Les objectifs de notre travail étaient : (i) de proposer un nouveau cadre conceptuel pour l’entraînement bimanuel chez les patients hémiplégiques (ii) de concevoir et tester une nouvelle approche de rééducation basée sur l’équilibre entre les différentes contraintes. Afin d’atteindre ces objectifs, nous avons adopté une approche du type preuve-de-concept.La première partie de ce document est consacrée à une revue critique de la littérature. La deuxième partie présente le travail expérimental qui était mené pour explorer ce concept, chez des sujets sains et des patients hémiparétiques. La première étude a exploré le comportement unimanuel dans une tâche de pointage discret pour une large gamme de d’indices de difficulté (ID). Dans la seconde étude, nous avons exploré l’effet de l’asymétrie bimanuelle induite par la tâche sur l’expression du couplage. La troisième étude aborde la problématique des asymétries induites par l’AVC et par la tâche chez des patients soufrant de déficits plus ou moins graves. Globalement, les résultats expérimentaux ont corroboré nos hypothèses initiales. Ainsi, ils nous ont permis de concevoir une nouvelle stratégie de rééducation bimanuelle. Cette stratégie de rééducation, avec le protocole de recherche clinique en cours, ont été présentés dans la troisième partie de la thèse. Notre approche a fourni une preuve de concept sur l’importance de l’équilibre entre couplage et rupture de symétrie dans le comportement bimanuel du patient hémiplégique. Elle a permis également d’envisager la manière dont les asymétries devraient être prises en compte dans la rééducation. Les perspectives futures ont été discutées dans la dernière partie du manuscrit. / In the present work we aimed at: (i) setting new conceptual foundations for bimanual movement training in stroke, and (ii) providing practical guidelines to appropriately design and test a comprehensive constraint-led bimanual rehabilitation strategy. In order to achieve these stated objectives, we adopted a proof-of-concept approach.The first part of the current manuscript includes a critical review of BMT literature on the basis of the theoretical principles and empirical findings of the dynamical systems approach. The second part reports the experimental work that was conducted to investigate this concept in healthy and in hemiparetic subjects. The first study investigated unimanual discrete rapid aiming, under different task conditions and for a wide range ID values. In the second study, the effect of task-induced inter-limb asymmetry on the expression of bimanual coupling was explored. The third study, addressed the issue of task- and stroke-induced asymmetries in patients with different degrees of impairments. Overall, experimental findings corroborated our initial hypotheses. It permitted the design of a new BMT strategy to (re)train stroke patient. This rehabilitation strategy and the on-going clinical protocol were presented in the third part of the thesis.Though voluntarily qualitative, our approach provided a preliminary proof of concept on how CVA- and task-induced inter-limb asymmetries should be taken into account in rehabilitation. The conclusions of our work along with the opened perspectives were discussed at the end of the manuscript.

L'hétérogénéité inter-patients des altérations motrices consécutives aux lésions cérébrales rend nécessaire le besoin d'individualiser la prise en charge du patient après AVC. Afin d'apporter une thérapie adaptée aux besoins du patient au moment opportun, il est nécessaire de prendre en compte plusieurs considérations théoriques afin de comprendre comment la rééducation influence la plasticité cérébrale. La récupération motrice est un phénomène complexe et non-linéaire, et identifier ses composantes caractéristiques est délicat. Au travers d'une étude observationnelle, nous avons investigué la récupération de la fonction motrice en condition unimanuelle (membre non-parétique, parétique) et bimanuelle chez des patients cérébro-lésés en phase subaigüe, sans interférer sur leur programme de rééducation classique. Nous avons d'abord validé l'analyse cinématique pour l'évaluation motrice des mouvements d'atteinte d'objets après AVC, en complément des tests cliniques. L'analyse cinématique permet de fournir des indicateurs de la récupération en temps réel de manière plus sensible que les échelles cliniques. En condition unimanuelle, la récupération du membre non-parétique progresse avant de se stabiliser après 9-10 semaines après AVC. En condition bimanuelle, la dynamique de récupération des coordinations bimanuelles change 6 semaines après AVC. Ces périodes pourraient être des fenêtres temporelles clés à prendre en compte en établissant des protocoles de rééducation. L'identification complète et précise de ces patterns naturels de récupération après AVC pourrait permettre de mieux comprendre les réseaux nerveux spécifiques qui sous-tendent les altérations du membre supérieur. A partir de ces indications cliniques prometteuses, proposer une rééducation adaptée au patient et au meilleur moment devient le challenge des travaux futurs. / Poststroke characteristics vary significantly between patients and over time, necessitating the introduction of individualized care. To provide to patients an appropriate and timely therapy, theoretical considerations must be taken into account to understand how a therapy may influence underlying neuroplasticity. Motor recovery is a nonlinear and complex function of time, and identifying its representative features remains intricate. Through observational analysis, we investigated in this thesis the time-related changes in unimanual (nonparetic, paretic upper-limb) and bimanual motor function in subacute poststroke patients, without interfering with standard rehabilitation. Overall, our results firstly validated the relevance of kinematics to assess recovery of reaching movements following stroke, in complement to clinical scores. Kinematics provides accurate real-time indicators of patients' recovery in a more sensitive way to current clinical scales. In unimanual reaching, motor function of nonparetic upper-limb recovered and then leveled off 9-10 weeks poststroke. In bimanual reaching, the dynamic of the recovery pattern of between-hands coordination changed after 6 weeks poststroke. These time-windows might be key periods to consider into designing rehabilitation protocols. Our results contribute to a better understanding of the natural pattern of motor recovery poststroke and could be of interest to understand specific neural network underlying upper-limb impairment. From these promising therapeutic guidelines, next challenge in future research includes tailoring rehabilitation training to patients at the most opportune time.

As industry becomes increasingly reliant on robotic assistance and human-computer interfaces, the demand to understand the human sensorimotor system’s characteristics intensifies. Although this field of research has been going on for over a century, new technologies push the limits of the human motor system and our knowledge of it. With new technologies come new abilities, and, in the area of medical care and rehabilitation, the need to expand our knowledge of the sensorimotor system comes from both the patient and physician. Two studies relating to human force interaction are presented in this thesis. The first study focuses on humans’ ability to bimanually recreate forces. That is, to feel a force on one hand and reproduce that force on the other. This skill is applicable in everyday lives from tasks such as a gardener using shears to trim a bush to a surgeon tying a delicate suture. These two tasks illustrate the different factors in this study on force recreation, which are the effects of: (1) occupational force dexterity, (2) force magnitude, and (3) the number of fingers used in the recreation task. Results showed statistical significance for force magnitude and number of fingers as factors in bimanual force recreation but not for occupation. The second study examines how humans compensate for force perturbations in different directions with respect to the line of action and the effects of restricting movement time. A dynamic tracking task was presented to participants in which they were told to follow a moving target as accurately as possible. During a fixed interval along the target’s path, a force field would perturb them in an undisclosed direction. Nine force conditions and three speeds were tested on both the left and right hands. Statistical analyses and comparison of error data indicate an effect of force direction on compensation accuracy. Speed is demonstrated as a statistically significant factor on accuracy, and a linear relationship between speed and error is posited.

La restauration fonctionnelle du membre supérieur chez l'hémiplégique séquellaire reste toujours l'objectif primordial recherché durant le processus de réhabilitation. De nos jours, les techniques émergentes de rééducation montrent de plus en plus d'efficacité et de réalisme, si elles sont accompagnées par les techniques conventionnelles et classiques. De plus, quelques idées anciennes ont évoluées vers l'utilisation du renforcement musculaire du membre atteint afin d'améliorer sa fonction motrice. En effet, le renforcement musculaire isocinétique constitue une technique potentiellement intéressante de rééducation pour des hémiplégiques. Dans le cadre de notre travail doctoral, nous avons utilisé le concept isocinétique pour réhabiliter les déficits moteurs et diagnostiquer les déficits de coordination du membre supérieur hémiplégique. En premier lieu, nous avons essayé de montrer le rôle de l'isocinétisme pour optimiser la prise en charge du membre supérieur chez l'hémiplégique. Nous avons d'abord présenté une revue de littérature sur le renforcement musculaire isocinétique après hémiplégie suite à une lésion cérébrale. Ensuite, nous avons évalué la faisabilité d'un programme basé sur ce type de renforcement, pour le coude et le poignet chez des hémiparétiques. Ainsi, l'utilité et l'efficacité de ce type de réentraînement isocinétique ont pu être mises en évidence. En second lieu, nous avons utilisé l'isocinétisme pour comprendre l'implication du rôle des afférences dans le déficit de coordination bimanuelle après accident vasculaire cérébral causant une hémiplégie. Dans l'ensemble, ces différents résultats autorisent à recommander l'outil isocinétique pour quantifier les déficits moteur et de coordination du membre supérieur chez l'hémiplégique, en vue d'une meilleure élaboration et mise en place de protocoles de rééducation isocinétique. / Functional restoration of the upper limb in sequelae hemiplegic remains the primary objective during the rehabilitation process. Nowadays, emerging rehabilitation techniques show more efficiency and realism, if they are accompanied by conventional and standard techniques. In addition, some old ideas have evolved to use the affected limb muscle strengthening to improve motor function. Indeed, the isokinetic muscle strengthening is a potentially interesting technique for rehabilitation of hemiplegic patients. As part of our doctoral work, we used the isokinetic concept to rehabilitate motor deficits and diagnose coordination deficits for hemiplegic upper limb. First, we tried to show the role of isokinetic to optimize the management of upper limb in hemiplegic patients. We firstly presented a review of literature on isokinetic muscle strengthening after hemiplegia following a brain injury. Then, we evaluated the feasibility of a training program based on this type of reinforcement for the elbow and wrist in the hemiparetic patients. Thus, the usefulness and effectiveness of this type of isokinetic exercise training have been highlighted. Second, we used the isokinetic to understand the contribution of afference-based processes to the impairment of bimanual coordination after stroke causing hemiplegia. On the whole, these results allow recommending the isokinetic tool to quantify motor and coordination deficits of upper limb in hemiplegic patients, for better development and implementation of isokinetic rehabilitation protocols.

No description available.

The research presented in this thesis investigates the motoric versus perceptual basis of bimanual coordination stability. A general introductory section provides an overview of Parkinson's disease, upper limb coordination in healthy younger and healthy older adults and individuals with Parkinson's disease, and the current views of the basis of bimanual coordination stability. Following the general introductory section are two manuscripts for the two experiments. Both experiments followed similar paradigms. Healthy young adults participated in the first experiment and individuals with Parkinson's disease and healthy older adults participated in the second experiment. Following the presentation of the empirical work is a general discussion section. This section is intended to summarize the two experiments, to discuss potential methodological issues and to provide ideas for future experiments. / Thesis / Master of Science (MS)

The research presented in this thesis investigates the motoric versus perceptual basis of bimanual coordination stability. A general introductory section provides an overview of Parkinson's disease, upper limb coordination in healthy younger and healthy older adults and individuals with Parkinson's disease, and the current views of the basis of bimanual coordination stability. Following the general introductory section are two manuscripts for the two experiments. Both experiments followed similar paradigms. Healthy young adult~ participated in the first experiment and individuals with Parkinson's disease and healthy older adults participated in the second experiment. Following the presentation of the empirical work is a general discussion section. This section is intended to summarize the two experiments, to discuss potential methodological issues and to provide ideas for future experiments. / Thesis / Master of Science (MSc)

Le Trouble Développemental de la Coordination (TDC) se caractérise par une altération des habiletés motrices. Si le déficit du contrôle moteur est univoque, les études testant un déficit d'apprentissage procédural moteur restent peu nombreuses et aboutissent à des résultats divergents. L'objectif principal de ce travail est de mettre en évidence les conditions dans lesquelles les enfants présentant un TDC manifestent ou non un déficit d'apprentissage procédural et de la mémoire procédurale. Quatre études ont été menées pour comparer l'apprentissage procédural moteur d'enfants présentant un TDC et d'enfants contrôles. Nous avons testé des tâches comportementales d'apprentissage variées telles que l'apprentissage d'une nouvelle coordination bimanuelle, l'apprentissage de séquences perceptivo-motrices et l'apprentissage de séquences motrices rythmiques dans différentes conditions. Nous avons investigué les corrélats cérébraux fonctionnels et structurels associés, en utilisant l'électroencéphalographie ou l'imagerie par résonance magnétique. Les résultats indiquent des différences comportementales et cérébrales lors de tâches d'apprentissage, révélées par des variables spécifiques. De plus, certaines conditions expérimentales ont amélioré l'apprentissage procédural et la mémoire procédurale des enfants présentant un TDC. Ces résultats amènent à penser que les conditions favorisant l'apprentissage et la mémoire procédurale des enfants présentant un TDC pourraient contribuer à une meilleure prise en charge. / Developmental Coordination Disorder (DCD) is characterized by impaired motor skills. While the motor control deficit is unambiguous, studies testing motor procedural learning are few and lead to contradictory results. The main objective of this work is to understand the conditions under which children with DCD demonstrate a procedural learning and procedural memory deficits. Four studies were conducted to compare the motor procedural learning of children with and without DCD. We tested various learning behavioural tasks such as learning a new bimanual coordination, learning perceptual-motor sequences and learning rhythmic motor sequences in different conditions. We investigated the associated functional and structural brain correlates, using electroencephalography and magnetic resonance imaging. The results indicate some behavioural and brain differences during learning tasks, revealed by specific variables. In addition, some experimental conditions have improved the procedural learning and procedural memory of children with DCD. These results suggest that conditions in which procedural learning and memory of children with DCD are improved could contribute to better therapeutic interventions.

In daily activities, the brain regularly assigns different roles to the hands dependingon task and context. Yet, little is known about the underlying neural processes. Thiscertainly applies to how the brain, where each hemisphere primarily controls onehand, manages the between-hand coordination required in bimanual objectmanipulation. By using behavioral, neurophysiological and functional magneticresonance imaging techniques, the present thesis examines neural mechanisms thatsupport hand coordination during tasks where the two hands apply spatiotemporallycoupled but opposing forces for goal attainment, e.g., as when removing the cap froma bottle. Although the two hands seem to operate symmetrically in such tasks, Study Ishowed that one hand primarily acts while the other assists. Moreover, this roledifferentiation was found to be flexible with the brain appointing either hand asprime actor depending on the spatial congruency between hand forces and desiredmovement consequences. Accordingly, when we remove a cap from a bottle, the handthat grasps the cap, be it left or right depending on overall task constraints, isappointed as prime actor because the twist forces it generates are aligned with thegoal to remove the cap, while the other hand, holding the bottle, applies stabilizingforces in the opposite direction. Changes in hand assignments are caused by amidline shift of lateralized activity throughout the motor system, from distal handmuscles to corticospinal pathways and primary sensorimotor and cerebellar corticalareas (Study I). Although the bimanual actions examined involved both within- andbetween-hand coordination, Study II failed to reveal additional brain activity duringbimanual as compared to matching unimanual actions, except for the primarysensorimotor areas where subpopulations of neurons were preferentially engagedduring either bimanual or unimanual actions. Thus, dedicated neurons in the motorcortices might support critical bimanual coordinative operations. While imagingresults indicated that a mainly left-lateralized parietal-premotor network managedthe task irrespective of prime actor, premotor areas presumably established handassignment by allocating the lead either to the left or the right primary sensorimotorareas (Study I and II). Regarding the process of prime actor selection and hence thecontrol of these premotor networks, imaging results indicate a transitory involvementof prefrontal cortical areas (Study III). The detected areas belong to a networkconsidered critical for cognitive operations such as judgment and decision-making,and for evaluation of utility of actions, including conflict detection. The implicitselection of prime actor during bimanual tasks thus seems to be supported by corticalareas traditionally associated primarily with complex cognitive challenges.

Multitouch technology allows the users to use both their hands and multiple fingers to manipulate digital content directly on the screen. This paper attempts to analyze the actual convenience of bimanual and multifinger manipulation on a multitouch display by conducting three observational experiments and studying how a group of volunteers use their hands and fingers when interacting with digital content on a touchscreen surface. In addition, the participants had to fill in a questionnaire where they give some additional insights on how they experienced the use of multitouch-based interface during the experiments. The results suggest that when participants were performing tasks in which they were instructed to manipulate the digital content as fast as they could, a high percentage of them resorted to the use of at least some level of bimanual manipulation of the digital content. However, when participants were told to perform the tasks calmly the big majority of participants decided to move the objects by using only one hand (unimanual). Same-hand multifinger manipulation was also used by a high percentage of participants when moving several objects simultaneously. Nevertheless, in all three experiments the most common way of moving objects across the screen was by dragging them one at a time (sequential move). Finally, in relation to the personal assessment made by the participants, a total of 70% feel that the possibility for engaging in bimanual interaction, that multitouch interface offers, is a clear benefit and advantage over traditional keyboard and mouse. However, 40% of the respondents feel that the use of mouse still is a more effective and natural form of interaction than multitouch technology.