科里奥氏加速度刺激诱发运动病和垂直眼震的关系

本文用Coriolis 加速度刺激检查了56名飞行员运动病敏感性。用数字打分法判断运动病严重程度,结果指出运动病发病者有25人(占44.6%)正常者有31人(占55.4%)。观察到coriolis 刺激可诱发出垂直眼震,并用简化模拟参数衰减率定量分析,发现运动病组与正常组垂直眼震衰减率有显著差异。本方法和其评定标准为预测航天员的运动病敏感性提供了参考。     

飞行员前庭剌激眼震电图的观察

为探讨前庭刺激方式、强度、运动病症状与ＥＮＧ变化的关系，对６２名飞行人员分成Ⅰ和Ⅱ两组（各３１名），用科氏加速度及角加、减速度的不同刺激强度诱发眼震（ＥＮＧ）进行分析。结果：科里澳利加速度刺激诱发眼震慢相波幅、快相波幅、慢相速度和快相速度值低。而角加、减速度刺激诱发这四项参数值高；柯氏刺激强度大，运动病症状重，刺激强度小症状轻；症状与旋转眼震的慢相波幅、慢相速度、快相速度和频率无关，与快相波幅相关。     

军事飞行员前庭诱发肌性电位临床正常值的建立

目的记录中国空军战斗机飞行员前庭诱发肌性电位（VEMP）参数,以便建立战斗机飞行员的正常值数据。方法 40名现役健康战斗机飞行员作为受试者,采用短纯音双侧给声双侧进行了记录。记录40名健康飞行员VEMP的p13和n23波潜伏期、p13/n23波间幅度以及双侧幅度不对称比,以获得正常值数据。结果 40名健康飞行员均记录到VEMP。p13波的潜伏期为（13.50±1.20）ms;n23波的潜伏期为（21.35±1.60）ms;p13/n23波间幅度为（169.70±38.50）μV;双侧幅度的不对称比（AR）为0.12±0.11。结论本研究建立了军事飞行员VEMP参数标准的常模,为促进VEMP在军事飞行员医学选拔鉴定中的应用,提供了实验依据。     

Eye movements to yaw, pitch, and roll about vertical and horizontal axes: adaptation and motion sickness

BACKGROUND: In the search for parameters to predict motion sickness that can be measured in the laboratory, we performed a longitudinal investigation in aviators. Since the vestibular system is involved in the generation of motion sickness as well as eye movements, vestibulo-ocular reflex (VOR) parameters seemed relevant. We investigated three topics: 1) the effect of axis orientation and its orientation to gravity on the VOR; 2) changes in VOR parameters depending on flight experience; and 3) differences in VOR parameters in aircrew with high and low susceptibility to motion sickness. HYPOTHESIS: Nystagmus decay after angular velocity steps would be faster for non-susceptible and trained aviators. METHODS: We recorded eye movements evoked by angular on-axis velocity steps (+/- 90 degrees x S(-2), to and from 90 degrees x S(-1)) in yaw, pitch, and roll, about both the Earth vertical and Earth horizontal axes in 14 subjects with a low susceptibility to motion sickness. These data were compared with those of 10 subjects with a high susceptibility. RESULTS: Horizontal axis rotations are nauseogenic. We found that during (per) and post-condition, left- and rightward rotation responses were equal, and the orientation with respect to gravity did not alter the basic nystagmus decay, apart from a sinusoidal modulation. Moreover, pitch and roll rotations show equal nystagmus decays, significantly faster than for yaw; yaw and pitch peak velocities were equal and were larger than for roll. With regard to changes in VOR parameters depending on flight experience, we found that repeated vestibular stimulation reduced nystagmus decay as well as the otolith modulation. With respect to the changes in VOR parameters and motion sickness susceptibility, we found that subjects highly susceptible to motion sickness showed a slower decay of nystagmus with a larger peak velocity than less susceptible subjects. CONCLUSIONS: Group averages indicate a difference in eye movement parameters, only in yaw, depending on flight experience; and between subjects with low and high susceptibility to motion sickness. The involvement of the velocity storage mechanism as realized by an internal model is given as a plausible explanation.     

Incidence of airsickness among military parachutists

This study describes the incidence of airsickness among military parachutists and analyzes the factors involved in its occurrence. Each of 45 healthy male subjects (28 students and 17 advanced parachutists) was studied. Each student participated in five parachute-jump exercises (one daily) and each advanced parachutist participated in one exercise only (proficiency). A questionnaire used for the diagnostic evaluation of motion sickness symptoms was completed by the subjects after each training exercise. A positive diagnosis of airsickness was established for 64% of the students on their first jump and for 35% of the advanced paratroopers on their proficiency jump. By the fifth jump, only 25% of the students experienced airsickness. This suggests that some students developed tolerance to airsickness after five consecutive exposures to inflight vestibular stimulation. Airsickness among student and advanced paratroopers occurred during the transport flight. This can be attributed to vestibular stimulation resulting from the aircraft maneuvers and inflight air turbulence.     

Comparative assessment of vestibular, optokinetic, and optovestibular stimulation in the development of experimental motion sickness

The contribution of vestibular, optokinetic, and optovestibular stimulation to experimental motion sickness was evaluated in 29 volunteer subjects. Vestibular stimulation (Coriolis effect) was found to induce the most significant vestibular-autonomic disorders. Optokinetic stimulation (pseudo-Coriolis effect) and optovestibular stimulation could provoke such disorders only in susceptible subjects. In quantitative terms, optokinetic and optovestibular stimulation were less effective than vestibular Coriolis stress. Nystagmic reactions of susceptible subjects to the three types of stimulation differed significantly from those of tolerant subjects. This may be important from the theoretical point of view because susceptibility to motion sickness and responses to vestibular and optokinetic stimulation may be universal and associated with the general CNS mechanism, i.e. inhibition mechanism. The identified correlation between the duration of postoptokinetic illusion and motion sickness susceptibility may be used to differentiate susceptible and tolerant subjects.     

Vestibular habituation in flightcrew.

Vestibular habituation is a general reaction to any repetitive sensory stimulation. It can be characterized by four main features: acquisition, retention, loss or dishabituation, and transfer. This study concerns three groups of subjects: The first group consists of a) 27 pilots at present serving in the French Air Force, b) 12 pilots at present serving in the major civil airlines, c) 8 navigators, radio-navigators, and crew mechanics, some of whom are flying club pilots, and d) 3 professional pilots trained in flying clubs. All of these subjects had more than 2000 h flying time. They were from 27 to 50 years old. The second group consists of airline stewards. The third group consists of trainee pilots still in flying school. All of these subjects were examined for their suitability, in particular undergoing a damped swing test. The first oscillation was in an anticlockwise direction and the damping extended over 20 periods. The following parametre was measured: the ratio of total left nystagmus frequency to total right nystagmus frequency. In "normal" control subjects the ratio is greater than 1. The results were: The first group: In 41 out of 50 subjects, the ratio of left tremors frequency to right tremors frequency was less than or approximately equal to 1. In the second group: The results showed no significant differences in comparison with a control group of subjects. In the third group: Zero flying time--the results were identical with those of control subjects; 40 h flying time--the ratio approached 1; 100 h flying time--the ratio was less than 1. Vestibular habituation, that is inversion of the preponderance of the total number of left tremors over the total number of right tremors, was observed in the technical flightcrew. The appearance of this inversion during the pilots' training was studied and its retention tested. This test for showing vestibular habituation may be of use for monitoring the function of equilibrium and the development of habituation during flight training. In this report, we shall first review the definition and characteristics of vestibular habituation, and the main body of recent work on this phenomenon in flightcrew. Our own findings will be then presented.     

Some influences of vision on susceptibility to motion sickness.

Two experiments were performed to evaluate the influence of vision on susceptibility to motion sickness during exposure to constant patterns of vestibular stimulation. The motion profile involved accelerating subjects at 20 degrees/s2 to 300 degrees/s, maintaining them at that constant velocity for 30 s, and decelerating them to a rapid stop in about 1.5 s. The number of stops tolerated by a subject before reaching the motion sickness endpoint served as his score. In Experiment 1, subjects were tested twice with their eyes open and twice with their eyes blindfolded. They tolerated fewer sudden stops when permitted sight of the experimental chamber. In Experiment 2, the effect of having the eyes-open or closed at different stages of the motion profile was evaluated. Having the eyes open during any stage of the test was more stressful than having the eyes closed, but this was especially true during the sudden stops. The findings are discussed in terms of their general implications for understanding a) situations in which vision alone elicits symptoms of motion sickness, and b) situations involving vestibular stimulation where vision heightens susceptibility.     

The effects of TTS-scopolamine, dimenhydrinate, lidocaine, and tocainide on motion sickness, vertigo, and nystagmus

The effects of TTS-scopolamine, dimenhydrinate, lidocaine, and tocainide on motion sickness and vertigo and on caloric and postrotatory nystagmus were evaluated in healthy volunteers. TTS-scopolamine was administered transdermally (delivering approximately 10 micrograms X h-1 scopolamine base) and 100 mg dimenhydrinate orally. Lidocaine and tocainide were administered intravenously (average plasma concentration of lidocaine 6 mol X L-1 and of tocainide 20 mol X L-1). TTS-scopolamine and dimenhydrinate significantly reduced vertigo induced by calorization of the ears, nausea provoked with Coriolis maneuvre, and nystagmus in caloric and rotatory tests. During treatment with lidocaine and tocainide no alleviation of vertigo and nausea was observed. Caloric nystagmus was reduced but rotation induced nystagmus was virtually unchanged. Presumably the motion sickness drugs act at the brain stem where TTS-scopolamine and dimenhydrinate have their target cells in the vestibular nuclei. Furthermore, the alleviation of motion sickness was linked to a decline of nystagmus. Lidocaine and tocainide, the action of which in vertigo and nausea in patients is proposed to be on the vestibular end organs and the supratentorial brain structures, consistently failed to alleviate motion sickness.     

飞行学员Coriolis加速度刺激时的胃电图观察

目的观察和比较飞行学员与地勤人员在Ｃｏｒｉｏｌｉｓ加速度刺激时的前庭植物神经反应。方法在平静状态和Ｃｏｒｉｏｌｉｓ加速度刺激时，描记３２名飞行学院经过检验飞行后的飞行学员和３２名地勤人员的胃电图（ＥＧＧ），同时记录诱发性运动病的症状。结果飞行学员和地勤人员相比，平静状态的ＥＧＧ频率和振幅及加速度刺激时ＥＧＧ频率均无明显差异。但Ｃｏｒｉｏｌｉｓ加速度刺激时飞行学员的ＥＧＧ振幅及诱发性运动病症状的发生率明显低于地勤人员。结论经过选飞和检验飞行训练的飞行学员其前庭植物神经反应的稳定性高于地勤人员。     

Effects of microgravity on the interaction of vestibular and optokinetic nystagmus in the vertical plane.

The extent to which the slow phase velocity (SPV) of nystagmus elicited by a vertical optokinetic stimulation with constant velocity could be modulated by sinusoidal angular motion in the vertical plane was investigated under normal gravity condition and during the microgravity period of parabolic flight. In normal gravity, when the angular head motion and the optokinetic stimulation were in the same direction, the peak SPV was slower than the velocity of the optokinetic display. When the head motion and the optokinetic stimulation were in opposite directions, the peak SPV was equal to the velocity of the optokinetic display. In microgravity, the peak SPV was approximately equal to the velocity of the optokinetic display when head rotation and optokinetic stimulation were in the same direction, and was faster than the velocity of the optokinetic display when head rotation and optokinetic stimulation were in opposite directions. In addition, the interaction of vestibular and optokinetic nystagmus was found to be non-linear in microgravity, especially when the optokinetic stimulation was directed downward. These results suggest an interaction between the vestibular and the optokinetic systems modulated as a function of the gravitational state, and support the observation that visual input is more effective in reducing sensory conflict experienced in microgravity.     

Some effects of sleep loss on vestibular responses

This study assessed ocular nystagmus and motion experiences of men exposed to both simple (angular acceleration) and complex (Coriolis) vestibular stimulation during approximately 55 h of sleep loss. Control and sleep-deprived groups each comprised 10 young men. Angular accelerations and Coriolis stimulation (30 degrees head movements during CW rotation) were accomplished in darkness in an enclosed Still-Werner rotating device. Nystagmus and motion experiences (turning, "diving," and "climbing") were recorded throughout each session. Tests were given at 0900 and 1300 on each of 3 successive days. Subjects ingested 10-mg of d-amphetamine at 1200 on Day 3. During simple stimulation, the sleep-deprived group showed regular declines across sessions in slow phase and duration measures of nystagmus but fast phase ocular frequency and measures of experienced turning resisted declines until the final predrug session; subjective response latencies increased with sleep loss. Declines during rotation for ocular output and measures of perceived displacement during rightward head tilts ("climbing" sensation) were obtained for the sleep deprived, but both nystagmus and sensations were unaffected by return (leftward) movements of the head ("diving" sensation). d-Amphetamine had no consistent effect on responses of control subjects, but significantly increased nystagmus and elevated (but not significantly) measures of turning experiences for the sleep deprived.     

Vestibular function and interanalyzer interaction following space flight

This paper presents the results of pre- and post-flight vestibular examinations using single and combined vestibular, optokinetic, proprioceptive, postural tests and cerebellar coordination tests. After extended flights most crewmembers showed spontaneous, position and positional nystagmus that points to vestibular dysfunction. The methods developed by the authors helped differentiate mechanisms of post-flight vestibular dysfunctions: in Group 1 subjects spontaneous nystagmus parameters varied during all tests; in Group 2 subjects they varied only in response to active tilt tests; in Group 3 subjects they varied only in response to vestibular, optovestibular and proprioceptive stimulation; and in Group 4 subjects they varied only in response to proprioceptive optovestibular stimulation and cerebellar coordination tests. Individual patterns of the above changes are associated with different pathways of adaptation of the vestibular function that depend on the involvement of various structures and compartments of the central nervous system.     

特发性一侧前庭功能异常与航空航天飞行

目的　探讨特发性一侧性前庭功能异常与航空航天飞行的关系。　方法　分析30例飞行人员特发性一侧前庭功能异常的病例。　结果　右前庭功能减弱者19例，左前庭功能减弱者9例，左前庭功能丧失者2例；11例飞行合格，19例永久停飞。　结论　一侧前庭功能异常可因飞行错觉和/或运动病反应而危及飞行安全；航空航天飞行也能诱发或加重前庭功能损害。     

Aerobic fitness and susceptibility to motion sickness

Susceptibility to motion sickness was evaluated in 29 males having high, moderate, and low levels of aerobic fitness. Subjects underwent Coriolis (cross-coupled) vestibular stimulation on a Stille-Werner rotator during a 10 min modification of the Brief Vestibular Disorientation Test (BVDT). Variables evaluated were: spin time before aborting (ST), heart rate (HR), respiratory rate (RR), mean skin temperature (Tsk), subject observation values (SV), and observation values (OV). Aerobic fitness and ST for the total population were inversely related (r = -0.506, p less than 0.01). Difference in ST was significant (F(2.26) = 6.67, p less than 0.01), with the high aerobic group demonstrating an earlier ST and greater SV than the low aerobic group (Student-Newman-Keuls; alpha = 0.05). Analysis of HR, RR, and Tsk between groups revealed limited differences. Based on these data, men with high aerobic fitness appear to have an increased susceptibility to motion sickness.     

The role of smooth pursuit in suppression of post-rotational nystagmus

Some authors have suggested that the smooth pursuit system (SPS) may be responsible for nystagmus suppression when a small visual target--stationary with respect to a subject receiving vestibular stimulation in the dark--is presented. Under five experimental conditions, post-rotational vestibular stimulations were combined in different ways with the presentation of a small visual target. The oculomotor responses of 15 normal subjects were recorded and analyzed. The characteristics of nystagmus suppression (latency, dynamics, and nonlinear behaviour) seem to be consistent with the hypothesis of SPS participation. A nonlinear mathematical model of the interaction between vestibulo-ocular reflex and SPS is presented. Computer simulation of the experimental conditions considered in this study provides theoretical results which closely approximate the actual experimental data.     

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

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.     

Visually-induced sickness in normal and bilaterally labyrinthine-defective subjects.

A group of nine normal subjects (with no overt vestibular dysfunction) and a group of 6 bilaterally labyrinthine-defective subjects were exposed to a visual field rotating about an Earth-horizontal axis (orthogonal to the gravity axis). The visual stimulus was provided by a 3-m diameter sphere with random dots rotating at 30, 45, and 60 degrees per second (degree/s) about the stationary subject's roll, pitch and yaw axes. The subject's head was positioned at the center of the sphere such that it experienced apparent motion in all three axes. Results indicated that in the normal group, symptoms of motion sickness were reported in 21 of 27 test-trials. When labyrinthine-defective subjects were exposed to the roll and pitch stimulus, no sickness symptoms were reported or observed. These results strongly suggest that the vestibular system is necessary for sickness induced by moving visual fields.     

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

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.     

Motion sickness susceptibility and aerobic fitness: a longitudinal study

A longitudinal study evaluated the susceptibility to motion sickness in initially unfit subjects before and after an endurance training program. Motion stimulation was provided by the Precision Angular Mover, in which the subject was tumbled head over heels about an Earth-horizontal axis at 20 cycles per minute in darkness. Maximal aerobic power and the blood lactate response to submaximal exercise were evaluated with cycle ergometry. The training program caused significant improvements in VO2max and endurance capacity, and a significant decrease in percent body fat. There was a significant (p less than 0.0125) increase in motion sickness susceptibility after the physical training, suggesting that increased physical fitness caused increased susceptibility to motion sickness in some individuals.