Training prosthesis users to switch between modes of a multi-articulating prosthetic hand

Purpose: Producing triggers to switch between modes of myoelectric prosthetic hands has proven to be difficult. We evaluated whether digital training methods were feasible in individuals with an upper limb defect (ULD), whether myosignals in these individuals differ from those of non-impaired individuals and whether acquired skills transfer to prosthesis use.

Materials and methods: Two groups participated in a 9-day pre-test–post-test design study with seven 45-minute training sessions. One group trained using a serious game, the other with their myosignals digitally displayed. Both groups also trained using a prosthesis. The pre- and post-tests consisted of an adapted Clothespin Relocation Test and the spherical subset of the Southampton Hand Assessment Procedure. After the post-test, the System Usability Scale (SUS) was administered. Clinically relevant performance measures and myosignal features were analysed.

Results: Four individuals with a ULD participated. SUS-scores deemed both training methods feasible. Three participants produced only a few correct triggers. Myosignals features indicated larger variability for individuals with a ULD compared to non-impaired individuals (previously published data [1]). Three participants indicated transfer of skill.

Conclusions: Even though both training methods were deemed feasible and most participants showed transfer, seven training sessions were insufficient to learn reliable switching behaviour.

Trial registration: The study was approved by the medical ethics committee of the University Medical Center Groningen (METc 2018.268).

Implications for rehabilitation:

Switching between pre-programmed modes of a myoelectric prosthetic hand can be learned, however it does require training.

Serious games can be considered useful training tools for trigger production in early phases of myoelectric prosthesis control training.

In order to evoke transfer of skill from training to daily life both task-specificity and focus of attention during training should be taken into account.