Does Embodiment Matter to Biomechanics and Function? A Comparative Analysis of Head-Mounted and Hand-Held Assistive Devices for Individuals with Blindness and Low Vision

2025-09-22

AI Summary

This study addresses the lack of biomechanical evaluation in assistive technologies for people who are blind or have low vision, by conducting the first systematic comparison of head-mounted versus hand-held visual assistance devices across daily tasks. Using an Xsens motion capture system, we quantified joint range of motion, angular path length, workspace volume, and movement smoothness, complemented by task completion time, success rate, and number of attempts. Results indicate that head-mounted devices significantly reduce upper-body biomechanical load and task duration—particularly excelling in document scanning—whereas hand-held devices achieve higher success rates for recognizing small-font and curved text. Critically, this work introduces biomechanical metrics into assistive technology evaluation, revealing a fundamental trade-off between physical burden and interaction intuitiveness imposed by device form factor. The findings establish a human-centered, sustainability-informed design paradigm for wearable assistive devices, grounded in empirical evidence.

Technology Category

• Humans and AI: Interaction Techniques and Devices
• Computer Vision: Biometrics, Face, Gesture & Pose
• Intelligent Robots: Manipulation

Application Category

• User Modeling, Personalization and Recommendation: Metrics for user behavior and evaluating success
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics
• Responsible Web: Human-perceived consequences of algorithmic deployment on the web

Abstract

Visual assistive technologies, such as Microsoft Seeing AI, can improve access to environmental information for persons with blindness or low vision (pBLV). Yet, the physical and functional implications of different device embodiments remain unclear. In this study, 11 pBLV participants used Seeing AI on a hand-held smartphone and on a head-mounted ARx Vision system to perform six activities of daily living, while their movements were captured with Xsens motion capture. Functional outcomes included task time, success rate, and number of attempts, and biomechanical measures included joint range of motion, angular path length, working volume, and movement smoothness. The head-mounted system generally reduced upper-body movement and task time, especially for document-scanning style tasks, whereas the hand-held system yielded higher success rates for tasks involving small or curved text. These findings indicate that both embodiments are viable, but they differ in terms of physical demands and ease of use. Incorporating biomechanical measures into assistive technology evaluations can inform designs that optimise user experience by balancing functional efficiency, physical sustainability, and intuitive interaction.

Problem

• Comparing biomechanical and functional impacts of head-mounted versus hand-held visual assistive devices
• Evaluating how device embodiment affects physical demands and task performance for visually impaired users
• Determining optimal device designs balancing functional efficiency with physical sustainability

Innovation

• Compared head-mounted and hand-held assistive devices
• Used motion capture to measure biomechanical outcomes
• Incorporated biomechanics to optimize user experience design