Posturography stands for quatitative assesment of body postural stability analysis. The present study developed a balance plate system to monitor patient's center of pressure(COP) movement and to analyze its stability. An equilateral triangular shaped plate was made of duralumin and forces were measured on the three vertices of the plate using industrial load cells. Specially designed electronic circuit picked up force signals fed into data acquisition system to calculate the cartesian coordinates of COP. COP calculation error was less than 2% and dynamic operation ranged 0~10Hz. The force signals enabled to compute stability measures, which were simply standard deviations of the signals. Clinical trials were made on 10 normal subjects and 4 patients of potential instability of the body posture. The results demonstrated that the present system was able to quantitatively differentiate the postures of presumed different stabilities, the effect of visual biofeedback, and increased instability of patients with statistical significance. With a customized PC-based package software, which is currently under development, the present system should be of great convenience to monitor and analyze postural stability in an accurate and quantitative way.
