title: Embodied prosthetic arm stabilizes body posture, while unembodied one perturbs it.
abstract: Senses of ownership (this arm belongs to me) and agency (I am controlling this arm) originate from sensorimotor system. External objects can be integrated into the sensorimotor system following long-term use, and recognized as one's own body. We examined how an (un)embodied prosthetic arm modulates whole-body control, and assessed the components of prosthetic embodiment. Nine unilateral upper-limb amputees participated. Four frequently used their prosthetic arm, while the others rarely did. Their postural sway was measured during quiet standing with or without their prosthesis. The frequent users showed greater sway when they removed the prosthesis, while the rare users showed greater sway when they fitted the prosthesis. Frequent users reported greater everyday feelings of postural stabilization by prosthesis and a larger sense of agency over the prosthesis. We suggest that a prosthetic arm maintains or perturbs postural control, depending on the prosthetic embodiment, which involves sense of agency rather than ownership.
authors: Graduate School of Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan; NTT Communication Science Laboratories, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan; Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda, Tokyo 102-0083, Japan. Electronic address: shuimaizumi@gmail.com.
authors: Shu
authors: S
authors: Imaizumi
authors: NTT Communication Science Laboratories, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan.
authors: Tomohisa
authors: T
authors: Asai
authors: Graduate School of Engineering, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan.
authors: Shinichi
authors: S
authors: Koyama
mesh_terms: D000674:Amputees / Q000706:statistics & numerical data*; D001132:Arm; D001186:Artificial Limbs / Q000706:statistics & numerical data*; D004644:Emotions; D006801:Humans; D007600:Judgment; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011795:Surveys and Questionnaires
keywords: Agency; Amputation; Embodiment; Postural control; Self; Upper-limb prosthesis