This dissertation is composed of three manuscripts based on two studies related to training and assessment methods used to evaluate change and overall quality in measures of performance, postural control, and functional movement. Study one evaluated the effect of sand training on athletic performance and postural control. Study two investigated the effect of scoring strata of the deep squat (DS) component of the Functional Movement Screen (FMS) on the weight-bearing lunge test (WBLT), Star Excursion Balance Test (SEBT), and Lateral Flexion Test (LFT) in 101 male and female college students. Study one results included significant overall improvements of the five repetition maximum (5RM) squat (p=0.002), and WBLT (p Study two results indicated that limited dorsiflexion will lead to a reduction in DS performance and asymmetry of performance on the LFT may result in further movement limitations. Subjects scoring a one or two on the deep squat performed significantly lower (p

Motor activities of daily life or sports are characterized by complex 3D rotational movements of the upper limbs can be done around distinct axes of rotation (i) joint (ii) inertia or (iii) through the center mass of arms, each under separate repositories. A recent study showed that within the constraints of speed, a change of axis of rotation occurs in the context of the implementation of a simple rotation of the arm relative to the trunk (Isableu et al., 2009) . In this context, the aim of the thesis was to complete this first analysis to evaluate the robustness of the assumption that the axes around which organizes the movement depends on the speed of motion and the constraints task in general. The assumption is that the axis corresponding to the minimum inertia reduced variability seen with speeds which increase with respect to a center axis associated with the mass (shoulder mass center of the upper limb) and geometric (pin-shoulder elbow). This study is done by considering "simple" and complex athletic movements including movements. Thus, studies have focused on the influence of the task constraints and their impact on the choice of axes of rotation. Firstly the role of initial instruction is tested. Secondly, the variability of the axis of minimum inertia is estimated in a precise task. Thirdly, the hypothesis is tested in an interception task that involves time constraints. Finally, we tested the role of axes in complex gestures, high speed, especially during launch and broken arm during the tennis serve. The results are used to discuss the hypothesis of the importance of the axis of minimum inertia during the execution of voluntary movements of the upper limb.

The focus of this thesis was to study an action that humans perform regularly, namely, to hold a morsel between the teeth and split it into smaller pieces. Three different issues related to this biting behavior were addressed:  (1) the effect of redu­c­ed perio­dontal tissues on food holding and splitting behavior; (2) the behavioral conse­quences of performing different bite tasks with different functional requirements, i.e., to split a peanut half resting on a piece of chocolate or to split both the peanut and the chocolate; and (3) the reflex modulations resul­ting from such a change in the intended bite action. The main conclusions from the experi­mental studies were the following: First, perio­dontitis, an inflam­matory disease that destroys the peri­o­dontal ligaments and the embedded perio­dontal mechanoreceptors, causes significant impairments in the masticatory abili­ty: the manipulative bite forces when holding a morsel are elevated compared to a matched control population and the bite force development prior to food split is altered. These changes are likely due to a combination of reduced sensory informa­tion from the damaged ligaments and to changes in the bite stra­tegy secon­d­ary to the unstable oral situation. Second, people exploit the anatomy of jaw-closing muscles to regulate the amount of bite force that dissipates following a sudden unloading of the jaw. Such control is necessary because without mechanisms that quickly halt jaw-closing movements after sudden unloading, the impact forces when the teeth collide could otherwise damage both the teeth and related soft tissues. Splitting a piece of chocolate, for instance, regularly requires >100N of bite force and the jaws collide within 5 ms of a split. On the other hand, when biting through heterogeneous food, the bite force needs to be kept high until the whole morsel is split. The required regulation is achieved by differen­tial­ly engaging parts of the masseter muscles along the anteroposterior axis of the jaw to exploit differences between muscle portions in their bite force generating capa­ci­ty and muscle shortening velocity. Finally, the reflex evoked by suddenly unloading the jaw—apparent only after the initial bite force dissipation—is modulated according to the bite intention. That is, when the intention is to bite through food items with multiple layers, the reflex response in the jaw opening muscles following a split is small, thus minimizing the bite force reduction. In contrast, when the intention is to rapidly decrease the bite force once a split has occurred, the reflex response is high. This pattern of reflex modulation is functionally beneficial when biting through heterogeneous food in a smooth manner. The presented studies show the significance of integrating cogni­tive, physiological and anatomical aspects when attempting to understand human masticatory control.

This thesis describes a brain-computer interface (BCI) system that was developed to allow direct cortical control of 7 active degrees of freedom in a robotic arm. Two monkeys with chronic microelectrode implants in their motor cortices were able to use the arm to complete an oriented grasping task under brain control. This BCI system was created as a clinical prototype to exhibit (1) simultaneous decoding of cortical signals for control of the 3-D translation, 3-D rotation, and 1-D finger aperture of a robotic arm and hand, (2) methods for constructing cortical signal decoding models based on only observation of a moving robot, (3) a generalized method for training subjects to use complex BCI prosthetic robots using a novel form of operator-machine shared control, and (4) integrated kinematic and force control of a brain-controlled prosthetic robot through a novel impedance-based robot controller. This dissertation describes each of these features individually, how their integration enriched BCI control, and results from the monkeys operating the resulting system.

Hand function is of great importance in the many daily activities that require well-coordinated hand and arm movements. Measurement of hand function is an essential element in the rehabilitation process, in order to facilitate medical diagnosis and determine developmental stages, functional levels, and the efficacy of treatment interventions. Basic requirements for any measurement used in clinics are that they are easy to use, relevant to the function being assessed, and valid and reliable. When scrutinizing the literature on hand function, important gaps were found with regard to measurement. For example, the reliability of grip strength with the Grippit in children has yet to be determined, and there are few evaluations of hand function measurements in Charcot-Marie-Tooth disease (CMT). Furthermore, laboratory measurements of hand function, which have the potential to provide more detailed information and insight into hand control, such as the role of the cerebellum in reactive grip control – have not been fully explored. The overall aim of the thesis was to achieve more knowledge on hand function; on the evaluation of measurements in different target populations; and on movement control of the hand. In the first study, the aim was to evaluate the test-retest reliability of the peak and sustained grip strength with Grippit in a sample of healthy children (n=58, 6-, 10- and 14-y-olds). This was followed by two studies examining hand function in an adult sample (n=20) diagnosed with CMT. The test-retest reliability of grip and pinch strength using Grippit, sensation with the Shape Texture Identification test (STI) and dexterity with the Box and Block Test (BBT) and Nine-Hole Peg test (NHP) were studied. The impact of the disease on daily life, measured with the Disability of the Arm, Shoulder and Hand questionnaire (DASH), and correlations between disability and various aspects of hand function, were also explored in this condition. The aim of the fourth study was to examine grip force response to unpredictable loadings of an object held in a pinch grip in subjects (n=9, 22-48 yrs) who had been diagnosed with a cerebellar lesion, compared with a healthy control group (n=11). The first study showed that test-retest reliability was good for both peak and sustained grip strength in healthy children. The mean and best of three trials were equally reliable, but differences in reliability were detected within different age groups. For example, the peak grip strength, best of three trials, was more reliable for the 6-y-olds (intraclass correlation coefficient (ICC)=0.96, standard error of measurement in percentage (SEM%)=6.3) and 14-y-olds (ICC=0.96, SEM%=5.2) compared with the 10-y-olds (ICC=0.78, SEM%=12.5). In the second study, evaluating measurements of hand function in subjects with CMT, grip strength proved to be reliable (ICC=0.99, coefficient of repeatability (CR)=26.7 N, coefficient of variation (CV)=6.6 %), but pinch strength was less reliable. The reliability was also good for the BBT (ICC=0.95, CR=11.5 blocks/min, CV=8.4%) and the NHP (ICC=0.99, CR=4.3 s, CV=3.9 %). However, a bias towards higher values was noted on the second test occasion with the BBT. The reliability of the STI test (kappa=0.87) was also very good in subjects with CMT. A limitation in this latter test was noted in terms of its ability to describe subjects either performing very well or very poorly. The results of the third study showed that hand function in CMT was reduced (p<0.001) to about 60% of that in healthy controls in each of the separate outcome measures, as well as by a constructed summary index of hand function. The median DASH score was 38.8 (range 0-66.7) and was clearly related to hand function (r=0.64-0.83). The results of the final study in subjects with cerebellar lesions showed that the ipsilateral hand had delayed and more variable response latencies e.g. 278±166 ms for loads delivered at 2 N/s, compared with healthy subjects (HS) 80±53 ms (p=0.005). The cerebellar subjects also used a higher pre-load grip force with the ipsilateral hand (1.6±0.8 N) than the HS (1.3±0.6 N (p=0.017)). Even the contralateral hand in subjects with unilateral cerebellar stroke showed a delayed onset of the grip response. In conclusion: Grip strength assessment in children with Grippit results in good reliability for peak and sustained grip strength, although the 10-y-olds were less reliable. In CMT the tested instruments can all be used to evaluate hand function, but certain factors, such as the number of trials used should be taken into consideration. The CMT subjects’ hand function was reduced and correlated with their self-experienced disability. However, clinicians should be aware that patients might score lower than expected on DASH, possibly due to a long process of adaptation. Cerebellar lesions can impair the reactive grip control in both the ipsilateral and the contralateral hand. These investigations have thus, as intended increased the knowledge of hand function. The studies have evaluated some measurements in different samples, which will help clinicians testing hand function.

As motion interactive games have become more widespread the interest in using these games in rehabilitation of children with motor disorders has increased among both clinical professionals and the families of these children. The general aim of this thesis was to evaluate the feasibility of using interactive games in rehabilitation of children to promote motivation for practice, physical activity, and motor control. A systematic review of published intervention studies was conducted to obtain an overview of existing research and the current levels of evidence for using interactive games in motor rehabilitation of children. Sixteen studies met the inclusion criteria, out of these three were randomized controlled trials while half were case series or case reports. Thirteen studies presented positive findings, which indicated a promising potential. However, more convincing research is needed. Commercially available motion interactive games have only been used in a few studies on motor control, and in none of these home based practice was provided. Moreover, no earlier studies have evaluated if these games may increase motivation for training and daily physical activity among children with disabilities. To address these issues a feasibility intervention including 15 children in the ages 6-16 years and with mild to moderate cerebral palsy was conducted. Each child was provided with a Sony PlayStation2â and the EyeToyâ games in Play3, and was recommended to practice with the provided games for at least 20 minutes/day during four weeks. The intervention was evaluated with gaming diaries, physical activity monitors (SenseWear Armband), interviews with the parents, and the clinical motor tests Movement Assessment Battery for Children-2 (mABC-2), Bruininks-Oseretsky Test of Motor Proficiency subtest 5:6, and the 1 Minute Walk Test. In addition, 3D motion analysis was used to evaluate effects on quality of goal-directed arm movements towards virtual and real objects, respectively. Motivation for practice and compliance of training were high, although declining somewhat during the course of the four weeks. The children’s physical activity increased significantly during the intervention. However, four children were excluded from this analysis due to lack of complete data from the physical activity monitors. According to mABC-2 the children’s motor performance improved, but there were both floor and ceiling effects, indicating a low sensibility of this test. The two additional motor tests showed only non-significant progress. Results from the 3D motion analysis suggest that the children improved movement precision when playing the games, movement smoothness when reaching for real objects, and used a more economic reaching strategy with less trunk involvement. In the interviews the parents expressed the view that motion interactive games promote positive experiences of physical training and add elements of social interaction to the training. They also experienced less urge to take on a coaching role. The training provided by the games was considered unspecific and there was a desire for individualized games to better address the unique rehabilitative need of each child. In conclusion, it is feasible to use motion interactive games in home rehabilitation for children with cerebral palsy to promote short term motivation for practice and general physical training. Specific effects on motor control need to be further explored and there is also a need for reliable tests that are adequate and sensitive enough to capture changes in movement control. In future development of interactive games for rehabilitation purposes, it is a challenge to preserve the motivational and social features of games while at the same time optimizing an individualized physical training.

In this thesis, a practical vector controlled elevator drive is presented. Indirect vector control of induction machine is investigated in theory and then implemented. Control technique is compared with scalar control and induction machine is compared with dc motor. The operation of the system depends on induction machine parameters, so how to accurately and automatically obtaining of the parameters is also presented. Finally, the elevator system is introduced, the application of this control system to the elevator system is described and a basic elevator control system is simulated.

Three-dimensional movement analysis was used to evaluate head and neck movement in patients with neck pain and matched controls. The aims were to further develop biomechanical models of head and neck kinematics, to investigate differences between subjects with non-specific neck pain and whiplash associated disorders (WAD), and to evaluate the potential of objective movement analysis as a decision support during diagnosis and follow-up of patients with neck pain. Fast, repetitive head movements (flexion, extension, rotation to the side) were studied in a group of 59 subjects with WAD and 56 controls. A back propagation artificial neural network classified vectors of collected movement variables from each individual according to group membership with a predictivity of 89%. The helical axis for head movement were analyzed in two groups of neck pain patients (21 with non-specific neck pain and 22 with WAD) and 24 matched controls. A moving time window with a cut-off angle of 4° was used to calculate finite helical axes. The centre of rotation of the finite axes (CR) was derived as the 3D intersection point of the finite axes. A downward migration of the axis during flexion/extension and a change of axis direction towards the end of the movements were observed. CR was at its most superior position during side rotations and at its most inferior during ball catching. This could relate to that side rotation was mainly done in the upper spine, while all cervical vertebrae were recruited to stabilize the head in the more complex catching task. Changes in movement strategy were observed in the neck pain groups: Neck pain subjects had lower mean velocities and ranges of movements as compared with controls during ball catching, which could relate to a stiffer body position in neck pain patients in order to stabilize the neck. In addition, the WAD group had a displaced axis position during head repositioning after flexion, while CR was displaced during fast side rotations in the non-specific neck pain group. Pain intensity correlated with axis and CR position, and may be one reason for the movement strategy changes. Increased amount of irregularities in the trajectory of the axis was found in the WAD group during head repositioning, fast repetitive head movements and catching. This together with an increased constant repositioning error during repositioning after flexion indicated motor control disturbances. A higher group standard deviation in neck pain groups indicated heterogeneity among subjects in this disturbance. Wireless motion sensors and electro-oculography was used simultaneously, as an initial step towards a portable system and towards a method to quantify head-eye co-ordination deficits in individuals with WAD. Twenty asymptomatic control subjects and six WAD subjects with eye disturbances (e.g. dizziness and double vision) were studied. The trial-to-trial repeatability was moderate to high for all evaluated variables (single intraclass correlation coefficients >0.4 in 28 of 32 variables). The WAD subjects demonstrated decreased head velocity, decreased range of head movement during gaze fixation and lowered head stability during head-eye co-ordination as possible deficits. In conclusion, kinematical analyses have a potential to be used as a support for physicians and physiotherapists for diagnosis and follow-up of neck pain patients. Specifically, the helical axis method gives information about how the movement is performed. However, a flexible motion capture system (for example based on wireless motion sensors) is needed. Combined analysis of several variables is preferable, as patients with different neck pain disorders seem to be a heterogeneous group.

L’hypothèse des voies visuelles attribue des rôles fonctionnels spécifiques aux réseaux cérébraux ventral et dorsal du système visuel. Ce modèle émet l’hypothèse selon laquelle la voie ventrale sous-tend le traitement de l'information pour la perception (vision-for-perception), alors que la voie dorsale est impliquée dans le traitement de l'information pour l'action (vision-for-action). L'idée de deux réseaux visuels distincts dans le cerveau humain a fait l’objet de très nombreux travaux de recherche au cours des 20 dernières années, mais les résultats apparaissent contradictoires. Cette thèse vise à éclaircir une partie du mystère de la façon dont la perception et l'action s’articulent. La figure d’Ebbinghaus a été utilisée pour distinguer la fonction d’une vision pour la perception, sensible aux illusions visuelles (taille relative), de la fonction d’une vision pour l’action affectée par les propriétés physiques de l’objet. Dans une première étude, nous avons quantifié l’illusion d’Ebbinghaus. Après, une démarche comparable de caractérisation des mouvements visuomoteurs a été implémentée sous des contraintes de précision et de vitesse. La caractérisation des mouvements visuomoteurs et la quantification de la perception des configurations Ebbinghaus ont ensuite permis de concevoir une tâche visuomotrice dont les cibles étaient des figures d’Ebbinghaus.La thèse a démontré que les voies ventrale et dorsale ne sont pas strictement distinctes fonctionnellement. Différentes variables informationnelles sont potentiellement utilisées pour ‘la vision pour la perception’ et ‘la vision pour l’action’ indépendamment du fait que certaines variables causent des illusions. / The influential two-visual streams hypothesis ascribes specific functional roles to the ventral and the dorsal network of the visual system. The ventral system has been hypothesized to process information for conscious perception (vision-for-perception), whereas the dorsal stream processes information for action (vision-for-action). The idea of two separate visual networks in the human brain inspired an enormous amount of research over the past 20 or so years. The results are conflicting and divisive about the idea, causing a seemingly insurmountable gap between supporters and opponents. This thesis aims to unravel a part of the jigsaw puzzle of how perception and action are functioning. The Ebbinghaus figure has been used to distinguish vision-for-perception that is susceptible to visual illusions (i.e., relative size) from vision-for-action that remain unaffected by perceptions of relative sizes. Therefore, we quantified the Ebbinghaus figure based on its geometry and systematically assessed its size illusion. Subsequently, a visuomotor task was implemented in which precision and speed of the voluntary movement were investigated. The description of the visuomotor task and of the perception of Ebbinghaus figures lead to combine both visuomotor task and Ebbinghaus figures. A dynamical model was fit to the experimental data to investigate the effect on the behavioral dynamics.This thesis demonstrated that the ventral stream and dorsal stream are not strictly functionally distinct, and that potentially different informational variables are used for ‘vision for perception’ and ‘vision for action’ irrespective of whether certain variables cause (perceptual) illusions.

Made available in DSpace on 2014-06-11T19:22:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-09-27Bitstream added on 2014-06-13T20:49:26Z : No. of bitstreams: 1 silva_jj_me_rcla.pdf: 327762 bytes, checksum: 4408f438c3d1b238dba6489318d19450 (MD5) / Fundação para o Desenvolvimento da UNESP (FUNDUNESP) / Considerando que indivíduo e ambiente encontram-se dinamicamente relacionados e que o indivíduo encontra no ambiente situações também em movimento, o presente estudo propôs-se a analisar as estratégias locomotoras da ultrapassagem de obstáculo que se movimenta em diferentes velocidades. Participaram 10 adultos jovens, universitários. Com marcadores passivos fixados em referências anatômicas de interesse, cada participante percorreu andando uma passarela de 6 m de comprimento delimitada por um corredor de 0,50 m de largura e ultrapassou o obstáculo que cruzou perpendicularmente sua trajetória em três condições de velocidade. Os resultados revelaram que a velocidade do obstáculo desencadeou ajustes espaciais e temporais nos passos anteriores ao obstáculo. Na ultrapassagem, os resultados evidenciaram que, na velocidade baixa, os participantes aproximaram-se mais do obstáculo antes da ultrapassagem, aumentaram a margem de segurança sobre o obstáculo e a distância após a ultrapassagem, erraram menos e demoraram mais para ultrapassar o obstáculo. Entretanto, na velocidade alta, os participantes aumentaram ainda mais a margem de segurança sobre o obstáculo e afastaram-se mais após a ultrapassagem. Estes resultados indicam que ocorreram modificações no padrão de aproximação e ultrapassagem do obstáculo de acordo com a velocidade. / Considering that both individual and environment are dynamically related and that the individual find in the environment situations also in movement, the purpose of the present study was to analyze the locomotor strategies during crossing the obstacle, which moved in different speeds. Ten young adults, undergraduate students participated. Passive markers were attached in anatomical landmarks. Each participant walked on a pathway of 6m long and 0.5m wide and passed over an obstacle that perpendicularly (90º) crossed his/her trajectory under three velocity conditions. The results revealed that the obstacle velocity unchained spatial and temporal adjustments in all steps prior to the obstacle. During the crossing phase, the results revealed that in low speed the participants got closer to the obstacle before crossing, increased the safety margin over the obstacle, increased the foot placement after the obstacle, decreased the errors, and increased the time to pass over the obstacle. However, on the high velocity, the participants increased even more the safety margin over the obstacle and increased foot placement after the obstacle. These results showed that the obstacle velocity modulated the approach and crossing patterns.