Alexandre Castro-Caldas

Influence of learning to read and write on the morphology of the corpus callosum.

Variations in the individual anatomy of the corpus callosum have been reported in several conditions. There seem to be genetic influencing factors, but it is impossible to rule out some environmental ones. This study focuses on the question of the environmental factors, using formal learning to read and write as the main difference in the groups to be compared. Based on magnetic resonance imaging sagital images, the contour of the corpus callosum (CC) of 41 carefully selected women (18 illiterate and 23 literate) was digitized. The comparison between the two groups showed a small difference in the region of the CC where parietal fibres are thought to cross. This region is thinner in illiterate subjects. As illiteracy in this group is the result of social constraints, and the two groups that were compared are well matched for other cultural and pragmatic aspects than literacy, the results are interpreted as showing the possible influence of formal learning to read and write, on the biological development of the brain.

Subjective experience in brain injured patients and their close relatives: A European Brain Injury Questionnaire study

Results are reported from an international project the aim of which has been to develop and validate a wide-ranging questionnaire suitable for administration to brain-injured patients and their relatives. A self-report questionnaire concerning subjective experience of cognitive, emotional and social difficulties (The European Brain Injury Questionnaire, EBIQ) was administered to a group of 905 brain-injured patients, and close relatives to these competed a parallel version of the questionnaire concerning the brain-injured person. The sample was drawn from seven European countries together with Brazil. The same questionnaire was also administered to a group of 203-non-brain-injured controls, similarly in self-report and relative-report versions. Scales relating to eight specific areas of functioning, together with a global scale, are derived from the questionnaire and their internal reliability was estimated in the present data. Analyses of the 63 items of the questionnaire showed consistently greater levels of problems for the brain-injured group, especially as indicated by relatives. This pattern was substantially replicated among the nine scales. The scales discriminated well between stroke patients and those who had suffered a traumatic brain injury. There was also a tendency for reported problems to be greater for patients who were surveyed later post-injury (> or = 19 months) rather than earlier. Comparison of sets of controls derived from two countries (France and Brazil) showed small but important differences. It is concluded that the questionnaire has an acceptable reliability and validity, but that it will be necessary to obtain culturally relevant non-brain-injured control data when employing it in different countries.

Formal schooling influences two- but not three-dimensional naming skills.

The modulatory influence of literacy on the cognitive system of the human brain has been indicated in behavioral, neuroanatomic, and functional neuroimaging studies. In this study we explored the functional consequences of formal education and the acquisition of an alphabetic written language on two- and three-dimensional visual naming. The results show that illiterate subjects perform significantly worse on immediate naming of two-dimensional representations of common everyday objects compared to literate subjects, both in terms of accuracy and reaction times. In contrast, there was no significant difference when the subjects named the corresponding real objects. The results suggest that formal education and learning to read and to write modulate the cognitive process involved in processing two- but not three-dimensional representations of common everyday objects. Both the results of the reaction time and the error pattern analyses can be interpreted as indicating that the major influence of literacy affects the visual system or the interaction between the visual and the language systems. We suggest that the visual system in a wide sense and/or the interface between the visual and the language system are differently formatted in literate and illiterate subjects. In other words, we hypothesize that the pattern of interactions in the functional-anatomical networks subserving visual naming, that is, the interactions within and between the visual and language processing networks, differ in literate and illiterate subjects.

Literacy: a cultural influence on functional left-right differences in the inferior parietal cortex.

The current understanding of hemispheric interaction is limited. Functional hemispheric specialization is likely to depend on both genetic and environmental factors. In the present study we investigated the importance of one factor, literacy, for the functional lateralization in the inferior parietal cortex in two independent samples of literate and illiterate subjects. The results show that the illiterate group are consistently more right‐lateralized than their literate controls. In contrast, the two groups showed a similar degree of left–right differences in early speech‐related regions of the superior temporal cortex. These results provide evidence suggesting that a cultural factor, literacy, influences the functional hemispheric balance in reading and verbal working memory‐related regions. In a third sample, we investigated grey and white matter with voxel‐based morphometry. The results showed differences between literacy groups in white matter intensities related to the mid‐body region of the corpus callosum and the inferior parietal and parietotemporal regions (literate > illiterate). There were no corresponding differences in the grey matter. This suggests that the influence of literacy on brain structure related to reading and verbal working memory is affecting large‐scale brain connectivity more than grey matter per se.

Botulinum toxin type A for the treatment of arm and hand spasticity in stroke patients

Background: Focal spasticity can be a major drawback in the rehabilitation of stroke patients. Previous studies suggest a beneficial effect for botulinum toxin A (BTX-A) for relief of spasticity. Objective: To evaluate the safety and efficacy of BTX-A in the treatment of spasticity in a homogeneous group of stroke patients. Methods: In this phase III open label trial 19 stroke patients stable for at least six months were enrolled (mean age 53.1 (SD 3.27) years; range 26-72). There were 16 males and 4 females. Assessments: Clinical (Ashworth spasticity rating scale, scores for joint mobility, pain and frequency of spasms, Frenchay arm test (FAT)) and subjective (semi-quantitative rating scale filled out by the patient). Only hand and finger flexors were injected. The maximum dosage was 150 U BOTOX® (25 U/muscle), the mean dosage was 92.1 ± 31.6 U BOTOX®. Results: Ashworth rating scale and joint mobility scores improved from a median value of 2 at baseline to a median value of 1 one month after treatment, FAT scores also improved from a median value of 0 at baseline to a median value of 1 one month after treatment (Kruskall-Wallis test p < 0.01). Two-thirds of the patients rated their functional improvement as none or mild. Conclusions: Our study confirmed that BTX-A has an anti-spastic effect but its functional impact needs further evaluation.

Influence of educational level of non brain-damaged subjects on visual naming capacities

Educational level of subjects is a variable often neglected in neuropsychological studies. However, there are pieces of evidence to suggest that illiterate subjects may perform worse than literate subjects in some tests. Visual naming is one of the tasks where a poor performance was reported in illiterate populations. The present study addresses this problem of comparing the performance in visual naming tasks of non-brain-damaged patients of different educational levels. The test materials were composed of three subtests: naming real objects, their photographs, and line drawings of the same objects. Results revealed that there is a clear influence of educational level on the ability to name photographs and line drawings of the objects. Naming line drawings is particularly difficult for the lower educated non-brain-damaged subjects. Visual analysis of two dimensional representations is a task that requires special learning. These results have to be taken into consideration in test selection for poorly educated populations.

Efficacy of piribedil as early combination to levodopa in patients with stable Parkinson's disease: A 6-month, randomized, placebo-controlled study

Piribedil is a non‐ergot D2/D3 agonist with a significant antagonist action on α2A and α2C adrenergic receptor subtypes. This double‐blind placebo‐controlled study was undertaken to confirm the efficacy of 150 mg/day piribedil po in improving motor symptoms of idiopathic Parkinsons disease (PD) in nonfluctuating patients insufficiently controlled by a stable daily dose of levodopa (L‐dopa). Efficacy was assessed using the Unified Parkinsons Disease Rating Scale (UPDRS) III score as primary criterion over 4 months. A second comparison was planned at 6 months, after possible adjustment of L‐dopa. At 4 months, the rate of response, defined as a 30% decrease from baseline on UPDRS III score, was significantly greater with piribedil compared with placebo (56.4% vs. 37.7%; P = 0.040). At 6 months, the better efficacy of piribedil was maintained (61.8% of responders vs. 39.6% on placebo; P = 0.020). The difference between groups on UPDRS III change from baseline reached statistical significance only at 6 months: −10.0 points in the piribedil group vs. −6.7 points in the placebo group (P = 0.037). Secondary end‐points were not significantly different. The most frequently reported adverse events were gastrointestinal symptoms (27 of 61 patients in the piribedil group vs. 13 of 54 patients in the placebo group). In conclusion, a 6‐month oral administration of 150 mg/day piribedil in combination with L‐dopa is well tolerated, except for minor gastrointestinal symptoms at the beginning of the treatment and significantly improves motor symptoms compared with placebo in PD nonfluctuating patients.

Issues in design and analysis of a randomized clinical trial to assess the safety of dental amalgam restorations in children

The Casa Pia Study of the Health Effects of Dental Amalgams in Children is a randomized clinical trial designed to assess the safety of low-level mercury exposure from dental amalgam restorations in children. It is being carried out in 507 students (8 to 12 years of age at enrollment) of the Casa Pia school system in Lisbon, Portugal, by an interdisciplinary collaborative research team from the University of Washington (Seattle) and the University of Lisbon, with funding from the National Institute of Dental and Craniofacial Research. Since the goal of the trial is to assess the safety of a treatment currently in use, rather than the efficacy of an experimental treatment, unique design issues come into play. The requirements to identify as participants children who have extensive unmet dental treatment needs and who can be followed for 7 years after initial treatment are somewhat in conflict, since those with the most treatment needs are usually in lower socioeconomic categories and more difficult to track. The identification of a primary study outcome measure around which to design the trial is problematic, since there is little evidence to indicate how health effects from such low-level exposure would be manifested. The solution involves the use of multiple outcomes. Since there are concerns about safety, multiple interim comparisons over time between treatment groups are called for which, in conjunction with the use of multiple outcomes, require an extension of statistical methodology to meet this requirement. Ethical questions that have to be addressed include whether assent of the children participating is required or appropriate, and whether the director of the school system, who is the legal guardian for approximately 20% of the students who are wards of the state and live in school residences, should provide consent for such a large number of children. Approaches taken to address these and other design issues are described.

Aphasia Following Right Striato‐insular Infarction in a Left‐handed Child: a Clinico‐radiological Study

The case of a six‐year‐old girl with non‐fluent aphasia following a subcortical right‐hemispheric cerebrovascular accident is reported. Examination by computerised tomographic scan revealed a right paraventricular area of diminished density involving the internal capsule, lenticular nucleus and the insula. The speech disturbance was followed by typical right‐hemispheric signs and by left‐channel extinction in dichotic listening tests. The aphasia cleared in two weeks, paralleled by an improvement in left‐channel performance, suggesting that language recovery was dependent on right‐hemispheric structures.

Those Were the (Phrenological) Days

Phrenology is nowadays often considered as a pseudoscience and a reason for ironic comments. This theory was based on the ideas of Franz Joseph Gall (1758-1828). He was indeed a fine neuroscientist that called attention to the cerebral cortex and suggested for the first time that mental functions were the result of the activity of cortical “organs.” The methodology used reveals interesting predictive aspects for what our current practice is. However, the interpretations of the observations were often more in accordance with the predicted heuristic model than with the real findings. Spurzheim (1776-1832) was first his student and then his collaborator. He traveled around the world lecturing and making phrenology a popular science.