Article

Clinicians need a simple method for quantifying gait
activity. The aim of this study was to develop and validate the reliability of a
quantitative gait assessment based exclusively on one magnetometer located on the
shank. METHODS: Twenty-five healthy volunteers were simultaneously equipped with
a magnetometer (MAG system) on the right shank, and two validated step-counter
systems: the StepWatch Activity Monitor (SAM) and three Force-Sensing Resistors
(FSRs). Volunteers performed a standard circuit including level walking, up and
down stairs and up and down a slope. The three step counting approaches were
compared using the Pearson correlation coefficient and the Bland-Altman method
for each of the surface-types. RESULTS: The step counts measured by the MAG and
FSR were highly correlated for all the surfaces (r>.83). Congruently, the
Bland-Altman analysis revealed an overall +/- 5% limit of agreement. The step
counts measured by the MAG and SAM were also well correlated for the
level-surface condition (r=.85), with a Bland-Altman +/- 5% limit of agreement
but comparisons were less satisfying for the other surfaces. CONCLUSIONS: These
results demonstrate that the use of a single magnetometer is an accurate tool for
step counting over varied surfaces. These small sensors are easy to set up and to
use and the signal processing is robust, making the MAG method highly applicable
for clinical purposes, especially for the analysis of long walking periods in
daily life conditions.
CI - Crown Copyright (c) 2011. Published by Elsevier B.V. All rights reserved.

Langue : ANGLAIS