HSL Special Seminar: W Brett Johnson, PhD (9 am, 12/12, 33-206)

"Teaching Able-Bodied People How to Walk Like They Are Paralyzed: Measuring and Modeling the Gait of Persons with Paraplegia"

W Brett Johnson, PhD
Research Engineer
Global Engineering And Research (GEAR) Laboratory
Mechanical Engineering Department


BRIEF SUMMARY: This talk will be a survey of Dr. Johnson’s work in studying and modeling how persons with paraplegia interact with walking orthoses. Walking is an important goal for persons with lower limb paralysis, and several devices have been designed to help them stand and walk. Studying how people use these devices helps designers make much-needed improvements; however, the small population of persons with paraplegia limits research subject recruitment. Able-bodied people may be useful models for predicting how people with paraplegia will respond to different device designs if the able-bodied people experience the same physical constraints as people with paraplegia. A novel Lower Limb Paralysis Simulator (LLPS) was created to constrain able-bodied people so that they walked as if they had paraplegia. Able-bodied subjects walking with the LLPS were tested to confirm that they walked like persons with paraplegia. Then, the subjects were used as models to predict how hip joint stiffness would affect locomotion with an assistive walking device known as a Reciprocating Gait Orthosis (RGO). These predictions were then tested with two RGO users. Able-bodied subjects have also been used to explore the human machine interface of a powered exoskeleton for persons with paraplegia. By performing different walking tasks in an exoskeleton using either a tilt sensor or manual buttons to initiate steps, the able-bodied subjects were able to reveal the strengths and weaknesses of each interface. While testing with able-bodied subjects will never be as accurate as with people with paraplegia, it can be used to identify promising solutions that are worth investing the time and resources needed to perform research with persons with paraplegia.