Abstract
The autonomy of individuals depends on the ability to perform daily-life activities which can be impaired both with aging and the onset of pathologies such as stroke. The preservation and/or recovery of the motor functional abilities are deeply linked to brain plasticity. Thus, a better knowledge of these brain activations reorganisation and how they are linked to functional movement would allow a better understanding of healthy aging effects and a better management of patient’s recovery. Association of functional neuroimaging methods such as electroencephalography (EEG) and near-infrared spectroscopy (fNIRS), with kinematic analyses of upper-limb (UL) movement could benefit in the understanding of movement and brain adaptations associated to aging and post-stroke recovery.In this context, this thesis work aims were to: i) develop a suitable methodology to evaluate the task-related brain activity coupled with kinematics of UL proximal movement and evaluate the brain and movement modifications ii) in healthy aging and iii) in post-stroke population.To respond to the first objective, we built an experimental setup to evaluate the task-related brain and kinematics activity during two functional tasks: i) a reaching target task, and ii) a circular steering task capturing the speed-accuracy trade-off. Combine fNIRS-EEG system was used to record the primary sensorimotor (SM1) activity. Then, two experimental studies were carried out to depict the brain and kinematics modifications during the two functional tasks related to healthy aging (2nd objective) and post-stroke (3rd objective). First, we found that healthy aging was leading to poorer performances in the circular steering task, but no kinematics modification in the reaching task. Moreover, we showed an increase SM1 ipsilateral activity in the older adults for the circular steering task. Second, we highlighted trunk use increase and a reduced movement velocity in both tasks for post-stroke patients. Regarding the brain activity, we found an increased activation during the reaching task with the paretic arm mainly in patients with higher impairment, and an increased use of trunk compensations.In conclusion, our work helped to better delineate the brain compensation/ adaptation strategies associated to functional movement modifications during healthy aging and/or post-stroke. From a clinical point of view, this work opens avenues for the identification of markers of an optimal functional recovery.