Characterisation of gravity-induced facial skin oedema using biophysical measurement techniques.

BACKGROUND/AIMS: In humans, the microgravity environment can be expected to induce swelling of facial tissues and shrinking of the tissues in the lower limbs, together with a loss in body weight. To evaluate fluid shifts in skin, the head-down bed-rest model was used. The aim of the present study was to evaluate the appearance of facial oedema in subjects undergoing anti-orthostatic bed-rest at an angle of -10 degrees. METHODS: The forehead of each of four subjects was measured before and after 1, 10 and 24 h in this head-down tilt position. At these time points, interstitial fluid migration and facial oedema were assessed using a high resolution B-scan ultrasound and a device for measuring the skin's mechanical properties. RESULTS: The results obtained showed a progressive increase in dermal thickness and initial stress, and a reduction in stiffness and elasticity of the skin during the study period. CONCLUSIONS: This preliminary study has demonstrated the feasibility of the method in measuring fluid displacement and retention in the skin. Furthermore, it highlights the influence of fluids on the mechanical behaviour of the skin. These techniques could be used for studying the redistribution of liquid masses during periods spent in space.

EDEN: a payload dedicated to neurovestibular research for Neurolab.

The European Space Agency contributes to the Neurolab mission through the delivery of the ESA Developed Elements for Neurolab (EDEN). Those elements include one set supporting the Autonomic Nervous System experiment and one set supporting the Neurovestibular (so-called ATLAS) experiment. This second set is called the Visual and Vestibular Investigation System (VVIS). This paper describes the main characteristics of the VVIS and its various subsystems. The scientific objectives and operational constraints of the ATLAS experiment to be carried out with this equipment during Neurolab are presented to underline the correspondence between the VVIS design and the scientific requirements. Further scientific and technical perspectives for the VVIS, particularly within the scope of the International Space station, are also proposed.

ESS, eye stimulator system for VVIS facility (Visual and Vestibular Investigation System).

The ESS (Eye Stimulation System) is one of four main Subsystems of the Visual and Vestibular Investigation System ( VVIS ), Facility developed in the field of EDEN program and aimed to the research in the area of neurosensors physiology under microgravity conditions. In particular, the ESS is an Optokinetic Stimulator that stimulates the Subject's eyes with moving black and yellow patterns, in order to allow, by another main Subsystem, video recording of the pupil movement and, successively, to elaborate the relevant data of the neurovestibular experiment. This Stimulator was designed by the Officine Galileo as Subcontractor of Aerospatiale, leader of the VVIS facility, developed under ESA contract and successfully flown in April 1998 aboard the Neurolab mission. The Eye Stimulation System, on the frame of the VVIS Facility, is used in conjunction with the Body Rotating Device and the Eye Movement and Recording System, in order to fulfill all operations that lead to carry-out the experiments proposed. The Subject, seated on the Rotating Chair, observes the stimuli on a display monitor through a set of lenses, mounted on a proper box, fixed to a main structure of the unit. The stimuli patterns are showed on a display, placed on a movable support in order to fix it in a proper position, depending on the optical characteristics of the Subject. The experiments are repeated with different kind of patterns. All the main components of the visual system are mounted on a structural base plate, that gives also the mechanical I/F with the other system, supporting the ESS.