Otolith Assessment During Postflight Re-adaptation (Otolith)
Research Area: Neurological and Vestibular Systems
Expedition(s): 17- 28
Principal Investigator(s): ● Andrew H. Clarke, PhD, Charite Medical School,
Berlin, Germany
RESEARCH OBJECTIVES
Otolith Assessment During Postflight Re-adaptation
(Otolith) explores the adaptive processes in the human
vestibular (inner ear) system as it readapts to ground
conditions after spaceflight. Given that the loss of the
gravitational force represents a loss of this sense for the
otolith organs, the working hypothesis is that the
dynamic otolith-ocular reflex (OOR) will be enhanced in
microgravity. Immediately after return to the 1-g
environment, a corresponding increase in the OOR gain
should be observed, and over the course of the following
days return to preflight baseline level. This should also be
the case with subjective visual vertical (SVV) estimation.
The same theory applies to the vestibular evoked
myogenic potentials (VEMPs); an increase in their
amplitude is expected during the period after re-entry.
The re-adaptation process is expected to proceed largely
over the first 12 days after landing.
RESULTS
The SVV findings indicated that after a 10-day mission, the readaptation of otolith function
proceeded over a period of 8-10 days. Considerable interindividual variability in response
change and adaptive time constants. The SVV data support the idea of a labyrinth dominance,
rather than a morphological asymmetry, as proposed previously.
PUBLICATION(S)
Clarke AH, Just K, Krzok W, Schonfeld U. Listing’s plane and the 3D-VOR in microgravity--the
role of the otolith afferences. Journal of Vestibular Research. January 1, 2013;23(2):61-70. doi:
10.3233/VES-130476.
Kornilova LN, Naumov IA, Makarova SM. Static torsional otolith-cervical-ocular reflex after
prolonged exposure to weightlessness and a 7-day immersion. Acta Astronautica. May – June,
2011;68(9-10):1462-1468. doi: 10.1016/j.actaastro.2010.04.016.
Clarke AH. Listing’s plane and the otolith-mediated gravity vector. Berlin: Progress in Brain
Research (2008); 2008.
Rotating drum vestibular testing with multi-
axis tilt device. ESA image.