Enhancing Voluntary Motion in Broad Patient Populations With Modular Powered Orthoses

The overall goal of this project is to develop modular, lower-limb, powered orthoses that fit to user-specific weakened joints and control force/torque in a manner that enhances voluntary motion in broad patient populations. This project aims to establish feasibility of assisting different populations with these modular powered orthoses. The investigators hypothesize that assisting lower-limb musculature with modular powered orthoses will improve 1) lifting/lowering posture in able-bodied subjects and 2) functional outcomes in elderly subjects.

Study Overview

• Status: Recruiting
• Conditions: Lower-limb Orthoses; Frailty/Sarcopenia; Chronic Overuse Musculoskeletal Injuries
• Intervention / Treatment: Device: Modular powered orthosis

Detailed Description

The overall goal of this project is to develop modular, lower-limb, powered orthoses that fit to user-specific weakened joints and control force/torque in a manner that enhances voluntary motion in broad patient populations. Conventional orthoses tend to immobilize joints, and emerging powered orthoses constrain voluntary motion by using highly geared electric motors and/or control methods that force the user to follow a specific gait pattern. Consequently, these devices have not seen widespread success across populations with weakened voluntary control due to advanced age, musculoskeletal disorders, etc. These heterogeneous populations require partial, not full, assistance of user-specific muscle groups during daily activities. However, there is a fundamental gap in knowledge about how to design and control powered orthoses to assist the user without constraining their motion. The central hypothesis of this project is that high-torque, low-inertia motor systems controlled with energetic objectives will enable modular powered orthoses to partially assist the joints. High-torque electric motors combined with minimal transmissions can be freely rotated (i.e., backdriven) by human joints, allowing the use of an emerging torque control method called energy shaping to reduce the perceived weight/inertia of the body during any motion. By mounting these modular actuators to commercial orthoses, this technology will be easily prescribed/configured by clinicians. This project aims to establish feasibility of assisting different populations with modular powered orthoses. The investigators hypothesize that assisting lower-limb musculature with modular powered orthoses will improve 1) lifting/lowering posture in able-bodied subjects and 2) functional outcomes in elderly subjects.

• Study Type: Interventional
• Enrollment (Estimated): 33
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Robert Gregg, PhD; Phone Number: 734-763-1156; Email: rdgregg@umich.edu
• Study Contact Backup: Name: Emily Klinkman, MS; Phone Number: 734-763-1156; Email: emilykk@umich.edu

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • Recruiting
      • Rehab Lab, University of Michigan
      • Contact: Emily Klinkman, MS; Phone Number: 734-763-1156; Email: emilykk@umich.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion criteria for able-bodied, young participants will be:

• Aged between 18 to 65 years
• Weigh less than 250 lbs due to limitations in the design of the orthoses
• Ability to lift and lower a 10 kg weight using the neutral-spine squat technique for 10 repetitions

Exclusion criteria for able-bodied, young adult participants will be:

• Pregnant (self-report)
• Any significant neuromuscular or musculoskeletal disorder that would interfere with the study
• Prior history of chronic lower-back pain
• Unable to walk for 20 minutes
• History of any cardiovascular, vestibular, or visual diseases and/or impairments that may interfere with the study
• Cognitive deficits that would impair their ability to give informed consent or impair their ability to follow simple instructions during the experiments. Cognitive deficits will be determined by a Mini-Mental State Examination (MMSE) score of <22.
• Adults with a known allergy to medical grade tape

Inclusion criteria for elderly participants will be:

• Aged between 65 to 85 years
• Weigh less than 250 lbs due to limitations in the design of the orthoses
• Ability to walk 6 minutes without assistance from a person (may use walking aid)

Exclusion criteria for elderly participants will be:

• Pregnant (self-report)
• Significant pain due to arthritis or other joint problems that would limit their ability to walk
• Any recent lower-extremity fracture (within 3 months)
• Significant neurological (e.g., stroke), orthopedic, or cardiovascular disorder that may affect the ability to walk
• Advised by a physician not to walk or exercise
• Uncontrolled hypertension or diabetes
• Cognitive deficits or visual impairment that would impair their ability to give informed consent or impair their ability to follow simple instructions during the experiments. Cognitive deficits will be determined by a Mini-Mental State Examination (MMSE) score of <22.
• Adults with a known allergy to medical grade tape

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Exoskeleton; Participants in this arm of the study will perform various tasks while wearing the modular powered orthosis

Device: Modular powered orthosis; This study will investigate modular, lower-limb, powered orthoses that fit to user-specific weakened joints and control force/torque in a manner that enhances voluntary motion in broad patient populations. The central hypothesis is that high-torque, low-inertia motor systems controlled with energetic objectives will enable modular powered orthoses to partially assist the joints. High-torque electric motors combined with minimal transmissions can be freely rotated (i.e., backdriven) by human joints, allowing the use of an emerging torque control method called energy shaping to reduce the perceived weight/inertia of the body during any motion. By mounting these modular actuators to commercial orthoses, this technology will be easily prescribed/configured by clinicians.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gait speed	Gait speed will be determined by the time to complete a 10-meter walk test. This will be the primary outcome measure for elderly subjects.	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)
Time to complete 10 reps of lifting/lowering	Time to complete 10 reps of L&L will be measured post-fatigue in healthy subjects.	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)
Powered orthosis effect (muscle effort)	For each orthosis module tested, electromyography (EMG) readings will be normalized per-muscle by the peak EMG observed during the no-orthosis condition, and then averaged over the cycle and across repetitions to obtain "normalized exertion" values. Performance will be assessed by the difference between the orthosis condition and no-orthosis condition, averaging across tasks and muscles measured for the joint module.	1 day
Powered orthosis effect (biological torque)	For each orthosis module tested, peak biological torque (estimated by inverse dynamics) will be averaged across repetitions. Performance will be assessed by the difference between the orthosis condition and no-orthosis condition, averaging across tasks.	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)
Minimum chair height for successful sit-to-stand	We will evaluate the minimum chair height from which elderly participants can successfully rise with and without the knee exoskeleton.	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)
Joint power	For elderly participants, we will evaluate the peak values of biological and total (exo+biological) joint power with and without the exoskeleton.	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Thorax angle	This is the global thorax angle (with respect to vertical) during a lifting/lowering cycle. This will be a secondary outcome measure for able-bodied subjects.	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)
Stair ascent gait style	Step-to-step vs. step-over-step gait style will be evaluated for the exo condition vs no exo condition for elderly participants.	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)
User satisfaction	User satisfaction / perception of device effectiveness over an ambulation circuit (sit-to-stand, walk up and down a ramp, walk up and down a staircase) will be measured post-fatigue in healthy subjects using a modified Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0) survey. The purpose of the scale is to evaluate user device satisfaction and consists of 12 items asking the user to rate their satisfaction on a scale of 1 to 5, where 1 = "not satisfied at all" and 5 = "very satisfied".	1 day, assessed per experimental condition (i.e. with orthosis and without orthosis)

Collaborators and Investigators

• Sponsor: University of Michigan
• Collaborators: National Institute for Biomedical Imaging and Bioengineering (NIBIB)

Study record dates

Study Major Dates

• Study Start (Actual): July 29, 2022
• Primary Completion (Estimated): September 20, 2026
• Study Completion (Estimated): September 21, 2026

Study Registration Dates

• First Submitted: January 13, 2022
• First Submitted That Met QC Criteria: February 14, 2022
• First Posted (Actual): February 15, 2022

Study Record Updates

• Last Update Posted (Actual): July 18, 2025
• Last Update Submitted That Met QC Criteria: July 15, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Neuromuscular Manifestations; Pathologic Processes; Pathological Conditions, Anatomical; Muscular Atrophy; Atrophy; Frailty; Sarcopenia
• Other Study ID Numbers: HUM00201957; R01EB031166 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No