Visuomotor processing and hand force coordination in dyslexic children during a visually guided manipulation task

Developmental Dyslexia negatively affects children's reading and writing ability and, in most cases, performance in sensorimotor tasks. These deficits have been associated with structural and functional alterations in the cerebellum and the posterior parietal cortex (PPC). Both neural structures are active during visually guided force control and in the coordination of load force (LF) and grip force (GF) during manipulation tasks. Surprisingly, both phenomena have not been investigated in dyslexic children. Therefore, the aim of this study was to compare dyslexic and non-dyslexic children regarding their visuomotor processing ability and GF-LF coordination during a static manipulation task. Thirteen dyslexic (8-14YO) and 13 age- and sex-matched non-dyslexic (control) children participated in the study. They were asked to grasp a fixed instrumented handle using the tip of all digits and pull the handle upward exerting isometric force to match a ramp-and-hold force profile displayed in a computer monitor. Task performance (i.e., visuomotor coordination) was assessed by RMSE calculated in both ramp and hold phases. GF-LF coordination was assessed by the ratio between GF and LF (GF/LF) calculated at both phases and the maximum value of a cross-correlation function (r(max)) and its respective time lag calculated at ramp phase. The results revealed that the RMSE at both phases was larger in dyslexic than in control children. However, we found that GF/LF, rmax, and time lags were similar between groups. Those findings indicate that dyslexic children have a mild deficit in visuomotor processing but preserved GF-LF coordination. Altogether, these findings suggested that dyslexic children could present mild structural and functional alterations in specific PPC or cerebellum areas that are directly related to visuomotor processing. (C) 2014 Elsevier Ltd. All rights reserved.

Desempenho em tarefas computacionais em função do uso de diferentes periféricos

With the popularization of information technology and government incentives for inclusion in the digital era, an important issue for science and for industry is the design of tool s for entrance of input to the device, that is , the peripherals at tached to the computer that are reaching the consumer. In order to minimize the impact of repetitive use of these tools for entry, whether when playing games or working, more studies are in need to developper ipherals that enable comfort and effi ciency. This study examined the per formance of individuals with differents izes of hand (i.e., large and small ) in performance of three task s on the computer us ing mouses of small and large sizes. For thi s study, 19 young adul ts were volunteers and asked to per form activities with greater precision and speed. In addition, al l participants were asked on the use of computers. The results showed no statistically significant differences in the performance related to the size of the mouse between subjects with small and large hands. However, an interest ingresult as observed with respect to the performance of individuals with a large hand to perform tas ks more quickly. The results of this study suggest that with both, the small and the large mouse, individuals with big hands have a fas terper formancein tasks of dragging and clicking when compared with the performance of indi viduals with small hand.

Movimento dos olhos e controle postural

The control of stances such as the upright stance seems not to have a purpose in itself; this control could facilitate the execution of other simultaneous tasks, the so-called suprapostural tasks. The goal of this study was to determine the effects of saccadic eye movements on the control of posture. Twelve adult participants had their body oscillations analyzed while standing upright, for 70 s, in the postural conditions of feet apart and feet together, performing fixation in the central target or horizontal saccadic movements, in the conditions slow (0,5 Hz) and fast (1,1 Hz). The results showed that saccadic movements, independently of their frequency, strongly reduced trunk and head oscillations in the anterior-posterior (AP) axis. In this axis, there was an effect of feet position only in head oscillation. In the medio-lateral (ML) axis, the results showed a strong effect of feet position with body oscillation decreased in the condition of feet apart. The effect of the visual task in the ML axis occurred only for trunk oscillation, not reaching significance level in the pairewise comparisons. In the AP axis, the data corroborate a facilitatory explanation of the control of posture: the reduction in body oscillation limited the variations of the stimulus image projected on the retina, facilitating the execution of saccadic movements as compared to fixation. In the ML axis, the effect of reducing the basis of support was more evident than the effect of saccadic movements, suggesting that the available resources were used primarily for the postural task in detriment of the visual task. Additionally, aspects like attentional focus and sensory information pick up are discussed as mechanisms involved in this task

Multi-task control strategy for grid-tied inverters based on conservative power theory

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Pre-task music improves swimming performance

The purpose of this study was to investigate the effects of pre--task music on swimming performance and other psychological variables. A randomized counterbalanced within--subjects (experimental and control condition) design was employed. Eighteen regional level male swimmers performed two 200m freestyle swimming time trials. Participants were exposed to either 5min of self--selected music (pre--task music condition) or 5min of silence (control condition) and, after 1 minute, performed the swimming task. Swimming time was significantly shorter (--1.44%) in the pre--task music condition. Listening to pre--task music increased motivation to perform the swimming task, while arousal remained unchanged. While fatigue increased after the swimming task in both conditions, vigour, ratings of perceived exertion and affective valence were unaltered. It is concluded, for the first time, that pre--task music improves swimming performance.

A influência da orientação motivacional durante o treinamento de atletas iniciantes no tênis de campo

The motivation in the sport has been one of the most studied subjects nowadays, as much that some authors say that the motivation is the base for the success of an athlete, that is, the psychological part must also well be stimulated so that if it reaches the maximum level of concentration during a game it will obtains the expected result. Tennis is one of the sports that more grew in recent years, and together with this fast ascension also increased the number of interested in researching in this area of the Psychology of the Sport. The present study has as objective to begin the adaptation and validation of the interest scale and to analyze the influence of the motivational orientation of the athletes in the sportive performance of the Tennis through the application of scale Teosq – Task and Ego Orientation in Sport Questionnaire (DUDA, 1992), translated, adapted and validated by Hirota and De Marco (2006), where we can identify if the individual is guided for a task or an ego’s goal. This research was carried through in a situated academy of Tennis in the City of Cotia – SP – Brazil, counting on the participation of 20 citizens with age between 09 and 18 years of both the practicing sexes of Tennis. The calculation of the Alpha Coefficient of Cronbach was adopted as statistical method, in order to identify the trust worthy and validity of the instrument beyond the average of each orientation, to be able to verify the athlete’s motivational orientation. For the analysis of the results, the Alpha Coefficient was observed high, compared with previous studies, reaching values of orientation for the ego of 0,90, and 0,70 of orientation for task. They had been registered the following averages, 4,20 (+0,93) and 2,42 (+0,85), respectively of orientation for task and ego. With those results we can point that, the scale applied with the proposal to identify the motivational orientation of the athletes of Tennis, revealed efficiency, and trust worthy in its application, and in accordance with the results, the athletes are guided for task, revealing self-determination, selfconfident, more creative and they judge its success for the quality of the carried through work.

Task complexity reveals expertise of table tennis players

AIM: The purpose of this study was to examine the effect of intensive practice in table-­tennis on perceptual, decision-­making and motor-­systems. Groups of elite (HL=11), intermediate (LL=6) and control (CC=11) performed tasks of different levels. METHODS: All subjects underwent to reaction-­time-­test and response-­time-­test consisting of a pointing task to targets placed at distinct distances (15 and 25-­cm) on the right and left sides. The ball speed test in forehand and backhand condition just for HL and LL group. RESULTS: In CC group reaction time was higher compared to HL (P< 0.05) group. In the response-­time-­test, there was a significant main effect of distance (P< 0.0001) and the tennis-­table expertise (P= 0.011). In the ball speed test the HL were constantly faster compared to the LL in both forehand stroke (P< 0.0001) and backhand stroke (P< 0.0001). Overall, the forehand stroke was significantly faster than the backhand stroke. CONCLUSION: We can conclude that table-­tennis-­players have shorter response-­times than non-­athletes and the tasks of reaction-­time and response-­time are incapable to distinguish the performance of well-­trained table tennis players of the intermediate player, but the ball speed test seems be able to do it.