Title: Pelvic floor muscle activity during exoskeleton-assisted walking in controls and individuals with complete spinal cord injury: Feasibility considerations and characterization
Thesis Supervisors: Dr. Tania Lam & Dr. Jean-Sébastien Blouin
Committee member: Dr. John Kramer
Defence Chair: Dr Hyosub Kim
Abstract:
Background: The pelvic floor muscles (PFM) are important for maintaining continence and a potential therapeutic target for bladder management after spinal cord injury (SCI). Locomotor training could be beneficial for bladder outcomes in people with motor-complete SCI (mcSCI), but it remains unclear if reported improvements are related to the PFM. The PFM are co-activated with abdominal and gluteal muscles, and active during regular walking in able-bodied controls; however, we do not fully understand if exoskeletons used for gait rehabilitation requiring more active engagement of the trunk muscles (e.g., the Ekso), could elicit more PFM activity compared to the Lokomat, which restricts trunk movement. Further, considering the invasiveness of the necessary procedures to record PFM activity, establishing the feasibility of the surface PFM electromyography (EMG) self-setup for dynamic tasks in controls will facilitate work in this area.
Objectives: To (1) determine the feasibility of PFM EMG self-setup in controls; (2) characterize PFM activation patterns with respect to exoskeleton device, speed, pelvis acceleration, and synergistic muscle activity in controls; and (3) explore the presence of PFM activity during exoskeleton-assisted walking in people with mcSCI.
Methods: Eleven able-bodied adults and 3 SCI participants enrolled in this within-subject, cross-sectional study. We obtained EMG from the PFM and lower back, abdominal, gluteal, and leg muscles, as well as pelvis acceleration data, during walking in the Lokomat and Ekso at different speeds. Control participants completed a survey to report their experiences and preferences related to the PFM EMG self-setup.
Results: There was a considerable left-right difference in signal quality in controls during walking with the PFM EMG self-setup. In controls, PFM activity was higher during walking in the Ekso than Lokomat at slow and fast speeds. Higher PFM EMG amplitude was observed with greater pelvic acceleration and trunk and gluteal muscle activation. Both the Lokomat and Ekso elicited PFM activity in SCI participants.
Conclusion: PFM EMG setup by a trained professional might be necessary to ensure signal quality during dynamic tasks. The Ekso is more effective in eliciting PFM activity in controls, and further investigation is needed to better understand this phenomenon in people with mcSCI.