Title: How to use exoskeletons to improve self-selected walking speed in older adults

Date: Friday, August 18th, 2023

Time: 10:00 AM – 1:00 PM EST

Location: Zoom meeting (https://gatech.zoom.us/j/96260213537?pwd=UExhWGpNYVdKdm5MOEE2TEF4NE1MUT09) and TBD (Whitaker 1214 pending)

Benjamin A. Shafer

Robotics Ph.D. Candidate

School of Mechanical Engineering

Georgia Institute of Technology

Committee:

Dr. Aaron J. Young, Advisor – George W. Woodruff School of Mechanical Engineering

Dr. Gregory S. Sawicki, Advisor – George W. Woodruff School of Mechanical Engineering

Dr. Lena H. Ting – Coulter Department of Biomedical Engineering (Emory University)

Dr. Jason R. Franz – Joint Department of Biomedical Engineering (University of North Carolina – Chapel Hill and North Carolina State University)

Dr. Fausto A. Panizzolo – CEO, Moveo Walks

Abstract:

Older adults are becoming the majority population across the globe and as we age quality of life and ability to live on our own declines. Self-selected walking speed is highly correlated with these declining traits and slows with age. The reason for slowing walking speed with age is unknown but some studies suggest it is due to muscle weakness and fatiguability. Current physical therapy techniques have been inconsistent at returning older adults to a more youthful gait in terms of speed and mechanics. Exoskeletons tested in younger adults have shown success to increase walking speed and affect biomechanics across the lower limb. In this work, we use lower -limb exoskeletons, targeting the hip and ankle independently, optimized to increase overground self-selected walking speed, and determine if/how older adults are optimally selecting their walking speed.

Our clinically implementable exoskeleton tuning protocol was successful at increasing walking speed and comfort. Younger adults accepted both ankle and hip powered assistance, increasing their walking speed with each. Older adults did not accept hip assistance and ankle assistance had a smaller effect, still positive effect, on their speed. At each joint, exoskeleton power injection is key to eliciting faster walking speeds. Both older and younger adults select their walking speeds by first optimizing energetic cost per unit distance then optimizing muscle loading.