Cognitive Workload in Conventional Direct Control vs. Pattern Recognition Control of an Upper-limb Prosthesis

The purpose of this study was to compare the cognitive workload of able-bodied individuals when using a myoelectric prosthetic under direct control (DC) or electromyography pattern recognition (PR) control. Different from existing clinical evaluations involving dual task performance, pupillography measured with an eye tracking system was used to quantitatively assess user cognitive workload in using a 2 degree-of-freedom prosthesis for a clothespin task. Test results revealed the PR control to produce superior task performance and to require lower cognitive load than demanded of participants under the DC condition. This study provided evidence of both performance and workload advantages of PR control over DC control. PR control was more intuitive to the prosthesis user and, therefore, required less cognitive effort. Furthermore, the study identified a new effective measure of cognitive workload in upper limb prosthesis use via pupillography.