Measuring Walking Stability with a Mobile Phone in Older Adults: A Validation Study

Area of Science:

• Biomechanics
• Gerontology
• Wearable Technology

Background:

• The local divergence exponent (LDE) is a sensitive metric for assessing walking stability and fall risk in older adults.
• Previous research relied on specialized equipment, limiting accessibility.
• Investigating mobile phone-based LDE measurement offers a practical alternative.

Purpose of the Study:

• To validate the accuracy of LDE measurements obtained using a mobile phone.
• To assess the mobile phone's ability to differentiate between young and older adults based on walking stability.

Main Methods:

• 20 older adults and 20 young adults walked for 6 minutes while wearing both a research-grade IMU and a mobile phone on their sternum.
• 3D acceleration data was collected, and LDE was calculated for various acceleration components (3D, VT, ML, AP, N) from both devices.
• Intraclass Correlation Coefficient (ICC) and Mann-Whitney U tests were used for validity and discriminability analysis.

Main Results:

• Mobile phone-derived LDE showed excellent agreement and validity compared to the research-grade IMU (ICC > 0.75).
• No statistically significant differences in LDE were found between the young and older adult groups using either device.
• This suggests LDE may not be a sensitive differentiator between these age groups in this context.

Conclusions:

• Local divergence exponent (LDE) measurements using a mobile phone are valid and reliable.
• The study did not find significant age-related differences in LDE between healthy young and older adults.
• Mobile phones offer a cost-effective and accessible tool for gait stability assessment.