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.

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.

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.

Right-left orientation and significance of systematic reversal in children.

Shortly before the acquisition of right and left, which generally occurs around age 6-7 years, a very simple right/left discrimination task makes it possible to distinguish groups of children with strikingly different cognitive abilities. Preschool children aged from 5 to 6.4 years were asked to show their left hand, right eye, left ear and right hand. On a variety of simple cognitive tasks exploring verbal fluency, syntactic comprehension, working memory, visuo-spatial ability and number processing, children who made from 1 to 3 errors (14% of the sample) performed significantly worse than those who showed systematic reversal (30%) and those who made no error. Differential use of logical thinking can partially explain these differences. Neuropsychological implications of these developmental findings are discussed.

A calculation and number processing battery for clinical application in illiterates and semi-literates.

Ten simple tasks assessing counting, number processing, elementary calculation and quantity estimation were proposed to 122 normal Brazilian adults aged between 18 and 58 years with 0, 1, 2, 3 or 4 years of education. Tasks such as counting the number of elements in small sets were almost perfectly mastered by these illiterate or semi-literate normal subjects; however in other tasks (e.g. those assessing knowledge of the correspondence between numbers and banknotes) a sizeable proportion of the sample showed errors. The pattern of errors was analysed to identify difficulty factors. A strong gender effect with better performance in men than women was observed, which was even greater than the expected effect of educational level. Results in normals allowed to propose cut-off scores for neuropsychological assessment in brain-damaged patients with very low levels of education, which were tested in a small sample of illiterate or semi-literate patients with cerebrovascular accident. It is argued that the relatively neglected area of neuropsychological assessment in illiterates is of great practical and theoretical interest.

Patterns of attentional impairment following closed head injury: a collaborative European study.

A comprehensive assessment of both selective (focused attention, divided attention) and intensive (alertness and vigilance) attentional processes was performed on 106 patients with closed head injury using a computerised battery for the evaluation of attention. All patients were tested at least five months after their accident. A high percentage of patients were pathological in tests mapping the selective components of attention while only a minority were impaired on tests mapping the intensive components of attention. Three different subgroups of patients with consistent performance patterns were evidenced. The psychometric characteristics of the battery and its possible clinical usefulness are discussed.

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.

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.

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.

Visual recognition in right brain-damaged patients: evidence from a tachistoscopic confrontation naming task.

Right brain-damaged patients performed a confrontation naming task. Pictures were tachistoscopically presented to the right visual field and selected for their high degree of canonicity and name agreement measured in control subjects. Compared to controls, patients exhibited significant errors. Misnamings were mainly perceptual, i.e., visual-semantic or purely visual errors. No evidence of pure semantic error was found. Half of visual-semantic misnamings referred to objects of a different size (scale error) within the correct semantic field. Misnamings are tentatively attributed to a disturbance of the visual-imagistic automatic encoding process at the level of the pictorial data store.

Picture confrontation oral naming: performance differences between aphasics and normals.

Oral confrontation naming was compared in 108 normal subjects controlled for education, age, and gender and in 18 aphasic patients for the same set of 115 pictures. Demographic variables influenced both normals' and aphasics' performance. However, the nature of aphasics' misnamings on the one hand and the differential effects of characteristics of pictures and words on normals' and aphasics' responses on the other indicated specific deficits in patients. The classical hypothesis that aphasics' misnamings and the production of word associations by normals should rely on similar mechanisms (Rinnert & Whitaker, 1973) is questioned. Nondominant responses observed in normals accounted for a larger proportion of verbal errors than associates to target words.

Factors affecting the clinical measurement of visuo-spatial neglect.

The present study examined a battery of tests to evaluate unilateral spatial neglect; the tests included different tasks involving several modalities of spatial exploration mapping perceptual, motor, attentional and personal or extrapersonal space dimensions. The subjects, 121 right-brain-damaged patients with unilateral neglect, were studied in seven laboratories in four European countries. Relationships among the various tests were examined by correlations, a cluster analysis and by an analysis of individual cases. Different sensitivity was found among various tests for detecting neglect performances. Both the cluster analysis and the single case analysis clearly showed a segregation between personal and extrapersonal neglect. Analysis of the large cluster, including a variety of tests of extra personal neglect, together with the study of single cases, suggests the possibility of differentiating the various manifestations of spatial neglect which can be interpreted on the basis of the descriptions of other individual cases previously reported in the literature. Finally, the present study indicated the relative stability of neglect following the acute phase and its independence from age.

[Programmed rehabilitation of a case of agraphia (author's transl)]. / Rééducation programmée d'un cas d'agraphie

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.

Diversity of patterns of improvement in confrontation naming rehabilitation: some tentative hypotheses.

A previous group analysis of the effects of a computerized written naming rehabilitation program revealed global improvement with generalization of benefits to untrained items and to untreated oral naming (Deloche et al., 1992). The present multiple single-case analysis of the data indicates a variety of patterns of improvement and of generalization effects among individual patients. Patterns of relationships between written and oral naming behaviors help to explain the type of improvement that was observed.

[Kinesthetic aphasia associated with a pseudothalamic syndrome (author's transl)]. / Aphasie kinésthésique associée à un syndrome pseudothalamique.

Kinesthetic aphasia, as described by Luria, was evoked in a case of aphasia associated with a "pseudothalamic syndrome" of partial superficial Sylvian infarction. A neurolinguistic study of oral utterances enabled qualitative and quantitative analysis of the errors: the disorder is characterized by the high incidence of articulation substitutions. A comparative study differentiated such disorders of oral expression from other aphasic disorders of expression (arthric disorders and phonemic jargon). Kinesthetic aphasia is distinguished by this clinical specificity and by the site of the lesion in the anterior parietal region of the dominant hemisphere.

Assessment of calculation and number processing by adults: cognitive and neuropsychological issues.

Calculation and number processing abilities were assessed in normal (n = 138) and traumatic brain-injured (n = 15) Brazilian literature subjects. The study aimed (i) to analyse the effects of demographic factors and to provide tentative norms adjusted for the relevant variables, (ii) to examine the factorial structure of the battery and to evaluate its clinical validity for diagnosis purposes, and (iii) to question the power of current models to account for effects and dissociations found for these groups. Analysis indicated a main effect of education on most subtests and of sex on three, but none for age. Cut-off scores for normality were defined at Percentile 10 with reference to education. The sensitivity of the battery to the presence of arithmetical impairments was considered satisfactory since 11 out of the 15 patients showed pathological scores. A principal component analysis indicated that the different sub-tests were grouped into three factors, which were tentatively interpreted with reference to current information-processing models. The multiple single-case analysis of dissociations in patients' performance suggested some limits with respect to anatomo-functional models of calculation and number processing.