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At least 19 recordsLinked to original sources
PubMed1979

Space motion sickness.

Space motion sickness, presumably triggered by sudden entry into a weightless environment, occurred with unexpected frequency and severity among astronauts who flew the Skylab missions. Recovery from symptoms was complete within 3-5 days, and as revealed by the Skylab M131 Human Vestibular Function Experiment, all crewmembers were immune to experimentally induced motion sickness after mission day 8. This syndrome has been recognized as a possible threat to the early mission well-being and operational efficiency of at least some individuals who will fly space missions in the future. The causes of space motion sickness are not clearly understood, nor have satisfactory methods been identified to date for its prediction, prevention and treatment. In order to minimize the potential impact of this syndrome on Space Shuttle crew operations the National Aeronautics and Space Administration has organized a broad program of inter-disciplinary research involving a large number of scientists in the United States. Current research on the etiology of space motion sickness is based to a large extent on the so called sensory conflict theory. Investigations of the behavioral and neurophysiological consequences of intralabyrinthine, as well as intermodality sensory conflict are being performed. The work in this area is being influenced by the presumed alterations that occur in otolith behavior in weightlessness. In addition to sensory conflict, the possible relationship between observed cephalad shifts of body fluids in weightlessness and space motion sickness is being investigated. Research to date has failed to support the fluid shift theory. Research underway to identify reliable test methods for the prediction of susceptibility to space motion sickness on an individual basis includes attempts to (a) correlate susceptibility in different provocative environments; (b) correlate susceptibility with vestibular and non-vestibular response parameters, the latter including behavioral, hemodynamic and biochemical factors and (c) correlate susceptibility with rate of acquisition and length of retention of sensory adaptation. Controlled studies are also being performed during parabolic flight as a means of attempting to validate predictive tests for susceptibility to this syndrome. Research to develop new or improved countermeasures for space motion sickness is underway in two primary areas. One of these involves anti-motion sickness drugs. Significant achievements have been realized with regard to the identification of new highly efficacious drug combinations, dose levels and routes of administration. Although pronounced individual variations must be accounted for in selecting the optimum drug and dose level, combinations of promethazine plus ephedrine or scopolamine plus dexidrine are presently the drugs of choice. Work is also underway to identify side effects associated with anti-motion sickness drug use and to identify new drugs which may selectively modify activity in central neural pathways involved in motion sickness. In addition to research on drugs, efforts are being made to develop practical vestibular training methods. Variables which influence rate of acquisition of adaptation, length of retention of adaptation and transfer of protective adaptation to new environments are being evaluated. Also, included in this area is the use of biofeedback and autogenic therapy to train individuals to regulate autonomic responses associated with motion sickness. While valuable new knowledge is expected to evolve from these combined research programs, it is concluded that the final validation of predictive tests and countermeasures will require a series of controlled space flight experiments.

Adaptation, Physiological↗
PubMed1998

Relationship between selected orientation rest frame, circular vection and space motion sickness.

Space motion sickness (SMS) and spatial orientation and motion perception disturbances occur in 70-80% of astronauts. People select "rest frames" to create the subjective sense of spatial orientation. In microgravity, the astronaut's rest frame may be based on visual scene polarity cues and on the internal head and body z axis (vertical body axis). The data reported here address the following question: Can an astronaut's orientation rest frame be related and described by other variables including circular vection response latencies and space motion sickness? The astronaut's microgravity spatial orientation rest frames were determined from inflight and postflight verbal reports. Circular vection responses were elicited by rotating a virtual room continuously at 35 degrees/s in pitch, roll and yaw with respect to the astronaut. Latency to the onset of vection was recorded from the time the crew member opened their eyes to the onset of vection. The astronauts who used visual cues exhibited significantly shorter vection latencies than those who used internal z axis cues. A negative binomial regression model was used to represent the observed total SMS symptom scores for each subject for each flight day. Orientation reference type had a significant effect, resulting in an estimated three-fold increase in the expected motion sickness score on flight day 1 for astronauts who used visual cues. The results demonstrate meaningful classification of astronauts' rest frames and their relationships to sensitivity to circular vection and SMS. Thus, it may be possible to use vection latencies to predict SMS severity and duration.

Adult↗
PubMed2002

Medical prevention of space motion sickness--animal model of therapeutic effect of a new medicine on motion sickness.

Space motion sickness (MS) is one of the most important problems in the field of space medicine. In order to prevent space MS, a new medicine, PMPA, has been prepared by means of synthesizing in our laboratory. The purposes of this study were to set up animal models of PMPA against MS, and to observe its effects on anti-MS, and to prove its function of antagonism to choline. Eight cats, forty rabbits and two hundred and ten rats were selected as animal subjects. The parallel swing stimulus, a method causing the reversal syndromes and tests of anti-choline function were used in our experiments. The results are as follows: (1) The score of MS symptoms in cats with PMPA or scopolamine (SCOP) is significantly lower than that in cats with placebo (p<0.01), while the incidences of efficiency and prevention of PMPA (87.5%, 75%) are higher than those of SCOP (75.0%, 50%) in cats. (2) PMPA of 1.6 mg/kg or 0.8 mg/kg could antagonize the reversal syndromes and repress reversal rotation significantly in rabbits like SCOP in comparison with placebo (p<0.01). (3) PMPA could inhibit tremor evoked by oxotremorine or by nicotine-procaine in rats like SCOP, and play an important role in the antagonism to central M-choline and N-choline receptors. The animal experiments demonstrate that PMPA is an effective medicine against MS with antagonism function to choline.

Acceleration↗
PubMedDate not supplied

Managing space motion sickness.

Space motion sickness is a well-recognized problem for space flight and affects 73% of crewmembers on the first 2 or 3 days of their initial flight. Illness severity is variable, but over half of cases are categorized as moderate to severe. Management has included elimination of provocative activities and delay of critical performance-related procedures such as extra-vehicular activity (EVA) or Shuttle landing during the first three days of missions. Pharmacological treatment strategies have had variable results, but intramuscular promethazine has been the most effective to date with a 90% initial response rate and important reduction in residual symptoms the next flight day. Oral prophylactic treatment of crewmembers with difficulty on prior flights has had mixed results. In order to accommodate more aggressive pharmacologic management, crew medical officers receive additional training in parenteral administration of medications. Preflight medication testing is accomplished to reduce the risk of unexpected performance decrements or idiosyncratic reactions. When possible, treatment is offered in the presleep period to mask potential treatment-related drowsiness. Another phenomenon noted by crewmembers and physicians as flights have lengthened is readaptation difficulty or motion sickness on return to Earth. These problems have included nausea, vomiting, and difficulty with locomotion or coordination upon early exposure to gravity. Since landing and egress are principal concerns during this portion of the flight, these deficits are of operational concern. Postflight therapy has been directed at nausea and vomiting, and meclizine and promethazine are the principal agents used. There has been no official attempt at prophylactic treatment prior to entry. Since there is considerable individual variation in postflight deficit and since adaptation from prior flights seems to persist, it has been recommended that commanders with prior shuttle landing experience be named to flights of extended duration.

Antiemetics↗
PubMed1990

Space motion sickness.

Space Motion Sickness (SMS) is the malady which frequently occurs shortly after attainment of sustained exposure to hypogravity. It is characterised by a variety of symptoms, which may proceed to nausea and eventually vomiting. Natural adaptation usually occurs if exposure to hypogravity is maintained. The condition appears to be the manifestation of motion sickness that is specific to hypogravity. It is associated with otolith-canal and otolith-eye conflict. SMS may have operational significance in impairing the performance of spacecraft crews. The condition is likely to be amenable to treatment with anti-motion sickness drugs. It may be possible to reduce any operational effects of SMS by suitable crew selection and training procedures.

Adaptation, Physiological↗
PubMed1987

Head movements in low and high gravitoinertial force environments elicit motion sickness: implications for space motion sickness.

Astronauts report that head movements in flight tend to bring on symptoms of space motion sickness (SMS). We evaluated how head movements in pitch, yaw, and roll--made both with normal vision and eyes-occluded--affect susceptibility to motion sickness in the zero G phase of parabolic flight maneuvers. The findings are clearcut: pitch head movements are most provocative, yaw least provocative, and roll intermediate. Susceptibility is greater with normal vision than with eyes occluded. The same susceptibility pattern emerged for head movements in the 1.8-2.0 G phase of parabolic flight. These experiments suggest that SMS is not a unique nosological entity but, rather, is the consequence of exposure to nonterrestrial force levels. Head movements during departures in either direction from 1 G elicit symptoms. This implies that, rather than speaking of "space motion sickness," it would be more appropriate to think in terms of "nonterrestrial motion sickness."

Gravitation↗
PubMed1986

Head movements in non-terrestrial force environments elicit motion sickness: implications for the etiology of space motion sickness.

Space motion sickness has become an operational concern in manned space flight. Considerable evidence exists that head movements in free fall, especially pitch movements, are provocative until adaptation occurs (3,4,8,9,11,17,18,22,26). The question arises whether space motion sickness is an unique nosological entity or is due to body movements in a nonterrestrial force environment, a force environment for which the body's dynamic sensory-motor adaptions to 1 G are no longer appropriate (14,16,18-21). To evaluate this issue, we had subjects make controlled head movements during exposure to high gravitoinertial force levels, 1.8-2.0 G, in parabolic flight maneuvers. Head movements in pitch with eyes open were most evocative of motion sickness, yaw movements with eyes covered were least provocative. This pattern is identical to that which occurs when the same types of head movements are made in the free fall phase of parabolic maneuvers (17,18). It appears that space motion sickness is the consequence of prolonged exposure to a non-terrestrial force background rather than of exposure to free fall per se.

Adult↗
PubMed2004

Stimulation of the semicircular canals via the rotary chair as a means to test pharmacologic countermeasures for space motion sickness.

OBJECTIVE: Space motion sickness is currently treated pharmacologically with the empiric use of the H1 antihistamine promethazine, but use of this intervention is limited by the side effect of significant sedation. This creates a dilemma, as full cognition is particularly important during the same conditions likely to exacerbate the symptoms of space motion sickness. Using overstimulation of the semicircular canals with a rotary chair as a paradigm for space motion sickness, we evaluated four medications, commonly used for the treatment of terrestrial motion sickness and vertigo, for their efficacy in alleviating the simulated symptoms of space motion sickness. STUDY DESIGN: Randomized, prospective, double-blind study. SETTING: Tertiary referral center. PATIENTS: Healthy male and female volunteers, 18 years of age or older, without history of neurologic or psychiatric disorders, and with no known allergies or any previous adverse reactions to the drugs used. INTERVENTIONS: Lorazepam 1 mg, meclizine 25 mg, promethazine 25 mg, scopolamine 0.4 mg, or placebo. MAIN OUTCOME MEASURE: The ability of each treatment to control the nausea and vomiting associated with our paradigm for space motion sickness was evaluated by measuring time of rotation pre- and posttreatment and time of symptom onset pre-and posttreatment. RESULTS: Only scopolamine effected a mean change in duration of rotation that reached statistical significance when compared with placebo (p <0.008), with a greater than 40% increase in rotation time. Results with promethazine were not statistically significant. CONCLUSION: Results showed a rank order of efficacy of scopolamine > promethazine > placebo > meclizine > lorazepam. Scopolamine significantly increased rotation time, but none of the treatments resulted in a significant delay to onset of symptoms.

Adolescent↗
PubMed1985

Space motion sickness and space vestibulology.

Given the relatively short period of the space flight missions and more inexperienced personnel expected to be aloft, if the time in space should be optimized, the critical processes which occur in the body equilibrium system during the period of initial exposure to space environment must be thoroughly investigated. It is most important that improved management of space motion sickness (including the prediction, prevention and countermeasures) is properly developed. The improvement will fully depend on advances in our research on the etiology and pathology of this debilitating condition.

Aerospace Medicine↗
PubMed1992

Comparison of treatment strategies for Space Motion Sickness.

Treatment strategies for Space Motion Sickness were compared using the results of postflight oral debriefings. Standardized questionnaires were administered to all crewmembers immediately following Space Shuttle flights by NASA flight surgeons. Cases of Space Motion Sickness were graded as mild, moderate or severe based on published criteria, and medication effectiveness was judged based on subjective reports of symptom relief. Since October 1989, medication effectiveness is reported inflight through Private Medical Conferences with the crew. A symptom matrix was analyzed for 19 crewmembers treated with an oral combination of scopolamine and dextroamphetamine (scopdex) and 15 crewmembers treated with promethazine delivered by intramuscular (IM) or suppository routes. Scopdex has been given preflight as prophaxis for Space Motion Sickness but analysis showed delayed symptom presentation in 9 crewmembers or failed to prevent symptoms in 7. Only three crewmembers who took scopdex had no symptoms inflight. Fourteen out of 15 crewmembers treated with IM promethazine and 6 of 8 treated with promethazine suppositories after symptom development had immediate (within 12 h) symptom relief and required no additional medication. There were no cases of delayed symptom presentation in the crewmembers treated with promethazine. This response is in contrast to untreated crewmembers who typically have slow symptom resolution over 72-96 h. We conclude that promethazine is an effective treatment of Space Motion Sickness symptoms inflight. NASA policy currently recommends treating crewmembers with Space Motion Sickness after symptom development, and no longer recommends prophylaxis with scopdex due to delayed symptom development and apparent variable absorption of oral medications during early flight days.

Aerospace Medicine↗
PubMed2006

Space motion sickness: incidence, etiology, and countermeasures.

Space motion sickness is experienced by 60% to 80% of space travelers during their first 2 to 3 days in microgravity and by a similar proportion during their first few days after return to Earth. Space motion sickness symptoms are similar to those in other forms of motion sickness; they include: pallor, increased body warmth, cold sweating, malaise, loss of appetite, nausea, fatigue, vomiting, and anorexia. These are important because they may affect the operational performance of astronauts. Two hypotheses have been proposed to explain space motion sickness: the fluid shift hypothesis and the sensory conflict hypothesis. The fluid shift hypothesis suggests that space motion sickness results from the cranial shifting of body fluids resulting from the loss of hydrostatic pressure gradients in the lower body when entering microgravity. The cranial fluid shifts lead to visible puffiness in the face, and are thought to increase the intracranial pressure, the cerebrospinal-fluid pressure or the inner ear fluid pressures, altering the response properties of the vestibular receptors and inducing space motion sickness. The sensory conflict hypothesis suggests that loss of tilt-related otolith signals upon entry into microgravity causes a conflict between actual and anticipated signals from sense organs subserving spatial orientation. Such sensory conflicts are thought to induce motion sickness in other environments. Space motion sickness is usually treated using pharmaceuticals, most of which have undesirable side effects. Further studies elucidating the underlying mechanism for space motion sickness may be required for developing new treatments.

Antiemetics↗
PubMed1993

Comparison of treatment strategies for Space Motion Sickness.

Treatment strategies for Space Motion Sickness (SMS) were compared using the results of postflight oral debriefings. Standardized questionnaires were administered to all crewmembers immediately following Space Shuttle flights by NASA flight surgeons. Cases of SMS were graded as mild, moderate, or severe based on published criteria, and medication effectiveness was judged based on subjective reports of symptom relief. Since October 1989, medication effectiveness is reported inflight through Private Medical Conferences with the crew. A symptom matrix was analyzed for 19 crewmembers treated with oral combination of scopolamine and dextroamphetamine (scopdex) and 15 crewmembers treated with promethazine delivered by intramuscular i.m. or suppository routes. Scopdex has been given preflight as prophylaxis for SMS, but analysis showed delayed symptom presentation in 9 crewmembers or failed to prevent symptoms in 7. Only 3 crewmembers who took scopdex had no symptoms inflight. Fourteen out of 15 crewmembers treated with i.m. promethazine and 6 of 8 treated with promethazine suppositories after symptom development had immediate (within 1-2 h) symptom relief and required no additional medication. There were no cases of delayed symptom presentation in the crewmembers treated with promethazine. This response is in contrast to untreated crewmembers who typically have slow symptom resolution over 72-96 h. We conclude that promethazine is an effective treatment of SMS symptoms inflight. NASA policy currently recommends treating crewmembers with SMS after symptom development, and no longer recommends prophylaxis with scopdex due to delayed symptom development and apparent variable absorption of oral medications during early flight days.

Aerospace Medicine↗
PubMed1984

Carbonic anhydrase inhibitors for prevention of space motion sickness: an avenue of investigation.

Space motion sickness (SMS) is an important medical problem facing NASA's space shuttle program. Two theories that have been advanced to explain SMS are the "fluid shift theory" and the "vestibulo-ocular sensory conflict theory". The "fluid shift theory" pre-supposes an active or passive shift of body fluid to the central nervous system (CNS) and vestibulo-auditory mechanisms. In contrast, the "sensory conflict theory" hypothesizes that unfamiliar accelerational and gravitational inputs from the middle ear conflict with visual inputs and lead to SMS. Carbonic anhydrase inhibitors (CAHI) are known to suppress active production of CSF and may be able to inhibit production of perilymph in the semi-circular canals. Therefore, CAHI may be able to diminish the hypothesized fluid shift to the CNS and inner ear under the fluid shift theory. It is suggested that carbonic anhydrase inhibitors merit clinical investigation to test their usefulness for prophylaxis of space motion sickness and to test the veracity of the fluid shift theory.

Body Fluids↗
PubMed2003

[Study on space motion sickness before, during and after spaceflight].

Space motion sickness has long been a difficult medical problem in human space flight. Because it is a group of syndromes of the astronauts in adaptation to the new space environment and is related to a wide range of factors, the research of space motion sickness is different from that of cardiovascular and pulmonary system. Subjective methods and qualitative investigation are frequently used, and quantitative analysis is limited since objective stimuli that can be used in specific space environment are few and the samples are small. So precise localization of the problem is very difficult. In this paper space vestibular experiments and works on perceptions of space motion sickness completed by Russian and American scientists are reviewed, in the hope that it may provide some references for future space medical researches.

Aerospace Medicine↗
PubMed1987

Gastrointestinal motility in space motion sickness.

Gastrointestinal (Gl) symptoms in space motion sickness (SMS) are significantly different from those in ordinary motion sickness (MS). Vomiting is sudden, often unexpected, infrequent, never prolonged and usually without nausea. Inflight bowel sounds are absent in those with SMS but present after recovery and in those not affected. Recording and tabulation of sounds was the only technique that could be used as a measure of motility during spaceflight operations. There were 17 subjects, 6 unaffected by SMS, who made ambulatory recordings pre- and inflight. With one exception, all those affected had sharply reduced sounds while those unaffected had increases or moderate reductions. The mechanism of vomiting in SMS appears to be secondary to this ileus in contrast to vomiting in ordinary MS, where the emesis center is thought to be directly triggered by the vestibular system. This ileus appears to be the only consistent and reliable indicator for SMS to date.

Auscultation↗
PubMed2001

[Mechanism of development of space motion sickness].

Astronauts and scientists are scheduled to stay aboard the International Space Station (ISS) for three-month periods, and various problems relating to the human ability to live in space for such long periods of time, as well as medical problems, are being studied. For the crews that have operated and worked on the US space shuttle, the longest time spent in the gravity-free (accurately speaking, microgravity) environment of space has been about two weeks. Even such short periods have generated reports of various physical changes and symptoms caused by the absence of gravity. Particularly striking effects are circulatory system changes, muscular atrophy and decalcification of bones. In addition, serious problems arise during the time in space due to the symptoms of space motion sickness, caused by neuro-otological changes. Space motion sickness is experienced by nearly 70% of the first-time astronauts, in the form of such symptoms as nausea, and vomiting. It is said that space motion sickness develops at the time of adaptation of the body to the gravity-free environment. Unlike motion sickness on Earth, space motion sickness is characterized by a feeling of fullness of the head, a hot face and reduced sweating. The provocative factors include movement of the head in the pitch and roll directions and the unusual visual field. This paper reviews the research that has been carried out to date on space motion sickness, and its counter measures comprehensively, in terms of the changes in the otolith organ as well as asynchronization of information between the movements of the head and eyeballs, the deep sensations and body fluid shifts. Other problems, which may be encountered as a result of yet longer stays in space, are also discussed.

Adaptation, Physiological↗
PubMed1988

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

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.

Female↗
PubMed1988

Space motion sickness during 24 flights of the space shuttle.

The incidence and severity of Space Motion Sickness (SMS) were determined from 24 flights of the Space Shuttle. A standardized questionnaire developed at the NASA-Johnson Space Center (JSC) was administered to all crewmembers postflight during an oral debriefing with the examining flight surgeon. Cases of SMS were graded mild, moderate or severe using criteria developed at the JSC. The incidence of SMS during a first Shuttle flight for 85 crewmembers was 67% (57 cases). There were 26 mild cases (30%), 20 moderate (24%), and 11 severe (13%). Differences were found between males and females, crew positions (Commander, Pilot, Mission Specialist, etc.), and age groups, which were not statistically significant (p greater than 0.05), but would suggest future research into the mechanism, prevention, and treatment of SMS. The 26 crewmembers with a second flight showed a reduction in SMS incidence to 46%, but the change was not significant compared with the first flight. Nine crewmembers (35%) showed a reduction in SMS severity comparing first and second flights, yet there was no significant difference in the mean time between flights for crewmembers with SMS versus asymptomatic crewmembers. Variability in crewmember training and flight experience may explain some of the differences observed.

Adult↗