Amputation, Prosthesis Use
Conditions
Keywords
Transradial Amputation, Direct Myoelectric Control, Pattern Recognition Controller (PRC)
Brief summary
Different ways of controlling an upper-limb prosthesis can affect how easy it is to use and how helpful it is in everyday activities. One common method, called direct control, uses signals from two muscles and can make switching between movements difficult. Another clinically available option, called pattern recognition control, uses signals from several muscles to better understand the user's intended movement and may feel more natural to use. This study compares these two control methods to see how they affect function for adults with below-the-elbow limb loss.
Detailed description
Pattern recognition controller (PRC) systems for upper-limb prostheses are a clinically established alternative to conventional direct control (DC) systems. For decades, two-site DC has been the primary method for controlling myoelectric upper-limb prosthetic devices. DC relies on surface electromyography (EMG) recordings from two control sites, typically an antagonistic muscle pair in the residual limb, and uses relative signal amplitude to generate movement commands for the prosthesis. PRC is a more recent, clinically established control strategy developed to address several limitations associated with DC. Rather than depending on isolated activation of two muscle sites, PRC captures EMG signals from multiple sensors across the residual limb and uses pattern-classification algorithms to identify the user's intended movement. By incorporating information from multiple EMG channels, PRC may provide more intuitive and natural control, support a broader range of wrist and terminal device motions, and reduce reliance on non-intuitive switching strategies-particularly during tasks requiring rapid transitions between movements. PRC systems also enable on-demand recalibration, allowing users to adjust control performance in response to day-to-day changes in socket fit or electrode positioning. Although both PRC and DC systems are clinically established and have been used in practice, this study provides an opportunity to directly compare two clinically established control strategies. This trial will evaluate the functional advantages and disadvantages of PRC relative to DC when used by adults with unilateral transradial limb loss.
Interventions
DEVICETraining with PRC
All participants will receive in-person training with an onsite study prosthetist for the assigned controller strategy. The purpose of the training will be to instruct users on the care of the device formally and to achieve a basic level of functional performance. Training will be individualized according to clinical discretion consistent with clinical practice. Training will consist of up to four sessions to facilitate participants' use of the assigned controller system. The number of sessions will be competency-based (i.e., determined by the ability of each participant to explain or perform specified tasks). A standardized protocol and training checklist have been developed by clinical subject matter experts (i.e., upper limb prosthetists and occupational therapists).
DEVICETraining with DC
All participants will receive in-person training with an onsite study prosthetist for the assigned controller strategy. The purpose of the training will be to instruct users on the care of the device formally and to achieve a basic level of functional performance. Training will be individualized according to clinical discretion consistent with clinical practice. Training will consist of up to four sessions to facilitate participants' use of the assigned controller system. The number of sessions will be competency-based (i.e., determined by the ability of each participant to explain or perform specified tasks). A standardized protocol and training checklist have been developed by clinical subject matter experts (i.e., upper limb prosthetists and occupational therapists).
DEVICEPRC Device use in community and home
After the training sessions, all subjects will use the PRC device in their homes, just in a different order.
DEVICEDC Device use in community and home
After the training sessions, all subjects will use the DC device in their homes, just in a different order.
Sponsors
Virginia Commonwealth University
United States Department of Defense
Hanger Institute for Clinical Research and Education, LLC
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
SUPPORTIVE_CARE
Masking
NONE
Intervention model description
This study uses a 6-month crossover trial to compare two clinically established myoelectric control strategies for upper-limb prostheses: pattern recognition control (PRC) and conventional direct control (DC). Adult participants with unilateral transradial limb loss who are current prosthesis users will serve as their own controls by using both control methods during the study period. The intervention condition is PRC, which utilizes EMG signals from multiple electrodes distributed across the residual limb and applies pattern-classification algorithms to determine intended movements. The control condition is DC, a two-site strategy that relies on relative EMG signal amplitude from an antagonistic muscle pair. All participants will be provided with a transradial prosthesis equipped with a wrist unit and multi-function hand. Functional performance under PRC and DC will be directly compared to evaluate relative advantages and limitations of each control approach.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* 18 years of age or older * Unilateral transradial limb loss * At least 6 months since loss * Previous or current use of a myoelectric device for 3 months or longer * Use of a prosthesis at least 4 days each week * Ability to read, write, and understand English * Willingness to use each control strategy as primary device for 3 months each (6 months commitment total)
Exclusion criteria
* Any health condition that would prevent safely completing trial activities * Discontinued use of a myoelectric prosthesis due to non-financial reasons
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Refined Clothespin Relocation Test (rCRT) | Collected at Baseline, 3-Month, and 6-Month Assessments | The rCRT measures upper limb prosthesis performance. The test requires participants to rotate each clothespin 90° before placing it onto the vertical bar, which necessitates use of more than one joint motion. Faster completion times are indicative of superior prosthesis control and dexterity. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Brief Activity Measure for Upper Limb Amputees (BAM-ULA) | Collected at Baseline, 3-Month, and 6-Month Assessments | The BAM-ULA measures an upper limb prosthesis user's ability to perform daily functional activities, including both unimanual and bimanual tasks. This outcome measure requires the participant to tuck their shirt into the back of their pants, place a 20-pound bag on a shelf, open a sealed water bottle and drink from it, remove a wallet from their back pocket, put wallet into their back pocket, take a gallon jug out of the refrigerator, open and pour with the jug, brush their hair, use a fork, and open a door with a doorknob. This outcome measure is scored based on task completion. A higher composite score is indicative of superior prosthesis control. |
| Jebsen-Taylor Hand Function Test (JTHF) | Collected at Baseline, 3-Month, and 6-Month Assessments | The JTHF is a standardized measure that tests an individual's unimanual hand function for completing activities of daily living. This test requires the participant to write, turn cards over, pick up and manipulate small objects, simulate feeding, stack checkers, and pick up lighter and heavier larger objects. Faster completion times are indicative of superior prosthesis control and hand function. |
| Orthotic and Prosthetic Users Survey (UEFS-P) | Collected at Baseline, 3-Month, and 6-Month Assessments | The UEFS-P measures functional status, quality of life, and satisfaction with devices and services among those receiving orthotic and prosthetic care. Participants will respond to 29 items. Higher scores reflect greater perceived function. |
| Patient Experience Measure (PEM) | Collected at Baseline, 3-Month, and 6-Month Assessments | The PEM measures social interaction, self-efficacy, embodiment, intuitiveness, wellbeing, and self-consciousness of upper limb prosthesis users. Higher scores reflect increased ability. |
| Prosthesis Task Load Index (PROS-TLX) | Collected at Baseline, 3-Month, and 6-Month Assessments | The PROS-TLX assesses the mental, physical, and emotional demands of using a prosthesis. The PROS-TLX is designed to rate the demand after a specified task is immediately finished. Participants will complete the measure after finishing the CRT. Lower ratings are indicative of lower mental, physical, or emotional demands. |
| Prosthetic Arm Control Survey (PACS) | Collected at Baseline, 3-Month, and 6-Month Assessments | A 7-item survey developed to assess differences in cognitive workload between PRC and DC of upper limb prostheses. The PACS is designed to rate workload after a specified task is just finished. Participants will complete the survey after finishing the CRT. Higher scores are indicative of less cognitive workload. |
| PROMIS® Upper Extremity Function - 9-item | Collected at Baseline, 3-Month, and 6-Month Assessments | This standardized questionnaire is adapted from the validated PROMIS measurement system and consists of nine items focused on bilateral upper extremity function. The item set was carefully selected by upper-limb amputation clinicians to ensure clinical relevance. |
| Prosthetic Limb Users Survey of Upper Limb Attention (PLUS-Au) | Collected at Baseline, 3-Month, and 6-Month Assessments | A 25-item survey that measures attention to the prosthesis during a range of common activities. A higher score indicates increased attentional demands associated with prosthesis use in routine daily tasks. |
Countries
United States
Contacts
CONTACTShane R. Wurdeman, PhD
CONTACTBretta L. Fylstra, PhD
PRINCIPAL_INVESTIGATORBenjamin Darter
Virginia Commonwealth University
PRINCIPAL_INVESTIGATORShane R. Wurdeman, PhD
Hanger Inc.
Outcome results
None listed