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Biomedical subjects

G Deloche

Publications and source records attributed to G Deloche.

16 recordsLinked to original sources
PubMed1992

Images of numbers, or "When 98 is upper left and 6 sky blue".

Some people declare that they possess a personal visual representation of numbers: some automatically "see" the numbers they are confronted with in a precise location in a structured mental space, others "associate" specific colours with given numbers. Such visuo-spatial representations of numbers were first described by Galton in 1880 but have since received little attention from psychologists. It is the aim of this article to describe these mental representations and discuss their role in number processing. The authors first review Galton's observations, and then present their own. Finally, they discuss the relevance of these visuo-spatial representations in relation to contemporary debates on number representation and calculation.

Adult↗
PubMed1991

Dot counting by brain damaged subjects.

In this study, we examine how brain damaged adults (aphasics, right-brain lesioned subjects (RBD), and demented subjects) perform a basic education skill: determining the cardinality of different sets of objects (dots). The RBD subjects encountered more difficulty with the spatial correspondence components of the task (correct pointing to the dots), while the aphasics experienced more difficulty with the verbal components (the production of the correct number-word sequence). The deficit evidenced by the demented patients was less systematic. However, qualitative analyses of patients' behavior suggested an organization that tended to minimize the impact of their cognitive deficits on the object-counting task, and an analysis of their counting indicates that the basic counting principles proposed by Gelman (1982) and Fuson (1988) may be preserved.

Aphasia↗
PubMed1987

Right hemisphere language processing: lateral difference with imageable and nonimageable ambiguous words.

Influence of imageability on hemispheric processing difference is studied in a lexical decision task with semantic priming. Homographs and ambiguous words were biased according to the prime toward their low or high imageable meanings and unilaterally presented in the visual field. A right visual field (RVF) superiority was observed; it was nonsignificant for the high imageable (HI) meaning but significant for the low imageable (LI) meaning of the ambiguous words. Thus the results seem to favor a bilateral hemispheric representation of HI words and a unilateral left representation of LI words. Theoretical implications of the results are discussed to the various models of ambiguous word access processing.

Adolescent↗
PubMed1985

Syntactical knowledge in a case of agrammatism: evidence from transcoding Roman and Arabic numerals.

The ability of an aphasic subject with agrammatism in both comprehension and production to transcribe quantities from Roman numerals to Arabic and the reverse was investigated. Systematic errors in the transcoding processes were observed that could not be accounted for by the peculiarities of the two ideographic coding systems or by difficulties with direct transcoding rules. The results are discussed in the framework of the current debate on preserved/impaired hierarchical syntactical knowledge of agrammatic subjects. The findings paralleled the results of previous studies on the transcoding skills of agrammatics from/to alphabetic numerals to/from digital forms. In the case of this particular patient, it is therefore tentatively concluded in favor of preserved syntactical knowledge.

Adult↗
PubMed1984

Semantic errors reconsidered in the procedural light of stack concepts.

The purpose of this paper is to demonstrate the relevance of the stack concept in neuropsycholinguistics, a stack being a file with serially ordered elements. Number names (one, two, three, . . .) and the names of the days in the week may be viewed in this way. In a stack structure, any element is identified by two pieces of information: the particular stack to which it belongs and its position within that stack. Two experiments are reported that demonstrate a double dissociation. A deep dyslexic patient with agrammatism was found to sort stack elements on the basis of identity of position-within-stacks, while a fluent aphasic with semantic verbal paraphasias used another criterion, grouping together the items of the same stack. First revealed when handling number names, the two psycholinguistic procedures are also shown to be differentially operative with other linguistic material. Introducing the stack concept thus permits a procedural reinterpretation of some "semantic confusions," particularly but not exclusively those dealing with quantities.

Adult↗
PubMed1981

Lexical meaning: a case report, some striking phenomena, theoretical implications.

A case of global aphasia is reported. In spite of severe impairments in auditory comprehension, as testified by failure in matching spoken words to pictured objects, the patient performed significantly higher than chance level in sorting out the odd item from a spoken list of semantically related words. This preserved ability to achieve the semantic processing of "non-understood" spoken words in the given task is compared to similar experimental data from the study of written word comprehension in dyslexic patients or normal subjects. Taken together, these data call for a procedural approach of the lexicon. In this theoretical framework, lexical meaning should not only be stored and retrieved but it should be computed at each word occurrence.

Adult↗
PubMed1977

Oligoclonal aspect in the CSF of multiple sclerosis patients: a statistical and physiopathological study.

Oligoclonal aspect (O.A.) is observed in 51 per cent of 468 MS patients investigated. Elevation of gammaglobulins and lymphocytic pleiocytosis increase significantly its frequency. O.A. is more frequent in presence of an inflammatory transsudate. Clinical aggravation and O.A seem significantly connected. In the first years of the MS, when the course is intermittent, the frequency of O.A. is significantly influenced by the proximity of the last bout. No such differences exist in patients with continuous course. In conclusion O.A. appears as intermittent expression of a local and general immunity reaction, in connection with the progression of the disease and as a very probable manifestation of persistant virus. We proposed 3 years ago in Göteborg a physiopathological hypothesis suggesting multiple sclerosis (MS) is a two-phase disease. In this first paper, we demonstrated the existence of two successive immunological reactions: The first one is an intermittent synthesis of IgG obviously linked to a lymphocytic pleiocytosis which is also intermittent. This firs CSF pattern appears in the same time of a bout and disappears quickly like the clinical symptoms. It may represent the manifestation of a brief and only infectious aggression. After a few years (more than 5 in average) a second mechanism progress slowly: The synthesis of IgG appears continuous, in remission as in aggravation, the lymphocyte count becomes normal and the level of albumin increases progressively. This second pattern suggests, contrary to the first, a continuous auto-immune processus with the intervention of the general (systemic) immunity. The purpose of this second paper is an attempt to elucidate the signification of oligoclonal aspect in relation to this schema.

Female↗
PubMed1976

Convolution computer processing of the brain electriacl image transmission.

A propagation model of electrical activities between the cerebral cortex and the scalp is presented in this paper. This work is based on a hypothesis of a distribution of cortical sources in a non-uniform dipolar sheet. The general field equations show that the electrical image of the cortex on the scalp is given by the convolution of the cortical potential and a transfer function. We then present several numerical evaluations with respect to the attenuation of the signal, the visual field of the electrodes and the approximation errors that have been introduced. Simulation experiments then enable us to test the behaviour of the model in comparison with complex electrical activities.

Brain↗
PubMedDate not supplied

[Programmed rehabilitation of a case of agraphia (author's transl)].

The authors describe a programmed method of rehabilitation suitable for patients with writing disorders resulting from cerebral lesions. The use of a visual display screen permits differential display and the immediate correction of errors. The application of the method is illustrated in the case of a patient with aphasic agraphia, and its general utility is briefly discussed in relation to the nature of various graphic disorders.

Adult↗