Stroke
Conditions
Keywords
Stroke
Brief summary
This work will focus on new algorithms for robotic exoskeletons and testing these in human subject tests. Individuals who have previously had a stroke will walk while wearing a robotic exoskeleton on a specialized treadmill as well as during other movement tasks (e.g. over ground, stairs, ramps). The study will compare the performance of the advanced algorithm with not using the device to determine the clinical benefit.
Detailed description
The focus of this work is a proposed novel artificial intelligence (AI) system to self-adapt control policy in powered exoskeletons to aid deployment systems that personalize to individual patient gait. Individuals post stroke have a broad range of mobility challenges including asymmetric gait, substantially decreased SSWS, and reduced stability, and therefore have greatly impaired overall mobility independence in the community. The investigators expect the proposed novel controller, capable of personalization to such variable and asymmetric gait patterns, will have significant benefits towards increasing community independence and mobility for patients post stroke. Patients post stroke will be fit with a hip exoskeleton (in a powered and/or unpowered state) and proceed to walk on a treadmill or perform various movement tasks. The same tasks will be performed by the patients without wearing the hip exoskeleton to serve as a baseline. The investigators expect improved outcomes in the powered hip exoskeleton compared to the unpowered hip exoskeleton and baseline conditions.
Interventions
DEVICEHip exoskeleton
The intervention is an experimental robotic hip exoskeleton in a powered state providing assistance to the user that has been previously developed by the team. It is used to improve walking gait performance.
OTHERBaseline
The intervention will serve as a baseline where participants will be asked to perform the tasks without wearing a hip exoskeleton.
Sponsors
Georgia Institute of Technology
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
The model used is a repeated measures single arm study
Eligibility
Sex/Gender
ALL
Age
18 Years to 85 Years
Healthy volunteers
No
Inclusion criteria
* Between 18-85 years of age * Had a stroke at least 6 months prior to study involvement * Are community dwelling, which means the participant does not live in an assisted living facility * Are able to provide informed consent to participate in the study activities * Can safely participate in the study activities (per self-report) * Must have a Functional Ambulation Category (FAC) score of 3 or above, which means the participant can walk without the assistance of another person
Exclusion criteria
* Require a walker to walk independently * Have a shuffling gait pattern overground * Have a Functional Ambulation Category (FAC) score of 2 or lower, which means the participant requires the assistance of another person in order to walk * Have a significant secondary deficit beyond stroke (e.g. amputation, legal blindness or other severe impairment or condition) that in the opinion of the Principal Investigator (PI), would likely affect the study outcome or confound the results * For exoskeleton-only studies, the exoskeleton device does not fit appropriately or safely, as determined by the research team during the fitting assessment.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Temporal Convolutional Network (TCN) Model Performance (Joint Moment Accuracy) | 5 Days | This outcome represents the error with which the deep learning model embedded into our hip exoskeleton's microprocessor predicts hip joint moments in stroke patients. Specifically, the coefficient of determination (R²) is computed between the predicted hip joint moments and the ground truth measurements. Ground truth measurements are obtained from a laboratory-grade force plate system and inverse dynamics calculations. For these measures, higher R² values (closer to 1.0) indicate better correlation between predicted and actual hip joint moments. This metric provides a comprehensive assessment of the exoskeleton's ability to accurately estimate hip joint moments in stroke patients during tasks, with improved outcomes representing better assistive capabilities for the user. |
| Metabolic Cost for Level Ground Walking | 5 days | Metabolic energy expenditure will be quantified using an indirect calorimetry system (Parvo Medics, UT) that measures oxygen consumption (VO₂) and carbon dioxide production (VCO₂) during experimental tasks. Measurements will be collected from each participant during a 5-minute baseline standing period followed by level ground walking trials under three conditions: without the exoskeleton, with the exoskeleton in a powered state, and with the exoskeleton in an unpowered state. Metabolic cost will be calculated from respiratory gas exchange data using standard equations for energy expenditure. |
| Biological Joint Work - Level Walking | 5 days | Mechanical work performed by the lower limb joints during level walking will be quantified through biomechanical analysis of motion capture data. Joint moments and angular velocities will be derived through inverse dynamics and kinematics, respectively. Joint power, calculated as the product of joint moment and angular velocity, will be integrated with respect to time using trapezoidal integration to determine mechanical work. Positive work will be calculated by integrating positive joint powers, providing comprehensive quantification of joint energy generation at each joint during level walking. |
| Biological Joint Work - Incline Walking | 5 days | Mechanical work performed by the lower limb joints will be quantified during incline walking through biomechanical analysis of motion capture data. Joint moments and angular velocities will be derived through inverse dynamics and kinematics, respectively. Joint power, calculated as the product of joint moment and angular velocity, will be integrated with respect to time using trapezoidal integration to determine mechanical work. Positive work will be calculated by integrating positive joint powers, providing comprehensive quantification of joint energy generation at each joint during the incline walking. |
| Biological Joint Work - Stair Ascent | 5 days | Mechanical work performed by the lower limb joints will be quantified during stair ascent through biomechanical analysis of motion capture data. Joint moments and angular velocities will be derived through inverse dynamics and kinematics, respectively. Joint power, calculated as the product of joint moment and angular velocity, will be integrated with respect to time using trapezoidal integration to determine mechanical work. Positive work will be calculated by integrating positive joint powers, providing comprehensive quantification of joint energy generation at each joint during the stair ascent task. |
| Biological Joint Work - Sit to Stand | 5 days | Mechanical work performed by the lower limb joints will be quantified during sit to stand through biomechanical analysis of motion capture data. Joint moments and angular velocities will be derived through inverse dynamics and kinematics, respectively. Joint power, calculated as the product of joint moment and angular velocity, will be integrated with respect to time using trapezoidal integration to determine mechanical work. Positive work will be calculated by integrating positive joint powers, providing comprehensive quantification of joint energy generation at each joint during the sit to stand task. |
| Biological Joint Work - go and Grab | 5 days | Mechanical work performed by the lower limb joints will be quantified during a go and grab task through biomechanical analysis of motion capture data. In the go and grab task, participants take several steps, lean forward, and pick up a weighted object from a low surface just above ground level. Joint moments and angular velocities will be derived through inverse dynamics and kinematics, respectively. Joint power, calculated as the product of joint moment and angular velocity, will be integrated with respect to time using trapezoidal integration to determine mechanical work. Positive work will be calculated by integrating positive joint powers, providing comprehensive quantification of joint energy generation at each joint during the go and grab task. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| 10 Meter Walk Test (Self-selected) | 5 days | This will be measured as the participant walks a distance of 10 meters across a gait mat at their self-selected (or comfortable) walking speed. This measure will be recorded in seconds with lower values indicating faster speed and higher values indicating slower speeds. Self-selected walking speed is highly correlated with functional ability and dependence. |
| The Timed up and go (TUG) | 5 days | This will be measured as the time it takes a participant to rise from a chair, walk three meters at a self-selected pace, turn, walk back to the chair and sit down. The total time taken will be measured in seconds with longer times indicating poorer physical performance. This test assesses functional mobility and dynamic balance. |
| 6 Minute Walk Test | 5 days | This is a measurement of endurance and functional ability that assesses the participants ability to walk a distance over a time period of 6 minutes. It is measured in distance with greater distances indicating improved levels of endurance and functional ability. |
| Modified Stroke Impact Scale | 5 days | The Modified Stroke Impact Scale (SIS) is a self-report questionnaire that evaluates disability and health-related quality of life after stroke. Each item is rated in a 5-point Likert scale in terms of the difficulty the patient has experienced in completing each item. Scores are transformed to a 0-100 scale, with 0 indicating the poorest perceived health status and 100 indicating the best, across domains of disability and health-related quality of life. Higher scores are indicative of improved quality of life. |
| Modified Activities-specific Balance Confidence | 5 days | The modified activities specific balance confidence is a self-report measure of balance confidence in performing various activities without losing balance or experiencing a sense of unsteadiness. Confidence is rated for various activities on a scale from 0% to 100% for each activity, with 0% indicative of no confidence and 100% indicative of complete confidence. Scores reflect balance confidence with higher scores indicative of improved balance confidence. |
| Fast Self-selected Walking Speed | 5 days | This will be measured as the participant walks on a treadmill at their fastest and safest walking speed. This measure will be recorded in meters/seconds with higher values indicating faster speed and lower values indicating slower speeds. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORAaron Young, Ph.D.
Georgia Institute of Technology
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Continuous | 51.2 Years STANDARD_DEVIATION 11.8 |
| Assistive Device Ankle Foot Orthosis | 2 Participants |
| Assistive Device Cane | 2 Participants |
| Assistive Device Cane and Ankle Foot Orthosis | 1 Participants |
| Assistive Device Cane and Ankle Mediolateral Support | 1 Participants |
| Assistive Device None | 6 Participants |
| Body Mass Index (BMI) | 30.7 Kilograms / Meters, Squared STANDARD_DEVIATION 4.5 |
| Fugl Meyer Assessment - Lower Extremity | 24.3 Unit on a scale STANDARD_DEVIATION 5.3 |
| Height | 174.5 Centimeters STANDARD_DEVIATION 6.6 |
| Mini Balance Evaluations Systems Test (Mini-BESTest) | 19.3 Units on a scale STANDARD_DEVIATION 4.1 |
| Paretic Side Left Side | 7 Participants |
| Paretic Side Right Side | 5 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 6 Participants |
| Race (NIH/OMB) More than one race | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 5 Participants |
| Region of Enrollment United States | 12 Participants |
| Self Selected Walking Speed | 0.81 Meters per second STANDARD_DEVIATION 0.25 |
| Sex: Female, Male Female | 3 Participants |
| Sex: Female, Male Male | 9 Participants |
| Stroke Type Hemorrhagic | 4 Participants |
| Stroke Type Ischemic | 7 Participants |
| Stroke Type Not Reported | 1 Participants |
| Time Since Stroke | 102.75 Months STANDARD_DEVIATION 64.06 |
| Weight | 93.2 Kilograms STANDARD_DEVIATION 13.1 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 12 | 0 / 12 |
| other Total, other adverse events | 0 / 12 | 0 / 12 |
| serious Total, serious adverse events | 0 / 12 | 0 / 12 |
Outcome results
None listed