Incorporating a robotic leg into one’s body image

(Press-News.org) An important goal of any prosthesis is for the device to become incorporated into the user’s body image, their subjective, conscious cognition of their own body’s form and movement. He (Helen) Huang and colleagues studied how people’s body image changed over a multi-day training session with a new robotic leg. The authors recruited 9 non-disabled participants to train with a robotic leg prothesis, with their own legs kept in a bent position. The participants were chosen because they were totally naive to the experience of walking with a prothesis. The authors measured participants’ ambulatory body image by asking them to select a gait pattern displayed on a screen that best matched their own gait. As participants improved walking performance over four days of training, participants’ body images became more certain and evolved toward normal walking patterns, suggesting that the wearers cognitively incorporated the robotic leg into their body image. However, participants initially underestimated—and then later overestimated—their walking quality compared to actual performance. Participants focused on trunk lean, contralateral leg step length, robotic leg step time, and step time symmetry index when forming body image perceptions. According to the authors, the findings highlight the need for sensory feedback from prosthetic devices and regular perceptual calibration during training to improve body image accuracy, which may enhance both motor learning and psychological well-being for individuals with lower limb loss.

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