Modeling

The place of the modelling axis within the IMAGINE team is located upstream of the therapeutic act. More specifically, the research area of this axis concerns the study of the control / shape / function relationship within the neuro-musculoskeletal system (NMS) in order to support therapeutic decision-making and the evaluation of therapies. The starting point of this axis is the acquisition of multimodal spatial and temporal data and the corresponding processing methods. In a second step, we aim at developing new 3D+t modelling techniques in a patient-specific approach to support therapeutic decision-making.

The neuro-musculoskeletal system (NMS) is defined as the set of organs involved in the production of motor skills, movement, and thus function (walking, running, catching, etc.). It therefore includes the neurological system at the origin of motor skills (brain, spinal cord, nerve, etc.) and on a more "peripheral" level the musculoskeletal system (bones, joints, cartilage, muscles, tendons, etc.). It is original, but natural, to think of this device leading to movement and function as an indivisible whole on a physiological and theoretical level. This vision is directly related to the reality of patients with so-called "neuro-orthopedic" pathologies (Cerebral Vascular Accident, Head Injury, Cerebral Palsy, etc.) but also to the health problems presented by patients with only one NMS system disease such as purely muscular (myopathy) or orthopedic (hip or shoulder arthritis) diseases. Lesions in the NMS system are varied: central lesions (motor control disorders, hypo or even hyper activation of muscles,...), muscular disorders (atrophy, fibrosis and muscle retraction), lesions of the skeletal system (bone and joint deformities, arthrosis, cartilage). They all have the same consequence: an impairment of the motor function. The complexity of these lesions requires a stage of pathophysiological understanding at the level of the pathology but especially at the level of the individual for whom a therapeutic decision (rehabilitation, surgery) must be taken. For example, equinus gait (i.e. on tiptoe), one of the most common walking disorders in stroke or cerebral palsy, gradually induces a disorder of the bone shape of the ankle/foot complex and a retraction of the triceps muscle which in turn induces a more pronounced walking disorder. Restoring a physiological gait involves understanding the musculoskeletal shape (imaging), function (motion analysis) and motor control (peripheral EMG). This combination of signals allows the links between motor control, 3D anatomical/geometric shape and 3D motion/product function to be finely explored.

Keywords: Medical Imaging (MRI, CT, Ultrasound, EOS), Signal Acquisition (EMG, motion capture, inertial sensors), Medical Image Analysis, Computational Anatomy, Statistical Shape Modeling, Biomechanics, Machine Learning, Motor Function, NMS development