Ground-based training for the stimulus rearrangement encountered during spaceflight.

Reschke MF, Parker DE, Harm DL, Michaud L.

Space Biomedical Research Institute, Johnson Space Center, Houston, Texas.

Approximately 65-70% of the crew members now experience motion sickness of some degree during the first 72 h of orbital flight on the Space Shuttle. Lack of congruence among signals from spatial orientation systems leads to sensory conflict, which appears to be the basic cause of space motion sickness. A project to develop training devices and procedures to preadapt astronauts to the stimulus rearrangements of microgravity is currently being pursued. The preflight adaptation trainers (PATs) are intended to: demonstrate sensory phenomena likely to be experienced in flight, allow astronauts to train preflight in an altered sensory environment, alter sensory-motor reflexes, and alleviate or shorten the duration of space motion sickness. Four part-task PATs are anticipated. The trainers are designed to evoke two adaptation processes, sensory compensation and sensory reinterpretation, which are necessary to maintain spatial orientation in a weightless environment. Recent investigations using one of the trainers indicate that self-motion perception of linear translation is enhanced when body tilt is combined with visual surround translation, and that a 270 degrees phase angle relationship between tilt and surround motion produces maximum translation perception.

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Pica as an index of motion sickness in rats.

Morita M, Takeda N, Kubo T, Matsunaga T.

Department of Otolaryngology, Osaka University School of Medicine, Japan.

Rats eat kaolin after treatment with poisons or rotation. Thus, eating of nonnutritive substances such as kaolin, so-called pica, is an illness-response behavior of rats analogous to vomiting in humans. For use of rotation-induced pica as a behavioral index of motion sickness in rats we examined what kind of rotation was effective for inducing pica in rats and whether the vestibular apparatus was necessary for its induction. Rats ate much kaolin after double rotation with continuously changing centrifugal and angular accelerations, but little after single rotation with no accelerative changes. However, even double rotation failed to induce pica in bilaterally labyrinthectomized rats. Thus, rotation-induced pica in rats was induced in the same way as motion sickness in humans, suggesting that it resulted from motion sickness in rats. We conclude that pica can be used as a behavioral index of motion sickness in rats.

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[Effect of adaptive biofeedback on the severity of vestibulo-autonomic symptoms of experimental motion sickness]

[Article in Russian]

Smirnov SA, Aizikov GS, Kozlovskaia IB.

The effect of biofeedback control on motion sickness symptoms was investigated in 27 test subjects with different susceptibility who had been trained to regulate their skin resistance and skin temperature. The efficacy of two schemes was compared: scheme 1 - transfer of controlling abilities, and scheme 2 - application of biofeedback during vestibular stimulation. Use of either scheme inhibited significantly the severity of motion sickness symptoms in moderate susceptibility individuals; in other words, this decreased respiratory arrhythmia, skin galvanic response, heart rate and objective motion sickness manifestations, i.e. nausea, paleness, perspiration. This caused vestibular tolerance to increase by 50% to 150% as compared to the baseline. Biofeedback control proved ineffective in high susceptibility individuals. Scheme 2 was found to be more effective than scheme 1. Biofeedback control of skin resistance had a stronger inhibitory effect than that of skin temperature. These results suggest that the prophylactic effect of biofeedback control is associated with the regulation of a component of the complex autonomic reaction triggered as a single program during motion sickness.

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Mental rotation: a key to mitigation of motion sickness in the virtual environment?

Parker DE, Harm DL.

Department of Psychology, Miami University, Oxford, Ohio 45056, USA.

NASA: Some of our recent observations suggest that mental rotation may be important for reduction of motion sickness in microgravity as well as in the microgravity simulator. Therefore, we suggest that development of the ability to perform mental rotation may be important for adaptation to many virtual environments. Training virtual environment operators to perform mental rotation may enhance operator performance both by increasing their ability to "locomote in" and manipulate that environment and by reducing motion sickness associated with transitions between virtual and normal environments. NASA Edited

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Salivary changes associated with experimental motion sickness condition in man.

Gordon CR, Ben-Aryeh H, Szargel R, Attias J, Rolnick A, Laufer D.

Motion Sickness and Human Performance Laboratory, Israel Naval Hyperbaric Institute, Haifa.

The effect of experimental motion sickness condition (rotation) on salivary flow and composition was studied in 34 healthy male volunteers. In most subjects, the flow rate of whole saliva was significantly decreased, while the potassium concentration was markedly increased during rotation. These results contrast with the classic reports of subjectively increased salivation in the first stages of motion sickness and may tentatively be explained in terms of sympathetic activation. The salivary protein concentration and secretion rate observed before and during rotation were consistently higher in those subjects categorized as moderately or severely sick during rotation. The salivary protein levels may perhaps be considered as an additional objective variable in the prediction of susceptibility to motion sickness.

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Comparison of aerobic fitness and space motion sickness during the shuttle program.

Jennings RT, Davis JR, Santy PA.

NASA/Johnson Space Center, Flight Medicine Clinic, Houston, Texas 77058.

Space motion sickness (SMS) is an important problem for short duration space flight and 71% of STS crewmembers develop symptoms. The search for effective countermeasures and factors that correlate with sensitivity has been extensive. Recently, several investigators have linked aerobic fitness with motion sickness sensitivity in the 1-G or high-G environment. This paper compares the aerobic fitness of 125 Shuttle crewmembers with their SMS symptom category. Aerobic fitness data were obtained from the exercise tolerance test (ETT) conducted nearest the time of launch. SMS data were derived from the medical debrief summaries. Mean VO2max for crewmembers in four SMS categories (none, mild, moderate, severe) were 44.55, 44.08, 46.5, and 44.24 ml.kg-1.min-1, respectively. Scattergrams with linear regression analysis comparing aerobic fitness and SMS symptom classification are also presented. Correlation coefficients comparing SMS categories vs. aerobic fitness for men and women reveal no definite relationship between the two factors. Due to the subjective nature of the data, further studies are suggested to corroborate these findings.

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Comparison of efficacy of ginger with various antimotion sickness drugs.

Wood CD, Manno JE, Wood MJ, Manno BR, Mims ME.

Department of Pharmacology and Therapeutics, Louisiana State University Medical Center, Shreveport 71130.

Ginger and several other medications were compared with scopolamine and d-amphetamine for effectiveness in prevention of motion sickness. Methods: Double-blind techniques were used. The subjects were given the medications two hours before they were rotated in a chair making head movements until a symptom total short of vomiting was reached. Standardized N.A.S.A. techniques were used for speed of rotation and end-point of motion sickness. Results: The three doses of ginger were all at the placebo level of efficacy. Amitriptyline, ethopropazine and trihexyphenidyl increased the tolerated head movements but the increase was not statistically significant. Significant levels of protection were produced by dimenhydrinate, promethazine, scopolamine and d-amphetamine. Protection was further increased by combination of these latter drugs with d-amphetamine. Efficacy was greatest as the dose was increased. Conclusions: The medication of choice in this study was scopolamine 0.6 mg with d-amphetamine 10 mg. This combination provided good protection with acceptable side effects.

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The effective intensity of Coriolis, cross-coupling stimulation is gravitoinertial force dependent: implications for space motion sickness.

Lackner JR, Graybiel A.

Coriolis, cross-coupled angular acceleration stimulation readily induces motion sickness under terrestrial conditions. Nevertheless, the Skylab astronauts, when tested with such stimulation in-flight, were insusceptible even though each had been susceptible pre-flight. It is unclear whether this decreased susceptibility was the consequence of in-flight adaptation or in part the result of immediate changes in sensory-motor and vestibulo-motor function that occur during exposure to microgravity conditions. To evaluate this issue, we have tested individuals both in the high and low force phases of parabolic flight maneuvers using constant levels of Coriolis, cross-coupled stimulation. Our findings indicate that 1.) subjects are less susceptible when tested in 0 G than +2 Gz; 2.) the perceived intensity and provocativeness of Coriolis stimulation decreases in 0 G and increases in +2 Gz relative to +1 Gz baseline values; and 3.) changes in the apparent intensity of Coriolis stimulation occur virtually immediately when background gravitoinertial force level is varied. These findings explain in large part why the Skylab astronauts were refractory to motion sickness during Coriolis stimulation in-flight. The general implications for space motion sickness are discussed.

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