Article

Estimates of gait characteristics may suffer from errors due to discrepancies in
accelerometer location. This is particularly problematic for gait measurements in
daily life settings, where consistent sensor positioning is difficult to achieve.
To address this problem, we equipped 21 healthy adults with tri-axial
accelerometers (DynaPort MiniMod, McRoberts) at the mid and lower lumbar spine
and anterior superior iliac spine (L2, L5 and ASIS) while continuously walking
outdoors back and forth (20 times) over a distance of 20 m, including turns. We
compared 35 gait characteristics between sensor locations by absolute agreement
intra-class correlations (2, 1; ICC). We repeated these analyses after applying a
new method for off-line sensor realignment providing a unique definition of the
vertical and, by symmetry optimization, the two horizontal axes. Agreement
between L2 and L5 after realignment was excellent (ICC>0.9) for stride time and
frequency, speed and their corresponding variability and good (ICC>0.7) for
stride regularity, movement intensity, gait symmetry and smoothness and for local
dynamic stability. ICC values benefited from sensor realignment. Agreement
between ASIS and the lumbar locations was less strong, in particular for gait
characteristics like symmetry, smoothness, and local dynamic stability (ICC
generally<0.7). Unfortunately, this lumbar-ASIS agreement did not benefit
consistently from sensor realignment. Our findings show that gait characteristics
are robust against limited repositioning error of sensors at the lumbar spine, in
particular if our off-line realignment is applied. However, larger positioning
differences (from lumbar positions to ASIS) yield less consistent estimates and
should hence be avoided.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS