To study and describe users’ experiences controlling a DEKA Arm with a pattern recognition system, researchers at the Providence VA Medical Center in Rhode Island created an integration of Coapt’s EMG pattern recognition (EMG-PR) system and the DEKA Arm. The results of the study indicated that the participants had mixed perspectives on the desirability of the EMG-PR control system in combination with the DEKA Arm.
The RC DEKA Arm and socket with EMG-PR prototype 1 controls.
Photograph courtesy of the study’s authors..
Twelve people with upper-limb amputations participated in the study; ten with transradial amputations, and two with transhumeral amputations. Ten of the participants were men, and 11 were prosthesis users at the beginning of the study. The two-part study included in-laboratory prosthetic training (Part A) and up to 12 weeks of prosthetic in-home use (Part B). Qualitative data was collected through open-ended survey questions and semi-structured interviews. The study used a qualitative case series design with a constant comparative approach to identify common categories of experience. The data was organized into groups of a primary category, major categories of experience, factors impacting experience, and broader contextual factors.
Major aspects of the users’ experiences related to the system complexity, the process of calibrating, and the functional benefits. Factors influencing the user experience included training and acclimation, fatigue, prosthesis design, technical issues, and control changes. Personal and environmental factors also impacted users’ experiences.
Two subjects with transradial amputations stated that they wanted to continue using the system, while two others (one with a transhumeral amputation and one with a transradial amputation) stated that they might want one in the future. Three subjects (one with a transhumeral amputation and two with a transradial amputations) said they did not want one.
At the end of Part B, six participants who were prosthesis users at baseline were asked to compare the controls of the DEKA Arm to the controls in their personal prostheses. Four (66 percent) indicated that they preferred their own controls, and two (33 percent) did not express a preference for either control type. Several subjects, including both users with transhumeral amputations and who had a history of targeted muscle reinnervation, made very positive comments about EMG-PR independent of the interface with the DEKA Arm. Most participants expressed a preference for the controls of their personal prostheses and controls rather than the devices used in the study, but most were positive about the future potential of EMG-PR as a control method.
The open-access study was published September 21 in PLOS One.
