Multigesture Electromyographic Control Complexity in Upper Limb Prostheses Actuated via Single Sensor Input Contraction Magnitude: Qualitative Study for Evaluating Performance and Cognitive Load.

The participants were able-bodied college-aged students, not upper limb prosthesis users, so the findings may not apply to patients learning a prosthetic arm. The sample was small and unevenly split, with 9 participants in 1 static cohort, 10 in another, 9 in the third, and 26 in the progressive cohort. All participants tested as right-handed, and 40 of the 54 participants were female, so the group may not represent the wider population. The study was a single session, so it cannot show what happens over longer training or after a prosthesis is fitted. The 1-zone task had a ceiling effect because every contraction above the threshold counted as successful, which may have distorted comparisons. The authors did not adjust results for multiple comparisons, and some between-cohort differences may reflect limited power rather than true equivalence. A participant withdrew and their data were removed, and a user ID was claimed by 2 participants, which the researchers separated before analysis.

The authors declared no conflicts of interest. The research team developed the testing app and the prosthesis control system in-house.

Do not conclude that too many gestures are impossible for patients or that progressive training improves accuracy for prosthesis users. The study tested able-bodied novices in a single session, and the progressive cohort was not better than the static cohorts for accuracy.