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Title: Autogenic-Feedback Training: A Potential Treatment for Orthostatic Intolerance in Aerospace
Crews Postflight orthostatic intolerance has been identified as a serious biomedical problem associated with long-duration exposure to microgravity in space. High priority has been given to the development of countermeasures for this disorder that are both effective and practical. A considerable body of clinical research has demonstrated that people can be taught to increase their own blood pressure voluntarily, and that this is an effective treatment for chronic orthostatic intolerance in paralyzed patients. The current pilot study was designed to examine the feasibility of adding training in control of blood pressure to an existing preflight training program designed to facilitate astronaut adaptation to microgravity. Using an operant conditioning procedure, Autogenic-Feedback Training (AFT), three men and two women participated in four to nine training (15-30 minute) sessions. At the end of training, the average increase in systolic and diastolic pressure, as well as mean arterial pressures, that the subjects made ranged between 20 and 50 mm Hg under both supine and 45o head-up tilt conditions. These findings indicate that AFT may be a useful alternative treatment or supplement to existing approaches for preventing postflight orthostatic intolerance. Furthermore, the use of operant conditioning methods for training cardiovascular responses may contribute to the general understanding of the mechanism of orthostatic intolerance. Title: The Effects of Promethazine on Human Performance, Mood States and Motion Sickness Tolerance Intramuscular (i.m.) injections of promethazine in 25 mg or 50 mg dosages are commonly used to treat space motion sickness in astronauts. The present study examined the effects of i.m. injections of promethazine on neuropsychological performance, mood states, and motion sickness tolerance in humans. Twelve men, mean age 36 + 3.1, in one training (no injections) and three treatment conditions: a 25 mg injection of promethazine, a 50 mg injection of promethazine, and a placebo injection of sterile saline. Each condition, spaced at 7 day intervals, required an 8-10 hour session in which subjects were given four repetitions of 12 performance tasks, and one rotating chair motion sickness tests. On the training day subjects were trained on each task to establish stability and proficiency. On treatment days, the order in which drug or placebo was assigned to subjects was counterbalanced and a double-blind technique was used. Statistically significant decrements in performance were observed on 10 of 12 tasks when subjects were given 25 mg or 50 mg of promethazine as compared to the placebo. Performance decrements were associated with mean blood alcohol dose equivalency levels of 0.085% for 25 mg and 0.13% for 50 mg dosages. The mood scale results showed significant changes in individual subjective experiences with maximum deterioration in the arousal state and fatigue level. When compared to placebo significant increases in motion sickness tolerance were found for both dosages of promethazine. These data suggest that effective dosages of promethazine currently used to counteract motion sickness in astronauts may significantly impair task components of their operational performance. Title: Autogenic-Feedback as a Treatment for Airsickness in High-Performance Military Aircraft: Two Case
Studies The purpose of this paper is to present a detailed description of the physiological and performance responses of two military pilots undergoing a treatment for motion sickness. The treatment used, Autogenic-Feedback Training (AFT), is an operant conditioning procedure where subjects are taught to control several of their autonomic responses and thereby suppress their motion sickness symptoms. Two male, active duty military pilots (U.S. Navy and U.S. Marine Corps), ages 30 and 35, were each given twelve 30-minute training sessions. The primary criterion for success of training was the subject's ability to tolerate rotating chair motion sickness tests for progressively longer periods of time and at higher rotational velocities. A standardized diagnostic scale was used during motion sickness to assess changes in the subject's perceived malaise. Physiological data were obtained from one pilot during tactical maneuvers in a F-18 aircraft after completion of his training. A significant increase in tolerance to laboratory induced motion sickness tests and a reduction in autonomic nervous system (ANS) response variability was observed for both subjects after training. Both pilots were successful in applying AFT for controlling their airsickness during subsequent qualification tests on F-18 and T-38 aircraft and were returned to active flight status. Title: The Effects of Autogenic-Feedback Training on Motion Sickness Severity and Heart Rate Variability In
Astronauts Space motion sickness affects 50 percent of all people during early days of spaceflight. The present study describes preliminary results of a Shuttle flight experiment in which Autogenic-Feedback training (AFT) was tested as an alternative to pharmacological management of this disorder. AFT is a physiological conditioning method which has been used to train people to voluntarily control several of their own physiological responses and thereby suppress motion sickness symptoms. Thirteen subjects participated in this study (four women and nine men) of whom six later flew aboard the Space Shuttle. Of the 13 subjects, 10 were given AFT. Of the six who were designated as flight subjects, three were given treatment and three served as control subjects (i.e., did not receive AFT). All subjects participated in baseline data collection sessions. These sessions included both rotating chair and vertical motion sickness inducing tests, and 12 hour mission simulations. Treatment subjects were given rotating chair motion sickness tests after 2, 4, and 6 hours of AFT. Preflight results showed that AFT produced a significant increase in tolerance to rotating chair motion sickness tests. Further, this increased tolerance was associated with changes in specific physiological responses and reports of reduced malaise. Spectral analyses of heart rate variability revealed that power in the low frequency band (0.005 to 0.05 Hz) decreased after AFT, while power in the mid-frequency band (0.05 to 0.1 Hz) increased. Further, coherence between heart rate and respiration was significantly higher after training. Inflight results showed that two of the three control subjects experienced multiple vomiting episodes on the first mission day, while one control subject experienced only moderate malaise. All control subjects took anti-motion sickness medications for symptom suppression and/or sedation. Of the three treatment subjects, one experienced only mild discomfort, one experienced moderate discomfort and one experienced severe symptoms (vomiting episode on mission day 2). None of the AFT treatment subjects took antimotion sickness (or other) medications. AFT given for control of autonomic activity beneficially influenced inflight measures in treatment subjects and was associated with increased vagal tone. Comparisons of flight to ground simulation data revealed significant differences, (i.e. dramatically reduced inflight ANS activity levels) in all flight crewmembers. Conclusions. These data suggest that AFT may be an effective treatment for space motion sickness, but this is not demonstrated conclusively with the small number of subjects who tested these methods in space (N=3 per group). Additional data inflight (N=8 per group) is necessary for statisically evaluating the efficacy of this treatment. Continuous physiological measurements combined with self-report of symptoms does provide an objective method for examining individually differences in adaptation to spaceflight and the time course of this adaptation. Further, is was possible to clinically predict from the preflight training performance which of the flight treatment subjects would be more resistant and least resistant to symptoms in space. Title: Heart Rate Variability During Early Adaptation To Space A recent report hypothesized that episodes of space motion sickness (SMS) were reliably associated with low frequency oscillations (<0.03 to <0.01 Hz) in heart rate variability. This paper archives a large data set for review of investigators in this field which may facilitate the evaluation of this hypothesis. Continuous recording of electrocardiography (EEG) and other measures were made for 6 to 12 hours per day (waking hours) of six Shuttle crewmembers for the first three mission days of two separate Shuttle flights. Spectral analyses of heart rate variability during approximately 200 h of inflight data is presented. In addition, nearly 200 h of data collected on these same individuals during ground-based tests prior to the mission are presented. The purpose of this publication is to document the incidence of low frequency oscillations of heart rate in four people exposed to microgravity over a period of five days. In addition, this report contains spectral analyses of heart rate data collected on these same individuals during ground-based mission simulations. By achieving these data in this manner, it is our intention to make this information available to other investigators interested in studying this phenomenon. Title: Autonomic Responses to Microgravity The purpose of this report is to describe how changes in autonomic nervous system responses may be used as an index of individual differences in adaptational capacity to space flight. During two separate Spacelab missions, six crewmembers wore an ambulatory monitoring system which enabled continuous recording of their physiological responses for up to 12 h a day for 3 to 5 mission days. The responses recorded were electrocardiography, respiration waveform, skin conductance level, hand temperature, blood flow to the hands and triaxial accelerations of the head and upper body. Three of these subjects had been given training, before the mission, in voluntary control of these autonomic responses as a means of facilitating adaptation to space. Three of these subjects served as controls, i.e., did not receive the training but took anti-motion sickness medication. Nearly 300 h of flight data are summarized. These data were examined using time-series analyses, spectral analyses of heart rate variability and analyses of variance. Information was obtained on responses to space motion sickness, inflight medications, circadian rhythm, workload and fatigue. Preliminary assessment was made on the effectiveness of self-regulation training as means of facilitating adaptation, with recommendations for future flights. Title: A Potential Treatment for Post-Flight Orthostatic Intolerance in Aerospace Crews: Autogenic-Feedback
Training Postflight orthostatic intolerance has been identified as a serious biomedical problem associated with long duration exposure to microgravity in space. High priority has been given to the development of countermeasures for this disorder which are both effective and practical. A considerable body of clinical research has demonstrated that people can be taught to increase their own blood pressure voluntarily and that this is an effective treatment for chronic orthostatic intolerance in paralyzed patients. The present pilot study was designed to examine the feasibility of adding training in control of blood pressure to an existing preflight training program designed to facilitate astronaut adaptation to microgravity. Using an operant conditioning procedure, Autogenic-Feedback Training (AFT), three men and two women participated in four to nine (15-30 training sessions). At the end of training, ranged between 20 and 50 mm Hg under both supine and 45O head-up tilt conditions. These findings suggest that AFT may be a useful alternative treatment or supplement to existing approaches for preventing postflight orthostatic intolerance. Further, the use of operant conditioning methods for training cardiovascular responses may contribute to the general understanding of the mechanisms of orthostatic intolerance. Title: Effects Of Autonomic Conditioning On Motion Sickness Tolerance This paper presents case studies of nine shuttle crewmembers (prime and alternates) and one U.S. Navy F-18 pilot, as they participated in all preflight training and testing activities in support of a life sciences flight experiment aboard Spacelab-J, and Spacelab-3. The primary objective of the flight experiment was to determine if Autogenic-Feedback Training (AFT), a physiological self-regulation training technique would be an effective treatment for motion sickness and space motion sickness in these crewmembers. Additional objectives of this study involved examining human physiological responses to motion sickness of Earth and in space, as well as developing predictive criteria for susceptibility tp s[ace motion sickness based on ground-based data. Comparisons of these crewmembers are made with a larger set of subjects from previous experiments (treatment and 'test-only' control subjects). This paper describes all preflight methods, results and proposed changes for future flight tests. |
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