# Prosthetic embodiment: systematic review on definitions, measures, and experimental paradigms

## TL;DR

This paper reviews how the concept of prosthetic embodiment is defined and measured, aiming to create a common framework for comparing prosthetic technologies.

## Contribution

The paper introduces a pragmatic definition of prosthetic embodiment as the combination of ownership and agency, enabling quantifiable metrics for research.

## Key findings

- Embodiment is often conceptualized through body representations or experimental phenomenology.
- A framework combining ownership and agency allows embodiment to be a measurable metric.
- Recommendations for metrics enable outcome comparisons between studies.

## Abstract

The term embodiment has become omnipresent within prosthetics research and is often used as a metric of the progress made in prosthetic technologies, as well as a hallmark for user acceptance. However, despite the frequent use of the term, the concept of prosthetic embodiment is often left undefined or described incongruently, sometimes even within the same article. This terminological ambiguity complicates the comparison of studies using embodiment as a metric of success, which in turn hinders the advancement of prosthetics research. To resolve these terminological ambiguities, we systematically reviewed the used definitions of embodiment in the prosthetics literature. We performed a thematic analysis of the definitions and found that embodiment is often conceptualized in either of two frameworks based on body representations or experimental phenomenology. We concluded that treating prosthetic embodiment within an experimental phenomenological framework as the combination of ownership and agency allows for embodiment to be a quantifiable metric for use in translational research. To provide a common reference and guidance on how to best assess ownership and agency, we conducted a second systematic review, analyzing experiments and measures involving ownership and agency. Together, we highlight a pragmatic definition of prosthetic embodiment as the combination of ownership and agency, and in an accompanying article, we provide a perspective on a multi-dimensional framework for prosthetic embodiment. Here, we concluded by providing recommendations on metrics that allow for outcome comparisons between studies, thereby creating a common reference for further discussions within prosthetics research.

The online version contains supplementary material available at 10.1186/s12984-022-01006-6.