头低位模拟失重状态对前庭功能的影响

Effect of Head-down Tilt on Vestibular Function

为研究头低位模拟失重对运动病症状、垂直视动眼震（ＶＯＫＮ）及体液重新分配的影响，在头低位－１０°的模拟失重状态下，采用大视野的垂直视动刺激，观察１８名正常人的运动病症状、ＶＯＫＮ、激素（ＡＶＰ、ＶＩＰ、ＣＯＲＴ、ＡＬＤＯ）的反应特点。结果表明，头低位－１０°状态下的大视野垂直视动刺激可以诱发出明显的运动病症状，头低位－１０°的垂直视动刺激比坐位更容易诱发运动病。坐位状态ＶＯＫＮ慢相速度有明显的方向性不对称，敏感组ＶＯＫＮ方向性不对称有显著差异（Ｐ＜０．０５）。头低位－１０°时ＶＯＫＮ的不对称现象不明显，向下方向运动的ＶＯＫＮ慢相速度显著增加。分析指出，头低位－１０°状态下垂直视动刺激比坐位和秋千刺激的贡献率大。尿中ＣＯＲＴ（皮质醇）在秋千和头低位的垂直视动刺激前后有显著性增加。提示：大视野的垂直视动刺激与头低位－１０°两种刺激的结合可能成为预测空间运动病的方法之一．

Characteristics of motion sickness(MS) symptoms vertical optokinetic nystag-mus(VOKN),antidiuretic homone(AVP),vasoactive intestinal peptide (VIP)and cortisol(CORT),and aldosterone(ALDO) in urine of 18 volunteer subjects were studied during ex-posure to vertical optokinetic stimulation(VOS) in head-down tilt(HDT-10°) position.The results showed that VOS in HDT-10° can provoke MS in the low tolerance subjects.It was found that VOS in HDT-10° was most stressful than sitting upright in provoking MS symptoms.The directional asymmetry of VOKN obviously exisists in upright subjects. Sig-nificant differences of the up-down asymmetry of VOKN among the Iow tolerance group were observed(P<0.05).While there was no up-down asymmetry of VOKN in HDT-10°.The slow phases of VOKN by downward motion were markedly increased in HDT-10°.The 11 items of MS and VOKN parameters revealed a large percentage of VOS in HDT-10°.CORT levels in urine were profoundly increased after parallel swinging and VOS in HDT-10°.These results suggested that the combination of VOS and HDT-10° might be helpful in predicting the susceptibility to pace MS.