Powered Hip Exoskeleton Assistance Study
Condition: Lower Limb Injury
MeSH terms: Leg Injuries
Study type: Interventional

Summary: 
      The increased metabolic and biomechanical demands of ambulation limit community mobility in
      persons with lower limb disability due to neurological damage. There is a critical need for
      improving the locomotion capabilities of individuals who have walking impairments due to
      disease to increase their community mobility, independence, and health. Robotic exoskeletons
      have the potential to assist these individuals by increasing community mobility to improve
      quality of life. While these devices have incredible potential, current technology does not
      support dynamic movements common with locomotion such as transitioning between different
      gaits and supporting a wide variety of walking speeds. One significant challenge in achieving
      community ambulation with exoskeletons is providing an adaptive control system to accomplish
      a wide variety of locomotor tasks. Many exoskeletons today are developed without a detailed
      understanding of the effect of the device on the human musculoskeletal system. This research
      is interested in studying the question of how the control system affects human biomechanics
      including kinematic, kinetics and muscle activation patterns. By optimizing exoskeleton
      controllers based on human biomechanics and adapting control based on task, the biggest
      benefit to patient populations will be achieved to help advance the state-of-the-art with
      assistive hip exoskeletons.
    

Detailed description: 
      One significant challenge in achieving community ambulation with exoskeletons is providing an
      adaptive control system to accomplish a wide variety of locomotor tasks. Many exoskeletons
      today are developed without a detailed understanding of the effect of the device on the human
      musculoskeletal system. The study is interested in exploring the question of how the control
      system affects human biomechanics including kinematic, kinetics and muscle activation
      patterns. By optimizing exoskeleton controllers based on human biomechanics and adapting
      control based on task, this work will be able to provide the biggest benefit to patients and
      advance the state-of-the-art with assistive hip exoskeletons. A large patient population that
      could benefit from lower limb assistive technology are stroke survivors, which is the
      specific population this proposal targets. One common characteristic of stroke survivors who
      regain their ability to walk is that the hip muscles are overtaxed due to distal weakness.
      The investigators propose to use a powered hip exoskeleton to augment their proximal
      musculature, which needs to produce significant power output in most locomotion activities
      such as standing up, walking, and going up stairs or slopes. Another biomechanical aspect of
      stroke survivors is an asymmetric gait in terms of kinematics, kinetics and muscle
      activations. The research team will examine what kind of exoskeleton assistance is most
      beneficial to stroke survivors for enhancing community ambulation. The hypothesis is that
      since the gait is asymmetric, the controller will need to be asymmetric to provide optimal
      assistance to aid in mobility. The group's long-term research goal is to create powered
      assistive exoskeletons devices that are of great value to individuals with serious lower limb
      disabilities by improving clinical outcomes such as walking speed and community ambulation
      ability. The overall objective of the proposed project is to study the biomechanical effects
      of using a hip exoskeleton with adaptive controllers for assisting stroke survivors with
      lower limb deficits to improve their community ambulation capabilities. The central
      hypothesis overarching both aims is that exoskeleton control that adapts to environmental
      terrain will improve mobility metrics for human exoskeleton users on community ambulation
      tasks. The rationale is that since human biomechanics change based on task, exoskeleton
      controllers likewise need to optimize their assistance levels to match what the human is
      doing. The first aim of the proposed study is to determine the benefit of exoskeleton control
      that adapts to the environment for improving community ambulation capability. The team has
      previously designed and extensively tested an autonomous hip exoskeleton in able-bodied
      subjects on a treadmill. The investigators plan to extend their control framework to over
      ground walking and tune assistance magnitude and timing levels to enable efficient locomotion
      over stairs and ramps on their novel terrain park. The investigators plan to compare a
      controller that adapts its assistance strategy based on locomotion task to a static
      controller as well as not wearing the exoskeleton. The primary hypothesis for this aim is
      that exoskeleton control that adapts to environmental terrain will improve mobility metrics
      such as task completion speed for human exoskeleton users on community ambulation tasks. The
      expected outcome of these aims will be an increased understanding of the biomechanical and
      clinical effects in applying hip assistance with a robotic exoskeleton in community
      ambulation tasks such as overground walking, ramps and stairs. This work will serve as a
      foundational start for a broader planned study of optimizing controllers to improve
      biomechanics in the walking impaired using powered hip autonomous exoskeletons.
    

Intervention name(s): Powered hip exoskeleton
Intervention type(s): Device
Intervention description(s): The study team will test a powered hip exoskeleton and its capability to improve locomotion.
Intervention model: Single Group Assignment
Intervention model description: The model used is a repeated measures single arm study. Multiple conditions including using and not using the device will be tested on the same subjects to have multiple test points on a per subject basis.
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Exoskeleton