Intrasubject variability of selected force-platform parameters in the quantification of postural control

Area of Science:

• Biomechanics
• Rehabilitation Science
• Human Motor Control

Background:

• Platform stabilometry is crucial for monitoring and re-educating standing balance in clinical rehabilitation.
• Understanding the validity, reliability, and sensitivity of force-platform parameters is essential for accurate postural control assessment.
• Intrasubject variability is a significant factor affecting the reliability of human motor skill studies.

Purpose of the Study:

• To determine the intrasubject variability of commonly used force-platform parameters during quiet standing.
• To identify the most consistent and stable parameters for quantifying postural control.
• To assess the sensitivity of these parameters to varying task conditions.

Main Methods:

• Ten repeated tests of quiet two-legged standing were conducted in healthy subjects.
• Variability of root mean square (RMS) amplitude, peak-to-peak amplitude, mean frequency, and RMS velocity of center-of-pressure fluctuations was analyzed.
• Analyses were performed for both fore-aft and lateral components under different visual and cognitive task conditions.

Main Results:

• All investigated parameters exhibited considerable intrasubject variability regardless of task context.
• RMS amplitude and RMS velocity showed no significant trend across repeated tests.
• RMS velocity in the fore-aft direction demonstrated the highest intrasubject consistency and sensitivity, particularly to visual deprivation.

Conclusions:

• RMS velocity in the fore-aft direction is a reliable and valid parameter for clinical postural control quantification.
• This parameter offers a consistent and sensitive measure for assessing standing balance.
• Findings support the use of fore-aft RMS velocity in rehabilitation settings for balance evaluation.