NEURAL CONTROL OF GAIT IN PEOPLE WITH HAEMOPHILIC ARTHROPATHY

Haemophilia is a bleeding disorder caused by a deficiency of coagulation factors VIII or factor IX. People with severe haemophilia may have spontaneous bleeding events or bleeding in response to minor trauma; most of the events occur in the joints and muscles. The most frequent clinical manifestation is haemophilic arthropathy, which results from repetitive intraarticular bleeding and inflamed synovial membrane, which may result in chronic pain and joint impairment. The overall aim of my thesis was to investigate the neural control of gait in people with haemophilic arthropathy (PWHA). I hypothesized that neural gait control is affected in PWHA, and the changes in neural control of gait are associated with joint damage and chronicity of the joint constraint. Gait was selected because the knees and ankles are the most prevalent affected joints in adults PWHA. The core of my thesis is investigating neural control by studying electromyography (EMG) activity patterns of single muscles and/or muscle synergies, as well as their interaction with joint kinematics and clinical outcomes. In chapter 1, I provide a general perspective about the impact of haemophilia on the musculoskeletal system, the current gaps in knowledge in the neural control of gait in haemophilic arthropathy, and how to assess the neural control of gait. In Chapters 2 and 4, through the assessments of muscle activation patterns of single muscles, coordination between antagonistic muscle pairs, and muscle synergy analysis, we confirmed the hypothesis that the neural control of gait is affected in PWHA. In chapters 3 and 5, we confirm that the altered neural control of gait in PWHA is associated with the severity of joint damage and chronicity of joint constraint. In chapter 6, we discussed the results of chapters focused on clinical and physiological perspectives of the altered neural control of gait in PWHA. In addition, we discuss how the evaluation of neural control through the Walk-DMC index can be an alternative to monitoring the motor impairment in PWHA. Based on our results, we also discussed on how to improve the outcomes of physical therapy and surgical interventions that aimed to improve the locomotion in PWHA. My thesis contributes to understanding the consequences of haemophilic arthropathy for the neuromechanics of gait. The findings of my thesis indicate that neural control of gait is affected in PWHA, and the changes in the neural control of gait are associated with joint damage, pain and chronicity of the joint constraint. From a scientific perspective, the changes in the neural control of gait in PWHA implicate altered activity patterns of single leg muscles and a modular reorganization of gait. From a clinical perspective, my thesis gives a new perspective on how to monitor disease progression in PWHA using the Walk-DMC index—providing new perspectives to improve the therapeutic interventions that aim to recover gait in PWHA.