A team of researchers at Heidelberg University, Mannheim, Germany, sought to identify amputation- and prosthesis-related factors that are significantly associated with prosthesis embodiment experiences in people with lower-limb amputations. The research model revealed that a lower level of amputation, less severe residual limb pain, more realistic visual appearance of the device, higher mobility, and more positive valence of prosthesis-induced residual limb stimulations individually and significantly explained variance in prosthesis embodiment. The results further indicated that residual limb pain was negatively associated with prosthesis embodiment.
The findings emphasized the importance of psychological factors for the integration of a prosthesis into the user’s body representation, which itself might represent a crucial factor associated with prosthesis satisfaction, the study’s authors concluded.
Between May 2019 and March 2020, the researchers recruited 166 participants with unilateral lower-limb amputations who used a prosthesis (71.69 percent male; mean age of 56.63 years). High- and low-amputation levels were equally distributed, and the amputations dated back more than 25 years on average (range: 0–72 years). About 56 percent of the participants indicated a traumatic event as the only reason for their amputation.
Mobility emerged as significant regressor for prosthesis embodiment, highlighting the importance of prosthesis functionality for the incorporation of the device. However, since neither time since amputation nor time with their current prostheses were significantly associated with prosthesis embodiment, and frequency of prosthesis use only emerged as a significant regressor when mobility was not included, the results suggest that the quality of prosthesis use, rather than passive or active use alone, is crucial for inducing embodiment experiences, the study said.
Besides prosthesis embodiment, only sex and age emerged as significant regressors for aesthetic prosthesis satisfaction, probably indicating the technical affinity in younger people and men.
The findings indicated that the interaction between body and prosthesis perception should be considered in addition to cosmetic and functional aspects of the prosthesis. The identification of perceptual deficits related to the prosthesis at an early stage might help to fix user problems that might be easily overlooked otherwise.
The study concluded that a prosthesis that successfully interacts with the user’s body perception could enhance prosthesis acceptance and thus reduce the risk of prosthesis abandonment.
The open-access study, “Factors Associated With Prosthesis Embodiment and Its Importance for Prosthetic Satisfaction in Lower Limb Amputees,” was published in Frontiers in Neurorobotics.