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Robin Marcus
07-19-1999, 01:02 AM
Thank you to all who so promptly replied to my queery concerning tracking head movement. The information was very helpful. The following is a summary of replies.

1. I've tracked head movement in more than 20 subjects (gait and various
balance tasks). I use Richard Baker's marker placement: mastoid
processes and glabellum. These three landmarks are easily and
repeatedly located and define a triangle with the centre of mass of the
head at its centre. I know the animation people usually use four markers
on a headband, but I think this is unnecessary and unrepeatable.

Dr. Chris Kirtley MD, PhD
Assistant Professor
Department of Rehabilitation Sciences
The Hong Kong Polytechnic University
Hung Hom
Hong Kong Special Administrative Region of the People's Republic of
China
Tel.: +852 2766 6755 Fax +852 2330 8656


2. This is a stretch, but there is a guy in New Jersey that says that he can teach you to determine head movement (and scads of other body actions) by looking at a barefoot print made in sand. See http://members.aol.com/trackerinc/ .

Del Morris

3. If you don't mind having a tethered system and your setup does not have
too much electromagnetic interference from other equipment, you may want
to look into a device made by Polhemus that can track fixed markers. It
works well for static tasks, but for gait it may be tougher since there is
a wire attached to the "marker".

Edward Auyang || auyanged@email.uc.edu
Department of Environmental Health
University of Cincinnati Medical Center

4. References

J Vestib Res 1997 Mar-Jun;7(2-3):161-77
Locomotor head-trunk coordination strategies following space flight.
Bloomberg JJ, Peters BT, Smith SL, Huebner WP, Reschke MF

Exp Brain Res 1990;82(1):97-106
Head stabilization during various locomotor tasks in humans. I. Normal
subjects.
Pozzo T, Berthoz A, Lefort L

These papers should give you references for a marker set in tracking the
movement of the head during gait. Essentially the marker set we use in the
Neurosciences Motion Lab here at JSC, NASA to study Head, trunk motion
during gait includes three markers placed on a helmet (light weight pulled
out of a welders hat) such that one coincides with the vertex of the head,
another near the occipital area and the third lines up just above the right
ear. You can possibly rearrange the markers as a matter of convenience for
your camera placement or other biomechanical calculation constraints.

Ajitkumar P. Mulavara, Ph.D.
Neurosciences Section,
Wyle Laboratories
1290 Hercules Blvd, Suite 120, MC: NL/B37
Houston, TX 77058

5. Try contacting Roni Cromwell, PhD at Temple University. She has been doing work looking at head on trunk movements during gait. She may have some ideas and I believe she is a member of the listserv. Her e-mail address is cromwell@vm.temple.edu.

Bob Wellmon


6. References
Woltring, H.J., Long, K., Osterbauer, P.J., Fuhr, A.W., 1994. Instantaneous
Helical Axis Estimation from 3 D Video Data in Neck Kinematics for Whiplash
Diagnostics. Journal of Biomechanics 27, 1415-1415.

Winters, J.M., Peles, J.D., Osterbauer, D.C., Derickson, K., Deboer, K.F.,
Fuhr, A.W., 1993. Three-dimensional head axis of rotation during tracking
movements. Spine 18, 1178-1185.

_________________________________________
Peter Cripton, MSc (Eng)
University of Bern
Mueller Institute for Biomechanics
P. O. Box 30
Murtenstrasse 35
3010 Bern, Switzerland


7. We did something similar but found it much easier to put a 3D accelerometer on the head, and calculated the displacements from the signals. In the end this proved much simpler.
Su
-----
STEWART Su


8. In a trial we recently performed tracking head movement,
although it was a seated trial. We identified and tracked the following
points:
left and right acromium
left and right zygomatic arch
glabella
tip of the nose.
The acromiums gave data relating to head orientation in comparison with
the body. Whilst the remaining points relate to head tilt, rotation and
directional aspects. Obviously this would only apply to tracking the
forward area of the head but it produced the relevant data about head
orientation etc.

Simon Wickes

Centre for Human Sciences
DERA Farnborough
Tel: (+44) 1252 392660
Fax: (+44) 1252 392097

Pozzo and Berthoz and their colleagues carried out a series of
experiments to investigate the stability of the orientation of the
head in space during various modes of locomotion. The first study is
a truly original piece of work, which was based on Muybridge's
studies: The Human Figure in Motion (1955). To summarise their
method: they placed their markers on: 1) the outer
canthus of the eye and 2) the auditory meatus. The angle between the
head "cantho-meatic" line and the earth vertical, as well as linear
and angular velocity was then used for further analysis.

9. References:

Berthoz A. & Pozzo T. (1988) Intermittent head stabilization during
postural and locomotory tasks in humans. In: B. Amblard, A.
Berthoz & F. Clarac (Eds.), Posture and gait: development, adaptation
and modulation (pp. 189-198). Elsevier Science Publishers B.V.
(Biomedical Division)

Pozzo T, Berthoz A., Lefort L. (1989) Head kinematics during various
motor tasks in humans. In: J. H.J. Allum & M. Hulliger (Eds.).
Progress in Brain Research (pp. 377-383). Elsevier Science
Publishers B.V. (Biomedical Division).

Pozzo T., Berthoz A., Lefort L. (1990a) Head kinematics during
complex movements. In: A. Berthoz, W. Graf & P.P. Vidal (Eds.)
Head-neck sensory-motor system. New York: Wiley & sons.

Pozzo T., Berthoz A., Lefort L. (1990b) Head stabilization during
various locomotor tasks in humans. Experimental Brain Research 82,
97-106

Berthoz A. & Pozzo T. (1994). Head and body co-ordination during
locomotion and complex movements. In: S.P. Swinnen, H. Heuer, J.
Massion & P. Casaer (Eds.), Interlimb co-ordination: neural, dynamical
and cognitive constraints (pp. 147-165). San Diego: Academic press.

This marker placement was also used in the following study which
investigated head-eye co-ordination during locomotion:
Van Wijck F. (1995) Watching your step: A literature and empirical
study into the co-ordination of gaze and foot movements duriing
stepping. Masters Thesis, Perception and Action Laboratories,
Department of Psychology, University of Edinburgh.



10. I used markers on the forehead, chin, and in front of the ears to track the
motion of the head when I did my research...I don't remember if I got that
from a reference or just decided to use them.

"Nichols-Ketchum, Martha"

11. If you are interested in 2D analysis, one suggestion would be the placement used by Pozzo and colleagues in a number of papers--one is in Progress in
Brain Research (1989) 80:377-383. If you are interested in 3D analysis I
would suggest work done by W.G. Darling in the 1990's using the Watsmart
system.

"Jan M. Hondzinski"

12. We are a Gait laboratory interested in all segmental movements during
walking. Recently, we have added head postion (tilt, lateral flexion,
and rotation) to our list. We are using a Motion Analysis 3-D
high-speed video system with 6 cameras operating at 60 Hz to capture a
full body set of retro-reflective markers. We use 3 markers arranged
on a baseball cap: one anterior, one top, and one posterior on the
midline of the head. We align the hat so that when the patient is
relaxed and looking forward, the line formed by the anterior and
posterior markers is parallel to floor. We call this neutral position.
We then create a coordinate system from the 3 markers and reference the
orientation of this system to our room system and the local system fixed
to the trunk.

We are using a program called Orthotrak 4.1 (Motion Analysis Corp.),
which automatically performs the above calculations.

Patrick W. Castagno
Manager/Biomechanist - Gait Analysis Laboratory
duPont Hospital for Children
1600 Rockland Road
Wilmington, DE 19899
Chestnut@udel.edu
(302-651-4615)

Robin L. Marcus, MS, PT, OCS
Clinical Assistant Professor
University of Utah
Division of Physical Therapy
phone 801.581.4813
FAX 801.585.5629

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