Thesis defense Damien Laurent 9/12/2011 1:30 pm
"Stimulations spécifiques pour la rééducation de déficits moteurs: biomécanique et modélisation"
Experimental paradigms of motor adaptation constitute an incubator where new ideas of treatments against motor deficits sometimes emerge. When a new adaptive competence of the sensorimotor system is discovered, one can wish it could contribute to sollicitate remanent adaptive capacities of patients. Our work follows this approach, trying to understand the underlying mechanisms of the adaptation process described by Magescas and Prablanc (2006), by mean of modeling tools, and suggesting new protocols aimed at testing patients with motor deficits.
The first chapter aims at giving evidence that the Magescas and Prablanc's paradigm induced little if any perceptual effects. This was of importance to circumscribe the studied paradigm. Thus, we ensured that our paradigm implicated the only phase of motor commands generation.
The second chapter deals with the generalization process of adaptation at the level of one joint (the elbow). In line with the hypothesis of vectorial coding of movement in joint space, our results allowed to suggest that the studied paradigm induced a focused change of the motor gain of the group of elbow extensor muscles. This experiment gave us a model for the generalization of adaptation, grounded on the modification of motor gains of the articulatory chain of the arm.
The third chapter details the development of methods to record the arm joint configuration. Beginning from a complete modeling, we show that it can be simplified to obtain hopeful results for the analysis of adaptation phenomena. Such a methodology has allowed to precisely compared the hypothesis of generalisation of adaptation in task space and in joint space.
In chapter 4, following an explorative approach, we have designed two protocols transposing the Magescas and Prablanc's experiment, in order to widen our ressources for a future research on patients with motor deficit. In the first protocol, a grasping task was substituted for the pointing task. The second protocol changed both the task, which was an object holding task, and the training signal, which was a change in the object's weight. Only the first protocol gave conclusive results.
At the end of the present work, we have: methodological means of recording and of modeling the joint chain of the arm; a theoretical model of the studied motor adaptation; and a new protocol of adaptation of grasping, which is more convenient than adaptation of pointing for clinical purposes.
Bâtiment B13 Amphi 2 Hôpital NeuroCardiologique