Sonomyographic Upper Limb Prosthetics: A New Paradigm
Trial Snapshot
- Phase
- Not Applicable
- Status
- Enrolling By Invitation
- Sponsor
- George Mason University
- Enrollment
- 16
- Locations
- 1
- Primary Endpoint
- Fitt's Law Throughput
Study Overview
Brief Summary
The vast majority of all trauma-related amputations in the United States involve the upper limbs. Approximately half of those individuals who receive a upper extremity myoelectric prosthesis eventually abandon use of the system, primarily because of their limited functionality. Thus, there continues to be a need for a significant improvement in prosthetic control strategies.
The objective of this bioengineering research program is to develop and clinically evaluate a prototype prosthetic control system that uses imaging to sense residual muscle activity, rather than electromyography. This novel approach can better distinguish between different functional compartments in the forearm muscles, and provide robust control signals that are proportional to muscle activity. This improved sensing strategy has the potential to significantly improve functionality of upper extremity prostheses, and provide dexterous intuitive control that is a significant improvement over current state of the art noninvasive control methods. This interdisciplinary project brings together investigators at George Mason University, commercial partners at Infinite Biomedical Technologies as well as clinicians at MedStar National Rehabilitation Hospital.
The investigators will optimize and implement algorithms for real-time classification and control with multiple degrees of freedom (DOF) using a miniaturized ultrasound system incorporated into a prosthetic socket. The investigators will then compare control performance between and sonomyography and myoelectric control (both direct control and pattern recognition) using a virtual environment as well as for performance of tasks related to activities of daily living. The investigators have two specific aims.
Specific Aim 1: Compare between sonomyography and myoelectric direct control Specific Aim 2: Compare between sonomyography and pattern recognition with velocity control The successful completion of this project will lead to the first in human evaluation of an integrated prototype that uses low-power portable imaging sensors and real-time image analysis to sense residual muscle activity for prosthetic control. In the long term, the investigators anticipate that the improvements in functionality and intuitiveness of control will increase acceptance by amputees.
Detailed Description
Specific Aim 1: Compare between sonomyography and myoelectric direct control The investigators would like to test the null hypothesis that there is no difference in performance on virtual environment and clinical outcome measures between sonomyographic and direct myoelectric control with mode-switching.
Participants: The investigators will recruit a total of 10 unilateral trans-radial amputees based on the inclusion and exclusion criteria. These participants will be naïve to use of myoelectric prostheses. This study is focused on trans-radial amputees who represent the largest population of users.
Protocol:
After informed consent is obtained, the investigators will perform a baseline evaluation of the subject's functionality using the Orthotics and Prosthetics User Survey Upper Extremity Functional Status (OPUS-UEFS). Then subjects will be randomized to either the Experimental first group (sonomyography control) or Standard first group (direct control). Subjects will be tested using both control systems following a two-by-two AB/BA crossover design.
The sonomyographic system will include a custom-fitted test socket incorporating ultrasound transducers and controlling a TASKA prosthetic hand. The direct control system will include a custom-fitted test socket incorporating dual-site electrodes and controlling a TASKA prosthetic hand. All socket fittings will be performed by a board-certified prosthetist as part of this study.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Treatment
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to 65 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Transradial unilateral amputation
- •Fluent in English
- •For active comparator intervention 1 (myoelectric direct control prosthesis): Naïve to use of myoelectric prosthesis (i.e., uses body-powered prosthesis or has not used a myoelectric prosthesis for at least 3 years)
- •For active comparator intervention 2 (myoelectric pattern recognition control prosthesis): Currently uses a commercially-available pattern recognition system (IBT Sense) with a terminal device having at least two degrees of freedom
Exclusion Criteria
- •Significant cognitive deficits as determined upon clinical evaluation
- •Significant neurological deficits as determined upon clinical evaluation
- •Significant physical deficits of the residual limb impacting full participation in the study as determined upon clinical evaluation
- •Uncontrolled pain or phantom pain impacting full participation in the study as determined upon OT evaluation
- •Serious uncontrolled medical problems as judged by the project therapist
Arms & Interventions
Sonomyographic control
Sonomyographic control involves the use of ultrasound signals from muscle deformation to control a prosthetic hand.
Intervention: Sonomyographic Prosthesis (Device)
Myoelectric control
Myoelectric control involves the use of surface electromyography signals from muscle activation to control a prosthetic hand.
Intervention: Myoelectric direct control prosthesis (Device)
Myoelectric control
Myoelectric control involves the use of surface electromyography signals from muscle activation to control a prosthetic hand.
Intervention: Myoelectric pattern recognition prosthesis (Device)
Outcomes
Primary Outcomes
Fitt's Law Throughput
Time Frame: at one week
The investigators will use throughput as the primary outcome measure for the Fitt's Law task. Throughput is defined as the ratio of index of difficulty to the movement time required for successful completion.
Southampton Hand Assessment Procedure (SHAP)
Time Frame: at two weeks
The Southampton Hand Assessment Procedure (SHAP) will be the primary clinical outcome measure. The SHAP is a time-based test of a standardized protocol of 26 timed activities of daily living (ADL) tasks. The SHAP has a set of common objects representative of everyday items for the user to pick up. The results of the SHAP is a score which directly compares the abilities of the subject with those of intact able-bodied individuals as well as more refined scores for six prehensile patterns. A SHAP score of 100 is what an intact person is expected to achieve. Lower scores indicate worse function. This test has been validated for normative data.
Secondary Outcomes
- Satisfaction with Prosthesis section of the Trinity Amputation and Prosthesis Scales - Revised (TAPES-R)(Baseline)
- Fitt's Law Path Efficiency(at one week)
- Fitt's Law Completion Rate(at one week)
- Clothespin Relocation Test (CRT)(at two weeks)
- Gaze and Movement Assessment (GaMA)(at two weeks)
- Orthotics and Prosthetics User Survey Upper Extremity Functional Status (OPUS-UEFS)(Baseline)