Enhancing Daily Posture Correction: Testing a Feedback-Based Assistive Technology for Individuals with Physical Disabilities
Authors: Takizawa Nao , Sugawara Mizuki , Watabe Isamu , Nakamura Hiroshi , Murayama Shuta , Saijo Miki , Ohashi Takumi 
Published: October 2023

People with physical disabilities often spend a significant amount of time in a sitting position. As a result of paralysis affecting the lower body, they may be unaware that they are assuming a high-load posture, which can contribute to issues such as pressure ulcers, shoulder stiffness, back pain, muscle imbalances, and diminished physical function. While seating technologies have been proposed to correct sitting posture, most existing methods are primarily designed for hospital settings and lack interventions for daily posture. To address this gap, we have developed a mat-type pressure-sensitive sensor device that can be mounted on a wheelchair. This device comprises 32 seat sensors and 12 back sensors, which estimates sitting posture during daily activities and provides feedback to the individual through smartphone alerts, heatmap review, and expert remote advice on posture improvement and training. This study aimed to evaluate the effectiveness of the device and identify areas for improvement.Seventeen wheelchair users with physical disabilities, including individuals with spinal cord injuries or cerebral palsy, participated in a five-week user test. Ten participants received device feedback, while seven participants did not. The device's effectiveness was assessed by comparing pre- and post-intervention outcomes and comparing outcomes between the intervention and non-intervention groups. Physical function was evaluated using a reach test, changes in internal symptoms and postural awareness were investigated through a questionnaire, and sitting posture was evaluated by the device. Additionally, Semi-structured interviews were conducted with seven participants from the intervention group to gather their perspectives on device usage and potential improvements.The results of the study demonstrated that the intervention had a positive impact on several aspects of postural change, secondary health issues prevention, and physical function improvement. Statistically significant differences were observed in a limited number of items, such as the lateral reach test results and anxiety related to pressure ulcers. The wide variance in the physical and living conditions of the participants, coupled with the fact that the effects of secondary disability and physical function take time to manifest, might have contributed to the non-significance of certain results within the five-week study period.The interviews provided valuable insights into the future direction of device improvement. Participants expressed concerns about the disparity between their perceived posture and the posture indicated by the equipment, as well as the challenges in understanding how to achieve an ideal posture. There is a recognized necessity to develop a novel feedback method that allows individuals to comprehend their posture from an external perspective and guide them toward a posture with minimal strain.In conclusion, our study demonstrates the effectiveness of the wheelchair-mounted pressure-sensitive sensor device in improving sitting posture, preventing secondary disabilities, and enhancing physical function among individuals with physical disabilities. While statistically significant results were partly observed, further research is needed to establish the long-term effects of the intervention. Additionally, the findings underscore the necessity of developing a feedback method that enables individuals to understand the discrepancy between their perceived posture and the correct posture, thus facilitating targeted posture improvement in daily life.