based on the expected verbal transcoded forms; this is easily interpretable in the semantic transcoding model (e.g. McCloskey et al., 1986), whereas in asemantic perspectives (e.g. Seron & Deloche, 1984; Cohen & Dehaene, 1991) no direct explanation is proposed. In this respect, a preferred entry code hypothesis is developed.

Calculation and number processing : assessment battery; role of demographic factors

This paper describes the structure and contents of EC301, a standardized testing battery for the evaluation of brain-damaged adults in the area of calculation and number processing. The battery was administered to 180 normal subjects stratified by education (3 levels), age (3) and gender. EC301 is composed of a large variety of tasks dealing with basic arithmetic skills, and their linguistic, spatial, and mnesic dimensions. The three main notational systems for numbers--Arabic digits, written verbal, and spoken verbal number forms--are explored. Analysis of error rates indicated the effect of some demographic factors (principally, education; incidentally, gender) on normal performance in some tasks.

Selective Preservation of Exceptional Arithmetical Knowledge in a Demented Patient

Neuropsychological methodology is generally founded on the description of functional dissociation after focal brain damage. The observation of exceptional abilities can also constitute a means of documenting the different cognitive systems. In this study, we report the performance of a demented elderly patient who, although he had impaired functions in several cognitive domains, showed exceptional calculating abilities, superior to those of young adults. This case study deals with the problem of various mathematical dissociations at different levels.