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Comparison of different methods to identify and quantify balance control.
Herman van der Kooij1, Edwin van Asseldonk, Frans C T van der Helm
1Institute for Biomedical Technology (BMTI), Department of Mechanical Engineering, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. h.vanderkooij@ctw.utwente.nl
Journal of Neuroscience Methods
|June 1, 2005
Summary
Accurate human balance assessment requires external perturbations and specific identification methods. The direct approach (DA) yields errors in closed-loop systems, unlike the indirect (IA) or joint input-output approach (JA).
Area of Science:
- Biomechanics
- Human Physiology
- Systems Identification
Background:
- Human balance control is commonly studied using measures like center of mass (CoM) and center of pressure (CoP).
- Existing methods often employ the direct approach (DA), which is unsuitable for closed-loop systems like human balance.
Purpose of the Study:
- To clarify methodological aspects of human balance studies.
- To differentiate between rigid body dynamics and physiological control mechanisms.
- To introduce and validate advanced identification methods for balance control.
Main Methods:
- Utilized external, known perturbations to analyze human balance.
- Applied indirect (IA) and joint input-output (JA) approaches for system identification.
- Introduced a novel JA application to identify passive and active feedback pathways.
Main Results:
- Demonstrated that the direct approach (DA) leads to erroneous results in closed-loop balance control.
- Showcased the efficacy of IA and a new JA in separating system dynamics from feedback mechanisms.
- Illustrated how descriptive measures (PSD, SDP) are confounded by unmeasured noise and perturbations.
Conclusions:
- The indirect approach (IA) and the joint input-output approach (JA) are essential for accurate human balance control analysis.
- These methods allow for the separation and estimation of passive and active feedback mechanisms.
- Avoidance of the direct approach (DA) is crucial for reliable balance research.