Assistive Hip Exoskeleton Study for Stroke

November 18, 2021 updated by: Georgia Institute of Technology

Improving Community Ambulation for Stroke Survivors Using Powered Hip Exoskeletons With Adaptive Environmental Controllers

The increased metabolic and biomechanical demands of ambulation limit community mobility in persons with lower limb disability due to neurological damage. There is a critical need for improving the locomotion capabilities of individuals with stroke to increase their community mobility, independence, and health. Robotic exoskeletons have the potential to assist these individuals by increasing community mobility to improve quality of life. While these devices have incredible potential, current technology does not support dynamic movements common with locomotion such as transitioning between different gaits and supporting a wide variety of walking speeds. One significant challenge in achieving community ambulation with exoskeletons is providing an adaptive control system to accomplish a wide variety of locomotor tasks. Many exoskeletons today are developed without a detailed understanding of the effect of the device on the human musculoskeletal system. This research is interested in studying the question of how the control system affects stroke biomechanics including kinematic, kinetics and muscle activation patterns. By optimizing exoskeleton controllers based on human biomechanics and adapting control based on task, the biggest benefit to patient populations will be achieved to help advance the state-of-the-art with assistive hip exoskeletons.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

One significant challenge in achieving community ambulation with exoskeletons is providing an adaptive control system to accomplish a wide variety of locomotor tasks. Many exoskeletons today are developed without a detailed understanding of the effect of the device on the human musculoskeletal system. The study is interested in exploring the question of how the control system affects human biomechanics including kinematic, kinetics and muscle activation patterns. By optimizing exoskeleton controllers based on human biomechanics and adapting control based on task, this work will be able to provide the biggest benefit to patients and advance the state-of-the-art with assistive hip exoskeletons. A large patient population that could benefit from lower limb assistive technology are stroke survivors, which is the specific population this proposal targets. One common characteristic of stroke survivors who regain their ability to walk is that the hip muscles are overtaxed due to distal weakness. The investigators propose to use a powered hip exoskeleton to augment their proximal musculature, which needs to produce significant power output in most locomotion activities such as standing up, walking, and going up stairs or slopes. Another biomechanical aspect of stroke survivors is an asymmetric gait in terms of kinematics, kinetics and muscle activations. The research will examine what kind of exoskeleton assistance is most beneficial to stroke survivors for enhancing community ambulation. The hypothesis is that since the gait is asymmetric, the controller will need to be asymmetric to provide optimal assistance to aid in mobility. The long-term research goal is to create powered assistive exoskeletons devices that are of great value to individuals with serious lower limb disabilities by improving clinical outcomes such as walking speed and community ambulation ability. The overall objective of the proposed project is to study the biomechanical effects of using a hip exoskeleton with adaptive controllers for assisting stroke survivors with lower limb deficits to improve their community ambulation capabilities. The central hypothesis overarching both aims is that exoskeleton control that adapts to environmental terrain will improve mobility metrics for human exoskeleton users on community ambulation tasks. The rationale is that since human biomechanics change based on task, exoskeleton controllers likewise need to optimize their assistance levels to match what the human is doing. The team has previously designed and extensively tested an autonomous hip exoskeleton in able-bodied subjects on a treadmill and plan to follow this up with a separate study on able bodied subjects during overground locomotion of walking, stairs, and ramps. The aim of this study is to translate an autonomous robotic hip exoskeleton to provide adaptive assistance in community ambulation for stroke survivors with mobility impairment. The team will analyze the biomechanical effects and clinical benefits with using an autonomous hip exoskeleton for a walking impaired user (due to stroke). The primary hypothesis for this aim is that stroke survivors will increase their mobility in community ambulation tasks using the adaptive control framework. A sub-hypothesis is that stroke survivors who present with unilateral impairment will have superior biomechanical and clinical outcomes using a controller with asymmetric assistance. The investigators expect a controller that provides a greater assistance to the impaired side to improve overall symmetry and help the stroke survivor maintain a more efficient gait pattern to help improve walking speed (primary outcome measure). The expected outcome of these aims will be an increased understanding of the biomechanical and clinical effects in applying hip assistance with a robotic exoskeleton in community ambulation tasks such as overground walking, ramps and stairs. This work will serve as a foundational start for a broader planned study of optimizing controllers to improve biomechanics in the walking impaired using powered hip autonomous exoskeletons. This aim will have a positive impact by helping to inform the design and control of future exoskeleton for assisting individuals with lower limb disabilities, with specific insight in stroke survivors with mobility impairment.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
10

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Georgia
      • Atlanta, Georgia, United States, 30332
        • Exoskeleton and Prosthetic Intelligent Controls Lab

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 81 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age: 18-85 years
  • Had stroke over 6 months prior
  • Greater than 17 on minimental state examination (MMSE)
  • Sit unsupported for a minimum of 30 seconds
  • Follow a 3 step command.
  • Ability to walk without support (a rail as needed is allowed), with a walking speed of at least 0.4 m/s (limited community ambulatory speed)
  • Ability to walk for at least 6 minutes
  • Willingness and ability to participate over a 1-4 hour experiment, with breaks enforced regularly and as needed
  • Ability to transfer (sit-to-stand and stand-to-sit) with no external support (arm rests support allowed)
  • Ability to ambulate over small slopes (3 degrees) and a few steps (6 steps)

Exclusion Criteria:

  • Loss of sensation in the legs
  • A complete spinal cord injury
  • History of concussion in the last 6 months
  • History of any severe cardiovascular conditions
  • Severe arthritis
  • Orthopedic problems that limit lower extremity passive range of motion (knee flexion contracture of >10 degrees, knee flexion active ROM 15 degrees)
  • Pre-existing neurological and other disorders such as Parkinson's disease, ALS, MS, dementia
  • History of head trauma
  • Lower extremity amputation
  • Non-healing ulcers of a lower extremity
  • Renal dialysis or end state liver disease
  • Legal blindness or severe visual impairment
  • Uses a pacemaker
  • Has a metal implants in the head region
  • Uses medications that lower seizure thresholds.
  • Lastly, if the subject is participating in another clinical trial and/or subject's condition relating to criteria that, in the opinion of the Principal Investigator (PI), would likely affect the study outcome or confound the results, subject will be excluded from the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Individuals post-stroke using a powered hip exoskeleton
This study will be conducted on a sample population of stroke subjects (single arm). Each subject will test with each condition of the exoskeleton (repeated measures).
Device: Powered hip exoskeleton
The study team will be testing a powered hip exoskeleton and its capability to improve locomotion in stroke survivors.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Overground Self-Selected Walking Speed Using Hip Exoskeleton Assistance
Time Frame: 4 hours
Using five different hip exoskeleton assistance strategies, the participant's overground self-selected walking speed was recorded. Assistance types are 1) Unilateral Paretic Assistance, 2) Unilateral Non-Paretic Assistance, 3) Bilateral Equal Assistance, 4) Bilateral Additional Paretic Assistance, and 5) Bilateral Additional Non-Paretic Assistance. The first information (unilateral or bilateral) refers to the leg(s) that the exoskeleton is providing assistance with. For example, unilateral assistance means that the assistance is provided to only one side (zero assistance for the other side). The second information (additional paretic/non-paretic or equal) refers to the leg that the assistance is provided more. For example, bilateral additional paretic assistance means that the exoskeleton is providing assistance to both hip joints but provides higher magnitude on the paretic side.
4 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Step Length Asymmetry Using Hip Exoskeleton Assistance
Time Frame: 4 hours
Step length asymmetry was calculated by dividing the paretic side step length by the sum of the paretic and non-paretic side step lengths, where an asymmetry of 0.5 indicates perfect symmetry between the paretic and non-paretic sides. Using five different hip exoskeleton assistance strategies, the participant's Step Length Asymmetry during overground walking was recorded. Assistance types are 1) Unilateral Paretic Assistance, 2) Unilateral Non-Paretic Assistance, 3) Bilateral Equal Assistance, 4) Bilateral Additional Paretic Assistance, and 5) Bilateral Additional Non-Paretic Assistance. The first information (unilateral or bilateral) refers to the leg(s) that the exoskeleton is providing assistance with. For example, unilateral assistance means that the assistance is provided to only one side (zero assistance for the other side). The second information (additional paretic/non-paretic or equal) refers to the leg that the assistance is provided more.
4 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Georgia Institute of Technology

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Aaron Young, Ph.D., Georgia Institute of Technology

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 24, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 19, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 19, 2020

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 19, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 19, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 23, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 15, 2021

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 18, 2021

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • H19179

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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