EDT - Measurement by Eye Tracking Device in orientation of the Listings plane
Physiology: Integrative gravitational physiology
ISS 8S (Soyuz TMA-4) Dutch "Delta" Mission
A.H. Clarke (1), J.E. Bos (2), T. Haslwanter (3)
|(1)||Vestibular Research Lab|
Klinikum Benjamin Franklin
|(2)||TNO Human Factors|
PO Box 23
|(3)||Dept. of Neurology|
|||A.H. Clarke, T. Haslwanter, (2007), "The orientation of Listing's Plane in microgravity", Vision Research, 47, 25, pp. 3132-3140.|
|||A.H. Clarke, L. Kornilova, (2007), "Ocular torsion response to active head-roll movement under one-g and zero-g conditions", Journal of Vestibular Research, 17, 2-3, pp. 99-111.|
|||A.H. Clarke, (2008), "Listing's plane and the otolith-mediated gravity vector", Progress in Brain Research, 171, http://dx.doi.org/10.1016/S0079-6123(08)00642-0, pp. 291-294.|
|||J.J.W.A. van Loon, F.J. Medina, H. Stenuit, E. Istasse, M. Heppener, R. Marco, (2007), "The National-ESA Soyuz missions Andromède, Marco Polo, Odissea, Cervantes, DELTA and Eneide", Microgravity Science and Technology, 19, 5-6, DOI: 10.1007/BF02919448, pp. 9-32.|
Using the Eye Tracking Device (ETD) figure 1 - the subjects are examined:
- Pre-flight, on ground, at L- 6 months, then four times leading up to the launch typically at L-3 months (+/- 2 weeks), L-21 days (+/-2 days), L 14 days (+/-2 days) and L-7 days (+/-2 days). The total duration of each session is approximately 30 minutes total for each subject except the last one at L-7 days, which has a duration of 1 hour.
- In-flight, at 48 hour intervals for a maximum of 4 sessions (Flight Day (FD) 3, 5, 7 and 9). Each session lasts approximately 30 minutes.
- Post-flight , for readaptation on days R+0, R+2, R+4, R+6, R+8, R+10 and R+12, and once again at approximately R+60.
The internal coordinates of the vestibular system are defined by the orientation of the 3-D vestibulo-ocular reflex (3-D VOR), and those of the oculomotor system by the so-called Listing's plane. The internal, neurally represented coordinate systems related to the vestibular and oculomotor systems are generally thought to be collinear under normal gravity conditions. The working hypothesis is that in microgravity the orientation of the Listing's plane diverges from that of the VOR coordinate frame. The orientation of the 3-D VOR is determined by measurement and analysis of eye and head movements during active head roll, pitch, and yaw movements.
Listing's plane is calculated from measurements of random saccades. All eye and head movements are recorded and measured with the DLR eye-tracking device, a flight version of which is installed on the International Space Station (ISS). To date, the results indicate that not only the orientation of the 3-D VOR, but also that of the Listing's plane of the individuals is altered during microgravity. This demonstrates that the otolith-mediated gravity vector represents a common spatial reference for the central nervous system, the loss of which may lead to a dissociation of these closely coupled systems.
|Figure 1 - Illustration of the ETD System Unit and Head Unit|
|Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, uses the Eye Tracking Device (ETD), a European Space Agency (ESA) payload in the Zvezda Service Module of the International Space Station. The ETD is used to measure eye and head movements in space with great accuracy and precision.|
|The European Space Agency (ESA) Eye Tracking Device (ETD) payload held by an Expedition 11 crewmember in the Zvezda Service Module of the international space station.|
|The Eye Tracking Device (ETD) payload.|
|The Eye Tracking Device (ETD) payload.|
|For a very comprehensive overview on the first six ESA missions to the ISS, please, consult the following reference document - see also document no. 4 in the list of references above:
The National - ESA Soyuz missions Andromède, Marco Polo, Odissea, Cervantes, Delta and Eneide;
Jack J. W. A. van Loon, F. Javier Medina, Hilde Stenuit, Eric Istasse, Marc Heppener and Roberto Marco;
Microgravity Science and Technology;
Volume 19, Numbers 5-6 (2007), 9-32, DOI: 10.1007/BF02919448|
Patrik Sundblad (e-mail: email@example.com)