A team of researchers studied user preference to improve acceptance of assistive robotic ankle prosthesis, including what factors influence preferences and the relationship with physiological variables such as muscle activity. While the researchers concluded that the participants generally preferred low to medium magnitudes of assistance, their preferred settings were not consistent across trials. In most of the trials, the preferred settings were associated with lower muscle intensity in most muscles and better motor coordination.
The findings suggested that physiological metrics, such as muscle intensity and muscle synergies, may influence the selection of preferred prosthesis settings, according to the study’s authors.
Three participants with unilateral transfemoral amputations walked on a treadmill at a self-selected speed using a knee-ankle prosthesis. In four trials conducted on the same day, participants identified their preferred push-off parameters by self-tuning the magnitude and timing of the assistance using a 2D grid interface through a self-exploration method.
Participants were blinded to the control parameters and relied on their perception of the assistance to guide the tuning. During the trials, the researchers recorded muscle activity from four muscles in the sound limb and calculated muscle intensity and muscle synergies to explore the relation between muscle activity and preference.
The open-access study, “User preference in the personalized control of an ankle prosthesis: A case study,” was published in the Journal of NeuroEngineering and Rehabilitation.
