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In the early 1970s, nine astronauts participated in missions to the Skylab space station. During two preflight testing sessions at the Naval Aerospace Medical Research Laboratory in Pensacola, the amplitudes of their ocular counter-rolling (OCR) during body tilts were assessed to determine if their vestibular functions were within normal ranges. We recently re-evaluated this data to determine asymmetry of each astronaut’s OCR response and their OCR slope from sigmoid fits during static leftward and rightward body tilts, which we then compared with their Coriolis sickness susceptibility index (CSSI) on the ground, their motion sickness symptom scores during 0 g maneuvers in parabolic flight, and the severity of the symptoms of space motion sickness (SMS) they reported during their spaceflights. We arranged the astronauts in rank order for SMS severity based on the SMS symptoms they reported during spaceflight and the amount of anti-motion sickness medication they used. As previously reported, the OCR amplitudes of these astronauts were within the normal range. We determined that the OCR amplitudes were not correlated with SMS severity ranking, CSSI, or motion sickness symptoms experienced during parabolic flight. Indices of asymmetry in the OCR reflex were generally small and poorly correlated with SMS scores; however, the only subject with a high index of asymmetry also ranked highly for SMS. Although OCR slope, CSSI, and motion sickness symptoms induced during parabolic flight were each only moderately correlated with SMS severity ranking (rho = 0.41–0.44), a combined index that included all three parameters with equal weighting was significantly correlated with SMS severity ranking (rho = 0.71, p = 0.015). These results demonstrate the challenge of predicting an individual’s susceptibility to SMS by measuring a single test parameter in a terrestrial environment and from a limited sample size. [ABSTRACT FROM AUTHOR]

Entry motion sickness (EMS) affects crewmembers upon return to Earth following extended adaptation to microgravity. Anticholinergic pharmaceuticals (e.g., Meclizine) are often taken prior to landing; however, they have operationally adverse side effects (e.g., drowsiness). There is a need to develop non-pharmaceutical countermeasures to EMS. We assessed the efficacy of a technological countermeasure providing external visual cues following splashdown, where otherwise only nauseogenic internal cabin visual references are available. Our countermeasure provided motion-congruent visual cues of an Earth-fixed scene in virtual reality, which was compared to a control condition with a head-fixed fixation point in virtual reality in a between-subject design with 15 subjects in each group. We tested the countermeasure's effectiveness at mitigating motion sickness symptoms at the end of a ground-based reentry analog: approximately 1 h of 2Gx centrifugation followed by up to 1 h of wave-like motion. Secondarily, we explored differences in vestibular-mediated balance performance between the two conditions. While Motion Sickness Questionnaire outcomes did not differ detectably between groups, we found significantly better survival rates (with dropout dictated by reporting moderate nausea consecutively over 2 min) in the visual countermeasure group than the control group (79% survival vs. 33%, t(14) = 2.50, p = 0.027). Following the reentry analogs, subjects demonstrated significantly higher sway prior to recovery (p = 0.0004), which did not differ between control and countermeasure groups. These results imply that providing motion-congruent visual cues may be an effective mean for curbing the development of moderate nausea and increasing comfort following future space missions. [ABSTRACT FROM AUTHOR]

In the early 1970s, nine astronauts participated in missions to the Skylab space station. During two preflight testing sessions at the Naval Aerospace Medical Research Laboratory in Pensacola, the amplitudes of their ocular counter-rolling (OCR) during body tilts were assessed to determine if their vestibular functions were within normal ranges. We recently re-evaluated this data to determine asymmetry of each astronaut’s OCR response and their OCR slope from sigmoid fits during static leftward and rightward body tilts, which we then compared with their Coriolis sickness susceptibility index (CSSI) on the ground, their motion sickness symptom scores during 0 g maneuvers in parabolic flight, and the severity of the symptoms of space motion sickness (SMS) they reported during their spaceflights. We arranged the astronauts in rank order for SMS severity based on the SMS symptoms they reported during spaceflight and the amount of anti-motion sickness medication they used. As previously reported, the OCR amplitudes of these astronauts were within the normal range. We determined that the OCR amplitudes were not correlated with SMS severity ranking, CSSI, or motion sickness symptoms experienced during parabolic flight. Indices of asymmetry in the OCR reflex were generally small and poorly correlated with SMS scores; however, the only subject with a high index of asymmetry also ranked highly for SMS. Although OCR slope, CSSI, and motion sickness symptoms induced during parabolic flight were each only moderately correlated with SMS severity ranking (rho = 0.41–0.44), a combined index that included all three parameters with equal weighting was significantly correlated with SMS severity ranking (rho = 0.71, p = 0.015). These results demonstrate the challenge of predicting an individual’s susceptibility to SMS by measuring a single test parameter in a terrestrial environment and from a limited sample size.

BACKGROUND: Coordination of motor activity is adapted to Earth's gravity (1 g). However, during space flight the gravity level changes from Earth gravity to hypergravity during launch, and to microgravity (0 g) in orbit. This transition between gravity levels may alter the coordination between eye and head movements in gaze performance. OBJECTIVE: We explored how weightlessness during space flight altered the astronauts' eye-head coordination (EHC) with respect to flight day and target eccentricity. METHODS: Thirty-four astronauts of 20 Space Shuttle missions had to acquire visual targets with angular offsets of 20°, 30°, and 49°. RESULTS: Measurements of eye, head, and gaze positions collected before and during flight days 1 to 15 indicated changes during target acquisition that varied as a function of flight days and target eccentricity. CONCLUSIONS: The in-flight alterations in EHC were presumably the result of a combination of several factors, including a transfer from allocentric to egocentric reference for spatial orientation in absence of a gravitational reference, the generation of slower head movements to attenuate motion sickness, and a decrease in smooth pursuit and vestibulo-ocular reflex performance. These results confirm that humans have several strategies for gaze behavior, between which they switch depending on the environmental conditions. [ABSTRACT FROM AUTHOR]

Objectives The authors formulated a hypothesis that, on completion of the training program by cadets, their vestibular habituation would increase, measured by the time of the duration of the test on the unlocked looping, in contrast to the initial values and the control group. Material and Methods The research involved 35 male cadets, first-year students of the Polish Air Force Academy in Dęblin. The examined persons were on average 20 years of age. They were divided into 2 groups. Group A (N = 25, tested) continued training on Special Aviation Gymnastic Instruments (SAGI). The cadets were a homogeneous group of participants in the jet pilot course, selected by the Military Aeromedical Board. Group B (N = 10, control) conducted the standard physical military education program. Groups A and B were tested on the unlocked looping before and after the training process. In the training process, the groups had heart rate (HR) monitored. Results The cadets in group A on the test in the unlocked looping, at the beginning of the training period, had an average score of 468.5±96.6 s, and on completion of the training period 575.6±47.9 s, which is a statistically significant difference at p < 0.000001. Similarly, the examined individuals in group B received an average score of 396.2±31.8 s, and at the end of the training period 473.4±72.0 s, which is a statistically significant difference at p < 0.01. In group A, a statistically significant decrease in the average HR value was observed. In group B, there was a statistically significant increase in the average HR value. Conclusions The exercises on SAGI have a beneficial impact on improving the habituation of the vestibular organ in training cadets in examination II, as opposed to examination I and the control group. Int J Occup Med Environ Health. 2020;33(4):497–506

Objectives: The authors formulated a hypothesis that, on completion of the training program by cadets, their vestibular habituation would increase, measured by the time of the duration of the test on the unlocked looping, in contrast to the initial values and the control group.Material and Methods: The research involved 35 male cadets, first-year students of the Polish Air Force Academy in Dęblin. The examined persons were on average 20 years of age. They were divided into 2 groups. Group A (N = 25, tested) continued training on Special Aviation Gymnastic Instruments (SAGI). The cadets were a homogeneous group of participants in the jet pilot course, selected by the Military Aeromedical Board. Group B (N = 10, control) conducted the standard physical military education program. Groups A and B were tested on the unlocked looping before and after the training process. In the training process, the groups had heart rate (HR) monitored.Results: The cadets in group A on the test in the unlocked looping, at the beginning of the training period, had an average score of 468.5±96.6 s, and on completion of the training period 575.6±47.9 s, which is a statistically significant difference at p < 0.000001. Similarly, the examined individuals in group B received an average score of 396.2±31.8 s, and at the end of the training period 473.4±72.0 s, which is a statistically significant difference at p < 0.01. In group A, a statistically significant decrease in the average HR value was observed. In group B, there was a statistically significant increase in the average HR value.Conclusions: The exercises on SAGI have a beneficial impact on improving the habituation of the vestibular organ in training cadets in examination II, as opposed to examination I and the control group. Int J Occup Med Environ Health. 2020;33(4):497-506. [ABSTRACT FROM AUTHOR]

This article presents a review of the current findings related to neurovestibular physiology, aetiology, and proposed theories on space motion sickness (SMS) during acute and sustained exposure to microgravity. The review discusses the available treatment options including medication and nonpharmacological countermeasure methods that help to prevent the development of SMS in weightlessness. Ground-based simulations using virtual reality, flight simulations, and Barany's chairs can be applied to study SMS and demonstrate its signs and symptoms to space crew members. Space motion sickness has been observed in approximately 70% of astronauts within the first 72 h in microgravity, having in general an instantaneous onset of signs and symptoms. Stomach discomfort, nausea, vomiting, pallor, cold sweating, salivation, tachypnoea, belching, fatigue, drowsiness, and stress hormone release have been documented. This can have detrimental effects on the well-being of astronauts in the initial phase of a space mission. Mental and physical performance may be affected, jeopardizing operational procedures and mission safety. [ABSTRACT FROM AUTHOR]

This paper presents a high-performance vision-based precision manipulation technique that does not rely on an object, contact, or gripper model, which are challenging and often times impractical to acquire. Instead, we utilize a simple process model that roughly maps object velocities to actuator velocities, and we maintain system efficiency and robustness via advanced vision-based control techniques with disturbance rejection mechanisms. For obtaining simple models, we derive a set of actuator coordination rules for achieving common task space motions. The performance degradation due to modeling inaccuracies is then minimized via the model predictive control framework and a correction matrix method. Our experimental results show that the proposed strategy results in high-performance precision manipulation with minimal modeling effort. Note to Practitioners—Compliant, soft robotic grippers make it easier to grasp objects with various shapes and sizes; these grippers adapt to the shape of the object, which provides robustness to positioning errors and often removes the necessity to precisely plan the contact locations. These advantages make compliant grippers ideal to use in industrial settings as well as in service robotics, where the variety of object shapes and sizes are immense. On the other hand, for the tasks that require precise object manipulation (e.g., for a peg-in-hole problem), these hands are more challenging to control than their rigid counterparts: it is harder to obtain their precise models, and they often do not have enough proprioceptive sensors to calculate the full pose of the system. In this paper, we propose solutions to utilize vision feedback for positioning an object using compliant hands. These solutions do not rely on precise models of the gripper or the full knowledge of the gripper state. We adopt various control techniques to provide precise positioning in steady state as well as to maintain efficiency in the transient. [ABSTRACT FROM AUTHOR]

BACKGROUD: Astronauts' orientation preferences tend to correlate with their susceptibility to space motion sickness (SMS). Orientation preferences appear universally, since variable sensory cue priorities are used between individuals. However, SMS susceptibility changes after proper training, while orientation preferences seem to be intrinsic proclivities. The present study was conducted to investigate whether o rientation preferences change if susceptibility is reduced after repeated exposure to a virtual reality (VR) stimulus environment that induces SMS. METHODS: A horizontal supine posture was chosen to create a sensory context similar to weightlessness, and two VR devices were used to produce a highly immersive virtual scene. Subjects were randomly allocated to an experimental group (trained throug h exposure to a provocative rotating virtual scene) and a control group (untrained). All subjects' orientation preferences were measured twice with the same interval, but the experimental group was trained three times during the interval, while the control group was not. RESULTS: Trained subjects were less susceptible to SMS, with symptom scores reduced by 40%. Compared with untrained subjects, trained subjects' orientation preferences were significantly different between pre-and posttraining assessments. Trained subjects depended less on visual cues, whereas few subjects demonstrated the opposite tendency. CONCLUSION: Results suggest that visual information may be inefficient and unreliable for body orientation and stabilization in a rotating visual scene, while reprioritizing preferences for different sensory cues was dynamic and asymmetric between individuals. The present findings should facilitate customization of efficient and proper training for astronauts with different sensory prioritization preferences and dynamic characteristics. [ABSTRACT FROM AUTHOR]

The vestibular system plays an important role in intersensory interactions and gravitation is a natural stimulus for its receptors. Weightlessness alters the input signals of the otoliths and their effect on the pattern and dynamics of changes in the vestibular function (VF), which is accompanied by development of space adaptation syndrome (SAS) and space motion sickness (SMS). These changes occur both during the spaceflight (SF) and after returning to Earth, but the mechanisms of their development are still poorly understood and require special studies. In total, 47 Russian cosmonauts (crewmembers of long-term International Space Station (ISS) missions) have participated in the studies into VF before and after SF and nine of them, in onboard studies during SF (129-215 days) as a part of the Virtual space experiment (stage 1). Electro- and video-oculography are used to record spontaneous eye movements (SpEM), static vestibular-ocular responses during head tilts to the right or left shoulder (static otolith-cervical-ocular reflex, OCOR), and dynamic vestibular-ocular response during the head rotation around the longitudinal axis of the body. The examination is accompanied by personal and questionnaire survey on subjective responses and complaints of cosmonauts about SAS and SMS. Significant changes in SpEM (drifts of eyes, spontaneous and gaze-evoked nystagmus, and arbitrary saccades) and a decrease in OCOR (statistically significant decrease in the amplitude of ocular counter-rolling in response to head tilts up to its absence or inversion, an atypical OCOR) are observed during SF. An atypical OCOR is observed at the beginning of adaptation to weightlessness in seven of the nine cosmonauts (the first one to two weeks of SF) and repeatedly throughout the flight in all cosmonauts regardless of whether it is their first flight or not. Atypical vestibular responses after SF, similar to the responses during SF, are observed in several cosmonauts by day 9 after flight. It has been shown that atypical OCOR variants are more frequently observed in the subjects lacking any previous space experience, as well as a more pronounced decrease in this response with a concurrent increase in the response of the semicircular canals. It is also demonstrated that repeated SFs lead to a considerable shortening in the after-flight readaptation to terrestrial conditions and a considerable decrease in the degree of vestibular disorders. In the initial period of SF, the changes in VF are correlated with the complaints and manifestations of SAS and SMS; however, the complaints and the corresponding symptoms are unobservable during the further flight despite significant changes in the VF state. The patterns of the VF disorders associated with the impact of weightlessness and observed during and after SF are very similar, allowing these disorders to be regarded as SAS and SMS of different severities (intensities). [ABSTRACT FROM AUTHOR]

INTRODUCTION: Zero-G parabolic flight reproduces the weightlessness of space for short periods. However, motion sickness may affect some fliers. The aim was to assess the extent of this problem and to find possible predictors and modifying factors. METHODS: Airbus zero-G flights consist of 31 parabolas performed in blocks. Each parabola consisted of 20 s of 0 g sandwiched by 20 s of hypergravity of 1.5-1.8 g. The survey covered N = 246 person-flights (193 men, 53 women), ages (M ± SD) 36.0 ± 11.3 yr. An anonymous questionnaire included motion sickness rating (1 = OK to 6 = vomiting), Motion Sickness Susceptibility Questionnaire (MSSQ), antimotion sickness medication, prior zero-G experience, anxiety level, and other characteristics. RESULTS: Participants had lower MSSQ percentile scores (27.4 ± 28.0) than the population norm of 50. Motion sickness was experienced by 33% and 12% vomited. Less motion sickness was predicted by older age, greater prior zero-G flight experience, medication with scopolamine, lower MSSQ scores, but not gender or anxiety. Sickness ratings in fliers pretreated with scopolamine (1.81 ± 1.58) were lower than for nonmedicated fliers (2.93 ± 2.16), and incidence of vomiting in fliers using scopolamine treatment was reduced by half to a third. Possible confounding factors including age, sex, flight experience, and MSSQ could not account for this. CONCLUSION: Motion sickness affected one-third of zero-G fliers despite being intrinsically less motion sickness susceptible compared to the general population. Susceptible individuals probably try to avoid such a provocative environment. Risk factors for motion sickness included younger age and higher MSSQ scores. Protective factors included prior zero-G flight experience (habituation) and antimotion sickness medication. [ABSTRACT FROM AUTHOR]

During infancy, smart perceptual mechanisms develop allowing infants to judge time- space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioral and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioral data when studying the neural correlates of prospective control. [ABSTRACT FROM AUTHOR]

BACKGROUND: Space motion sickness (SMS) remains a troublesome problem during spaceflight. The subjective vertical (SV) conflict theory postulates that all motion sickness provoking situations are characterized by a condition in which the SV sensed from gravity and visual and idiotropiccues differs from the expected vertical. This theory has been successfully used to predict motion sickness in different vehicles on Earth. METHOD: We have summarized the most outstanding and recent studies on the illusions and characteristics associated with spatial disorientation and SMS during weightlessness, such as cognitive map and mental rotation, the visual reorientation and inversion illusions, and orientation preferences between visual scenes and the internal z-axis o f the body. RESULTS: The relationships between the SV and the incidence o f and susceptibility to SMS as well as spatial disorientation were addressed. CONCLUSION: A consistent framework was presented to understand and explain SMS characteristics in more detail on the basis o f the SV conflict theory, which is expected to be more advantageous in SMS prediction, prevention, and training. [ABSTRACT FROM AUTHOR]

Introduction: Space motion sickness in astronauts during spaceflight causes significant discomfort, which might impede their functionality. Pharmacological treatment has been mainly restricted to promethazine. Transdermal and oral scopolamine have also been used in space; however, their use was reduced due to unpredictable effectiveness and side effects. Recently, intranasal scopolamine administration has gained much interest, since this route ensures fast and reliable absorption with a decreased incidence of undesirable side effects. The aim of this study was to evaluate the effect of intranasal scopolamine on cognitive performance and to determine its side effects.Methods: This double-blind, placebo controlled, repeated measures study evaluated vigilant attention, short-term memory, implicit memory and working memory. Side effects were reported on a 22-item questionnaire and sleepiness was assessed by the Karolinska, Stanford and Epworth Sleepiness Scales.Results: Scopolamine had no effect on cognitive function. Only the Karolinska score was significantly increased for scopolamine compared to placebo. Participants reported a dry mouth and dizziness after receiving scopolamine.Discussion: Results show that intranasal scopolamine did not impair cognitive performance. Intranasal scopolamine might be a good alternative to promethazine for the alleviation of space motion sickness, since the agent has minimal sedative effects and does not hamper cognitive performance. [ABSTRACT FROM AUTHOR]

Background: Space motion sickness (SMS) is the most relevant medical problem during the first days in microgravity. Studies addressing pathophysiology in space face severe technical challenges and microgravity is frequently simulated using the 6° head-down tilt bed rest test (HDT).Aim: We were aiming to test whether SMS could be simulated by HDT, identify related changes in gastrointestinal physiology and test for beneficial effects of exercise interventions.Methods: HDT was performed in ten healthy individuals. Each individual was tested in three study campaigns varying by a 30-min daily exercise intervention of either standing, an upright exercise regimen, or no intervention. Gastrointestinal symptoms, stool characteristics, gastric emptying time, and small intestinal transit were assessed using standardized questionnaires, (13)C octanoate breath test, and H2 lactulose breath test, respectively, before and at day 2 and 5 of HDT.Results: Individuals described no or minimal gastrointestinal symptoms during HDT. Gastric emptying remained unchanged relative to baseline data collection (BDC). At day 2 of HDT the H₂ peak of the lactulose test appeared earlier (mean ± standard error for BDC-1, HDT2, HDT5: 198 ± 7, 139 ± 18, 183 ± 10 min; p: 0.040), indicating accelerated small intestinal transit. Furthermore, during HDT, stool was softer and stool mass increased (BDC: 47 ± 6, HDT: 91 ± 12, recovery: 53 ± 8 g/day; p: 0.014), indicating accelerated colonic transit. Exercise interventions had no effect.Conclusion: HDT did not induce symptoms of SMS. During HDT, gastric emptying remained unchanged, but small and large intestinal transit was accelerated. [ABSTRACT FROM AUTHOR]

Space motion sickness (SMS), a condition caused by an intravestibular conflict, remains an important obstacle that astronauts encounter during the first days in space. Promethazine is currently the standard treatment of SMS, but scopolamine is used by some astronauts to prevent SMS. However, the oral and transdermal routes of administration of scopolamine are known to have substantial drawbacks. Intranasal administration of scopolamine ensures a fast absorption and rapid onset of therapeutic effect, which might prove to be suitable for use during spaceflights. The aim of this study was to evaluate the effects of intranasally administered scopolamine (0.4 mg) on the semicircular canals (SCCs) and the otoliths. This double-blind, placebo-controlled study was performed on 19 healthy male subjects. The function of the horizontal SCC and the vestibulo-ocular reflex, as well as the saccular function and utricular function, were evaluated. Scopolamine turned out to affect mainly the SCCs centrally and peripherally but also the utricles to a lesser extent. Centrally, the most probable site of action is the medial vestibular nucleus, where the highest density of muscarinic receptors has been demonstrated and afferent fibers from the SCCs and utricles synapse. Furthermore, our results suggest the presence of muscarinic receptors in the peripheral vestibular system on which scopolamine has a suppressive effect. Given the depressant actions on the SCCs, it is suggested that the pharmacodynamic effect of scopolamine may be attributed to the obliteration of intravestibular conflict that arises during (S)MS. [ABSTRACT FROM AUTHOR]

Orientation preference should appear when variable weightings of spatial orientation cues are used between individuals. It is possible that astronauts’ orientation preferences could be a potential predictor for susceptibility to space motion sickness (SMS). The present study was conducted to confirm this relationship on Earth by quantifying orientation preferences and simulating SMS in a virtual reality environment. Two tests were carried out. The first was to quantitatively determine one's orientation preference. Thirty-two participants’ vision and body cue preferences were determined by measuring perceptual up (PU) orientations. The ratio of vision and body vector (ROVB) was used as the indicator of one's orientation preference. The second test was to visually induce motion sickness symptoms that represent similar sensory conflicts as SMS using a virtual reality environment. Relationships between ROVB values and motion sickness scores were analyzed, which revealed cubic functions by using optimal fits. According to ROVB level, participants were divided into three groups – body group, vision group, and confusion group – and the factor of gender was further considered as a covariate in the analysis. Consistent differences in motion sickness scores were observed between the three groups. Thus, orientation preference had a significant relationship with susceptibility to simulated SMS symptoms. This knowledge could assist with astronaut selection and might be a useful countermeasure when developing new preflight trainings. [ABSTRACT FROM AUTHOR]

Conclusion: This study showed that GABAB agonist baclofen (10 mg) affects the semicircular canals (SCCs), both centrally and peripherally, but does not influence the otolithic function. Objectives: The aim of the study was to identify the effects of baclofen on the complete vestibular system, i.e. semicircular canals, saccules and utricles. Methods: The study had a double-blind, placebo-controlled, repeated measures design and was conducted on healthy male volunteers. With electronystagmography (ENG), the SCC function was evaluated, whereas utricular function was determined by means of unilateral centrifugation (UC). Cervical vestibular evoked myogenic potentials (cVEMPs) tested saccular integrity. Results: Baclofen caused a significant increase of the vestibulo-ocular reflex (VOR) phase and a significant decrease of the total caloric response (TCR), both measured during ENG. The drug also decreased the maximal contribution of the SCCs to ocular counter-rolling (OCR) evaluated during UC. No effects on saccules and utricules were observed. [ABSTRACT FROM AUTHOR]

In the framework of further space exploration, countermeasures to combat the drawbacks of human space flights are essential. The present study focuses on the influence of microgravity on the otolith-ocular reflex and aims to test the hypothesis of artificial gravity being an adequate countermeasure for the deconditioning of the aforementioned reflex. The so-called SPIN study, commissioned by the European Space Agency, can be considered as a control experiment in the broad sense for the Neurolab mission (STS-90) during which 4 crewmembers of the space shuttle were subjected to in-flight centrifugation on the visual and vestibular investigation system (VVIS). After their nearly 16-day mission, they did not suffer from orthostatic intolerance and spatial disorientation. In addition, the relevant parameters of the otolith-ocular interaction remained unaffected. For this study cosmonauts from a long duration stay in the International Space Station that were not centrifuged in-flight were tested on the VVIS (1 g centripetal interaural acceleration) on 6 different days. Three measurements were taken about 1.5-2 months prior to launch and 3 were taken at 1, 4 and 9 days after return from space. Ocular counter-rolling was measured before, during and after rotation on the VVIS using infrared video goggles and compared pair wise using Friedman tests. The perception of verticality was monitored using an ultrasound system for perceptual evaluation. The preliminary results of 4 cosmonauts showed a surprisingly large inter-individual variability of the measurements. Although OCR and perception of verticality appeared to be influenced overall by the exposure to microgravity, the wide variability among the cosmonauts obscured any statistical significance, in particular due to one cosmonauts being inconsistent with the other 3. Despite the specificity of the tests under normal conditions, the diverse response to spaceflight of our subjects exposes the complexity of the peripheral and central neural adaptive processes. [ABSTRACT FROM AUTHOR]

November 20, 2010, marked a significant milestone in the annals of human endeavors in space since it was the twelfth anniversary of one of the most challenging and complex construction projects ever attempted by humans away from our planet: The construction of the International Space Stations. On November 20, 1998, the Zarya Control Module was launched. With this simple, almost unnoticed launch in the science community, the construction of a continuously staffed research platform, in Low Earth Orbit, was underway. This paper discusses the research that was performed by many occupants of this research platform during the year celebrating its twelfth anniversary. The main objectives of this paper are fourfold: (1) to discuss the integrated manner in which science planning/replanning and prioritization during the execution phase of an increment is carried out across the United States Orbital Segment since that segment is made of four independent space agencies; (2) to discuss and summarize the research that was performed during increments 16 and 17 (October 2007 to October 2008). The discussion for these two increments is primarily focused on the main objectives of each investigation and its associated hypotheses that were investigated. Whenever available and approved, preliminary research results are also discussed for each of the investigations performed during these two increments; (3) to compare the planned research portfolio for these two increments versus what was actually accomplished during the execution phase in order to discuss the challenges associated with planning and performing research in a space laboratory located over 240 miles up in space, away from the ground support team; (4) to briefly touch on the research portfolio of increments 18 and 19/20 as the International Space Station begins its next decade in Low Earth Orbit. [ABSTRACT FROM AUTHOR]

Abstract: Background and Purpose: Space motion sickness (SMS) and related symptoms remain a major limiting factor in Space operations. A recent comprehensive literature review [J.R. Lackner, Z. DiZio, Space motion sickness, Experimental Brain Research 175 (2006) 377–399, doi 10.1007/s00221-006-0697-y] concluded that SMS does not represent a unique diagnostic entity, and there is no adequate predictor of SMS’ susceptibility and severity. No countermeasure has been found reliable to prevent or treat SMS symptoms onset. Recent neurophysiological findings on sensory–motor controls monitoring [P.A. Souvestre, C. Landrock, Biomedical-performance monitoring and assessment of astronauts by means of an ocular vestibular monitoring system, Acta Astronautica, 60 (4–7) (2007) 313–321, doi:10.1016/j.actaastro.2006.08.013] and heart-rate variability (HRV) measurements relationship could explain post-flight orthostatic intolerance (PFOI) in astronauts [A.P. Blaber, R.L. Bondar, M.S. Kassam, Heart rate variability and short duration space flight: relationship to post-flight orthostatic intolerance, BMC Physiology 4 (2004) 6]. These two methodologies are generally overlooked in SMS’ analysis. In this paper we present the case for a strong relationship between sensory–motor controls related symptoms, including orthostatic intolerance (OI) and SMS symptoms. Methods: This paper expands on several previously published papers [J.R. Lackner, Z. DiZio, Space motion sickness, Experimental Brain Research 175 (2006) 377–399, doi 10.1007/s00221-006-0697-y; P.A. Souvestre, C. Landrock, Biomedical-performance monitoring and assessment of astronauts by means of an ocular vestibular monitoring system, Acta Astronautica, 60 (4–7) (2007) 313–321, doi:10.1016/j.actaastro.2006.08.013] along with an updated literature review. An analysis of a 10-year period clinical data from trauma patients experiencing postural deficiency syndrome (PDS) show assessment and monitoring techniques which successfully identify trauma impacts on core regulatory sensory motor and cognitive mechanisms. Static postural analysis provides specific central neurophysiological markers that can reliably identify PDS occurrence among classic peripheral musculoskeletal and spinal data [C. Landrock, P.A. Souvestre, Static postural analysis: a methodology to assess gravity related sensory motor controls’ status for astronauts, 2006-01-2298, 36th SAE-ICES]. Many astronauts experience PFOI and recent research has implicated altered autonomic cardiovascular regulation caused by microgravity. HRV measurements have been used to determine if some pre-flight autonomic indicators relating to PFOI may exist by differentiating parasympathetic and sympathetic activity. Results: This review suggests a new approach to SMS mitigation based on specific neurophysiological assessment criteria. While SMS may not be a “unique diagnosis”, it should be treated as result, or symptom of, the condition space adaptation syndrome (SAS), which can be shown to be a unique diagnosis. This methodology can identify and measure brain functional status in specific areas during pre-flight and post-flight examinations. This could provide further understanding on why, how and when SMS and PFOI might occur in Astronauts, and lead to criteria that predict susceptibility to SMS. An additional test component is presented that relates to using static central sensory–motor data towards understanding SMS and OI occurrence. Recent investigations indicate relationship between HRV autonomic indicators with Motion Sickness [B. Cheung, K. Hoffer, R. Heskin, A. Smith, Physiological and behavioral responses to an exposure to pitch illusion in the simulator, Aviation Space, 2004; Y. Yokota, M. Aoki, K. Mizuta, Y. Ito, N. Isu, Motion sickness susceptibility associated with visually induced postural instability and cardiac autonomic responses in healthy subjects, Acta Oto-laryngological, 2005]. It is found that astronauts with lower sympatho-vagal balance and higher supine parasympathetic activity pre-flight may present with PFOI indicators. Not only HRV provides information on autonomic regulation, but HRV pattern appears to be chaotic and/or fractal. Beat-by-beat HRV yields fractal dimension of the cardiovascular control system [C.K. Peng, J. Mistus, J.M. Hausdorff, S. Havlin, H.E. Stanley, A.L. Goldberger, Long-range anticorrelations and non-Gaussian behavior of the heartbeat, Physics Review Letters 70 (1999) 1343–1346]. Similar properties can be found in other physiological signals such as breathing intervals and gait pattern [N. Scafetta, R. Moon, B.J. West, Physiological signals and their fractal response to stress conditions, environmental changes and neurodegenerative diseases, in: Proceedings of The 25th Army Science Conference (ASC), Orlando, Florida, November 27–30, 2006]. Conclusions: A strong correlation between unmitigated SMS and PFOI related symptoms in astronauts has been presented. There is also strong correlation with PDS related symptoms, which can be accurately identified, measured, and monitored via a specific ocular-vestibular-postural monitoring system along with relevant clinical data. Along with the associated autonomic interactions detected by HRV, the fractal nature of the HRV data may provide useful information on the nature and complexity of central neural controls in relation to physiological [A.P. Blaber, R.L. Bondar, R. Freeman, Coarse grained spectral analysis of HR and BP variability in patients with autonomic failure, American Journal of Physiology 271 (1996) H1555–H1564] and mental stress [Y. Hoshikawa, Y. Yamamoto, Effects of Stroop color-word conflict test on the autonomic nervous system responses, American Journal of Physiology, 1997]. The data presented provide strong evidence that proper biomedical assessment methodologies employed with appropriate technology can lead to better understanding Astronauts’ pre-flight and post-flight biomedical status, necessary to further human exploration in Space on a safe and successful path. [Copyright &y& Elsevier]

The current method of choice for astronauts to treat space motion sickness is an intra-muscular injection of promethazine hydrochloride (PMZ HCl) which is invasive and causes considerable local irritation and discomfort at the site of injection. Intra-nasal delivery is considered a feasible alternative route for administration of medications to treat space motion sickness. The purpose of this research is to develop a PMZ HCl formulation that can be administered intra-nasally without irritation (i.e. leukocyte infiltration) in the nasal epithelium when dosed at PMZ HCl concentrations greater than the cytotoxic limit. The biocompatibility of PMZ HCl was tested in vitro and was shown to be cytotoxic at concentrations greater than 10-5 molar regardless of pH. A controlled-release microencapsulated dosage formulation was developed using spinning disk atomization and release rates for the PMZ HCl microcapsules were determined in phosphate buffered saline. An animal study was conducted to determine the irritation response of rat nasal mucosa when dosed with encapsulated and non-encapsulated PMZ HCl. [ABSTRACT FROM AUTHOR]

Reduction in bone formation may have been the main reason for the lower calcium content of the otoconia after simulated weightlessness in rats. The head-ward distribution of blood volume may explain the morphological changes observed in the middle and inner ears. To observe morphological changes in the vestibular organs and measure the calcium content of otoconia in rats after simulated weightlessness. We used a tail suspension model of simulated weightlessness and then investigated changes in the vestibular organs using scanning electron microscopy and X-ray microanalysis. In comparison to untreated rats, the vestibular otoconia of the rats subjected to simulated weightlessness were small, irregularly shaped or fissured, and were arranged loosely and out of order. In addition, the calcium content of the otoconia was markedly decreased. [ABSTRACT FROM AUTHOR]