Kinematic analysis of a myoelectric transradial prosthesis: functional and biomimetic evaluation

This paper describes a motion analysis of a myoelectric upper limb prosthesis, focusing on kinematic synergies with respect to those of the human hand, during manipulation of several objects. Continuous research in prosthetic systems is seeking organ replacement with full functionality restoration. Reproducing kinematic coordination of the numerous DoFs of the hand plays a key role. We used an optoelectronic system and reflective markers to acquire grasping positions of a hand and a state-of-art prosthesis available on the market. Using Principal Components Analysis, we evaluated the preponderance of the first two components (PC1 and PC2) both in the hand and in the prosthesis. PC1 and PC2 expressed over 90% of the variance in most of the prosthesis postures. Statistical analysis was conducted to evaluate differences between the level of variance expressed by each PC in the two data samples, to evaluate biomimicry. Building on findings regarding the joints involved in PC1 and PC2, future developments could involve thumb mechanics and the implementation of the principal synergistic schemes in the movement control algorithms of the prosthesis. This work offers a protocol and a testing methodology that could be replicated in clinical studies, on a larger sample of users and with the latest generation prosthesis.