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Biomedical subjects

J R Kass

Publications and source records attributed to J R Kass.

10 recordsLinked to original sources

Operational evaluation of the EXEMSI project. Experimental Campaign for the European Manned Space Infrastructure.

In general the EXEMSI project has proved to be very successful mission. It has demonstrated that it is indeed possible to perform a major and useful project in a short time and on a moderate budget. In addition to achieving the scientific objectives, this simulation project provided valuable experience in the training of members of chamber crew and ground control crew for their tasks. It covered all aspects of a mission from call for experiment proposals, crew selection and training, integration and testing of the facility and its equipment, to daily monitoring and managing of the mission, and finally post-isolation data collection and evaluation. These other activities were accomplished by a small team of experts in the astoundingly short time of 8 months. What was lacking in manpower, time and funds, was more than made up for by enthusiasm, expertise, team spirit, hard work and long hours well beyond the call of duty of all those involved. In addition to the specific and technological objectives reached, many lessons learned in this operation have been identified, which could help to improve future missions. The experience has shown pitfalls to be avoided in future mission, as well as points where some small increase in effort can make a considerable difference. With the prospect of long-term manned spaceflights looming in the near future and the ever increasing costs of such endeavors, the possibilities offered by running simulated missions on the ground should be seriously considered. Such simulations permit the study of scientific and operational aspects of a space mission prior to its actual implementation. A ground based simulation of an extended space mission may be run at a fraction of the cost of an in-orbit precursor mission of even one-week duration. However, careful planning of the simulation mission is required so that it may yield relevant information and useful experience. Lessons learned from the EXEMSI project should be taken into account in such planning. At the start clear goals should be formulated, that can provide clear guidelines for building up the infrastructure and defining the operational scenario. A long duration mission simulating the conditions on the Russian space station MIR could provide a valuable source of information and experience in preparing for the MIR '95 Mission.

Astronauts↗

Automation in manned spaceflight.

With the ever increasing complexity and use of advanced technologies in the development of equipment and experiments in spaceflight, the possibility offers itself to automating repetitious or very sensitive operations. The implementation of such automation lends itself well to teleoperations and the eventual introduction of artificial intelligence. In this paper the criteria for introducing automation are discussed, and its impacts examined. New problems such as command and control are discussed, with some guidelines suggested.

Artificial Intelligence↗

Parabolic flight as a tool to measure ocular counterrotation in a reduced force environment.

Five unmedicated subjects were flown in parabolic flight. The aircraft, a Caravelle, performed single parabolae every 2 to four minutes. This resulted in alternating phases of normal, hyper-, hypo- and again hyper-gravity. Subjects sat yoga fashion upright facing towards the aircraft cockpit. Head and/or trunk were deflected 30 degrees from the upright, stimulating otolith and/or neck receptors. During each pullup, low-g phase and pullout of the parabolae a picture of the left eye was recorded on video tape. On the ground ocular roll (OCR) was determined from these video recordings. OCR ranged from 0.9 to 6.9 degrees in l-g and from 1 to 7.2 degrees under high-g, depending on head and trunk position. Neck receptor contribution was found to induce OCR of 0.2 degree to 2.1 degrees in two subjects.

Adult↗

European vestibular experiments on the Spacelab-1 mission: 2. Experimental equipment and methods.

A series of vestibular experiments were performed in conjunction with the first Spacelab mission, consisting of sets of pre-, in- and postflight tests. A multipurpose experimental apparatus used for the diverse flight and ground tests is presented. Additional apparatus together with the multi-purpose package were used in the baseline data collection facility at the landing site at NASA Dryden Flight Research Facility for the ground tests. The tests involved optokinetic, caloric and mechanical (whole-body or head-alone) stimulation. The latter included linear acceleration in the subject's x, y and z axes, static roll and yaw about an earth-vertical axis. Physiological parameters such as electro-oculogram (EOG), blood-volume-pulse (BVP), respiration, as well as the stimulus variables such as acceleration and caloric temperature were transmitted to the ground and recorded there. The flight and ground testing schedules are outlined. Problems arising from this complex venture are discussed, and some suggestions are made for future improvement.

Acceleration↗

European vestibular experiments on the Spacelab-1 mission: 4. Thresholds of perception of whole-body linear oscillation.

Thresholds for the detection of linear oscillatory motion at 0.3 Hz in the X, Y and Z body axes were determined during the flight of Spacelab-1 and on the ground pre- and post-flight, using the method of limits with a single staircase procedure. Pre-flight, Z axis thresholds (mean 0.077 ms-2) were significantly higher than X and Y thresholds (mean 0.029 ms-2). Measures obtained on three crew members in-flight exhibited thresholds greater, by a factor of 1.5-4.3, than those obtained pre-flight. Post-flight, two crew members had significantly elevated X and Y axis thresholds whereas the other two crew members had lowered thresholds in X, Y and Z axes. In general, thresholds had returned to pre-flight levels by the second post-flight day. A possible explanation for these somewhat disparate responses is presented.

Acceleration↗

European vestibular experiments on the Spacelab-1 mission: 7. Ocular counterrolling measurements pre- and post-flight.

The static ocular counterrolling (OCR) of the four scientific crew members in the first Spacelab mission was measured during baseline-data-collection before and after the flight of SL-1. It was presumed that the modification of otolithic responses during spaceflight will be reflected in specific changes of the OCR-gain on the first days after recovery. The magnitude of OCR was determined analysing colour-transparencies of subjects right eyes that were produced in different positions of lateral body tilt. In general, one subject did not show any changes at all; three subjects exhibited a significant decrease of OCR-gain after exposure to weightlessness, whereby differences could be found between the responses for small and large angles of lateral body tilt. Moreover, asymmetrical effects of OCR-gain were found between body tilt to the left and tilt to the right side. Two subjects already demonstrated such an asymmetry before the flight with the higher gain on left-tilt (or right eye up), and three subjects exhibited left-right asymmetries after the spaceflight with the higher gain tilting to the right (or right eye down). A possible correlation between these vestibular asymmetries and space-sickness susceptibility is discussed.

Adaptation, Physiological↗

Subjective vertical before and after space flight.

Three scientist astronauts on the D1 spacelab mission participated in a series of orientation experiments before and after exposure to orbital weightlessness. Each subject was tilted about a roll axis at 15 deg intervals up to +/- 90 deg. At each angle the subject set a luminous line to what he perceived to be the vertical. The results of these tests are presented.

Adaptation, Physiological↗

Nausogenic properties of various dynamic and static force environments.

Motion sickness can occur when an accelerating force acting on the human body repeatedly changes amplitude and direction or both. It also can occur without any motion after transfer into a constant force field significantly different from Earth-gravity. Dynamic and static causes of motion sickness can be distinguished accordingly. Space sickness, too, has dynamic as well as static aspects. Dynamic space sickness might depend on increased bilateral differential sensitivity of the peripheral and central vestibular apparatus, whereas static space sickness may be caused by erroneous compensation of bilaterial asymmetries of the otolith-system in the microgravity environment. Experiments in airplanes, cars and on a vestibular sled have shown that the susceptibility to motion sickness is highest for changes of acceleration in the negative X-axis (as compared to the other axes) of the body. During reciprocating linear accelerations on the vestibular sled, standstill periods of movement and the direction of movement cannot correctly be indicated, because the peripheral vestibular apparatus lacks true motion detectors.

Acceleration↗

Serous otitis media.

Serous otitis media, as seen in children, may be an insidious disease which provides few signs and symptoms. Its effects may cause significant problems in the preschool and school-age child with respect to acquisition of necessary developmental skills. The nurse practitioner can effectively diagnose, treat, and manage children with serous otitis media. An algorithm is presented to aid in effective differential diagnosis of the disease.

Child↗