Estimation procedures affect the center of pressure frequency analysis

Brazilian Journal of Medical and Biological Research

T.m.m. Vieira²  L.f. Oliveira¹  J. Nadal¹ 

[1] ,Politecnico di Torino Laboratorio di Ingegneria del Sistema Neuromuscolare Torino TO ,Italia

关键词: Center of pressure;    Spectral analysis;    Quiet standing;    Estimators;    Median frequency;   

DOI  :  10.1590/S0100-879X2009000700012

来源: SciELO

【 摘 要 】

Even though frequency analysis of body sway is widely applied in clinical studies, the lack of standardized procedures concerning power spectrum estimation may provide unreliable descriptors. Stabilometric tests were applied to 35 subjects (20-51 years, 54-95 kg, 1.6-1.9 m) and the power spectral density function was estimated for the anterior-posterior center of pressure time series. The median frequency was compared between power spectra estimated according to signal partitioning, sampling rate, test duration, and detrending methods. The median frequency reliability for different test durations was assessed using the intraclass correlation coefficient. When increasing number of segments, shortening test duration or applying linear detrending, the median frequency values increased significantly up to 137%. Even the shortest test duration provided reliable estimates as observed with the intraclass coefficient (0.74-0.89 confidence interval for a single 20-s test). Clinical assessment of balance may benefit from a standardized protocol for center of pressure spectral analysis that provides an adequate relationship between resolution and variance. An algorithm to estimate center of pressure power density spectrum is also proposed.

【 授权许可】

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