Clinical Trial Details
— Status: Enrolling by invitation
Administrative data
| NCT number |
NCT05376332 |
| Other study ID # |
1492070-2 |
| Secondary ID |
1U01EB027601 |
| Status |
Enrolling by invitation |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
February 1, 2023 |
| Est. completion date |
January 31, 2025 |
Study information
| Verified date |
May 2022 |
| Source |
George Mason University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial 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.
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.
After being fit with the sonomyography system, subjects in the Experimental first group will
undergo 4 hours of standard occupational therapy training by a certified therapist. The
training will be distributed over 2 days with 2 hours of training per day. At the end of each
hour of training, subjects will perform a Fitts' Law task in a virtual environment. The task
and the primary and secondary outcome measures are described below. After the training has
been completed, subjects will evaluated using a series of primary and secondary clinical
outcome measures, as described below. Finally, subjects will complete the Satisfaction with
Prosthesis section of the Trinity Amputation and Prosthesis Scales - Revised (TAPES-R) to
assess satisfaction with the sonomyography system. After a washout period of 4 weeks,
subjects will cross-over to the Standard system. Subjects will be fitted with the direct
control system and undergo the same training and testing procedure described above.
Subjects in the Standard first group will be trained and tested with the direct control
system first, and then cross over to the sonomyography system.
Details of Fitts' Law task protocol:
Subjects will move their limb into one of 4 positions following a display indicated on a
screen (Fig. 16 in Research Strategy). Achieving each target position requires a different
amount of shoulder abduction. When participants have reached the required limb position, an
annulus-shaped target will be displayed. Subjects will use their prosthesis to perform a
Fitts' Law task that involves controlling the position and size of a ring-shaped cursor in
order to match the target. The Fitts' Law task will have one, two, or three degrees of
freedom, where each degree of freedom is mapped to a specific motor intent. For example,
wrist flexion can control horizontal cursor movement, pronation/supination can control
vertical cursor movement, and hand open/close can control the cursor's radius. Subjects will
be allowed to activate the degrees of freedom sequentially or simultaneously.
The annulus width (W) and distance (D) from the initial cursor position will be varied to
create six indices of difficulty according to ID = log2(1+ D/W). There will be three levels
of target complexity based on the number of degrees of freedom that must be activated to
achieve the task (i.e., one degree of freedom targets require activity in only one degree of
freedom, etc.). Each possible combination of levels of difficulty (6) and target complexities
(3) will be repeated 3 times per limb position.
Subjects will have 10 seconds to match the target and hold for two seconds, or the attempt
will be considered failed. After 12 seconds, the display will indicate the next target.
Data Analysis:
Data will be evaluated to determine the distribution and the variability of performance
within and between the different prosthesis systems. The investigators will test whether the
sonomyography and direct control systems are equivalent using the primary outcome measures.
Secondary outcome measures will also be explored in order to develop a more detailed
understanding of differences in performance between the systems. If significant differences
are found in baseline functional measures using OPUS-UEFS, the investigators will perform
stratified analyses on our primary and secondary outcome measures.
Specific Aim 2. Compare between sonomyography and pattern recognition with velocity control
Participants: The investigators will recruit a total of 6 unilateral trans-radial amputees
based on the inclusion and exclusion criteria noted above. These participants will be
experienced users of myoelectric pattern recognition control (IBT Sense). 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 (pattern recognition 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. All socket fittings will be performed by
a board-certified prosthetist as part of this study. The pattern recognition system will
include the subject's clinically-prescribed socket and commercially-available pattern
recognition technology (IBT Sense). The pattern recognition system will not be fitted as part
of this study, as subjects will already be trained users prior to enrolling in the study.
After being fit with the sonomyography system, subjects in the Experimental first group will
undergo 4 hours of standard occupational therapy training by a certified therapist. The
training will be distributed over 2 days with 2 hours of training per day. At the end of each
hour of training, subjects will perform a Fitts' Law task in a virtual environment. The task
and the primary and secondary outcome measures are described below. After the training has
been completed, subjects will evaluated using a series of primary and secondary clinical
outcome measures, as described below. Finally, subjects will complete the Satisfaction with
Prosthesis section of the Trinity Amputation and Prosthesis Scales - Revised (TAPES-R) to
assess satisfaction with the sonomyography system. After a washout period of 4 weeks,
subjects will cross-over to the Standard system. Subjects will not undergo training, and will
instead be immediately tested with the pattern recognition system using both the Fitts' Law
task and clinical outcome measures.
Subjects in the Standard first group will be tested with the pattern recognition system
first, and then cross over to the sonomyography system.
Data Analysis:
Data will be evaluated to determine the distribution and the variability of performance
within and between the different prosthesis systems. The investigators will test whether the
sonomyography and pattern recognition control systems systems are equivalent using the
primary outcome measures. Secondary outcome measures will also be explored in order to
develop a more detailed understanding of differences in performance between the systems. If
significant differences are found in baseline functional measures using OPUS-UEFS, the
investigators will perform stratified analyses on our primary and secondary outcome measures.
