Development of application software for analyzing signals from stabilometry using Microsoft Excel

Abstract

　This paper is a preliminary report about a software application for analyzing stabilometry signals, which we developed using Microsoft Excel. Signals from three force plate pressure sensors (Unimec Co. Ltd.) were amplified and stored in a computer by way of an analog to digital (AD) converter. These signals were converted to comma-separated values format with software (Wizard Analyze System) and manually transferred to the Excel worksheets. This software is able to analyze 100Hz or 20Hz sampling data. The analysis consists of two parts. Part I examines Coordinates and mean values of foot pressure center position, Enveloped area, Rectangular area, Root mean square area, Length of sway path during 60 seconds and 1 second, Length of sway path per unit area, Amplitude histogram and skew/kurtosis, Romberg quotient, Velocity vector in 8 directions, Location vector in 8 directions, and Fast Fourier Transform. In clinical stabilometric examination, Part I items are mandated by the health insurance system. Part II examines the Area of 95% confidence ellipse, Velocity chart during 60 seconds, Velocity vector in 8 directions during 15 seconds, Discrete Fourier transformation, Estimation of body movement at the level of the waist using inverse discrete Fourier transformation, Short-time Fourier transformation, Autocorrelation function graph, Cross correlation function graph, Animation of Statokinesiogram, and so on. Part II analysis items were included to better understand the Part I analysis results and to further develop them. Using Microsoft Excel to analyze stabilometry data offers new analyses that could not previously be performed.