Kinematic characterization of fast and accurate cervical rotations during point-to-point test in healthy and neck pain individuals

Neck pain is major health care cost and it is the second largest cause of disability right after low back pain in Belgium. The lack of correlation between structural pathologies and symptoms has influenced the classification of most patients with neck pain as “non-specific” neck disorders. Therefore, in order to better manage patients clinically, therapeutic interventions for neck pain should be conducted using both quantitative (range of motion) and qualitative (sensorimotor control appraisal) assessment of the neck and particularly during the head rotation movements. Moreover, the evaluation of kinematic axial neck rotation performance is of major importance in the context of studying sensorimotor control of the neck. Thus, to better define the clinical aspect of non-specific neck pain patients by focusing on sensorimotor control assessment during neck axial rotation, we developed a reliable, simple and clinically applicable test: the DidRen laser test. This test uses a laser beam placed on the subject’s head guiding them to produce fast, low amplitude, and accurate rotational movements of the head-neck complex in response to real visual targets placed in front of the subjects. In this context, the aim of this thesis was to investigate the different kinematic patterns of the neck's fast rotation motion performed during a sensorimotor task. We compared kinematic patterns of the neck fast rotation motion performed during the DidRen laser test induced between groups, taking difference in age, pathology and treatment into account. First, we validated the DidRen laser test by recording kinematic patterns in healthy subjects aged between 8 and 85 years. We observed that age-related kinematic performance, especially for children and seniors, was a key parameter during a fast-head rotation tasks standardized with the DidRen Laser test device. Secondly, we validated a low-cost and ecological kinematic measurement tool, the inertial measurement unit (IMU), by showing that the IMU was as relevant as a gold‐standard optoelectronic system to assess fast and precise neck rotation in healthy controls and patients with non-specific neck pain. This validation allowed us to demonstrate the IMU utility in clinical environment. Finally, we examined cervical sensorimotor behavior in acute non-specific neck pain patients. The total time to perform the DidRen test and the average speed are the most sensitive variables for differentiating the kinematic pattern of patients with acute neck pain compared to the control subjects. Besides, these parameters allowed to differentiate the kinematic pattern of patients before and after treatment. In conclusion, this thesis contributes significantly to the improvement of knowledge on the sensorimotor behaviour of patients suffering from non-specific acute cervical pain.