id_795. ACCELEROMETRY IS A RELIABLE METHOD FOR DETECTING POSTURAL CHANGES UNDER VIRTUAL HEIGHT EXPOSURE
Zuzana Hirjaková1, Jana Kimijanová1, Martin Marko1,2, Igor Riečanský1,3, Diana Bzdúšková1
1 Department of Behavioural Neuroscience, Institute of Normal and Pathological Physiology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
2 Department of Applied Informatics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Bratislava, Slovakia
3 Department of Psychiatry, Faculty of Medicine, Slovak Medical University in Bratislava, Bratislava, Slovakia
INTRODUCTION: Wearable inertial sensors are effective, portable and low-cost tools for measuring postural stability. They capture the acceleration of body segments, allowing us to objectively assess postural control via body sway. However, their use for balance assessment at height remains insufficiently investigated, even though height-related situations are common in everyday life. Height exposure can also evoke fear and anxiety, which may modify postural sway.
AIM(S): In this study, we examined whether inertial sensors can sensitively capture postural adjustments associated with height-related fear.
METHOD(S): Forty-two young adults were exposed to virtual heights (0 m, 20 m and 40 m) in an immersive virtual-reality setting, while postural sway was recorded using accelerometers placed on the lower trunk at the level of the fifth lumbar vertebra (L5) and on the upper trunk at the level of the sternum (ST). Participants were divided into two groups: low fear and high fear. To characterize postural sway to each height level and each sensor location, four variables were calculated: 1) root mean square of the acceleration (RMS), 2) mean velocity (MV), 3) mean frequency (MF) and 4) integrated squared jerk (JERK).
RESULTS: Virtual height induced faster and jerkier trunk sway in participants with a high fear of heights, suggesting greater postural stiffening compared with those reporting low fear. Among the sway metrics examined, JERK emerged as the most sensitive and reliable indicator for distinguishing fearful individuals.
CONCLUSIONS: These findings show that accelerometry-based trunk sway assessment can help identify individuals with stability deficits, particularly under challenging conditions. Virtual height exposure revealed clear segmental differences in trunk sway, strong associations with fear of height, and identified JERK as the most sensitive and discriminative measure to distinguish low vs high fear individuals.
FINANCIAL SUPPORT: This work was supported by the Scientific Grant Agency of the Ministry of Education, Research, Development and Youth of the Slovak Republic and the Slovak Academy of Sciences (VEGA) grant No. 2/ 0098/25.