No methods and systems effectively assess the quality of the hand movements in unilateral stroke patients with motor impairments of the upper limb in measurable way. This project will explore the problem focusing on methodological and technological development of a new tool for the evaluation of the quality of upper limb movements.
In particular, it aims to improve (a) the acquisition set-up commonly used to decode upper limb residual muscle activity in stroke patients, integrating it of systems for acquiring kinematic and kinetic magnitudes and (b) the protocol of analysis of myoelectric signals (electrical activity generated by muscles), using pattern recognition techniques validated for others application fields. The project will study how to merge the quantitative multimodal (myoelectric and biomechanical) information and the qualitative evaluation by clinicians for characterizing movements considered correct/wrong. Indeed, the goals of the rehabilitation strategy (considered in this project) are to reinforce voluntary movements reflecting correct movement (if any) and discourage pathological synergies, co-contraction of antagonist muscles, leading to spasticity. In this way stroke patients could re-learn motor scheme by having voluntary (covert and/or overt) access to the affected limb.
Developing a flexible and affordable Brain Computer Interface-driven rehabilitation device, in which a combined approach based on reinforcement of both mental rehearsal of (hand) movements and residual motor ability will positively affect individual post-stroke function motor outcome, is the ultimate goal of the project.
This research project takes place in the context of a new rehabilitation strategy supporting post-stroke upper limb motor recovery. This strategy rests on the EEG/EMG combined approach to reinforce overall individual patient's sensorimotor experience based on motor imagery and/or residual motor abilities, re-learning motor scheme by having voluntary (covert and/or overt) access to the affected limb. In order to reinforce the sensorimotor experience, residual motor abilities need to be assessed quantitatively and qualitatively.
EMG signals give information about the onset and intensity of the muscle activations. But that information does not complete the evaluation of the motor abilities. Therefore, we propose a new integrated approach in which the motor abilities will be assessed from both myoelectric signals and mechanical magnitudes. Forces involved in the flexion and extension of the fingers and joint angles could build up the knowledge about upper limb movements in stroke patients. We will also transfer the myoelectric pattern recognition techniques, used to identify different kinds of grasping in trans-radial amputees for instance, from that population to stroke population, validating their applicability.
Training the classifier with the multimodal information and the evaluations by clinicians, we could be able to characterize a movement in order to reinforce only voluntary movements reflecting correct movement (if any) and discourage pathological synergies, co-contraction of antagonist muscles, leading to spasticity.
In an exploratory manner, the device and the protocol developed in the project could be used on its own for the evaluation of the movement quality in stroke patients. Once the parameter have been defined to evaluate which activations are considered correct/wrong, the same principle could be applied in the evaluation of efficacy of other rehabilitative treatments for the upper limb. This tool will be a user-adjustable system, which could follow the subject's improvements and changes in time. An instrumental scale for clinical assessment of the quality of a physical exercise could be designed and validated in the future by evaluating the correlation between this instrumental scale and scales commonly used by clinicians (e.g Fugl-Meyer scale).
Furthermore, the validation of the device and protocol in contexts different from that hospital, could allow developing a tool (in a prototypal version) usable by patients at home for evaluating by themselves the quality of movements.