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.
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.
Eligibility
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
