OFF-VERTICAL AXIS ROTATION: EYE MOVEMENTS AND MOTION PERCEPTION INDUCED BY OFF-
AXIS ROTATION AT SMALL ANGLES OF TILT AFTER SPACEFLIGHT, DETAILED SUPPLEMENTARY
OBJECTIVE 499 (OVAR)
Research Area: Human Research: Nervous and Vestibular Systems
Expedition(s): 10- 11
Principal Investigator(s): ● Gilles Clement, PhD, International Space University,
Strasbourg, France
RESEARCH OBJECTIVES
The Eye Movements and Motion Perception Induced
By Off-Axis Rotation at Small Angles of Tilt After
Spaceflight (OVAR) study allows for better
understanding of normal balance and suggests causes
for abnormal balance after spaceflight.EARTH BENEFITS
This study will allow for better understanding of normal
balance and suggest causes for abnormal balance in
patients on Earth. If OVAR, associated with a 3-D eye
movement measuring system, proves that reliable
information about otolith organs can be obtained, then
this test has obvious clinical value to assess vestibular
disorders.SPACE BENEFITS
This study will allow for better understanding of normal
balance and suggest causes for abnormal balance
related to microgravity exposure. In particular,
spaceflight will provide knowledge and understanding
of the vestibular system (sensory system that
contributes to balance and sense of orientation), which is one of the systems most affected by
gravity.
RESULTS
OVAR has the advantage of generating cyclic testing control of OCR, allowing averaged
measurements over several cycles, presumably improving measurement accuracy over static
head tilt tests. Results show there was no significant difference in OCR during OVAR
immediately after landing compared to preflight. However, the perceived degree of the roll tilt
during OVAR was significantly larger immediately postflight, and then returned to control
values in the following days. Since the OCR response is mainly due to the shearing force exerted
on the otoliths by tilt relative to gravity, the absence of change in OCR postflight suggests that
the peripheral otolith organs function normally after short-term spaceflight. However, the
increased sense of roll tilt indicates an adaptation in the central neural processing of
Off Vertical Rotation - Measurement of
Perception and Video Recording of Eye
Movements. ESA image.