Comparing the Attentional Demands and Functional Outcomes in People With Transradial Amputation

Virginia Commonwealth University32 enrolled

Overview

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.

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

Interventions

Training with PRCDEVICE

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).

Training with DCDEVICE

PRC Device use in community and homeDEVICE

After the training sessions, all subjects will use the PRC device in their homes, just in a different order.

DC Device use in community and homeDEVICE

After the training sessions, all subjects will use the DC device in their homes, just in a different order.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Refined Clothespin Relocation Test (rCRT)

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.