Time and frequency analysis of the static balance in young adults with Down syndrome

The main objective of this study is to understand the differences in equilibrium control between normal subjects and those with Down syndrome. A total of 54 subjects participated voluntarily, divided into control group and Down syndrome group. The equilibrium of the subjects was tested under two conditions: bipedal support with eyes open and closed. The signals were analyzed in a time and frequency domain. The statistical parameters selected (i.e., RMS distance, mean velocity, mean frequency and sway area) to analyze the behavior of the center of pressures (CoP) are calculated employing the result of the combination of the time series data in both directions (i.e. resultant distance). In order to calculate the frequency bands produced by the displacements of the CoP, a Fast Fourier Transform of the data was performed. The group with Down syndrome showed poorer static equilibrium control than the control group in the time domain. In the frequency domain, we found differences between the groups in the distribution of energy in the frequency bands analyzed. In addition, we observed the existence of an interaction effect of the group and the condition tested (p