Postural instability assessment using trunk acceleration frequency analysis

Abstract

The main tools for measuring postural instability of the body during quiet stance are stabilometric platforms. Frequency domain analysis of center of pressure excursions is used for detecting and quantifying specific diseases. The disadvantage of such platforms is their higher price and large dimensions. The main aim of this work was to identify the applicability of the frequency domain analysis of the trunk acceleration measured by one-axis accelerometer. In order to test the new technique, 10 patients with degenerative cerebellar ataxia and 11 healthy subjects were chosen to participate. The trunk acceleration of each subject with opened/closed eyes was measured during quiet stance on a firm/foam surface. The distribution of the power spectral density in the frequency spectrum of acceleration in the anterior–posterior direction is a suitable tool for quantifying postural instability. The percentages of the area under the power spectral density curve of middle frequency range (2.4–3.5 Hz) of acceleration in patients and healthy subjects were compared, and significant differences were found. The finding of our research is that a single cheap one-axis accelerometer placed on trunk to measure the acceleration in AP direction, together with the method based on the power spectral density of acceleration, could be a new tool for examinations of body instability.

Keywords:

• Posture control
• stabilometry
• cerebellar disease
• trunk acceleration

Acknowledgements

We thank Department of Neurology and Department of Rehabilitation and Sports Medicine at the Faculty Hospital Motol for their help in measurement of participants. The authors would also like to thank Andrej Madoran, B.A. for the language check of this article.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

This work was done in the Joint Department of the Faculty of Biomedical Engineering CTU and Charles University in Prague in the framework of research program No.VG20102015002 (2010–2015, MV0/VG), sponsored by the Ministry of the Interior of the Czech Republic, and project SGS 15/107/OHK4/1T/17 Prague.