Perceptual correlates of successful body–prosthesis interaction in lower limb amputees: psychometric characterisation and development of the Prosthesis Embodiment Scale

Robin Bekrater-Bodmann

doi:10.1038/s41598-020-70828-y

Abstract

Prostheses are used to at least partly restore the body after limb amputation. Making the user accepting the prosthetic device as part of his or her body, i.e., inducing prosthesis embodiment, has been identified as major aim of prosthetic treatment. However, up to now, there is no consensus about the psychometric nature of prosthesis embodiment in limb amputees. In the present study, 118 unilateral lower limb amputees using a prosthesis were asked to complete an online questionnaire targeting prosthesis embodiment. Principal axis factoring revealed the factor structure of prosthesis embodiment, i.e., Ownership/Integrity, Agency, and Anatomical Plausibility, which resembles the embodiment structure previously identified for normally-limbed participants. The majority of amputees achieved prosthesis embodiment as assessed with the final version of the newly developed Prosthesis Embodiment Scale. Internal consistency was excellent, and test–retest reliability was satisfying, while the instrument was also sensitive for new prosthetic equipment. Validation on the basis of relationships to prosthesis satisfaction and adjustment to prosthesis use was performed. The Prosthesis Embodiment Scale could be a valuable tool for the assessment of perceptual correlates of successful body–prosthesis interaction in rehabilitative and research contexts, the latter which might further benefit from the comparability of psychometrically evaluated data.

Highlights

Prostheses are used to at least partly restore the body after limb amputation
The present study sought to elucidate the perceptual correlates of successful body–prosthesis interaction in terms of prosthesis embodiment in lower limb amputees
Data suggest that most amputees experience some level of prosthesis embodiment, as indicated by positive PEmbS-LLA scores

Summary

Introduction

Prostheses are used to at least partly restore the body after limb amputation. Making the user accepting the prosthetic device as part of his or her body, i.e., inducing prosthesis embodiment, has been identified as major aim of prosthetic treatment. These results indicate that the prosthesis can be represented at least as extension of the body; the question remained open whether the artificial limb can be perceived as integral part of the body, that is, whether or not true embodiment for the prosthesis can be achieved This difference is anything but trivial, since it has been proposed that prosthesis embodiment, rather than perceiving the device as mere tool attached to the body, is an important perceptual correlate of successful body–prosthesis interaction[1,6,7], and might constitute a crucial marker of prosthesis satisfaction and adjustment to prosthesis use (e.g.,1,8,9). The dimensions of embodiment have been repeatedly identified as crucial contributors to bodily self-experiences (e.g.,24–26); whether or not the psychometrics of embodiment assessed in short-term and experimental contexts apply for long-term and real-life prosthesis use, remains u nknown[27]

Methods

Results

Conclusion