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To examine the experience of people with Parkinson's disease when walking in different social situations, and improve understanding of how this affects participation in meaningful activity. A convenience sample of fourteen people with Parkinson's disease and a history of gait dysfunction was recruited. In-depth interviews and direct observations were conducted in the participants' home environments. Specific examples from community mobility were reviewed using first person interviewing techniques with the support of video footage. Interview transcripts were analyzed using an interpretive phenomenological approach to derive key themes. The feeling of 'being looked at' (le regard des autres) was the central theme in participant discourse. This sentiment was inextricably linked to the given norms of the social setting, and the relationships between participants and others within that environment. Participants sought to manage how they were perceived by others through modification of posture/gait patterns; disclosure of their neurological disease; and avoidance/withdrawal from social situations. Further to the functional aspects of mobility, gait is important for maintaining self-image in people with Parkinson's disease. Affective gaze interactions have significant consequences upon participation restriction. These findings underscore the interest of activities which strengthen self-image and validate movement diversity in PD rehabilitation. [ABSTRACT FROM AUTHOR]

Characterizing human movement is essential for understanding movement disorders, evaluating progress in rehabilitation, or even analyzing how a person adapts to the use of assistive devices. Thanks to the improvement of motion capture technology, recording human movement has become increasingly accessible and easier to conduct. Over the last few years, multiple methods have been proposed for characterizing inter-joint coordination. Despite this, there is no real consensus regarding how these different inter-joint coordination metrics should be applied when analyzing the coordination of discrete movement from kinematic data. In this work, we consider 12 coordination metrics identified from the literature and apply them to a simulated dataset based on reaching movements using two degrees of freedom. Each metric is evaluated according to eight criteria based on current understanding of human motor control physiology, i.e, each metric is graded on how well it fulfills each of these criteria. This comparative analysis highlights that no single inter-joint coordination metric can be considered as ideal. Depending on the movement characteristics that one seeks to understand, one or several metrics among those reviewed here may be pertinent in data analysis. We propose four main factors when choosing a metric (or a group of metrics): the importance of temporal vs. spatial coordination, the need for result explainability, the size of the dataset, and the computational resources. As a result, this study shows that extracting the relevant characteristics of inter-joint coordination is a scientific challenge and requires a methodical choice. As this preliminary study is conducted on a limited dataset, a more comprehensive analysis, introducing more variability, could be complementary to these results. [ABSTRACT FROM AUTHOR]

Upper limb exoskeletons may confer significant mechanical advantages across a range of tasks. The potential consequences of the exoskeleton upon the user's sensorimotor capacities however, remain poorly understood. The purpose of this study was to examine how the physical coupling of the user's arm to an upper limb exoskeleton influenced the perception of handheld objects. In the experimental protocol, participants were required to estimate the length of a series of bars held in their dominant right hand, in the absence of visual feedback. Their performance in conditions with an exoskeleton fixed to the forearm and upper arm was compared to conditions without the upper limb exoskeleton. Experiment 1 was designed to verify the effects of attaching an exoskeleton to the upper limb, with object handling limited to rotations of the wrist only. Experiment 2 was designed to verify the effects of the structure, and its mass, with combined movements of the wrist, elbow, and shoulder. Statistical analysis indicated that movements performed with the exoskeleton did not significantly affect perception of the handheld object in experiment 1 (BF01 = 2.3) or experiment 2 (BF01 = 4.3). These findings suggest that while the integration of an exoskeleton complexifies the architecture of the upper limb effector, this does not necessarily impede transmission of the mechanical information required for human exteroception. [ABSTRACT FROM AUTHOR]

Understanding and quantifying inter-joint coordination is valuable in several domains such as neurorehabilitation, robot-assisted therapy, robotic prosthetic arms, and control of supernumerary arms. Inter-joint coordination is often understood as a consistent spatiotemporal relation among kinematically redundant joints performing functional and goal-oriented movements. However, most approaches in the literature to investigate inter-joint coordination are limited to analysis of the end-point trajectory or correlation analysis of the joint rotations without considering the underlying task; e.g., creating a desirable hand movement toward a goal as in reaching motions. This work goes beyond this limitation by taking a model-based approach to quantifying inter-joint coordination. More specifically, we use the weighted pseudo-inverse of the Jacobian matrix and its associated null-space to explain the human kinematics in reaching tasks. We propose a novel algorithm to estimate such Inverse Kinematics weights from observed kinematic data. These estimated weights serve as a quantification for spatial inter-joint coordination; i.e., how costly a redundant joint is in its contribution to creating an end-effector velocity. We apply our estimation algorithm to datasets obtained from two different experiments. In the first experiment, the estimated Inverse Kinematics weights pinpoint how individuals change their Inverse Kinematics strategy when exposed to the viscous field wearing an exoskeleton. The second experiment shows how the resulting Inverse Kinematics weights can quantify a robotic prosthetic arm's contribution (or the level of assistance). [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the contributions of feedforward and feedback processes on grip force regulation and object orientation during functional manipulation tasks. One patient with massive somatosensory loss resulting from large fiber sensory neuropathy and 10 control participants were recruited. Three experiments were conducted: 1) perturbation to static holding; 2) discrete vertical movement; and 3) functional grasp and place. The availability of visual feedback was also manipulated to assess the nature of compensatory mechanisms. Results from experiment 1 indicated that both the deafferented patient and controls used anticipatory grip force adjustments before self-induced perturbation to static holding. The patient exhibited increased grip response time, but the magnitude of grip force adjustments remained correlated with perturbation forces in the self-induced and external perturbation conditions. In experiment 2, the patient applied peak grip force substantially in advance of maximum load force. Unlike controls, the patient's ability to regulate object orientation was impaired without visual feedback. In experiment 3, the duration of unloading, transport, and release phases were longer for the patient, with increased deviation of object orientation at phase transitions. These findings show that the deafferented patient uses distinct modes of anticipatory control according to task constraints and that responses to perturbations are mediated by alternative afferent information. The loss of somatosensory feedback thus appears to impair control of object orientation, whereas variation in the temporal organization of functional tasks may reflect strategies to mitigate object instability associated with changes in movement dynamics. NEW & NOTEWORTHY This study evaluates the effects of sensory neuropathy on the scaling and timing of grip force adjustments across different object handling tasks (i.e., holding, vertical movement, grasping, and placement). In particular, these results illustrate how novel anticipatory and online control processes emerge to compensate for the loss of somatosensory feedback. In addition, we provide new evidence on the role of somatosensory feedback for regulating object orientation during functional prehensile movement. [ABSTRACT FROM AUTHOR]

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Impairments in dexterous upper limb function are a significant cause of disability following stroke. While the physiological basis of movement deficits consequent to a lesion in the pyramidal tract is well demonstrated, specific mechanisms contributing to optimal recovery are less apparent. Various upper limb interventions (motor learning methods, neurostimulation techniques, robotics, virtual reality, and serious games) are associated with improvements in motor performance, but many patients continue to experience significant limitations with object handling in everyday activities. Exactly how we go about consolidating adaptive motor behaviors through the rehabilitation process thus remains a considerable challenge. An important part of this problem is the ability to successfully distinguish the extent to which a given gesture is determined by the neuromotor impairment and that which is determined by a compensatory mechanism. This question is particularly complicated in tasks involving manual dexterity where prehensile movements are contingent upon the task (individual digit movement, grasping, and manipulation...) and its objective (placing, two step actions...), as well as personal factors (motivation, acquired skills, and life habits...) and contextual cues related to the environment (presence of tools or assistive devices...). Presently, there remains a lack of integrative studies which differentiate processes related to structural changes associated with the neurological lesion and those related to behavioral change in response to situational constraints. In this text, we shall question the link between impairments, motor strategies and individual performance in object handling tasks. This scoping review will be based on clinical studies, and discussed in relation to more general findings about hand and upper limb function (manipulation of objects, tool use in daily life activity). We shall discuss how further quantitative studies on human manipulation in ecological contexts may provide greater insight into compensatory motor behavior in patients with a neurological impairment of dexterous upper-limb function. [ABSTRACT FROM AUTHOR]

The present study sought to evaluate how mental effort modulates premotor activity within forearm muscles in the context of an isometric grasping task. Muscle activity of the flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC) was recorded during the application of maximum grip forces in nineteen healthy adult subjects. Each subject was examined under two experimental conditions: 1) spontaneous initiation of grasp (SI) and 2) focused concentration preceding the initiation of grasp (CA). Two novel parameters, the mean premotor duration (MPD) and the mean premotor power (MPP) were used to distinguish patterns of muscle activity. Here we tested the hypothesis was maximal grip strength is primed by muscle activity during the premotor phase. Our results demonstrate that MPD for each muscle group was significantly longer in the CA condition than for the SI condition (BF10 = 491497) and that MPP was significantly greater in EDC than in FDS (BF10 = 4305). Furthermore, both the MPD and MPP of the EDC were significantly correlated with maximum grip force. These results suggest that the increase of premotor activity consequent to the mental effort (focused concentration) may support internal biomechanical and physiological mechanisms which serve to enhance patterns of neuromuscular synergies. [ABSTRACT FROM AUTHOR]

Featured Application: The present study has potential applications in sport, ergonomics and clinical practice. Orientation of the head relative to the trunk may be measured in different settings using inertial sensors. This may prove important for injury prevention and for treatment of musculo-skeletal disorders affecting the neck and shoulder, both in elite and recreational athletes and in work situations. In the clinical field, this study has application for the biomechanical assessment and rehabilitation of patients with shoulder and/or cervical spine pathologies. Upper limb activities imply positioning of the head with respect to the visual target and may impact trunk posture. However, the postural constraints imposed on the neck remains unclear. We used kinematic analysis to compare head and trunk orientation during arm movements (pointing) with isolated movements of the head (heading). Ten right-handed healthy adults completed both experimental tasks. In the heading task, subjects directed their face toward eight visual targets placed over a wide frontal workspace. In the pointing task, subjects pointed to the same targets (each with their right arm). Movements were recorded using an electromagnetic spatial tracking system. Both orientation of the head and trunk in space (Euler angles) and orientation of the head relative to the trunk were extracted. The orientation of the head in space was closely related to target direction during both tasks. The trunk was relatively stable during heading but contributed to pointing, with leftward axial rotation. These findings illustrate that the neck compensates for trunk rotation during pointing, engaging in specific target-dependent 3D movement in order to preserve head orientation in space. Future studies may investigate neck kinematics of people experiencing neck pain in order to identify and correct inefficient movement patterns, particularly in athletes. [ABSTRACT FROM AUTHOR]

Purpose: This study sought to characterize the way patients with Parkinson's disease consciously perceive and respond to their surroundings while walking in everyday situations. Method: A qualitative research program designed around an ecological data collection protocol was employed. A convenience sample of 14 patients with a diagnosis of Parkinson's disease and a history of gait difficulties were recruited. Details regarding patients' subjective experience of walking in everyday environments were obtained using first person interviewing techniques with the support of video footage from their daily-life activity. Interview transcripts were analyzed using an interpretive phenomenological approach in order to derive key themes. Results: The sense of proximity and the way in which an individual perceived themselves with respect to their surroundings appeared central to the way patients organized their locomotor behavior. Further to this, the patient relationship to different features and obstacles appeared conditioned by prior experiences in those circumstances. Patients described managing gait difficulties by consciously regulating their walking trajectory and gaze with respect to their environment. Conclusion: Perceptual challenges, visual flow and the dynamic valence of features in the patient's surroundings may have important effects upon the gait stability of patients with Parkinson's disease and warrant further attention in planning rehabilitation interventions. Walking abilities of patients with Parkinson's disease should be conceptualized in terms of perceptuomotor coupling to a given environment. The functional significance of a patient's environment is dynamic and might be seen to vary in accordance with their physical capacities. Valency, or the subjective relationship between a patient and their surrounds, appears to be an important component of the "fit" between a person and their environment. Novel rehabilitation strategies for the management of parkinsonian gait disturbances might seek to integrate psychological, sensorimotor and environmental elements in order to have individually tailored, ecologically valid home assessment and community rehabilitation programs. [ABSTRACT FROM AUTHOR]

Objective: Limitations with manual dexterity are an important problem for patients suffering from hemiparesis post stroke. Sensorimotor deficits, compensatory strategies and the use of alternative grasping configurations may influence the efficiency of prehensile motor behavior. The aim of the present study is to examine how different grasp configurations affect patient ability to regulate both grip forces and object orientation when lifting, holding and placing an object. Methods: Twelve stroke patients with mild to moderate hemiparesis were recruited. Each was required to lift, hold and replace an instrumented object. Four different grasp configurations were tested on both the hemiparetic and less affected arms. Load cells from each of the 6 faces of the instrumented object and an integrated inertial measurement unit were used to extract data regarding the timing of unloading/loading phases, regulation of grip forces, and object orientation throughout the task. Results: Grip forces were greatest when using a palmar-digital grasp and lowest when using a top grasp. The time delay between peak acceleration and maximum grip force was also greatest for palmar-digital grasp and lowest for the top grasp. Use of the hemiparetic arm was associated with increased duration of the unloading phase and greater difficulty with maintaining the vertical orientation of the object at the transitions to object lifting and object placement. The occurrence of touch and push errors at the onset of grasp varied according to both grasp configuration and use of the hemiparetic arm. Conclusion: Stroke patients exhibit impairments in the scale and temporal precision of grip force adjustments and reduced ability to maintain object orientation with various grasp configurations using the hemiparetic arm. Nonetheless, the timing and magnitude of grip force adjustments may be facilitated using a top grasp configuration. Conversely, whole hand prehension strategies compound difficulties with grip force scaling and inhibit the synchrony of grasp onset and object release. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the emergence of a subject now called digital heritage, and considers where it has come from and in what form it might progress. The paper contrasts the rise of theory within the subject of museum studies with the more practical preoccupations of its sub-discipline, museum computing. It highlights the emergence of more sociological and theorised readings of museum computing (what is termed here the cultural turn within the subject''s approach), alongside the co-ordinated expansion of research activity in this area, particularly through inter-governmental sponsorship. The early showings of a critical framework for this new active discipline are then explored, and a series of trajectories for enquiry and approach are suggested and stressed, including an engagement with ‘change’, an acknowledgement of the agency of new media, a recognition of the value of historical methodologies, and the aspiration for a more nuanced discourse. [Copyright &y& Elsevier]

Focuses on the implementation of a glass fracture routine in the BRANZFIRE zone model, based largely on the heat transfer model. Success of implementing the model as a spreadsheet; Function of the model; Results from a Monte Carlo based sensitivity analysis.

Argues that the analysis of a three-dimensional image demanded a three-dimensional approach. Examples used to expose the shortcomings of a two-dimensional approach; Advantages of the hypermedia approach; Hermeneutic issues associated with the historical application of computer-aided design.

Introduction Les troubles de la marche et de l’équilibre sont fréquents au cours de la maladie de Parkinson. Leur quantification dans la vie quotidienne reste un enjeu pour l’évaluation de leur sévérité. L’objectif ici était de décrire et quantifier le pattern de l’activité musculaire des membres inférieurs des patients parkinsoniens en condition de vie réelle. Matériel et méthodes L’activité des muscles vaste latéraux (VL), biceps fémoris (BF), gastrocnémius (G), soléaire (Sol) et tibialis anterior (TA) a été enregistrée chez 8 patients parkinsoniens et 8 sujets sains, à l’aide d’un système portatif. La durée et la quantité d’activité EMG étaient mesurées pour chacune des phases du cycle de marche : double (poser et phase pré-oscillante) et simple appuis, et comparées entre les 2 groupes. Résultats La durée du cycle de marche n’était pas différente mais la durée des phases de double appui était augmentée chez les patients parkinsoniens. Chez les patients parkinsoniens, des modifications du pattern EMG du cycle de marche étaient retrouvées : – une augmentation de l’amplitude de la co-contraction des muscles agonistes-antagonistes au niveau de la cheville (Sol-TA) et du genou (BF-VL) lors du poser du pied ; – un allongement de l’activation des muscles Sol, BF et VL lors des phases d’appui simple ; – une augmentation de l’amplitude et de la durée de l’activité des muscles Sol, G et VL lors de la phase pré-oscillante ; – une diminution de la durée de l’activité des muscles TA et VL lors de la phase oscillante. Discussion–conclusion L’évaluation en condition de vie réelle représente une nouvelle approche permettant de quantifier de façon précise et spécifique les troubles de la marche des patients parkinsoniens. La dégradation du pattern EMG des membres inférieurs existe en dehors des épisodes de freezing ou de chutes, avec une augmentation de la durée de la phase de double appui associée à une co-contraction et une sur-activation des muscles antigravitaires pouvant résulter d’un phénomène adaptatif à l’instabilité posturale. [ABSTRACT FROM AUTHOR]

The article discusses the conservation of digital heritage of museums. It mentions that technological innovations, particularly digital media, helped the management of museums to better protect the archives and documents. The author states that development of digital heritage is important since it preserves historic events, materials and people.

An introduction to the journal is presented in which the editors discuss the article of Ramesh Srinivasan and colleagues on the use of new digital media technologies in tribal museums.