Effect of spaceflight on the ability to sense and control roll
tilt: human neurovestibular studies on sls-2.
Merfeld, Daniel M.
Man-Vehicle Laboratory, MIT, Cambridge, MA 02139 USA
APStracts 2:0375A, 1995.
To measure adaptive changes in the ability to sense tilt following
spaceflight, we measured the ability of four astronauts to control
roll tilt in the presence of a pseudo-random motion disturbance
before and after a fourteen day spacelab mission. The subjects were
tested 1) in the Dark, 2) with an independent Sum-of-Sines visual
display, and 3) using a control condition in which the visual cues
confirmed the motion cues (Counter-rotating). The two subjects tested
on the landing day exhibited significant decrements (p<0.05) in
their ability to control roll tilt in the dark, while no significant
performance decrements were observed in the control condition. The
absence of changes in the control condition suggests that changes in
the neuromuscular component of the task and postflight fatigue were
not major factors contributing to the observed performance decrement
in the dark. These findings indicate an adaptive change in the way
the nervous system interprets tilt cues. Readaptation of all
responses appeared to be rapid with a return to preflight values
within 1-2 days after landing.
Received 23 June 1995; accepted in final form 17 August 1995.
APS Manuscript Number A680-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 15 September 1995.