Navegando por Orientadores "MARTIN, William Lee Berdel"

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Desempenho na grafia e na direção grafológica em função da postura e da dominância manual em destros e canhotos em famílias de renda baixa e média
(Universidade Federal do Pará, 2007-04-17) SILVEIRA, Francisca Morais da; MARTIN, William Lee Berdel; http://lattes.cnpq.br/8591034699611752
There are three distinct theories that seek to explain the origin of the inverted hand posture (IHP) in left-handers. McKeevers genetic model assumes that the trait is sex-linked, tied to maternal transmission via the X-chromosome, which accounts for the higher prevalence of IHP among males. According to the pathological model, the IHP stems from neuropathological factors, whereas the technical adaptation theory views it as a manual adaptation for coping with abductive demands implicit in the Roman writing system. Many adherents of the latter theory regard the posture as maladaptive, leading to physical problems and illegible script; they recommend that the noninverted posture be used. A previous study was conducted among 96 lower-income adolescents, 48 left- and 48 righthanded, subdivided by sex and writing posture. This investigation extended that study by evaluating an additional 106 students from middle income families, 64 right- and 66 lefthanders. The main objectives were to ascertain whether the IHP was associated with physical problems, birth complications, different patterns of graphological direction and inferior calligraphic performance, as well as to verify whether these characteristics varied with socioeconomic status. As a whole, the findings showed no relationship between IHP, physical and pre-natal problems. On the graphological stimuli, IHP left-handers, more so than noninverters and dextrals tended to draw horizontal lines right-to left; however on other drawing tasks they did not differ from the other groups. On the cursive and printed writing task, females consistently outperformed males. Left-handers committed more errors when printing, but not when In general writing cursively. Response time was the only dependent variable related to socioeconomic status: Middle class students wrote and printed sentences faster than lower-class students. In general, these results do not support the contention that the IHP causes physical problems or inferior calligraphic performance, and thus do not justify attempts to oblige left-handers to adopt the noninverted posture.
Acesso aberto (Open Access)
Os efeitos da idade sobre o padrão de assimetrias táteis, visuais e hemiespaciais em destros e canhotos
(Universidade Federal do Pará, 2008-06) LIMA, Fábio Djan Oliveira de; MARTIN, William Lee Berdel; http://lattes.cnpq.br/8591034699611752
When bisecting horizontal lines, normal individuals tend to err leftwards of the true center, or zero point, a phenomenon known as "pseudonegligence. Previous clinical investigations indicated that lestions in the inferior portion of the right hemisphere parietal lobe impaired mechanisms controling the allocation of attention to the left side of extracorporal space. In addition, heminegligence was not restricted to the visual system, and has been observed in certain tactile and motor modalities as well. In this context, studies have shown that changes in manual preference and proficiency were also related to aging. At present, explanations for these age-realted trends have been incorporated into three alternative hypotheses: differential hemispheric deterioration, bilateral deterioration, and invariant asymmetry. In this study, data were obtained for 61 individuals of both sexes, right- and left-handers, in three age groups: 18 to 30 year olds, 35 to 55 year olds, and a group at age level 60 and above. Individuals were assessed on the Lateral Preference Inventory, the Tactile Line Bisection Test (TLBT), and the Visual Line Bisection Test (VLBT), and we sought to ascertain whether manual, visual, tactile and hemispatial performance would vary as a function of handedness and age. On the TLBT there were few significant differences from the zero point, trends were weak, inconsistent, and not related to handedness or age. The interdependence activation hypothesis as proposed by Bowers and Heilman was not supported, and in conclusion, this version of the TLBT was considered to be unreliable. In contrast, in response to the VLBT, pseudonegligence ocorred consistently in all of the groups. There was a significant interaction between hand and hemispace in all groups, especially when the left-hand divided lines in the left and central fields, a finding that supported the activation hypothesis. There were no significant differences between right- and left-handers, and no reliable trends across the age levels in either group. In sum, there was no evidence indicating the presence of early right hemisphere deterioration, because pseudonegligence also was also robust among the oldest groups. This finding lends more cogent support to the invariant asymmetry hypothesis.
Acesso aberto (Open Access)
Padrões de dominância manual, podálica e performance motora em gêmeos
(Universidade Federal do Pará, 2011-06-27) HORA, Ana Flávia Lima Teles da; MARTIN, William Lee Berdel; http://lattes.cnpq.br/8591034699611752
The twin method involves analyses of MZ-DZ differences in order to ascertain the proportion of variance in a given trait attributable to genetic and environmental effects. Being genetically identical, MZ twins tend to show high concordance rates for many behavioral attributes, whereas DZs, having about 50% of their genetic configuration in common, should manifest a reduced degree of concordance. However, researchers investigating possible genetic mechanisms underlying the development of cerebral dominance for handedness have not found the twin method to be useful, because in all of the twin-handedness studies since 1924, the discordance rates for left- and right-handedness are similar for MZs and DZs. Furthermore, twins often show a higher prevalence of left-handedness than singletons. Rather than a concern with hereditability, the purpose of this study was to investigate possible differences between right- and left-handed twins (MZs and DZs combined) and singletons on specific phenotypic variables related to handedness, including: footedness (penalty kicking), consistent handedness, gender differences, familial sinistralty (FS+), hand posture, and manual skills measured on three tests: Key tapping, Annett’s Pegboard, and circle-dotting. There were 286 individual twins (255 dextrals, 34 sinistrals), and 251 singletons (141 dextrals and 110 sinistrals). Data analyses revealed a three-fold increase on left-handedness among males than females. Furthermore, twin right- and left-handers were more mixed in their hand dominance and had a higher incidence of FS+ among first-degree relatives than singleton right- and left-handers. In line with previous studies, the frequency of contralateral kicking preference was higher in those with mixed than with consistent handedness, especially among left-handers. With regard to hand skill, no reliable between-group differences emerged on the three tests of manual skill. As per expectations, right-handers and left-handers were more proficient when manipulating the stimuli with their dominant hands. On all three measures, in contrast with right-handers, left-handers (twin and singleton) showed reduced between-hand asymmetries. By extension, the increased prevalence of left-handedness among twins could not be attributed to pathological influences, asymmetry reversal or birth order. It is possible, taking into the account the robust differences in mixed-handedness that the pattern of neuromotor lateralization might be more diffusely organized across the hemispheres in twins than in singletons, but this suggestion requires direct evidence, at least from neuroimaging experiments.
Acesso aberto (Open Access)
Pseudonegligência, dominância manual e habilidades motoras em alunos das artes em comparação com alunos de outros cursos
(Universidade Federal do Pará, 2008-05-02) MELO, Thiago Martins de; MARTIN, William Lee Berdel; http://lattes.cnpq.br/8591034699611752
A prominent line of research dealing with cerebral lateralization in artists have investigated the behavior of artists afflicted with various neuropathological syndromes affecting either the right or left hemisphere. In contrast, Bertrand (2001), noting that a few studies have reported an increased prevalence of left-handedness and ambidextrality among artists, suggested the need for systematic research into the laterality characteristics of normal artists. In the absence of such studies, and because it was not possible to obtain data from professional artists, this project was designed to investigate in detail, lateral asymmetries in handedness, motor abilities and visuospatial attention in art and non-art students. These students were recruited from the Art Department at the Federal University of Maranhão, and a public school of art in São Luis. There were 50 non-art students (24 right- and 26 left-handers), and 51 art students (27 right- and 24 left-handers) in the sample. Data were obtained on handedness, eyedness, and footedness, and two measures of motor proficiency: Finger tapping and the Grooved Pegboard Test. In addition, a version of the Visual Line Bissection Test (VLBT) was administered in order to compare the degree of pseudonegligence among and between art and non-art students. We sought to ascertain whether, in comparison with non-artists, the art students would evince a reduced degree of intermanual asymmetry in handedness and motor ability, as well as higher-level accuracy on the VLBT. Our predictions regarding such performance differences, were in fact, supported. Art students, especially left-handers were much less consistent, and more ambidextrous than dextral and sinistral non-art students, and displayed a lower between-hand performance on both motor tests. Also, whereas the degree of pseudonegligence was increased among non-art students, art students were more accurate in their responses, and produced fewer errors around the true zero point. Consistent with previous research among musicians, art students in general, showed a balanced level of visuospatial attention, and these differences were related to the cognitive demands of visual art training.