Horizontal angular vestibulo-ocular reflex changes in orbital and
parabolic flight: human neurovestibular studies on sls-2 .
Oman, Charles M., Christopher F. Pouliot, and Alan Natapoff.
Man Vehicle Laboratory, Center for Space Research, Massachusetts
Institute of Technology, Cambridge, MA 02139 Charles M. Oman, PhD,
Room 37-219, MIT, Cambridge, MA 02139, (617) 253-7508,
cmo@space.mit.edu
APStracts 3:0196A, 1996.
Further evidence was found for adaptive changes in the vestibular
"velocity storage" (VS) component of the VOR in four Shuttle
astronauts tested in parabolic flight, and before, during, and after
a 14 day mission. Nystagmus was recorded during and after one minute
of 120 deg/sec rotation. Gains and time constants were determined by
computer analysis. Responses correlated with experience: Two subjects
were making their first space flight. In parabolic flight, their time
constants shortened to an average of 60% of 1-G values, presumably
because unfamiliar otolith cues reduced VS. However, after 4-10 days
in orbit, their time constants were similar or greater than pre
-flight, indicating VS recovery. The other two subjects had previously
flown in space. Their time constants shortened in orbit to an average
of 69% of 1-G values, indicating a persisting reduction of VS. This
correlation with space flight experience has been seen in 9/11
subjects on 3 missions. Head pitch did not significantly
"dump" nystagmus as it does on earth.
Received 23 December 1994; accepted in final form 21 December
1995.
APS Manuscript Number A1323-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 23 April 96