Background

Robotic wearable technology is advancing to augment human functions. As an example, lower-limb exoskeletons can help people with gait impairments to walk faster and easier. The ideal lower-limb wearable devices should be light, powerful, and easily used in the real world. However, most devices have only been tested in the lab at current stage.

A major part of my postdoctoral research is to evaluate a custom untethered ankle exoskeleton and quantify its performance on the treadmill, on multiple terrains, and in controlled real-world environment. We also looked at the potential benefits of using the device in gait training for people with neurological conditions.

The primary target population are people with cerebral palsy (CP); additionally, we have tested the device in those with spinal cord injury, stroke, or Guillain-Barré syndrome.

Purpose

1) Evaluate wearable ankle exoskeleton assistance on graded and real-world mixed-terrain walking in individuals with gait impairments.

2) Determine how repeated back-to-back over-ground walking with ankle exoskeleton assistance affects gait and muscle activity in individuals with CP.

3) Compare unilateral vs. bilateral assistance.

Findings

  1. Wearable adaptive ankle exoskeleton assistance can safely and effectively increase ankle function and improve the energy cost of steady-state incline walking and stair ascent in individuals with CP. All participants can safely navigate level ground and stairs in controlled real-world environments wearing the device, with more impaired participants exhibiting a marked benefit.

  2. Back-to-back over-ground gait training using an untethered ankle exoskeleton improved walking speed and step length in CP. Following training, we observed improved ankle plantar-flexor activation patterns while walking with the exoskeleton, and a favorable increase in stride-to-stride repeatability of the ankle plantar-flexor and knee extensor muscles during walking both with and without the device.

  3. Bilateral assistance was more reliably effective than unilateral assistance in improving clinically relevant treadmill and over-ground walking performance. However, because each participant responded differently, our results suggest that clinicians should adopt personalized interventions to maximize patient outcomes.

Future directions

  1. Completing longer, randomized controlled trial of wearable ankle exoskeleton assistance with larger sample size.

  2. Exploring the potential factors (i.e., age, impairment level, etc.) influencing participant responses.

  3. Implementing longer duration mixed-terrain walking in controlled settings, and eventually longer-term testing in uncontrolled free-living environments.

Resources

Publications

Others

ASB2021 Podium Presentation