Otolith Assessment During Postflight Re-adaptation (Otolith) - 05.13.15
Otolith Assessment During Postflight Re-adaptation (Otolith) assesses otolith (small bones of the inner ear) function in crewmembers preflight and postflight. Science Results for Everyone
Our eyes and ears like gravity. This investigation found that the reduced sensory input of weightlessness caused changes in the function of otoliths, the small inner-ear bones, in 90 percent of astronauts. These included both typical and atypical forms of spontaneous rapid eye movements, indicating changes in functioning of the body’s vestibular or balance system. Such changes represent a typical adaptation of sensory systems to an altered sensory environment and are specific to individuals in terms of the level, time, duration, and dynamics. This seems to suggest that the pattern of changes is determined by the combined effect of various sensory inputs and their relationship. Experiment Details
Andrew H. Clarke, Ph.D., Charite Medical School, Berlin, Germany
Floris L. Wuyts, Ph.D., University of Antwerp, Antwerp, Belgium
Scott J. Wood, Ph.D., Azusa Pacific University, Azusa, CA, United States
Kayser Threde, Munich, Germany
Sponsoring Space Agency
European Space Agency (ESA)
ISS Expedition Duration
April 2008 - September 2011
Previous ISS Missions
Otolith first began on ISS Expedition 18.
- Otolith Assessment During Postflight Re-adaptation (Otolith) will assess otolith (small bones of the inner ear) function before and after space flight to this evaluate otolith-ocular response (OOR) and the subjective visual vertical (SVV) to assess unilateral utricle function. Vestibular evoked myogenic potentials (VEMP) will be recorded in order to assess unilateral saccule function.
- Together this represents a comprehensive examination of all aspects of the otolith system, providing critical information on the validity of the otolith asymmetry hypothesis and on the post flight adaptation of the individual otolith functions.
The compensatory eye movements with the head/neck movements, or the otolith–cervical–ocular reflex (OCOR), was studied to determine the roll the vestibular system plays in ocular impairments in 16 ground subjects after a seven days of “dry” horizontal immersion, and 14 cosmonauts after a prolonged exposure to weightlessness (for 126–195 days). After spaceflight, the absence, inversion (feeling of hanging upside down), or a sharp decrease in eye movements evoked by head movements indicates a deep deconditioning of the otolith (inner ear) function because of reduced sensory input to the central nervous system from the vestibular organs from weightlessness. A study of spontaneous oculomotor activity (SOA) and OCOR after prolonged exposure to microgravity and in subjects who were exposed to the immersion bath demonstrated that the responses to both environments were similar. However, the patterns, duration, and depth of changes observed after spaceflight versus immersion were different. After immersion, these reactions were found only in 60% of the examined subjects and they were less pronounced and less durable, while the same impairments were observed in 90% of cosmonauts and in addition, they were more profound and long lasting. In 33% of the cosmonauts examined, the amplitude of the compensatory eye counter rolling remained still reduced at 8−9 days post-flight as compared to the pre-flight value. The increase of SOA in 55% of cosmonauts after flight and in 12% of the subjects exposed to immersion (development of gaze-evoked nystagmus; i.e., involuntary eye movement, and both typical and atypical forms of spontaneous nystagmus) indicates involvement of the vestibular system’s central mechanisms and reflects changes in functioning of the vestibular nuclei, the midbrain reticular formation (parts of the brainstem, important in regulating consciousness or wakefulness), and the cerebellum. OCOR restoration after returning to Earth requires a certain amount of time for readaptation of the otolith function to Earth’s gravity. The changes in the vestibular system represent a typical adaptation response of the sensory systems to the altered sensory environment; these changes depend on the time of rearrangement between sensory connections under the conditions of Earth’s gravity. However, these reactions have individual specific features in terms of the level of expression, time, duration, and dynamics. This seems to suggest that the pattern of changes in OCOR is determined by the combined effect of various sensory input signals and their collective relationship.^ back to top
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 - Equilibrium & Orientation. 2013 January 1; 23(2): 61-70. DOI: 10.3233/VES-130476. PMID: 23788133.
Clarke AH. Listing's Plane and the 3D-VOR in microgravity. 2008 Life in Space for Life on Earth Symposium, Angers, France; 2008 June 22-27 2 pp. [Also: AH. Clarke, (2008) Listing’s Plane and the 3D VOR in microgravity. J Gravit. Physiol, , Vol 15:1, 29-30.]
Kornilova LN, Naumov IA, Makarova SM. Static Torsional Otolith-Cervical-Ocular Reflex After Prolonged Exposure to Weightlessness and a 7-day Immersion. Acta Astronautica. 2011 May - Jun; 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.
Ground Based Results Publications
Clarke AH, Haslwanter T. The orientation of Listing’s Plane in microgravity. Vision Research. 2007 November; 47(25): 3132-3140. DOI: 10.1016/j.visres.2007.09.001.
Diamond SG, Markham CH, Clarke AH. Dynamic pitch rotation affects eye torsion. Acta Oto-Laryngologica. 2006 March; 126(3): 248-253. DOI: 10.1080/00016480500280090. PMID: 16618649.
Clarke AH. Perspectives for the comprehensive examination of semicircular canal and otolith function. Biological Sciences in Space. 2001 December; 15(4): 393-400. DOI: 10.2187/bss.15.393. PMID: 12101365.
von Brevern M, Schmidt T, Schonfeld U, Lempert T, Clarke AH. Utricular dysfunction in patients with benign paroxysmal positional vertigo . Otology and Neurotology. 2006 January; 27(1): 92-96. PMID: 16371853.
Helling K, Schonfeld U, Scherer H, Clarke AH. Testing utricular function by means of on-axis rotation. Acta Oto-Laryngologica. 2006 June; 126(6): 587-593. DOI: 10.1080/00016480500450008. PMID: 16720442.
Clarke AH, Grigull J, Mueller R, Scherer H. The three-dimensional vestibulo-ocular reflex during prolonged microgravity. Experimental Brain Research. 2000 October; 134(3): 322-334. DOI: 10.1007/s002210000476. PMID: 11045357.
The information on this page is provided courtesy of the ESA Erasmus Experiment Archive.