短臂离心机不同转速暴露时躯体重力错觉及前庭自主神经反应对比

目的观察短臂离心机不同转速暴露时躯体重力错觉诱发效果及前庭自主神经反应情况,寻求短臂离心机用于地面模拟训练的适合转速。方法在SAC-Ⅲ型短臂离心机不同转速下,对105名健康歼击机飞行员进行躯体重力错觉模拟,对比错觉诱发情况及前庭自主神经反应情况。结果短臂离心机启动加速、匀速运行及制动减速阶段可分别诱发出前倾扭转错觉、前倾错觉及后倾错觉等躯体重力错觉,3种转速下各躯体重力错觉形态表现相同,但错觉强度随离心机转速加快而增强。37 r/min暴露时,各错觉诱发率均大于30 r/min和21 r/min暴露时的诱发率(P0.01);30 r/min和21 r/min暴露时,各错觉诱发率差异均无统计学意义P0.05)。3种转速下前庭自主神经反应评分分值随转速增加有增高趋势,但差异无统计学意义(P0.05)。结论 37 r/min短臂离心机暴露时躯体重力错觉的诱发率高,且前庭自主神经反应较轻,此转速用于飞行人员躯体重力错觉的地面模拟训练较为适合。     

短臂离心机诱发前庭本体性错觉形态多样性表现的观察

目的观察短臂离心机不同暴露阶段前庭本体性错觉的形态表现特点,探寻可用短臂离心机进行模拟训练的前庭本体性错觉类型。方法在SAC-Ⅲ型短臂离心机上对145名健康歼击机飞行员进行前庭本体性错觉模拟,观察其在离心机启动加速、匀速不动头、匀速动头和制动减速4个阶段的主观感觉。结果启动加速阶段诱发出前倾扭转错觉,诱发率47.6%;匀速不动头阶段诱发出前倾错觉,诱发率47.6%;匀速动头时诱发出科里奥利翻转错觉(包括头右旋和头左旋时)和科里奥利旋转错觉(包括头前倾和头回靠时),诱发率分别为95.2%,94.5%,68.3%和24.1%;制动减速阶段诱发出离心机反旋转错觉和后倾错觉,诱发率分别为100%和35.9%。各错觉诱发率差异有统计学意义(χ2=393.089,P0.01)。前倾扭转错觉、前倾错觉和后倾错觉均为躯体重力错觉,离心机反旋转错觉为躯体旋动错觉。结论在短臂离心机上可诱发出3种前庭本体性错觉:躯体旋动错觉、躯体重力错觉和科里奥利错觉,短臂离心机可用于以上错觉的地面模拟训练。     

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.     

短臂离心机用于军事飞行人员前庭习服训练效果观察

目的观察短臂离心机前庭习服训练效果,探讨其用于军事飞行人员地面前庭习服训练的可行性。方法在SAC-Ⅲ型短臂离心机上对9名前庭稳定性水平较低的飞行人员进行连续7天的科里奥利加速度前庭习服训练,观察耐受时间变化趋势,对比训练前后耐受时间和前庭自主神经反应主观分值的变化。结果随着训练次数的增加,耐受时间呈持续上升趋势。经7 d训练后耐受时间明显延长(P0.01),前庭自主神经反应主观分值明显降低(P0.01)。结论短臂离心机用于前庭习服训练效果显著,可用于飞行人员前庭稳定性训练。     

径向加速度作用下科里奥利错觉的空中诱发

目的 建立Y轴径向加速度作用下科里奥利错觉的空中模拟方案,为我军飞行员进行错觉训练提供依据。方法在歼教-7飞机上,由同一名飞行教员在前舱带飞,10名男性受试飞行员分别在后舱闭眼并在盘旋时由低头位抬头,在规定的时间点报告感觉到的飞机姿态,记录其语音信号,同时用飞行参数记录系统记录飞机的实际姿态、并与飞机实际姿态比较,判断受试飞行员是否出现错觉。结果 在盘旋时抬头诱发出坡度变化错觉7人次(左坡度增大1人次,左坡度减少6人次),诱发成功的比例为7/10;右盘旋时抬头有8人次诱发出错觉(右坡度增大1人次,右坡度减少7人次),诱发成功的比例为8/10。结论 本训练方案可以在飞行员受到一定Y轴径向加速度作用时诱发出科里奥利错觉,可以应用于该错觉的空中模拟训练。     

高＋Gz暴露对飞行员唾液α淀粉酶浓度的影响

目的 通过研究高正加速度（＋Gz）应激与飞行员唾液α淀粉酶（Salivary α-amylase,SAA）之间的关系,探讨SAA作为＋G2应激身体机能评价手段的可行性. 方法 47例高性能战斗机飞行员着HP抗荷服在载人离心机上进行训练,分别在＋6.5Gz、＋7.0Gz和＋8.0Gz暴露前、后取其唾液,采用酶动态比色法检测SAA水平. 结果 ①SAA、唾液皮质醇在不同＋Gz作用后的变化有统计学差异（F＝17.712、3.427,P＜0.01或0.05）;多重比较的结果显示＋6.5Gz、＋7.0Gz、＋8.0Gz暴露前与暴露后SAA差异有统计学意义（P＜0.01）,3种不同＋Gz暴露后较暴露前SAA均有明显升高（t＝5.256～5.449,P＜0.01）;＋7.0 Gz、＋8.0Gz暴露后的皮质醇浓度高于基础值（P＜0.05或0.01）,＋8.0Gz暴露后较＋6.5Gz、＋7.0Gz、＋8.0Gz前唾液皮质醇浓度显著升高（P＜0.05）.②机种、年龄、飞行总时间对不同＋Gx暴露后飞行员SAA及唾液皮质醇浓度变化无影响.③飞行员唾液皮质醇浓度与年龄、飞行机种呈负相关（r＝-0.328、-0.694,P＜0.05）,与飞行总时间、＋Gz值呈正相关（r＝0.466、0.141,P＜0.05）,飞行员SAA与＋Gz值呈正相关（r＝ 0.354,P＜0.01）.④不同＋Gz暴露前后唾液皮质醇与SAA之间无显著相关性. 结论 SAA可随＋Gz应激快速灵敏地升高,并迅速恢复至基础值,可作为＋Gz应激的有效评价指标.     

不同强度的科里奥利加速度刺激对人体主观感觉及眼震的影响

目的观察不同强度的科里奥利加速度刺激对人体主观感觉及眼震的影响,以探讨科里奥利错觉与不同强度的科里奥利加速度刺激间的相关性及眼震电图作为反映科里奥利错觉客观指标的可行性.方法在VTS-Ⅲ型前庭功能评定系统上,12名男性青年健康志愿者,每人按随机次序分别接受三次不同强度(π2/30、π2/20、π2/15cm/s2)的科里奥利加速度刺激2每次刺激后休息5min再进行下一次刺激.在刺激过程中嘱受试者用秒表记录下主观感觉(即科里奥利错觉)持续时间,并实时记录下受试者的眼震电图(包括水平眼震与垂直眼震),刺激后询问受试者的错觉形态.三次刺激完后让受试者对三次的错觉强度进行比较.结果不同强度的科里奥利加速度刺激对错觉形态具有一定影响,错觉持续时间、错觉强度随科里奥利加速度的增加而增加(P＜0.05),不同科里奥利加速度刺激下的眼震电图各参数差别均无显著性意义(P＞0.05).结论科里奥利错觉强度、错觉持续时间随科里奥利加速度的增加而增加,错觉形态也随之有一定的改变,但伴随的眼震电图各参数并没有明显变化.     

不同环境下前庭自主神经反应对暗焦点影响的研究

目的：观察地面与飞行环境中前庭自主神经反应对调节暗焦点的影响。方法：采用氦一氖激光视力计游标法，测量受试者眼暗焦点的变化。地面环境健康受试者19例，受科里奥利（Coriolis）加速度后，以Graybiel急性运动病不同严重水平诊断分类标准评定其自主神经反应程度，并测量暗焦点的变化；测量飞行学员35例飞行前后的暗焦点变化。结果：受Coriolis加速度作用后地面人员暗焦点值随自主神经反应程度加重而内移加大；飞行学员无症状、轻度症状组和飞行教员无症状组暗焦点比较，差异不显著（P〉0．05）；飞行教员轻度症状组暗焦点变化差异显著（P〈0．05）。结论：前庭自主神经反应可使暗焦点向近视方向变化，飞行中暗焦点的变化对飞行员有累积效应。     

人力短臂离心机训练后心血管功能的改变

目的 观察人力短臂离心机训练后心血管功能的改变，探讨人力短臂离心机的训练效果。方法 9名健康男性青年利用人力短臂离心机进行训练，转速为30-34r／min，持续时间为5min，1次／d，连续训练7d。测量心血管功能的变化。结果 人力短臂离心机训练3d后，心率显著降低(P＜0．05)，左室射血时间(LVET)显著延长(P＜0．01)；训练7d后，心率进一步降低(P＜0．01)，左室射血时间显著延长(P＜0．05)，每搏量显著增加(P＜0．05)。结论 人力短臂离心机连续训练7d后可明显改善心脏泵血功能。     

不同轴向的径向加速度对科里奥利错觉的影响

目的 X、Y轴向的径向加速度对科里奥利错觉的影响。方法 分别对10名青年男性健康志愿者在GL－2000高级空间定向模拟器上，由X轴向径向加速度为 0.27Gx与0Gz时，Y轴向径向加速度为 0.27Gy或0Gy时等量的科里奥利加速度刺激（0.16cm/s^2)引起的科里奥利错觉形态、持续时间、强度进行了比较。结果 同无径向加速度作用相比，在X轴向径向加速度为0.27Gx及Y轴向径向加速度为0.27Gy时，等量的科里奥利加速度刺激引起的科里奥利错觉形态不改变，错觉持续时间明显降低（P＜0.05)，错觉强度明显增强（P＜0.05)。结论 X、Y轴向径向加速度对科里奥利错觉形态无影响，对错觉持续时间及强度均有一定影响，必须加强对径向加速度作用下的科里奥利错觉的预防与克服措施的研究。     

Rotation rate and duration effects on the somatogyral illusion

INTRODUCTION: Aviation spatial disorientation mishaps remain a concern, especially due to their fatality rate. Some of the most insidious disorientations are due to vestibular stimuli in the absence of visual cues. A category of such disorientations are known as somatogyral illusions. METHODS: To determine the effects of spin rate and duration on the perception of the somatogyral illusion, we examined the subjective response of pilots and non-pilots to rotation around the yaw axis in a flight simulator in a manner that would mimic two vestibular illusions found in flight: the washout of the semi-circular canals following sustained turns, and the illusory counter-rotation following return to straight and level flight. There were 29 subjects (14 pilots) who were seated blindfolded in a flight simulator which accelerated to constant plateau rotation rates of 20, 70, and 120 degrees x s(-1) and then decelerated to stationary; plateaus were 10, 20, or 40 s. Subjects reported 1) the time when the perception of rotation ceased (i.e., the subjective time until washout was reached); 2) the relative magnitude of the counter-rotation experienced; and 3) the time until the perception of counter-rotation ceased. Subjects also manipulated a slider to provide a continuous subjective measure of their experience of rotation. RESULTS: The two time measures increased with increases in both the duration and magnitude of the spin. The increase in perceived washout time with spin rate was non-linear (geometric). There was an interaction between spin duration and spin rate on the experience of illusory counter-rotation magnitude such that at low rates, spin duration had no effect, but its effect increased at faster rates. The time constant of adaptation of the semicircular canals was estimated to be 8.3 s. DISCUSSION: The effects were validated against a model of semicircular canal and cupola adaptation, which predicted the data with high accuracy. Pilots and non-pilots did not differ in their illusory experience.     

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.     

Visual sensations of roll rotation during complex vestibular stimulation

BACKGROUND: In aviation, vestibular-induced spatial disorientation is a significant cause of accidents. Recreating flight-like vestibular stimuli in simulators might be a means for training pilots to respond adequately in disorienting situations. Due to the physical constraints of land-based simulators, the question arises whether a given illusion may be created in different ways. For instance, is it possible to induce sensations of tilt by rotary stimuli? The present study concerns the relationship between sensations of rotation and tilt during complex vestibular stimulation. METHODS: The visual sensation of roll rotation was quantified by means of a velocity-matching procedure. In a large gondola centrifuge eight subjects underwent four runs (2 G, 2 min) with different heading positions (forward, backward, centripetally, and centrifugally). The inclination of the gondola persistently corresponded with the vector sum of the Earth gravity force and the centrifugal force (60 degrees at 2 G). Thus, the semicircular canal stimulus in roll was combined in different ways with stimuli in yaw and pitch, as well as with an increasing or decreasing G vector. RESULTS: The magnitude of the responses was only dependent on the roll component of the stimulus. The gain, defined as the ratio between the response and the roll stimulus, was 7-10%. The responses decayed with a time constant ranging from 4 to 5.5 s. CONCLUSION: The visual sensation of roll rotation reflects the roll plane canal velocity stimulus independently of other stimulus components. This is in contrast to earlier findings on the sensation of changes in position (roll tilt).     

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.     

Postural responses to vibration of neck muscles in patients with uni- and bilateral vestibular loss

Postural responses to vibration applied unilaterally to the dorsal neck muscles were recorded with a sway platform in 11 patients with bilateral vestibular loss (BLD), 13 patients with unilateral vestibular lesions (ULD) and 19 normal subjects. In the normals, the vibration induced a forward postural deviation. Vibration failed to induce postural sway in the BLD patients but induced a backwards head movement in 7 patients. In the ULD patients, vibration contralateral to the lesion induced normal forward sway, whereas ipsilateral vibration resulted in sway directed to the side of the lesion and backwards. The findings demonstrate the importance of concurrent vestibular signals in determining the behavioural response to neck afferent input. We propose that in normal subjects the intact vestibular signal gives no confirmation that a head movement has occurred so it is assumed that the lower body has tilted forwards which provokes a compensatory sway. In the total absence of vestibular function the neck signal may represent a real head movement so the preferential response is a head tilt to restore upright posture. The vestibular imbalance in the ULD patients is roughly equivalent to the asymmetrical signals obtained in a normal subject during head rotation to the intact side. The stretch signal induced by ipsi-lesional vibration confirms possible head rotation, thus provoking a compensatory postural sway.     

Coriolis加速度刺激适应豚鼠前庭传出系统神经元活性的变化

目的 探索动物前庭适应产生的神经生理基础。方法 采用胃电图波幅值作为观察植神经反应的指标,利用小剂量、多次重复的Ｃｏｒｉｏｌｉｓ加速度刺激,建立前庭适应动物模型。采用免疫组化染色和显微相对灰度分析方法,观察动物在产生前庭适应前后,以及前庭适应消退后,脑干前庭传出系统神经元细胞活性的变化,及其与胃电图波幅值变化的联系。结果 建模成功豚鼠受到运动刺激时,刺激前后的胃电图波幅相近。在前庭适应的豚鼠身上,其脑干前庭传出系统神经元内胆碱乙酰化酶的含量明显增加;但在前庭适应消退后,这种含量的差别消失。这表明在豚鼠出现适应性时此神经元对于前庭终器感觉细胞的抑制性作用明显增强。结论 脑干前庭传出系统神经元可能通过降低前庭终器感觉细胞向中枢神经系统的信号发放的程度,参与了适应性的产生过程。     

能谱CT对碘含量测量准确性的实验研究

目的:利用CT能谱成像(GSI)技术测定不同浓度含碘溶液在静止及运动状态下的碘含量,分析GSI碘基图像上碘浓度的测量值与真实值之间的关系。方法:采用GE公司标准体模,其内放置有9种不同浓度的碘溶液试管,浓度依次为0.4、0.7、2.0、5.0、10.0、20.0、30.0、50.0和100.0mg/ml。使用能谱CT GSI模式进行扫描,球管旋转一周时间分别为0.6、0.8及1.0s/r。利用碘基图,选择相同层面、相同大小兴趣区,测量在静止及运动状态下(振幅为10mm,频率为15bpm)体模试管内碘含量,采用相关分析及配对t检验分析碘含量的测量值与真实值间的关系。结果:球管转速为0.8及1.0s时,无论是静止还是运动状态下,碘含量的测量值与真实值之间均具有明显的相关性(r=0.999,P<0.001),且两者之间的差异无统计学意义(P>0.05);而球管转速为0.6s/r时,碘浓度测量值与真实值之间仅存在相关性(P<0.001,r=0.999),两者数值之间差异有统计学意义(P<0.05)。结论:能谱CT在球管转速为0.8及1.0s/r时能准确测量不同浓度溶液中的碘含量,即使在运动状态下亦可以用于定量分析,有望成为一种可靠的物质成分分析方法。