We examined the effect of changing from an internally prepared motor plan to a revised action which potentially differed from the original plan along two dimensions: wrist orientation (horizontal or vertical) and left/right hand. Participants were instructed to prepare a particular hand grasp action and then were cued either to execute that motor plan or cancel it and plan a new action. In Experiments I and II, if the change from the original motor plan to an alternate response implied an action different from the prepared one, there was a slowing in response time. Moreover, if there was a change, maintaining the originally planned wrist orientation produced faster responses than changing orientation, but only if the response hand remained constant between planned and alternate actions and the cue was an image of a hand depicting a goal posture. In Experiment III, when the alternate action was cued by an image of an object inviting a particular grasp action, there was transfer only of the hand feature. In a final experiment, participants switched from a prepared action to naming a manipulable object. The motor features of the object differed from the original motor plan in the same way as in previous experiments. No effect of the previously cancelled motor plan was seen on naming latencies. These results elucidate the nature of motor plans and the role of motor actions in the representation of objects. / Graduate

Aim: To study patient-related functional outcome measures, implant survival and radiographic loosening after total wrist arthroplasty (TWA) using four different implants. To evaluate a new TWA design biomechanically and clinically. Methods: The studies included two cohort studies with prospectively collected data (n=206 and n=219), an anatomic and kinematic analysis in a cadaveric model and a pilot study (n=20). Results: The Maestro TWA had a significantly greater improvement of radial/ulnar deviation than the Biax and Remotion TWAs. Summarized patientrelated functional outcome was significantly better for the Maestro than for the Remotion TWA. Cumulative implant survival after 8 years was 94% for Remotion, and 95% for Maestro implants. Radiographic loosening five years postoperatively was present in 26% of the Biax wrists, 18% of those with Remotion, and 2% of those with Maestro. Following TWA with the new implant design in a cadaveric model, there were no statistically significant changes compared to a native wrist regarding flexion, extension, radial deviation, the extension/radial deviation component of the dart-thrower’s motion, or the circumduction range of motion. Clinically, there was significant improvement of COPM, PRWE and VAS pain scores. Wrist extension and ulnar deviation improved, while grip strength remained largely unchanged. Conclusions: TWA is a surgical procedure which may offer a high level of patient satisfaction. Implant design may affect patient-related functional outcome after TWA. Implant survival as well as the frequency of radiographic loosening differed considerably between the four types of implants and might be a result of different implant design. Kinematic analysis of the new TWA design suggests that a stable and functional wrist is achievable with this design. Surgical placement of the new total wrist implant was reproducible and the implant yielded good patient-related outcome measures in the short term. Since TWA is an evolving procedure, further studies are warranted in order to refine indications and the place for TWA in modern hand surgery.

Immobilisation has been one of the common forms of treatments for orthopaedic injuries and diseases. Immobilisation of injured limbs using dynamic splinting is routinely recommended by clinicians for fast healing as it promotes blood flow and provides the require stability. There are several dynamic splints available in the market that make use of different materials and mechanical elements. This research was set out to investigate the applicability of Magneto-Rheological(MR) fluids for the development of a smart fabric for orthopaedic splints. The fabric would be woven with hollow fibres containing MR fluid, which will change stiffness in an applied magnetic field. The concept was tested by measuring changes in the stiffness of silicone tubings in two different diameters filled with MR fluid, under different magnetic flux densities. The corresponding changes in stiffness of a preliminary fabric specimen built with woven tubings and cast liner was also investigated. The magnetic field was created after a set of detailed experimental and numerical analyses (Finite Element Method). It was found that although the electromagnets are much more versatile and easier to control for a required magnitude of magnetic flux density, they were found to be unsatisfactory due to their weight, bulk, and substantial requirement of batterie power. Permanent magnets offered a much better solution. After detailed preliminary analyses, an array of 21 neodymium magnets was chose for the experiments, which provided the required magnitude and uniformity of the magnetic field. The specimens were loaded in steps by small weights, and the resulting deflection was measured using an optical deformation analysis system. The equivalent Young’s modulus was found to increase from 16 MPa to 122 MPa under an average magnetic flux density of 0.0139 Tesla, which is an in- crease of 70%. A finite-element (FE) model of the single tubing test set up was developed and validated against the experimental results. The FE analysis was extended to the fabric specimens. The difference between the experimental and numerical results for the single tubing was as small as 2.5%, and 9.2% for the fabric. Furthermore, a preliminary numerical model and analysis of the hand was developed, which set the basis in the development of a further numerical analysis in the final development of the fabric. Upon the completion of the tests and simulation, it was concluded that a woven fabric made up of hollow fibres containing MR fluid can be an effective dynamic splint over a small area such as the wrist. However a fully functional product would require further research.

This study tested the hypothesis that grip and wrist strength affect performance on wall volley tests that were designed to test ability in tennis, badminton, and volleyball.

A espasticidade é uma das alterações decorrentes do Acidente Vascular Encefálico (AVE) que causa limitação no tônus muscular podendo gerar graves comprometimentos funcionais nos membros superiores. Pela característica do tecido neurológico lesado, frequentemente ocorre a cronificação das sequelas e incapacidades e atuar na minimização desses comprometimentos é objetivo dos profissionais da saúde. No entanto, há dificuldades na escolha da intervenção, análise de sua eficácia e aprimoramento dos estudos na área da reabilitação decorrentes da limitação nas estratégias de avaliação, sendo que nessa área as escalas são utilizadas com frequência. Dessa forma, esse estudo buscou desenvolver e validar a utilização clínica de um instrumento de medida da resistência isométrica ao estiramento passivo do grupo muscular flexor do punho em adultos e idosos com espasticidade decorrente do AVE. Foi desenvolvido um instrumento portátil capaz de medir a resistência da musculatura com um torquímetro. Foram realizados testes para analisar a validade, confiabilidade, sensibilidade e praticabilidade. Os testes foram feitos com os sujeitos sentados e com o antebraço e mão fixados no aparelho em seis diferentes posições do arco do movimento do punho, sendo que a articulação permaneceu estável por 20 segundos em cada posição. Foi realizada a avaliação de 108 sujeitos. A avaliação unilateral foi realizada em 21 sujeitos sem lesão neurológica e 27 sujeitos com AVE. A avaliação bilateral por dois examinadores foi realizada em 60 sujeitos, sendo 19 sem lesão e 41 com lesão neurológica. O instrumento mostrou-se capaz de mensurar as diferenças da resistência da musculatura em cinco das seis posições sendo relevante salientar que o instrumento foi sensível para apresentar a diferença entre população normal e com lesão e posteriormente apresentando a diferença entre lado comprometido e não comprometido. Os testes inter-examinadores mostraram boa correlação, no entanto, considerou-se a distribuição da segunda avaliação mais uniforme, sugerindo que se deve padronizar o uso para que o examinador realize a sequência de avaliação do arco do movimento por, no mínimo, duas vezes. Evidenciou-se ainda que o instrumento foi sensível para graduar a intensidade da sequela utilizando-se da comparação entre o lado não comprometido e o comprometido, sempre que a sequela seja apenas do hemicorpo visto que a graduação atribuída pela Escala Modificada de Ashworth possibilitou identificar correlação com as resistências apenas na avaliação grau 3, sendo que nos demais graus, não houve evidência estatística, corroborando com os também apresentados na literatura. Sugere-se, como continuidade do estudo, correlacionar os dados obtidos da avaliação da resistência estática à dinâmica. Esse instrumento desenvolvido pode ser utilizado para avaliação dos efeitos de órteses posicionadoras de punho, contribuindo assim, para o aprimoramento das estratégias de reabilitação. / Spasticity is one of the changes resulting from stroke which causes limitation in muscle tone and may cause severe functional impairment of the upper limbs. For the feature damaged neurological tissue often occurs chronicity of disabilities and act on these commitments is minimization objective of health professionals. However, there are difficulties in the choice of intervention, analysis and improvement of its effectiveness studies in rehabilitation due to limitations in assessment strategies, and this area scales are frequently used. Thus, this study sought to develop and validate the clinical use of an instrument for measuring isometric resistance to passive stretching of the wrist flexor muscle group in adult and elderly patients with spasticity due to stroke. We developed a portable instrument capable of measuring the muscular strength of a torquemeter. Tests were conducted to examine the validity, reliability, sensitivity and practicability. Tests were performed with the subjects seated with the forearm and hand set in the apparatus in six different positions of the arc of movement of the wrist, and the joint remained stable for 20 seconds at each position. Our evaluation of 108 subjects. The evaluation was performed unilaterally in 21 subjects without neurological injury and 27 subjects with stroke. A bilateral assessment by two examiners was performed in 60 subjects, 19 with and 41 without injury neurological injury. The instrument was able to measure differences in muscle strength in five of the six positions is important to note that the instrument was sensitive to show the difference between normal population and with injury and presents the difference between the affected and non-affected. The tests showed good inter-rater correlation, however, was considered a distribution more uniform the second evaluation, suggesting that it should use to standardize the examiner performs the evaluation sequence of the arc of movement by at least twice . It is further demonstrated that the instrument was sensitive to grade the intensity of the sequel using comparing the committed and uncommitted side where the sequel of the hemisphere is only seen that the graduation given by the Modified Ashworth Scale possible to identify a correlation with resistance only in the evaluation grade 3, and in the remaining degrees, there was no statistical evidence, corroborating also presented in the literature. It is suggested, as a continuation of the study, correlate data obtained from the evaluation of the resistance to static dynamic. This tool developed can be used to assess the effects of splint of wrist, thus contributing to the improvement of rehabilitation strategies.

Generic simulations of tremor propagation through the upper limb have been achieved using a previously developed postural tremor model, but this model had not yet been compared with experimental data or utilized for subject-specific studies. This work addressed these two issues, which are important for optimizing peripheral tremor suppression techniques. For tractability, we focused on a subsystem of the upper limb: the isolated wrist, including the four prime wrist muscles (extensor carpi ulnaris, flexor carpi ulnaris, extensor carpi radialis, and flexor carpi radialis) and the two degrees of freedom of the wrist (flexion-extension and radial-ulnar deviation). Muscle excitation and joint displacement signals were collected while subjects with Essential Tremor resisted gravity. System identification was implemented for three subjects who experienced significant tremor using two approaches: 1. Generic linear time-invariant (LTI) models, including autoregressive-exogenous (ARX) and state-space forms, were identified from the experimental data, and characteristics including model order and modal parameters were compared with the previously developed postural tremor model; 2. Subject-specific parameters for the previously developed postural tremor model were directly estimated from experimental data using nonlinear least-squares optimization combined with regularization. The identified LTI models fit the experimental data well, with coefficients of determination of 0.74 ± 0.18 and 0.83 ± 0.13 for ARX and state-space forms, respectively. The optimal model orders identified from the experimental data (4.8 ± 1.9 and 6.4 ± 1.9) were slightly lower than the orders of the ARX and state-space forms of the previously developed model (6 and 8). For each subject, at least one pair of identified complex poles aligned with the complex poles of the previously developed model, whereas the identified real poles were assumed to represent drift in the data rather than characteristics of the system. Subject-specific parameter estimates reduced the sum of squared-error (SSE) between the measured and predicted joint displacement signals to be between 10% and 50% of the SSE using generic literature parameters. The predicted joint displacements maintained high coherence at the tremor frequency for flexion-extension (0.90 ± 0.10), which experienced the most tremor. We successfully applied multiple system identification techniques to identify tremor propagation models using only tremorogenic muscle activity as the input. These techniques identified model order, poles, and subject-specific model parameters, and indicate that tremor propagation at the wrist is well approximated by an LTI model.

Magister Chirurgiae Dentium (MChD) / Skeletal age assessment is not only an important aspect in orthodontic treatment planning, but is also widely used in forensic medicine and physi cal anthropology. Vari aus studi es have shown that chronological age may be at variance with an individual's biologic age. Current research would seem to indicate that the hand-wrist radiograph provides the most accurate method of assessing skeletal age for diagnostic purposes. In recent years the number of patients presenting with malocclusions of a skeletal nature at the University of the Western Cape has increased si gnifi cantly. If it i s accepted that treatment of jaw di screpancies associated with malocclusion is dependent on a large component of dentofacial orthopedics, then by implication it is necessary that a substanti al amount of faci al growth remai ns. The need has therefore arisen for the establishment of skeletal maturation trends in the Western Cape. Skeletal maturity was assessed from hand-wrist radiographs in a sample of 318 Western Cape children aged 6 to 16 years for both sexes, utilising the bone specific Tanner-Whitehouse TW-2 scoring system. Data obtai ned from the present study showed a marked difference in skel etal maturati on trends between femal es of the Western Cape to that of the British norm, while the males showed less divergence. Further, these findings show that in both sexes the epiphyseal bones matured in advance of the TW-standard. Carpal maturation, however, was delayed in the male when compared to the British standard, while that of the female conformed to that of the British standard.

The dynamics of wrist rotations are dominated by joint stiffness, which the neuromuscular system must account and compensate for when controlling wrist movements. Because wrist stiffness is anisotropic, movements in some directions require less torque than movements in others, creating opportunities to follow "paths of least resistance." Forearm pronation-supination (PS) can combine with wrist flexion-extension (FE) and radial-ulnar deviation (RUD) to allow the wrist to rotate in directions of least stiffness. Evaluating this hypothesis, and understanding the control of combined wrist and forearm rotations in general, requires a knowledge of the stiffness (the dominant mechanical impedance) encountered during combined wrist and forearm rotations. While wrist and forearm stiffness have been measured in isolation, there are no measurements of coupled wrist and the forearm stiffness. This study characterizes the passive stiffness of the wrist and forearm in combinations of FE, RUD, and PS. Using a wrist and forearm robot, we measured coupled wrist and forearm stiffness for 15° movements from neutral position in 10 young, healthy subjects. We found the stiffness in PS to be significantly smaller than the stiffness in RUD, but similar in magnitude to the stiffness in FE, indicating that the torque required to overcome stiffness in combinations of PS and FE is significantly smaller than the torque required to overcome stiffness in combinations of FE and RUD (assuming equal displacements). The coupled stiffness measured here will enable future studies to determine optimal paths and to compare these optimal paths to observed movements involving wrist and forearm rotations.

Wrist and forearm motion is governed both by its dynamics and the control strategies employed by the neuromuscular system to execute goal oriented movement. Two experiments were conducted to increase our understanding of wrist and forearm motion. The first experiment involved 10 healthy subjects executing planned movements to targets involving all three degrees of freedom (DOF) of the wrist and forearm, namely wrist flexion-extension (FE), wrist radial-ulnar deviation, and forearm pronation-supination (PS). A model of wrist and forearm dynamics was developed, and the recorded movements were fed into the model to analyze the movement torques. This resulted in the following key findings: 1) The main impedance torques affecting wrist and forearm movements are stiffness and gravity, with damping and inertial effects contributing roughly 10% of the total torque. 2) There is significant coupling between all degrees of freedom (DOF) of the wrist and forearm, with stiffness effects being the most coupled and inertial effects being the least coupled. 3) Neglecting these interaction torques results in significant error in the prediction of the torque required for wrist and forearm movements, suggesting that the neuromuscular system must account for coupling in movement planning. A second experiment was conducted in which 10 different healthy subjects pointed to targets arranged on a plane in front of the subjects. This pointing task required two DOF, but subjects were allowed to use all three DOF of the wrist and forearm. While subjects could have completed the task with FE and RUD alone, it was found that subjects recruited PS as well. Hypotheses regarding why subjects would recruit PS even though it was not necessary included the minimization of a number of cost functions (work, effort, potential energy, path length) as well as mechanical interaction between the DOF of the wrist and forearm. It was found that the pattern of PS recruitment predicted from the mechanical interaction hypothesis most closely resembled the observed pattern. According to this hypothesis, the neuromuscular system uses a simplified 2 DOF model of the joints most critical to the task (FE and RUD) to plan the task, while leaving the third DOF (PS) uncontrolled. The resulting interaction torques create the observed pattern of PS movement.

Cumulative trauma disorders have become common among workers in industry. Grocery stores are an industry with one of the highest number of repeated trauma illnesses. Checkout departments have a rate of musculoskeletal injuries two to three times higher than other supermarket departments. The primary objective of this study was to quantify the wrist motions required to bag groceries. Subjects participated in the laboratory or in the supermarket. The wrist motions included wrist deviations, velocities, and accelerations for flexion-extension, radial-ulnar, and pronation-supination deviations. The dependent variables were handle type and object location. A wrist motion monitor designed at Ohio State University was used to quantify wrist posture and movement. Objects with finger-thumb handle couplings required more extreme ulnar deviations, more extreme pronations, greater wrist velocities for pronation-supination deviations, and greater wrist accelerations for pronation-supination deviations than did other objects. When comparing soft and solid objects, or round and square objects, there were few differences in wrist positions, velocities, or accelerations. Objects with 10-cm wide hand couplings required more extreme flexion, larger ranges of movement for radial-ulnar deviations and pronation-supination deviations, and greater wrist velocities in the radial, ulnar, and pronation directions than did 5-cm wide objects. The right and front locations required more extreme positions than did the left and back locations. Subjects participating at the supermarket site picked up objects with greater wrist velocities and accelerations than those in the laboratory; conversely, wrist positions were not affected by site. Because finger-thumb and 10-cm wide hand couplings required larger wrist deviations and greater velocities, these objects may pose a greater risk to the bagger of developing cumulative trauma disorders. / Master of Science