A passive exoskeleton can assist split-belt adaptation

Area of Science:

• Biomechanics
• Rehabilitation Engineering
• Neuroscience

Background:

• Gait deficits impact functional recovery, particularly in conditions like stroke.
• Gait adaptation is crucial for flexible movement but is often impaired in neurological disorders.
• Passive exoskeletons offer an affordable and user-friendly option for gait rehabilitation.

Purpose of the Study:

• To characterize gait adaptation patterns in healthy individuals using a unilateral passive exoskeleton during a split-belt treadmill task.
• To compare gait adaptation between a group using exoskeletal assistance and a control group without assistance.
• To investigate the effects of passive exoskeleton use on spatiotemporal gait variables and power generation during adaptation.

Main Methods:

• Healthy participants were assigned to either a unilateral exoskeleton or a no-exoskeleton group.
• Participants performed a split-belt treadmill adaptation task with independently controlled belt speeds.
• Symmetry indices of spatiotemporal variables and positive leg power were calculated to quantify adaptation.

Main Results:

• Passive exoskeleton use altered gait adaptation, mainly in the temporal domain, compared to the control group.
• Adaptive changes were observed in both early and late phases, predominantly in intra-limb measures like stance time.
• While positive power symmetry decreased in the exoskeleton group, this was driven by increased power in the non-assisted leg.

Conclusions:

• Passive exoskeletons modify gait adaptation strategies, offering a potential tool for rehabilitation.
• The observed adaptations suggest a reduced neural and mechanical burden during bilateral gait coordination tasks.
• Future research should consider balance control implications during unilateral exoskeletal assistance.