Development of a system for measurement of postural bias in sitting

In this study, we developed a system for measurement of postural bias in sitting using the unstable board with accelerometer. 20 healthy subjects were participated in this study. Subjects were instructed to sit the board with their arms crossed and without leaning back for 60 seconds. Angular variation in the anterior-posterior and left-right direction as well as body pressure distribution of left and right side including contact area, maximum force, peak pressure, and mean pressure were assessed while sitting. Also, intra class correlation coefficient (ICC) was used to evaluate the reliability of the system using COP sway path and area. Tilting angle increased in anterior and right direction. All parameters of pressure distribution data showed an inclination to increase the right side. COP sway path and area did not differ significantly between tests and ICC value was excellent. This paper suggest that system for measurement of postural bias in sitting can be utilized not only to check bad sitting posture but also provide useful information about patients with idiopathic scoliosis in rehabilitation medicine. Also, results from this study can be used to evaluate the difference postural balance between normal and patient group for developing new clinical quantitative measurement system.