Article

This study aims to address shortcomings of the relative phase analysis, a widely
used method for assessment of coupling among joints of the lower limb.
Goniometric data from 15 individuals with spastic diplegic cerebral palsy were
recorded from the hip and knee joints during ambulation on a flat surface, and
from a single healthy individual with no known motor impairment, over at least 10
gait cycles. The minimum relative phase (MRP) revealed substantial disparity in
the timing and severity of the instance of maximum coupling, depending on which
reference frame was selected: MRP(knee-hip) differed from MRP(hip-knee) by
16.1+/-14% of gait cycle and 50.6+/-77% difference in scale. Additionally,
several relative phase portraits contained discontinuities which may contribute
to error in phase feature extraction. These vagaries can be attributed to the
predication of relative phase analysis on a transformation into the
velocity-position phase plane, and the extraction of phase angle by the
discontinuous arc-tangent operator. Here, an alternative phase analysis is
proposed, wherein kinematic data is transformed into a profile of joint coupling
across the entire gait cycle. By comparing joint velocities directly via a
standard linear regression in the velocity-velocity phase plane, this regressed
phase analysis provides several key advantages over relative phase analysis
including continuity, commutativity between reference frames, and
generalizability to many-joint systems.
CI - Copyright (c) 2010 Elsevier B.V. All rights reserved.

Langue : ANGLAIS