Markerless Analysis of Upper Extremity Kinematics during Standardized Pediatric Assessment

Children with hemiplegic cerebral palsy experience reduced motor performance in the affected upper extremity and are typically evaluated based on degree of functional impairment using activity-based assessments such as the Shriners Hospitals for Children Upper Extremity Evaluation (SHUEE), a validated clinical measure, to describe performance prior to and following rehabilitative or surgical interventions. Evaluations rely on subjective therapist scoring techniques and lack sensitivity to detect change. Objective clinical motion analysis systems are an available but time-consuming and cost-intensive alternative, requiring uncomfortable application of markers to the patient. There is currently no available markerless, low-cost system that quantitatively assesses upper extremity kinematics to improve sensitivity of evaluation during standardized task performance. A motion analysis system was developed, using Microsoft Kinect hardware to track motion during broad arm and subtle hand and finger movements. Algorithms detected and recorded skeletal position and calculated angular kinematics. Lab-developed articulating hand model and elbow fixation devices were used to evaluate accuracy, intra-trial, and inter-trial reliability of the Kinect platform. Results of technical evaluation indicate reasonably accurate detection and differentiation between hand and arm positions. Twelve typically-developing adolescent subjects were tested to characterize and evaluate performance scores obtained from the SHUEE and Kinect motion analysis system. Feasibility of the platform was determined in terms of kinematics and as an enhancement of quantitative kinematic reporting to the SHUEE, and a population mean of typically developing subject kinematics obtained for future development of performance scoring algorithms. The system was observed to be easily operable and clinically effective in subject testing. The Kinect motion analysis platform developed to quantify upper extremity motion during standardized tasks is a low-cost, portable, accurate, and reliable system in kinematic reporting, and has demonstrated quality of results in both technical evaluation of the system and a study of its applicability to standardized task-based evaluation, but has hardware and software limitations which will be resolved in future improvements of the system. The SHUEE benefits from improved quantitative data, and the Kinect system provides enhanced sensitivity in clinical upper extremity analysis for children with hemiplegic cerebral palsy

Muscle activation mapping of skeletal hand motion: an evolutionary approach.

Creating controlled dynamic character animation consists of mathe- matical modelling of muscles and solving the activation dynamics that form the key to coordination. But biomechanical simulation and control is com- putationally expensive involving complex di erential equations and is not suitable for real-time platforms like games. Performing such computations at every time-step reduces frame rate. Modern games use generic soft- ware packages called physics engines to perform a wide variety of in-game physical e ects. The physics engines are optimized for gaming platforms. Therefore, a physics engine compatible model of anatomical muscles and an alternative control architecture is essential to create biomechanical charac- ters in games. This thesis presents a system that generates muscle activations from captured motion by borrowing principles from biomechanics and neural con- trol. A generic physics engine compliant muscle model primitive is also de- veloped. The muscle model primitive forms the motion actuator and is an integral part of the physical model used in the simulation. This thesis investigates a stochastic solution to create a controller that mimics the neural control system employed in the human body. The control system uses evolutionary neural networks that evolve its weights using genetic algorithms. Examples and guidance often act as templates in muscle training during all stages of human life. Similarly, the neural con- troller attempts to learn muscle coordination through input motion samples. The thesis also explores the objective functions developed that aids in the genetic evolution of the neural network. Character interaction with the game world is still a pre-animated behaviour in most current games. Physically-based procedural hand ani- mation is a step towards autonomous interaction of game characters with the game world. The neural controller and the muscle primitive developed are used to animate a dynamic model of a human hand within a real-time physics engine environment

Humanoid Robots

For many years, the human being has been trying, in all ways, to recreate the complex mechanisms that form the human body. Such task is extremely complicated and the results are not totally satisfactory. However, with increasing technological advances based on theoretical and experimental researches, man gets, in a way, to copy or to imitate some systems of the human body. These researches not only intended to create humanoid robots, great part of them constituting autonomous systems, but also, in some way, to offer a higher knowledge of the systems that form the human body, objectifying possible applications in the technology of rehabilitation of human beings, gathering in a whole studies related not only to Robotics, but also to Biomechanics, Biomimmetics, Cybernetics, among other areas. This book presents a series of researches inspired by this ideal, carried through by various researchers worldwide, looking for to analyze and to discuss diverse subjects related to humanoid robots. The presented contributions explore aspects about robotic hands, learning, language, vision and locomotion

Functional adaptation of internal bone structure in the wrist of extant hominids and fossil hominins

The shape of wrist bones (carpals) in living hominids are thought to be adapted to the primary function of the hand, which in Homo sapiens is for manipulation, and in non-human hominids, locomotion. However, the hominid hand is inherently versatile in its use, and parsimony would suggest that the hominid last common ancestor was capable of manipulating and using simple tools. Therefore, key questions in palaeoanthropology ask when, why, and how tool use moved from facultative, as it is in other hominids, to obligate, as it is in H. sapiens. Inferring this transition within the fossil record is challenging as habitual behaviours are not always reflected in the external morphology of the skeleton. As the internal microstructure of bone is known to adapt to load dynamically, bone functional adaptation analyses provide an avenue to investigate how a joint has actually been loaded over an individual’s lifetime. The central question asked by this thesis was: ‘How and why does the internal structure of wrist bones differ among extant and extinct hominids?’. To achieve this aim, I investigated 1) whether functionally meaningful differences exist in the microarchitecture of extant hominid carpals; 2) how to detect signals of functional adaptation within the complex biomechanical environment of the wrist; 3) what can be inferred about hand use from the proximal capitate bone of fossil hominins? This thesis undertook three research projects, which all use ‘whole-bone’ methodologies for investigating functional signals of hand use. Using micro-computed tomography, I quantified and compared trabecular and cortical bone microarchitecture in 264 individual carpal bones across four extant hominids (Pongo, Gorilla, Pan, and H. sapiens) and four extinct hominins (Australopithecus sediba, Homo naledi, Homo floresiensis and Neanderthals). In the first project, I used inter- and intraspecific analyses to compare the trabecular and cortical microstructure of the proximal and distal capitate in extant hominids. Unique combinations of microarchitecture across the two segments of the bone differentiated the extant taxa. Notably, non-human hominids exhibited a distinctive pattern of extremely thick cortical bone in the distal capitate. This result suggested that highly localised functional adaptation responses were occurring across the capitate, and studying biomechanically distinct subregions of the carpus may be required to detect signals of functional adaptation. I then conducted intraspecific analyses on the scaphoid, lunate and triquetrum's trabecular and cortical bone microstructure across extant hominids. Results identified that microarchitectural differences across the three bones could be linked to the known or assumed biomechanics of the proximal row. Relative differences in the three bones differentiated locomotor mode between the genera: Gorilla and Pan expressed the same relative patterns of architecture, with Pongo and H. sapiens showing unique patterns. This project demonstrated that establishing relative patterns across a biomechanically distinct subregion of the wrist can differentiate hand use among extant hominids. Using a novel canonical holistic morphometric analysis, my final research project indicated that extant hominids have statistically distinct distributions of relative bone volume in the proximal capitate. Neanderthals and fossil H. sapiens exhibited the same pattern of relative bone distribution in the proximal capitate as modern H. sapiens suggesting a functional commitment to tool use leaves a distinct distribution of bone in the proximal capitate. Despite being the geologically oldest fossil, A. sediba was the only other species to exhibit a human-like distribution of bone, with evidence of a highly strained capitolunate and capitoscaphoid joint. Although H. naledi has human-like carpal morphology, it showed no evidence for human-like force transfer and loading at the midcarpal joint suggesting its hand use was not similar to a typical modern H. sapiens. The distribution of bone in H. floresiensis suggested that Oldowan-type tools were made and used with high ulnar-side loading of the hand and relatively lower loading of the thumb. This thesis demonstrated that a hand used primarily for manipulation has distinctive and statistically differentiated microarchitecture in the carpal bones. Unique microarchitectural features within the hominin species support a model of adaptive radiations of hand and tool behaviours among hominins. The similarity in microarchitecture at the midcarpal joint of H. sapiens and Neanderthals suggests it may be a strong signal of human-like commitment to tool use but is unlikely to capture variation in tool behaviour. Further analyses are needed to better understand how manipulation and arboreality are reflected in bone architecture. In particular, this thesis discussed how both climbing and transverse grips might be biomechanically compatible behaviours, as both emphasise high loading at the ulnar side of the hand and wrist and deemphasise the use of the thumb. Thus the use of transverse-type grips may have provided fossil hominins with an opportunity to improve the functional efficiency of tool behaviours without highly compromising climbing ability. Future analyses are likely to be most informative when numerous bones across biomechanically meaningful subregions of the wrist are analysed together. Analyses at the ulnar side of the wrist may be informative for identifying signals of climbing and grip preference differences in H. sapiens and Neanderthals

Attention and time constraints in performing and learning a table tennis forehand shot

This is a section on p. S95 of article 'Verbal and Poster: Motor Development, Motor Learning and Control, and Sport and Exercise Psychology' in Journal of Sport and Exercise Psychology, 2010, v.32, p.S36-S237published_or_final_versio

EEG coherence between the verbal-analytical region (T3) and the motor-planning region (Fz) increases under stress in explicit motor learners but not implicit motor learners

This journal supplement contains abstracts of NASPSPA 2010Free Communications - Verbal and Poster: Motor Learning and Controlpublished_or_final_versionThe Annual Conference of the North American Society for the Psychology of Sport and Physical Activity (NASPSPA 2010), Tucson, AZ., 10-12 June 2010. In Journal of Sport and Exercise Psychology, 2010, v. 32 suppl., p. S13

Action execution, action perception and 'mirror' neurones

Imperial Users onl