Organization/Location Investigators
Purpose Please note that reviewers have recommended an additional 2 groups that would serve as a control and/or alternative comparison for AFTE. This design would better control for ameliorative “expectation effects,” in AFTE subjects. Further, reviewers recommended increasing the N to 45 (15 subject per group). The design now consists of 3 groups: 1. No treatment control – that attend baseline and 3 sleep deprivation sessions (36 hours ea) only; 2. AFTE treatment group, that attend all baseline and sleep deprivations sessions – as well as 12 AFTE sessions for training control of autonomic responses; and 3. Neural feedback group, same as AFTE group but will receive 12 training sessions in control of electroencephalogorapy (EEG). Background Psychological tension, sleep disturbances and psychosensory discomforts (i.e., vestibular-autonomic reactions or space motion sickness, perceptual and sensory illusions) are the most typical states that affect crew members neuropsychological adaptation to flights of up to 15 days in duration. These adverse conditions or states, occurring separately or together, essentially determine the formation of more generalized states (e.g., psychological fatigue or exhaustion) which may occur during extended duration flights” (2). Cumulative fatigue is indicative of “asthenia”, which describes an abnormal state marked by weakness, increased tendency for fatigue, irritability and disorders of attention and memory. This condition constituted a risk factor with regard to psychological and professional reliability of crewmembers, and has been confirmed by observations of incidences of impaired operational performance and conflict among crewmembers (3-5). Russian scientists have developed a set of methods for describing functional state: the physiological and psychological state during which performance is highest. An index representing optimum performance can be calculated using both performance and physiological indices. These physiological indices include heart rate, arithmetic mean of the duration of the cardiac cycle, respiration rate, galvanic skin response, and electromyogram (6-8). In general, those individuals whose physiological indices were elevated substantially above group means were also those individuals who performed poorly (9). During performance of assigned tasks for a 26-hour uninterrupted period physiological changes tend to precede associated performance decrements (10). In a study of sensorimotor performance capacity during the initial period of weightlessness, five cosmonauts decreased the quality of their performance. Simultaneously, heart rate increased from 15-35%. As cosmonauts participated in more sessions, the quality and accuracy of performance increased, with heart rate decreasing to baseline levels (11). The cosmonaut selection process in addition to psychiatric interviews and psychological testing includes crew monitoring during training and mission simulations for tolerance, ability to self-regulate mental, somatic and autonomic functions (1). The inclusion of muscle relaxation and autonomic conditioning techniques (i.e., Autogenic Training and biofeedback) in Russian training programs are aimed at preventing the occurrence of psychologic disability during long duration spaceflight.” Autogenic Training (AT) (12) was developed as a psychotherapy for anxiety disorders, and involves self-suggestion exercises and imagery of specific somatic sensations. The effects of this training are increased stability of cardiovascular parameters with simultaneous improvements on various psychomotor skills. Russian research suggests that the process of autonomic conditioning may have direct effect on CNS function as well. In a study on 18 women factory workers (13), subjects were trained in AT and biofeedback for muscle relaxation. Self-reports showed that general well being increased by 13% and reports of acute fatigue decreased by 32%. Physiological data showed “…a significant tendency for heart rate and blood pressure to normalize”, (i.e., reduced range and response variability). Measurements of various psychomotor skills throughout a working day showed clear improvements from start to finish of the program.” In two other studies (10), subjects participated in 56-72 hour sessions of uninterrupted work, including perceptual tasks, information processing and decision- making. Subjects previously given training in AT were required to practice AT for 15 minutes at 6 hr intervals. Operators following these procedures showed less pronounced changes in heart rate than control group (i.e., no treatment) counterparts. Electroencephalographic (EEG) data of the AT-trained operators showed higher levels of beta activity throughout the period with theta activity increasing only after the 36th hour of work. The authors interpreted these results as showing that AT slows the development of inhibition in the CNS and describe AT operators as having compensated for fatigue. Although the AT-trained operators do show a task performance decrement after the 39th hour, their performance was 17% better than operators in the control group. Further, it was concluded that physiological changes tended to precede associated performance decrements by 1-4 hours. The literature on CNS research supports the Russian assertion that autonomic training may influence EEG and that observed performance improvements are associated with changes in CNS function. EEG spectral correlates have been found of different functional states, like arousal and vigilance, and as a task specific index of mental activity (14,15). The association of low frequency EEG rhythms and performance decrements has also been reported previously (16-18). The analyses of time trends of EEG rhythms or coherence, reveals reproducible changes during relaxation training (19), and decades of research have shown that people can readily be trained to directly self-regulate EEG activity with biofeedback (20). |
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