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J Mickelborough
02-22-1999, 01:30 AM
At 05:20 PM 2/16/99 , I wrote:
>We are collecting temporal and spatial measures of gait from elderly
>people, some of whom are hemiparetic.
>I am searching for an index of symmetry to apply to these parameters.
>
>I recall seeing an argument recently that such an index should be based
>upon differences between right and left side values, rather than upon a
>ratio of the two. This made sense, but unfortunately I cannot now find the
>paper in which I read this.
>
>There are a few references in the archives, which I am following up, but I
>would appreciate any further thoughts on this matter.


I received a variety of replies, some giving a formula for side-to-side
symmetry, while others suggested references, a summary of which I have put
below.

Many thanks to all who replied - I'm still trying to get hold of some of
these papers - special thanks to those who emailed copies
Jane

First: A summary of the references given:

Allard, P, Capopozzo A, Lundberg, A, & Vaughan C. (eds) Three-dimensional
Analysis of Human Locomotion" 1997, John Wiley & Sons pp. 307-334

Dingwell, J.B., Davis, B.L., and Frazier, D.M., (1996) "Use Of An
Instrumented Treadmill For Real-Time Gait Symmetry Evaluation And Feedback
In Normal And Below-Knee Amputee Subjects," Prosthetics And Orthotics
International, 20: 101-110.

Giakas G and V Baltzopoulos, (1997). Variability and inter-trial symmetry
of ground reaction forces during walking using time and frequency domain
parameters. Gait & Posture 5, 189-197.

Giakas G, V Baltzopoulos, PH Dangerfield, JC Dorgan and S Dalmira. (1996).
Comparison of gait patterns between healthy and scoliotic patients using
time and frequency domain analysis of ground reaction forces. Spine 21(19),
2235-2242.

Herzog, W., Nigg, B.M., Read, L.J., and Olsson, E. (1989). Asymmetries in
Ground Reaction Force Patterns in Normal Human Gait. Medicine and Science
in Sports and Exercise, 21 (1): 110 - 114.

Jeng, Holt, Fetters and Certo, (1996). Self-optimization of walking in
nondisabled children and children with spastic hemiplegic cerebral palsy.
Journal of Motor Behavior, 28(1), 15-27.

Kaufman & al. (1996). Gait asymmetry in patients with limb length
inequality. Journal of Pediatric Orthopaedics 16: 144-150.

Kulkarni J., Curran B., Ebdon-Parry M., Harrison D., (1995) 'Total contact
silicone partial foot prostheses for partial foot amputations'. The Foot
vol.5, pp.32-35.

Liu & al. (1998). Kinematic and kinetic asymmetry in patients with
leg-length discrepancy. Journal of Pediatric Orthopaedics 18: 187-189.

Peham C, Scheidl M, Licka T. A method of signal processing in motion
analysis of the trotting horse
J. Biomechanics, Vol. 29, No. 8, pp. 1111-1114, 1996

Peham C, Licka T, Scheidl M, Girtler D. Supporting forelimb lameness:
clinical judgement versus computerised symmetry measurement. Equine
Veterinary Journal, in print


Here are the replies I received:

I did some work on gait symmetry in BK amputee patients for my maters
thesis a few years ago. After looking at the various ways several other
people had used to quantify asymmetries, we decided on the following
formula:
Symmetry Index ("SI") = (Xl - Xr) / (Xl + Xr) * 100%
where "Xl" and "Xr" are the values of any variable X for the left and right
sides. This equation resulted in SI values with a continuous linear range
from -100% to +100%, where 0% denoted perfect symmetry between left and
right. We modified this from a paper by Herzog et al. (1989) where they
had used the difference divided by the average, which resulted in a similar
distribution, with a range of -200% to +200%.
I have a *.pdf file of the manuscript we published in Prosth. & Orth Intl.
which I can send you if you would like.
References:
Dingwell, J.B., Davis, B.L., and Frazier, D.M., (1996) "Use Of An
Instrumented Treadmill For Real-Time Gait Symmetry Evaluation And Feedback
In Normal And Below-Knee Amputee Subjects," Prosthetics And Orthotics
International, 20:
101-110.
Herzog, W., Nigg, B.M., Read, L.J., and Olsson, E. (1989). Asymmetries in
Ground Reaction Force Patterns in Normal Human Gait. Medicine and Science
in Sports and Exercise, 21 (1): 110 - 114.
>--------------------------------------------------------
----------------------------------------------------------
Jonathan Dingwell, Ph.D.
Postdoctoral Research Associate
Rehabilitation Institute of Chicago
345 East Superior, room 1406
Chicago, Illinois, 60611
Phone: (312) 908-8738
FAX: (312) 908-2208
E-Mail: j-dingwell@nwu.edu
Web: http://www.smpp.nwu.edu/
----------------------------------------------------------
You might consider calculating the residual difference between the right
and left data sets as an index of asymmetry. This is the Root Mean Squared
RMS difference and the RMS value will be directly proportional to the
degree of asymmetry between right and left sides. I have attached an excel
file to illustrate the process. I used this method for determining a
Right-Left asymmetry in the following paper on partial foot prostheses:
Kulkarni J., Curran B., Ebdon-Parry M., Harrison D., (1995) 'Total contact
silicone partial foot prostheses for partial foot amputations'. The Foot
vol.5, pp.32-35.
Drew Harrison
Have a hunt for work by Pat Goldie (probably in Archives), she has done
some work on gait symmetry after stroke but I can't recall if this has been
published.
I would suggest that you contact her directly but at present she is away
from La Trobe University (Australia) on sick leave. She will be back in
April sometime [P.Goldie@latrobe.edu.au]
Good luck
Julie
Julie Bernhardt, PhD
Physiotherapy Research Coordinator
North West Sector
North Western Health Care
Melbourne, VIC, Australia

Malcolm Granat - working at theUniv of Strathclyde carried out work on
assessing gait in a hemiparertic stroke population. Their work has been
published and a search should provide you with a possible reference. David
Dr. Anand.D.Pandyan
Centre for Rehab. Eng. Studies
M25-Stephenson Bldg
University of Newcastle
Newcastle Upon Tyne
UK - NE1 7RU

Tel ++ 44 (0)191 - 222 5434
Fax ++ 44 (0)191 - 222 8600
e-mail A.D.Pandyan@ncl.ac.uk
http://www.ncl.ac.uk/crest/

We use a symmetry index to evaluate the lameness of horses. I think this
method is also useful in human motion analysis. We place a marker in the
symmetry-axis (e. g. head) and than we calculate the Fourier-coefficients
of the vertical motion. The Fourier-coefficients separate the motion in
symmetrical and asymmetrical parts. We described this method in:
"A method of signal processing in motion analysis of the trotting horse"
C. Peham, M. Scheidl and Theresia Licka J. Biomechanics, Vol. 29, No. 8,
pp. 1111-1114, 1996

"Supporting forelimb lameness: clinical judgement versus computerised
symmetry measurement"
C. Peham, Theresia Licka, M. Scheidl and D. Girtler Equine Veterinary
Journal, in print

This method can be extended to use all three motion direction, but you have
to take care, because in vertical and horizontal (running direction) the
fundamental wave and the odd harmonical parts are the asymmetrical part and
the even harmonical waves are the symmetrical parts of the motion. In the
transversal motion the fundamental wave represents a symmetrical motion.
Christian Peham [christian.peham@vu-wien.ac.at]

I'm using a transformation of right and left kinetic parameters (obtained
from force plates) into a common differential mode, in clear analogy with
electronics.
If p1 were a parameter obtained with the left plate and p2 were the same
parameter measured with the right plate, the derived parameters would be
defined as follows:
p(COM)=(p1+p2)/2
p(DIF)