User performance with a transradial multi-articulating hand prosthesis
during pattern recognition and direct control home use
Abstract
With the increasing availability of more advanced prostheses individuals
with a transradial amputation can now be fit with single to multi-degree
of freedom hands. Reliable and accurate control of these multi-grip
hands still remains challenging. This is the first multi-user study to
investigate at-home control and use of a multi-grip hand prosthesis
under pattern recognition and direct control. Individuals with a
transradial amputation were fitted with and trained to use an OSSUR
i-Limb Ultra Revolution with Coapt COMPLETE CONTROL system. They
participated in two 8-week home trials using the hand under myoelectric
direct and pattern recognition control in a randomized order. While at
home, participants demonstrated broader usage of grips in pattern
recognition compared to direct control. After the home trial, they
showed significant improvements in the Assessment of Capacity for
Myoelectric Control (ACMC) outcome measure while using pattern
recognition control compared to direct control; other outcome measures
showed no differences between control styles. Additionally, this study
provided a unique opportunity to evaluate EMG signals during home use.
Offline analysis of calibration data showed that users were 81.5%
[7.1] accurate across a range of three to five grips. Although EMG
signal noise was identified during some calibrations, overall EMG
quality was sufficient to provide users with control performance at or
better than direct control.