Modified Fukuda stepping motion assessment of young healthy adults using portable inertial measurement units

Currently, vestibular rehabilitation approaches used to monitor body position and movement during rehabilitation training require specialized equipment or rely on clinician observation. Thus, a simpler position-sensing approach that can be used to monitor movement during vestibular rehabilitation is required. This study used wearable motion sensors with built-in ac-celerometers and gyrometers to assess movement in adults. We explored stepping patterns in adults using this motion-sensing system. Six healthy adults (men, age 27.3 +/- 5.8 years) under-went a modified Fukuda stepping test (Foulage test [FT]) while wearing a six-axis motion sensor (accelerometer: X-axis, Y-axis, Z-axis; gyrometer: X-axis, Y-axis, Z-axis) positioned at the head, thorax, and lumbar spine. For motion sensor parameters, we calculated the root mean square (RMS), autocorrelation coefficient (AC), power spectrum (PS) of the AC, and Euler angles from the six-axis motion sensor. For the FT parameters, the FT value, step variance, and theta values were calculated. Data were analyzed, and multivariable regression analysis was performed using the FT value, step variance, and theta value as the dependent variables to investigate their influence on dynamic equilibrium. The explanatory variables included the motion sensor parameters, RMS, AC, and PS. Our results suggested that almost no head and lumbar spine movement occurred while stepping with eyes open. Contrastingly, the head and lumbar spine swayed with eyes closed. This accelerometric and gyroscopic device is easy to use, does not require specialized equipment, and can be used to analyze performance in the modified Fukuda stepping test in clinical practice. Inertial sensors have many advantages over other sensing technologies.