Test–Retest Reliability of the FIBOD System for Postural Stability Assessment
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Keywords
Sensor-based balance assessment, Postural stability, FIBOD, Balance board, Single Trial
Abstract
Accurate balance assessment is essential for rehabilitation and fall-risk evaluation. Traditional observation-based tools such as the Balance Error Scoring System (BESS) and Berg Balance Scale (BBS) are widely used but are limited by subjectivity and observer bias. The FIBOD is a novel sensor-based wobble board system that provides objective and quantitative assessment of postural stability using integrated inertial measurement unit (IMU) sensors. This study aimed to evaluate the within-session test–retest reliability of the FIBOD system and to determine whether a simplified single-trial protocol can provide results comparable to repeated measurements. A cross-sectional study was conducted with 171 healthy adults (mean age = 36.5 ± 13.4 years) who performed two consecutive FIBOD balance assessments. The Overall Stability Index (OSI) values from both trials (T1, T2) were analysed using the Shapiro–Wilk test for normality, Bland–Altman analysis for agreement, and the Intraclass Correlation Coefficient (ICC (2,1)) for reliability. Post-hoc power analysis was performed to confirm statistical adequacy. The first trial exhibited an approximately normal distribution (p = 0.065), whereas the second showed a significant deviation (p = 0.001). A small mean bias of +0.12 OSI units and narrow 95% limits of agreement (–1.30 to +1.54) indicated good agreement between trials. Reliability analysis demonstrated good within-session consistency (ICC (2,1) = 0.88; 95% CI: 0.83–0.92). Post-hoc power analysis (α = 0.05, d = 0.40) yielded a statistical power of 0.999. The FIBOD system demonstrated strong reliability and agreement between consecutive trials. These findings suggest the potential feasibility of a single-trial protocol as a time-efficient and clinically practical approach for balance assessment.
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Eileen L. M. Su, Universiti Teknologi Malaysia
She received the B.Eng. degree in Mechatronics and the M.Eng. degree in Electrical Engineering from Universiti Teknologi Malaysia, and the Ph.D. degree in Bioengineering from Imperial College London. She is currently an Associate Professor in the Faculty of Electrical Engineering at Universiti Teknologi Malaysia. Her research interests include medical monitoring devices, surgical simulators, virtual reality systems, rehabilitation robots, haptic devices, machine vision, robotics, automation, and artificial intelligence. She holds the titles of Chartered Engineer (Engineering Council UK), Professional Engineer (Board of Engineers Malaysia), and Professional Technologist (Malaysia Board of Technologists).
Nurul Ashikin Binti Abdul Kadir , Universiti Teknologi Malaysia
She is a Senior Lecturer at Universiti Teknologi Malaysia (UTM), specializing in biomedical instrumentation, medical electronics, and physiological signal processing such as ECG and EEG. She holds a PhD in Electrical Engineering alongside earlier degrees in Medical Electronics and Electrical Engineering, all from UTM. Passionate about bridging technology and healthcare, she has contributed to research and publications that explore innovative electronic solutions for medical applications.
Muhammad Najib bin Abdullah, Taman Perindustrian Ringan Pulai
He is currently serving as an engineer at Techcare Innovation, specializing in engineering solutions and innovation in rehabilitation technology. He holds a Bachelor’s degree in Aeronautic-Mechanical Engineering and a Master of Philosophy from Universiti Teknologi Malaysia (UTM), where his research focused on applying machine learning for performance prediction in sports. Prior to this, he gained valuable industry experience at Dyson, a global leader in the vacuum industry, with key contributions in testing and experimentation.
Sivakumar Balasubramanian, The Christian Medical College
He received a B.Tech in Electronics and Communication Engineering from Pondicherry Engineering College, an M.Tech in Biomedical Engineering from IIT Bombay, and a Ph.D. in Bioengineering from Arizona State University, USA. He is currently Professor and Head of the Department of Bioengineering at Christian Medical College, Vellore, India, and previously served as Honorary Associate Professor at The University of Queensland, Australia. His research focuses on neurorehabilitation, human movement analysis, sensorimotor control, functional electrical stimulation, and technology-based rehabilitation systems.
Satria Mandala , Telkom University
He received the Ph.D. degree in computer science from Universiti Teknologi Malaysia. Currently, he is the Director of the Human Centric (HUMIC) Engineering Research Centre and also a member of the School of Computing (SoC), Telkom University, Indonesia. His research interests include issues related to wireless network security, the Internet of Things (IoT), biomedical engineering, digital signal, and image processing.