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Michel Guerraz, Josephine Shallo–Hoffmann, Kielan Yarrow, Kai V. Thilo, Adolfo M. Bronstein, Michael A. Gresty; Visual Control of Postural Orientation and Equilibrium in Congenital Nystagmus. Invest. Ophthalmol. Vis. Sci. 2000;41(12):3798-3804.
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© 2015 Association for Research in Vision and Ophthalmology.
purpose. To investigate how humans with congenital nystagmus (CN) use visual
information to stabilize and orient their bodies in space.
methods. Center of foot pressure (COP) and head displacements in the lateral
plane were recorded using a sway platform and Schottky barrier
photodetector, respectively. In experiment 1, a comparison was made of
the oscillatory characteristics of body sway with eyes open compared
with eyes closed. Experiment 2 studied the postural readjustments made
in response to absolute or relative motion (motion parallax) of objects
in the visual scene, generated by lateral displacement of background
results. Experiment 1 revealed that subjects with CN were not able to use visual
information to stabilize COP but were able to stabilize the head at
frequencies lower than 1 Hz. Experiment 2 showed that in response to
the displacement of a visual display, for both absolute motion and
motion parallax, subjects with CN reoriented their body in space in a
manner similar to control subjects.
conclusions. The results suggest that despite involuntary eye movements, subjects
with CN use orientation cues to control their posture, but not dynamic
cues useful to control the rapid oscillations that are particularly
important at the level of COP. These findings suggest that in CN,
visual control of posture is restricted by low-frequency sampling of
the visual scene.
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