短臂离心机不同转速暴露时飞行员前庭性错觉及前庭自主神经反应对比

目的 观察飞行员短臂离心机不同转速暴露时前庭性错觉诱发效果及前庭自主神经反应情况,寻求利用短臂离心机进行前庭性错觉地面模拟训练时的合适转速. 方法 90名健康歼击机飞行员根据不同离心机转速（21、30、37 r/min）分为3组,每组30人.参考电动转椅的前庭性错觉模拟训练方案,采用适合短臂离心机运行特点的前庭性错觉诱发方法,在SAC-Ⅲ型短臂离心机上进行反旋转错觉及科里奥利错觉模拟.每组仅进行1个转速下的错觉模拟.对比不同转速下飞行员错觉诱发情况及前庭自主神经反应情况. 结果 ①离心机不同转速时飞行员反旋转错觉、科里奥利翻转错觉（包括头右旋及左旋时）及科里奥利旋转错觉（包括头前倾和回靠时）的诱发率差异均有统计学意义（X2 ＝6.477～20.000,P＜0.01或P＜0.05）.21 r/min暴露时的诱发率低于30 r/min和37 r/min暴露时（x2＝0.073～0.351,P＞0.05）.②3种转速下,离心机反旋转错觉形态表现相同,但错觉强度随离心机转速加快而增强.科里奥利翻转错觉形态表现稳定,3种转速下其表现分布差异无统计学意义（（x2＝0.090、0.056,P＞0.05）.科里奥利旋转错觉形态表现较为多样,3种转速下头前倾时错觉形态表现分布差异无统计学意义（X2＝1.810,P＞0.05）;头回靠时错觉发生例数较少,未行统计学处理.③3种转速下前庭自主神经反应评分分值随转速增加而增高,且差异有统计学意义（F＝ 15.058,P＜0.01）;37 r/min暴露时的分值明显高于21 r/min和30 r/min暴露时（P＜0.01或P＜0.05）;30 r/min与21 r/min暴露时的分值差异无统计学意义（P＞0.05）. 结论 臂长2 m的短臂离心机上以30 r/min暴露时,飞行员前庭性错觉的诱发率较高,且前庭自主神经反应较轻,此转速用于飞行人员前庭性错觉的地面模拟训练较为合适.     

Short-term vestibular responses to repeated rotations in pilots

INTRODUCTON: It has been suggested that vestibular function in pilots differs from that of non-pilots. METHODS: Short-term vestibular responses to repeated rotations were explored in pilots and non-pilots using a rotating chair. Vestibulo-ocular reflex tests were done in 30 pilots (VOR-P) and 30 non-pilots (VOR-NP) at rotation frequencies of 0.01, 0.02,0.04, 0.08, 0.16, and 0.32 Hz. In a separate experiment, VOR tests were done at 0.16 Hz before and after four successive velocity-step tests in twenty-five pilots (STEP-P) and their results were compared with the results of twenty-five non-pilots (STEP-NP) who were studied earlier. RESULTS: VOR-P exhibited normal VOR gains (mean values 0.47, 0.57, 0.63, 0.69, 0.67, and 0.74, respectively, for the frequencies listed above) compared with those of VOR-NP (0.48, 0.54, 0.59, 0.67, 0.72, and 0.79). VOR gain at 0.16 Hz showed little change in STEP-P (0.64 +/- 0.04 to 0.58 +/- 0.032), while it increased in STEP-NP (0.59 +/- 0.03 to 0.78 +/- 0.06). DISCUSSION: VOR gain may be a useful measurement for differentiating pilots' vestibular function from that of non-pilots. After-rotary VOR may be suppressed in pilots.     

飞行员地面错觉模拟及其反应参考值

目的 验证地面错觉训练方案在我军飞行员航空医学训练中应用的可行性,为评价地面错觉模拟训练效果提供参考值.方法 在我军现有错觉模拟训练方案基础上,参照北大西洋公约组织推荐的地面错觉模拟训练方案,依据现有的设备,对80名健康飞行员进行地面错觉模拟训练.在VTS-0型电动转椅上进行躯体旋动错觉、科里奥利错觉模拟,在VTS-Ⅲ型前庭功能检查系统上进行相对运动性错觉、自动性错觉模拟,观察错觉的诱发情况,并进行相应错觉反应参数（错觉持续时间、潜伏期）的记录.结果 躯体旋动错觉、科里奥利错觉、相对运动性错觉和自动性错觉的诱发率分别为100.0%、90.7%、72.5%和49.2%.前庭性错觉的诱发率要大于视性错觉（χ2=5.01,P〈0.05）.飞行员躯体旋动错觉、科里奥利翻转错觉、科里奥利滚转错觉的持续时间分别为（8.4±4.5）s、（4.9±2.3） s、（5.4±3.0） s;相对运动性错觉、自动性错觉的潜伏期分别为（34.8±19.0） s、（42.8±15.2） s.5种错觉反应数据的参考值分别为：躯体旋动错觉持续时间≤17.4 s,科里奥利滚转错觉持续时间≤11.4 s,科里奥利翻转错觉持续时间为0.3～9.5 s,相对运动性错觉潜伏期≤72.8 s,自动性错觉潜伏期为12.4～73.2 s.结论 立足现有训练装备,我军飞行员躯体旋动错觉、科里奥利错觉、相对运动性错觉及自动性错觉的地面模拟训练方案是有效的、可行的.5种错觉反应数据的参考值可望为飞行员地面错觉模拟效果评价提供依据.     

垂直半规管功能检查研究进展及其在军事飞行员中的应用

目的对垂直半规管功能检查方法及在战斗机飞行员中的应用前景进行综述。资料来源与选择该领域的相关研究论文和综述。资料引用国内外公开发表的论文和综述25篇。资料综合对目前国内外常用的五项垂直半规管功能检查方法及其在军事飞行员中的应用进行分析和总结。结论旋转试验、甩头试验、冷热试验、旋转知觉测试、主动头旋转测试是5项常用的垂直半规管功能检查方法,在战斗机飞行员前庭功能的全面评估中必将发挥越来越重要的作用。     

Simulator-induced spatial disorientation: effects of age, sleep deprivation, and type of conflict

INTRODUCTION: Spatial disorientation mishaps are greater at night and with greater time on task, and sleep deprivation is known to decrease cognitive and overall flight performance. However, the ability to perceive and to be influenced by physiologically appropriate simulated SD conflicts has not previously been studied in an automated simulator flight profile. METHODS: A set of 10 flight profiles were flown by 10 U.S. Air Force (USAF) pilots over a period of 28 h in a specially designed flight simulator for spatial disorientation research and training. Of the 10 flights, 4 had a total of 7 spatial disorientation (SD) conflicts inserted into each of them, 5 simulating motion illusions and 2 involving visual illusions. The percentage of conflict reports was measured along with the effects of four conflicts on flight performance. RESULTS: The results showed that, with one exception, all motion conflicts were reported over 60% of the time, whereas the two visual illusions were reported on average only 25% of the time, although they both significantly affected flight performance. Pilots older than 35 yr of age were more likely to report conflicts than were those under 30 yr of age (63% vs. 38%), whereas fatigue had little effect overall on either recognized or unrecognized SD. DISCUSSION: The overall effects of these conflicts on perception and performance were generally not altered by sleep deprivation, despite clear indications of fatigue in our pilots.     

Results of a study of vestibular function and space perception among members of the crew of the first and second "Sal'iut 6" space station expedition

The results of studies of the vestibular function and spatial perception function in crewmembers of long-term (96- and 140-day) space missions aboard Salyut-6 are presented. Similar changes and individual variations are revealed. All the cosmonauts have shown the following changes: increased reactivity of the otolith organ, decreased sensitivity of the cupular system, asymmetry of most parameters studied, and illusory reactions inflight, individual reactions are as follows: level of changes, dynamics and time of recovery, development of vestibulo-vegetative symptomocomplex during early adaptation to zero-g, signs of decline in vestibulo-vegetative tolerance postflight, and changes in reciprocal relations between the otolith organ and semicircular canals.     

Visual field influence on manual roll and pitch stabilization

Human control performance in nulling perceived tilt angles was investigated for combinations of pseduo-random vestibular disturbances and different waveforms of low frequency wide visual field motions. For both roll and pitch axes, subjects tilted the trainer in which they were seated in the direction of field rotation. This visual bias was much stronger for pitch backwards with upward field rotation. Frequency response analysis showed the dominance of visual cues at low frequencies (below 0.06 Hz) and the reliance on vestibular information in the high frequency range for both axes. Models suggest that operator balancing responses at high frequencies are mainly processed by the semicircular canals rather than the otolith organs. The results also suggest that the subject tends to rely less on the otolith organs for pitch perception than for roll.     

空军飞行员飞行错觉后反应分析

目的 掌握现阶段空军飞行员发生飞行错觉后反应状况,以期制定相应对策. 方法 运用"飞行错觉水平量表"对来院疗养的1275名空军飞行员进行飞行错觉问卷调查. 结果 有效量表1221份,飞行错觉总发生率为91.5%,发生错觉后看仪表不能克服的占8.1%,发生错觉后影响操纵的占32.7%,发生了错觉不知道的占6.9%,发生错觉后不能识别周围环境的占1.4%,出现不适症状的占56.6%.歼击机、强击机飞行员飞行错觉后的反应水平明显高于其他机种(P＜0.05).结论 空军飞行员飞行错觉后反应影响飞行安全,急待建立飞行错觉系统训练体系,减少飞行错觉后反应发生,降低飞行错觉反应水平. Abstract： Objective To investigate the Air Force pilots' response to the flight illusion for finding countermeasures. Methods A questionnaire entitled" the level scale of flight illusion" was inquired from 1275 pilots. Results The incidence of flight illusion was 91. 5% by analyzing 1221applicable replies. Among which even 8. 1% pilots could not overcome the illusions by observing instruments. 32.7% pilots reported illusion caused difficulties on aircraft control while 6.9% and 1.4% pilots respectively showed unawareness of illusion and lost the awareness of environment when illusion happened. 56. 6% pilots appeared discomfort. Fighter and attacker pilots showed stronger response than the other type of aircrafts' (P＜0.05). Conclusions Pilot's negative responses to flight illusions have effectively influenced flight safety. It is suggested to build up corresponding training system to control the pilot's negative response to flight illusions.     

Distortion product of otoacoustic emissions as a sensitive indicator of hearing loss in pilots

BACKGROUND: When the ear is presented with two simultaneous pure tones, the cochlea produces intermodulation products called distortion product otoacoustic emissions (DP-OAEs). When cochlear function is affected by noise or ototoxic drugs, DP-OAEs decrease in amplitude or disappear. The aim of this study was to investigate whether DP-OAEs are a sensitive indicator of hearing loss in pilots, for whom flying time presumably correlates with exposure to steady noise. METHODS: Subjects were 105 pilots, ages 25-44 yr, with flying times of 500-3500 hours. Pilots were divided into three groups according to their flying time and age-matched against control subjects (non-pilots) with normal hearing with no history of occupational exposure to noise. All subjects were tested by pure-tone audiometry, tympanometry, and measurement of DP-OAEs. RESULTS: DP-OAEs were significantly different among the three pilot groups, decreasing gradually at 8 frequencies with flight time. For high frequency tones (F2 7966 and 5623 Hz), age and noise were cofactors. However, 11% of the pilots in this study showed resistance to noise-induced hearing loss. DISCUSSION: DP-OAEs are a sensitive measure for monitoring early noise-induced hearing loss in pilots. Accumulating flight hours, presumed to involve steady noise exposure, initially affected high-frequency hearing, then progressed to affect middle and low frequency hearing with increased flight time. There is individual variability in susceptibility and resistance to noise-induced hearing loss in humans.     

Vestibulo-ocular responses in man to +Gz hypergravity

The influence of high +Gz gravito-inertial force on the vestibular system in man was investigated in a 4-m centrifuge with a freely swinging gondola. The Gz profile was: acceleration +0.2 Gz/s, +3 Gz sustained for 3 min, deceleration -0.2 Gz/s. The subject was exposed to this profile under two conditions in randomized order: facing forward and facing backward. Under these conditions, the effective angular velocity in the plane of the vertical semicircular canals is opposed. Adding the slow phase velocity responses from these conditions yields the Gz effect only; subtracting yields the angular velocity effect only. Vertical vestibular nystagmus was analysed in five subjects. Results indicate that +3 Gz induced a subject-dependent vertical nystagmus with slow phase downwards. The average amplitude of this nystagmus reached a maximum of 27 degrees/s at 16 s from G onset, and was 11 degrees/s after 3 min of sustained +3 Gz. The vestibular stimulation by +Gz could result in false subjective perception of attitude, and play a major role in spatial disorientation in flight.     

高性能战斗机飞行员前庭习服训练效果观察

目的 通过前庭习服训练,提高高性能战斗机飞行员前庭稳定性,以降低空晕病的发生.方法 应用VTS-0型电动转椅对45例前庭稳定性评定等级为D、E级的高性能战斗机飞行员进行每天1次,持续2周的前庭习服训练,记录训练前后前庭稳定性评定中的Coriolis加速度耐受值及训练耐受时间.结果 训练后,45例高性能战斗机飞行员的前庭稳定性较训练前有不同程度提高,均达到C级以上,Coriolis加速度耐受值和训练耐受时间明显提高,且有统计学意义(t=14.55、12.66,P＜0.01).结论 前庭习服训练对提高高性能战斗机飞行员的前庭稳定性效果明显. Abstract： Objective To explore the effects of vestibular accliratization training of highperformance fighter pilots for improving their vestibular stability and reducing airsickness. Methods Forty-five high-performance fighter pilots, who were graded as D and E in vestibular stability evaluation, performed vestibular acclimatization training by VTS-0 rotational chair once a day for 2weeks. In vestibular stability evaluation, tolerated Coriolis acceleration value and endurable duration of rotation were compared between the states before and after training.Results All 45 pilots'vestibular stability was variously improved and reached or exceeded grade C by training. Tolerated Coriolis acceleration value and endurable duration were significantly increased (t=14.55, 12.66, P＜0.01).Conclusions Vestibular acclimatization training shows significant effects on improving the vestibular stability of high-performance fighter pilots.     

Vestibular nystagmus as a result of the interactions between semicircular canals and the otolithic membrane subsystems of the vestibular system]

Untreated and treated (unilateral section of utricular and saccular branches of the vestibular nerve) pigeons Columba livia were rotated in the dark in the horizontal plane, the head being in a different position relative to the axis of rotation. The range of angular acceleration was 7-19 deg/c2 and the peak value of centrifugal acceleration was 0.5 g. The neck and eye nystagmus was recorded. It was found that: 1) the result of canal-otolith interaction was not directly related to the pattern of changes of otolith afferentation but was determined by the ratio of otolith afferent signals in the right and left labyrinths and, consequently, by the ratio of patterns of activities in the CNS paired structures that receive otolith afferentation; 2) the same result of interaction (enhancement or attenuation of vestibular responses) can be achieved through both increase or decrease of otolith afferentation; 3) if joint stimulation of semicircular canals and otolith organs induces asymmetry of neuronal activities of paired brain structures that perceive otolith afferentation, then, irrespective of the mechanism of origin of this asymmetry, it is followed by changes of oppositely directed nystagmus of different sign (increase for one nystagmus and decrease for the other). It is concluded that the symmetry of reactions recorded in response to isolated stimulation of semicircular canals (otolith organs) cannot be considered as a reliable criterion of functional symmetry of semicircular canals (otolith organs).     

Simulator sickness in the U.S. Army UH-60A Blackhawk flight simulator.

Realistic training in aviation now includes the use of sophisticated flight simulators which can provide near total perception of aircraft flight. Reports of simulator sickness seem to be increasing in simulators with multi-directional motion, computer-generated imagery, and infinity optics. A voluntary, subjective, symptom-oriented questionnaire was completed by 141 pilots after training in the UH-60A 2B38 Blackhawk flight simulator. Thirty-six percent reported positive symptoms of motion sickness. Pilots may be at risk if they fly too soon after simulator training and a mandatory grounding time is advised.     

高性能战斗机大强度飞行对飞行员生理指标及飞行劳动负荷主观评价的影响

目的观察高性能战斗机大强度飞行对飞行员的生理指标及飞行劳动负荷主观评价的影响。方法5名健康男性高性能战斗机飞行员在1个飞行日内共进行22架次的大强度飞行。记录飞行过程中的心电信号,分析心率及心率变异性（heart rate variability,HRV）;飞行后进行飞行劳动负荷和疲劳程度主观评价。结果飞行员大强度飞行时,随着飞行负荷的降低,心率和HRV频域及时域指标呈现一定的规律性变化。心率在夜问较日问低;夜间校正高频功率（high frequency normalized unit,HFnu）高于日间,校正低频功率（low frequency normalized unit,LFnu）及低频高频比值（LF／HF）则低于日问。飞行员飞行劳动负荷及疲劳程度主观评价分值均较低,没有明显的主观疲劳感。结论高性能战斗机大强度飞行对飞行员生理指标有一定影响,但尚未引起飞行疲劳。合理的飞行安排及有力的航卫保障有利于飞行员身体机能的恢复,预防飞行疲劳,保障飞行安全。     

Depth perception after prolonged usage of night vision goggles

The present study was initiated following a report that a few helicopter pilots had failed a test of stereoscopic depth perception after a prolonged training flight employing night vision goggles (NVGs). In order to determine the cause of the loss, 12 helicopter pilots/copilots were assessed for depth perception, lateral and vertical phoria, and contrast sensitivity before and after training flights requiring the pilots to wear night vision goggles for the duration of the flight. Pilots flew one to three missions while wearing either PVS-5A or AN/AVS-6 goggles. Mission duration ranged from 1 to 4 h. The results indicate that contrast sensitivity and depth perception when monocular cues are present did not degrade over the course of the mission. Lateral phoria, however, did demonstrate an average exophoric shift of 1.5 prism diopters for 12 out of the 24 missions. The results indicate that the original report of a loss of depth perception based on a test of depth requiring stereopsis might have been caused by a shift in lateral phoria. It would be expected that as additional fusional effort is required, the minimum resolvable disparity degrades due to the increase in accommodation brought about through vergence accommodation. Possible causes for the phoria shift and future testing are discussed.     

Optokinetic drum tilt hastens the onset of vection-induced motion sickness

BACKGROUND: Under optokinetic drum conditions, a stationary participant views the patterned interior of a rotating drum. Quickly, most participants perceive illusory self-rotation in the direction opposite to the drum's true rotation (vection). It has been documented that up to 60% of participants experience motion sickness-like symptoms under optokinetic conditions perhaps because of conflicting sensory information from the visual and vestibular systems. METHODS: Keeping rotation speed constant (10 RPM), drum tilt relative to the axis of rotation was systematically manipulated (0 degrees, 5 degrees, 10 degrees), producing a wobble effect. Overall well-being and eight motion sickness symptoms were assessed every 2 min using subjective scales. RESULTS: Participants reported 1) a complex type of circular vection that included a "wobble" or "sway" component and 2) a quicker onset of motion sickness-like symptoms as tilt increased. CONCLUSION: In a tilted drum, the vestibular system correctly indicates that the participant is stationary while the visual system indicates a complex type of self-rotation. This type of sensory conflict is more severe than what takes place under typical optokinetic drum conditions (no tilt). Results suggest that as visual/vestibular sensory conflict increases, so does the speed at which motion sickness symptoms occur.     

Neck muscle activation and head postures in common high performance aerial combat maneuvers

INTRODUCTION: Neck injuries are common in high performance combat pilots and have been attributed to high gravitational forces and the non-neutral head postures adopted during aerial combat maneuvers. There is still little known about the pathomechanics of these injuries. METHODS: Six Royal Australian Air Force Hawk pilots flew a sortie that included combinations of three +Gz levels (1, 3, and 5) and four head postures (Neutral, Turn, Extension, and Check-6). Surface electromyography from neck and shoulder muscles was recorded in flight. Three-dimensional measures of head postures adopted in flight were estimated postflight with respect to end-range of the cervical spine using an electromagnetic tracking device. RESULTS: Mean muscle activation increased significantly with both increasing +Gz and non-neutral head postures. Check-6 at +5 Gz (mean activation of all muscles = 51% MVIC) elicited significantly greater muscle activation in most muscles when compared with Neutral, Extension, and Turn head postures. High levels of muscle co-contraction were evident in high acceleration and non-neutral head postures. Head kinematics showed Check-6 was closest to end-range in any movement plane (86% ROM in rotation) and produced the greatest magnitude of rotation in other planes. Turn and Extension showed a large magnitude of rotation with reference to end-range in the primary plane of motion but displayed smaller rotations in other planes. DISCUSSION: High levels of neck muscle activation and co-contraction due to high +Gz and head postures close to end range were evident in this study, suggesting the major influence of these factors on the pathomechanics of neck injuries in high performance combat pilots.     

Acceleration effects on neck muscle strength: pilots vs. non-pilots

BACKGROUND: Conditioning of neck muscles, if any, due to repeated exposures to +Gz forces has received little research attention. OBJECTIVE: This study was conducted to evaluate and compare the neck muscle strength of test volunteers representative of the general populations of fighter aircraft pilots and non-pilots. METHODS: The tests were performed using a special attachment device on a computerized dynamometer. Ten pilots and ten non-pilots volunteered as test subjects. Each individual's maximal isometric neck muscle strength was evaluated in the extension, flexion, and left and right lateral bending directions in a single day. Peak values from the measurements were used for data analysis. Overall neck strength was calculated as the mean values for the four directions in each group. RESULTS: The overall muscular strength of the necks of pilots did not differ significantly from that of non-pilots, nor did exposure to +Gz forces lead to specific changes in isometric muscle strength across any of the four principal directions. Neck muscle strength in the four measured directions pooled across the two subgroups were statistically significant. The widespread practice of adopting protective head-positioning strategies to minimize neck strains, coupled with results from this research study, suggest that the neck muscles are subjected to reduced in-flight strengthening workouts during exposures to +Gz forces. CONCLUSIONS: To maximize in-flight performance and minimize +Gz-induced neck injuries, fighter pilots should be encouraged to perform on-land neck muscle strengthening exercise and in-flight head-positioning techniques. More research is needed to fine-tune this countermeasure strategy against cervical spine injury.     

健康成年人骨性半规管和椭圆囊的MSCT显微解剖研究

目的:利用MSCT测量骨性半规管的径线、相互间的角度,椭圆囊的径线及体积,并估算健康成年人前庭器官参考值。方法:对60例健康成人行颞骨MSCT靶扫描及双斜位MPR,以显示各骨性半规管的全程和椭圆囊的全貌,并测量骨性半规管的径线、半规管间夹角以及椭圆囊的长径、短径和体积。用SPSS v16软件进行差异性t检验和参考值估算。结果:①前骨性半规管的内径、高度、跨度的测量值分别为(1.82±0.16)mm、(5.34±0.32)mm、(4.90±0.62)mm;后骨性半规管分别为:(1.57±0.14)mm、(4.89±0.50)mm、(3.06±0.47)mm;外骨性半规管分别为:(2.32±0.31)mm、(2.11±0.46)mm、(3.74±0.44)mm;椭圆囊的长径、短径分别为:(5.01±0.34)mm、(3.51±0.43)mm,体积为(56.7±7.71)mm3。②相应骨性半规管的径线及椭圆囊的体积比较在性别及侧别上差异均无统计学意义(P>0.05);不同半规管间的径线比较差异有统计学意义(P<0.05)。③骨性半规管间夹角测量值:前骨性半规管和后骨性半规管间91.80°±7.18°,前骨性半规管和外骨性半规管间89.71°±4.95°,后骨性半规管和外骨性半规管间91.19°±1.46°。④骨性半规管间夹角比较在性别及侧别上差异均无统计学意义(P>0.05)。结论:①利用MSCT靶扫描结合双斜位MPR可以很好地显示骨性半规管的全程和椭圆囊的全貌。②本组骨性半规管的径线和椭圆囊的测量值处于95%的置信区间内,可以作为正常参考值。③外骨性半规管的内径最大,前骨半规管最小;前骨半规管的高度和跨度最大,外骨半规管最小。骨性半规管间的相互夹角并非严格相互垂直。