The sensitivity of posturographic parameters to acquisition settings

The test–retest reliability of centre of pressure measures in bipedal static task conditions – A systematic review of the literature

“…It has been shown that COP measures and its reliabilities vary depending on both the acquisition and cut-off frequency chosen [30,36]. In the literature, sampling frequencies ranging from have been reported [9,16,17,22,27,[37][38][39][40][41] and it seems that the reported variations in COP reliability across similar experimental setups are at least partially due to the different frequencies chosen.…”

“…The effect on parameters defined on the basis of frequency distribution of data such as mean power frequency is marked, whereas measures of mean displacement such as mean velocity or mean amplitude are far less sensitive to different sampling frequencies [36]. It has been shown that COP mean displacement velocity and path length were 26.1% greater when sampling frequencies of 50Hz were used compared to 10Hz [30] as it would be expected with more data points describing the shape of the COP.…”

“…The results for mean velocity for example showed low variation from ICC2,1 0.75 at 0.8Hz to 0.71 at 10Hz, while the reliability values of mean power frequency dropped from 0.21 to 0.13 under the same condition. A cut-off frequency of 10Hz has been suggested as the best compromise to reject noise power [36].…”

“…There have been few attempts to provide recommendations on both the length and number of trials that should be used when assessing balance. While earlier studies suggest that reliable data may be obtained with sample durations of 10 to 60sec [18,36,42,43]. This has later been disputed by studies investigating multiple time intervals of up to 120sec.…”

“…While the evaluation of COP excursions is a commonly used method for measuring postural stability [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] no standardization of this method exists. Further, the reliability of COP needs to be determined if studies using this method are to be considered valid.…”