Étude du contrôle postural quasi-statique et dynamique en position debout des personnes ayant une lésion médullaire incomplète
Sensorimotor impairments resulting from a traumatic spinal cord injury affect the ability to stand safely. Individuals with incomplete spinal cord injury commonly experience falls while performing locomotor tasks after rehabilitation, resulting in injuries that affect social participation and quality of life. A better understanding of postural control in the clinical setting would help to identify effective interventions in this regard. The main objective of this thesis was to investigate standing postural control during various tasks among individuals with traumatic spinal cord injury using biomechanical assessments. The specific objectives were to explore the various aspects of postural control associated with each task and to identify explanatory factors of postural control. Twenty-five (25) people with incomplete traumatic spinal cord injury were recruited and underwent biomechanical assessments in a pathokinesiology laboratory. These assessments examined quasi-static stance with eyes open and closed, comfortable multidirectional limits of stability, natural gait, and gait initiation and termination. Biomechanical measures characterizing the displacement of the center of pressure (COP) as well as the stabilizing/destabilizing force model were used to compare the postural control of individuals with spinal cord injury with 33 able-bodied individuals. The results showed a decrease in quasi-static and dynamic postural control in people with spinal cord injury compared to their healthy counterparts. This decrease was accompanied by excessive reliance on visual information during quasi-static standing and correlated with the scores achieved on the Mini-BESTest. Displacement of the COP during the comfortable multidirectional limits of stability test was characterized by difficulty in following the indicated direction. This lack of precision increased the distance required to reach the maximal position in each direction. Measures of quasi-static stance did not correlate with those of the comfortable multidirectional limits of stability test. The single-support phase of gait among individuals with spinal cord injury was found to have a lower maximal stabilizing force and a greater destabilizing force compared to able-bodied individuals, whereas gait termination was more challenging than gait initiation for individuals with spinal cord injury. For all gait tasks, the COM velocity and the distance between the COP and the base of support were the main explanatory factors of stabilizing and destabilizing forces. To summarize, the results confirm the clinical impression of standing postural control impairment among individuals with spinal cord injury and identify the characteristics and parameters to consider for rehabilitation.
Ambulation Spinal cord injury Standing postural control Gait Biomechanics Rehabilitation