EFFECT OF THE PLACEMENT OF THE INERTIAL SENSOR ON THE HUMAN MOTION DETECTION

There are numerous possibilities of assessments of the human activity, offered by the ActimedARM -a wearable inertial sensor we developed. This device features a triaxial magnetometer, a trixial accelerometer, a micro-processing unit, a Zigbee module and a μSD card. Its embedded algorithms make it able to compute postures, transfers of the subject and also to characterize the walking episodes. We recently succeeded in computing the relative displacements of the sensors, from double integration of the acceleration signals, in order to qualify specific physical activities such as rising from chairs or stools. The experiments highlighted the impact of the location of the sensor on the body on the correlation between objective motion and signals processed from acceleration measurements, showing a better correlation coefficient of 11.41% when the sensor is located on the navel

Muscle activation during gait in children with Duchenne muscular dystrophy

The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity

The Project Management Office and its functions: A pharmaceutical plant case study

The Project Management Office (PMO) is an organizational structure created in order to promote and improve project, program and project portfolio management practices. The PMO adopts appropriate methodologies to achieve high levels of efficiency and effectiveness. Several models and functions of PMO are proposed by many authors, varying from the PMO with a sole function of reporting project execution, to the one who participates in the definition of organizational strategies. This work is a case study that assesses the relevance of having such structure in a pharmaceutical plant located in Lessines, Belgium. This work aims also to specifying the role that this potential PMO should fulfil. To answer these questions, the current state of the project management in Lessines was analyzed. A questionnaire was used as means for determining the roles that the PMO should perform. A total of 71 respondents have participated in the survey. Respondents were divided into groups based on their hierarchical level in the organization. The outcome of the case study suggests the implementation of a PMO with a low number of project managers and a low number of projects in the scope of the PMO. A major finding is that most projects undertaken by the organization depend on external decision centers which limits the scope of action of the PMO for optimal functioning. Regarding roles that the PMO should perform, there is little difference between expectations of the different groups. The six functions proposed appear to be important for all groups. Only one function is more desired by the top management group than for other groups, being the follow-up, control and maintaining projects status and reporting to the upper management.Master [120] en sciences de gestion (horaire décalé à Mons), Université catholique de Louvain, 2018La diffusion de ce mémoire n'est pas autorisée par l'institutio

Tool Use and Generalized Motor Programs: We All Are Natural Born Poly-Dexters

For most people, human tool use is inextricably entwined with manual dexterity. This folk belief is widespread among scientists too. In this line, human tool use is based on motor programs about how the hand interacts with tools, implying that the use of end-effectors other than the hand should generate motor control difficulties (e.g., inability to reproduce a specific tool-use action over time), because these so-called programs characterize the spatiotemporal parameters of hand movements, but not of other end-effectors. To test this, we asked participants to perform three tool-use actions (e.g., pounding a nail) with four end-effectors (i.e., right foot, right elbow, left hand, right hand). We show that participants not only spontaneously performed the tool-use actions effectively, but also crucially kept tools' spatiotemporal parameters constant among the end-effectors. This phenomenon, which we call poly-dexterity, is at odds with the view that the human brain stores hand-centered motor programs for tool use. Poly-dexterity is instead consistent with the idea that, once the tool-use action is formed mentally, general motor programs can be applied to a variety of end-effectors. Reversing the usual evolutionary perspective, our findings support that, in the course of evolution, manual dexterity has come after tool-use skills

Inter-task transfer of prism adaptation depends on exposed task mastery

International audienceThe sensorimotor system sets up plastic alterations to face new demands. Terms such as adaptation and learning are broadly used to describe a variety of processes underlying this aptitude. The mechanisms whereby transformations acquired to face a perturbation generalize to other situations or stay context-dependent remain weakly understood. Here, we compared the performance of hand pointing vs throwing to visual targets while facing an optical shift of the visual field (prismatic deviation). We found that the transfer of compensations was conditioned by the task performed during exposure to the perturbation: compensations transferred from pointing to throwing but not at all from throwing to pointing. Additionally, expertise on the task performed during exposure had a marked influence on the amount of transfer to the non-exposed task: throwing experts (dart players) remarkably transferred compensations to the pointing task. Our results reveal that different processes underlying these distinct transfer properties may be at work to face a given perturbation. Their solicitation depends on mastery for the exposed task, which is responsible for different patterns of inter-task transfer. An important implication is that transfer properties, and not only after-effects, should be included as a criterion for adaptation. At the theoretical level, we suggest that tasks may need to be mastered before they can be subjected to adaptation, which has new implications for the distinction between learning and adaptation

Testing for optic ataxia in a blind field

International audienc

Complex regional pain syndrome associated with hyperattention rather than neglect for the healthy side : a comprehensive case study

Complex regional pain syndrome (CRPS) is a dehabilitating chronic condition occurring with peripheral lesions. There is growing consensus for a central contribution to CRPS. Although the nature of this central body representation disorder is increasingly debated, it has been repeatedly argued that CRPS results in motor neglect of the affected side. The present article describes a comprehensive and quantitative case report demonstrating that: (1) not all patients with chronic CRPS exhibit decreased spatial attention for the affected side and (2) patients may actually exhibit a substantial, broad and reliable attentional bias toward the painful side, akin to spatial neglect for the healthy side. This unexpected result agrees with the idea that patients can be hyper-attentive toward their pathological side as a manifestation of lowered pain threshold, allodynia and kinesiophobia. (C) 2016 Published by Elsevier Masson SAS

Prisms to Shift Pain Away: Pathophysiological and Therapeutic Exploration of CRPS with Prism Adaptation

Complex Regional Pain Syndrome (CRPS) is an invalidating chronic condition subsequent to peripheral lesions. There is growing consensus for a central contribution to CRPS. However, the nature of this central body representation disorder is increasingly debated. Although it has been repeatedly argued that CRPS results in motor neglect of the affected side, visual egocentric reference frame was found to be deviated toward the pain, that is, neglect of the healthy side. Accordingly, prism adaptation has been successfully used to normalize this deviation. This study aimed at clarifying whether 7 CRPS patients exhibited neglect as well as exploring the pathophysiological mechanisms of this manifestation and of the therapeutic effects of prism adaptation. Pain and quality of life, egocentric reference frames (visual and proprioceptive straight-ahead), and neglect tests (line bisection, kinematic analyses of motor neglect and motor extinction) were repeatedly assessed prior to, during, and following a one-week intense prism adaptation intervention. First, our results provide no support for visual and motor neglect in CRPS. Second, reference frames for body representations were not systematically deviated. Third, intensive prism adaptation intervention durably ameliorated pain and quality of life. As for spatial neglect, understanding the therapeutic effects of prism adaptation deserves further investigations

Non-invasive brain stimulation shows possible cerebellar contribution in transfer of prism adaptation after-effects from pointing to throwing movements

International audienceWhether sensorimotor adaptation can be generalized from one context to others represents a crucial interest in the field of neurological rehabilitation. Nonetheless, the mechanisms underlying transfer to another task remain unclear. Prism Adaptation (PA) is a useful method employed both to study short-term plasticity and for rehabilitation. Neuro-imaging and neuro-stimulation studies show that the cerebellum plays a substantial role in online control, strategic control (rapid error reduction), and realignment (after-effects) in PA. However, the contribution of the cerebellum to transfer is still unknown. The aim of this study was to test whether interfering with the activity of the cerebellum affected transfer of prism after-effects from a pointing to a throwing task. For this purpose, we delivered cathodal cerebellar transcranial Direct Current Stimulation (tDCS) to healthy participants during PA while a control group received cerebellar Sham Stimulation. We assessed longitudinal evolutions of pointing and throwing errors and pointing trajectories orientations during pre-tests, exposure and post-tests. Results revealed that participants who received active cerebellar stimulation showed (1) altered error reduction and pointing trajectories during the first trials of exposure; (2) increased magnitude but reduced robustness of pointing after-effects; and, crucially, (3) slightly altered transfer of after-effects to the throwing task. Therefore, the present study confirmed that cathodal cerebellar tDCS interferes with processes at work during PA and provides evidence for a possible contribution of the cerebellum in after-effects transfer