Objective: To investigate whether the direction of air stimulation in caloric test affects the results, and to provide evidence for standardizing the procedure and quality control. Methods: The study subjects were 160 patients with vestibular peripheral vertigo who were treated in Tianjin First Central Hospital from June 2023 to May 2024, including 53 males and 107 females, aged from 12 to 84 years, with an average age of 51.9 years.Video nystagmography (VNG) and a thermal air stimulator were used to perform caloric tests on 160 patients with vertigo, who were randomly assigned to two groups by computer random number table method. In Group 1 (n=80), both ears were first stimulated in the posteroinferior direction, followed by anterosuperior stimulation of the left ear in 40 cases and the right ear in 40 cases. In Group 2 (n=80), the order was reversed: the left and right ears received anterosuperior stimulation first, followed by posteroinferior stimulation in both ears. The maximum slow phase velocity (SPV) of induced- nystagmus, unilateral weakness (UW), and directional preponderance (DP) were recorded and compared between different stimulation directions. Statistical analyses were performed using SPSS 26.0 software. Results: In Group 1, the slow-phase velocity (SPV) of nystagmus elicited by posterior-inferior air stimulation was consistently higher than that induced by anterior-superior stimulation. This difference was statistically significant, as determined by the Wilcoxon signed-rank test (P<0.05). Among the 31 participants who exhibited normal unilateral weakness (UW) following posterior-inferior stimulation, 24 (77.4%, 24/31) developed abnormal UW after subsequent anterior-superior stimulation. Conversely, among the 32 participants with initially abnormal UW after posterior-inferior stimulation, 14 (43.8%, 14/32) showed normalization of UW following anterior-superior stimulation. With respect to directional preponderance (DP), 65 participants had normal DP and 15 had abnormal DP after posterior-inferior stimulation. Following anterior-superior stimulation, 4 individuals with initially normal DP values became abnormal, whereas 3 individuals with initially abnormal DP values reverted to normal. In Group 2, the SPV of nystagmus induced by anterior-superior stimulation was significantly lower than that elicited by posterior-inferior stimulation, with a statistically significant difference (P<0.05) confirmed by the Wilcoxon signed-rank test. Among the 29 participants with normal UW after anterior-superior stimulation, 11 (37.9%, 11/29) exhibited abnormal UW upon subsequent posterior-inferior stimulation. Of the 39 participants with abnormal UW after anterior-superior stimulation, 21 (53.8%, 21/39) demonstrated normalized UW following posterior-inferior stimulation. Regarding DP, 70 participants had normal and 10 had abnormal baseline values after anterior-superior stimulation; after posterior-inferior stimulation, 2 participants with initially normal DP values developed abnormalities, while, 3 with initially abnormal values returned to normal. Conclusions: The direction of thermal stimulation in caloric testing significantly influences test outcomes. Posterior-inferior air stimulation appears to provide a more robust vestibular response. Standardization of airflow direction is therefore essential for ensuring reliability and accuracy in caloric testing, and should be considered a critical component of quality control in clinical vestibular assessment.
目的： 探讨冷热气试验吹气方向不同是否会对试验结果产生影响，为冷热气试验的规范和质控提供依据。 方法： 研究对象为2023年6月至2024年5月就诊于天津市第一中心医院的160例前庭外周性眩晕患者，其中男53例，女107例，年龄12~84岁，平均年龄51.9岁。应用视频眼震图和冷热气刺激仪进行冷热气试验。160例眩晕受试者采用计算机随机数字表法分为两组（各80例），第一组80例受试者双耳先通过外耳道向后下方吹气，再分别对其中40例左耳、另外40例右耳通过外耳道向前上方吹气；第二组80例受试者先分别对其中40例左耳、另外40例右耳通过外耳道向前上方吹气，然后再对这80例受试者双耳通过外耳道向后下方吹气。观察比较两组受试者冷热气试验不同方向吹气诱发的眼震最大慢相角速度（slow phase velocity，SPV）、单侧减退（unilateral weakness，UW）和优势偏向（directional preponderance，DP）的差异。采用SPSS 26.0软件进行统计学分析。 结果： 第一组（先后下再前上）受试者后下方向吹气诱发的眼震SPV值均大于前上方向吹气诱发的SPV值，经Wilcoxon符号秩和检验，差异有统计学意义（P<0.05）；后下方向吹气UW正常的31例受试者中，再向前上方向吹气后出现24例UW异常（77.4%，24/31）；后下方向吹气UW异常的32例受试者中，再向前上方向吹气出现14例UW正常（43.8%，14/32）；后下方向吹气65例DP值正常、15例异常，前上方向吹气后第一次结果正常的受试者中4例转为异常，而第一次结果异常的受试者中3例转为正常。第二组（先前上再后下）受试者前上方向吹气诱发的眼震SPV值显著低于后下方向吹气诱发的SPV值，经Wilcoxon符号秩和检验，差异有统计学意义（P<0.05）；前上方向吹气UW正常的29例受试者中，再向后下方向吹气出现11例UW异常（37.9%，11/29）；前上方向吹气UW异常的39例受试者中，再向后下方向吹气出现21例UW正常（53.8%，21/39）；前上方向吹气70例DP值结果正常、10例异常，后下方向吹气后第一次结果正常的受试者中2例转为异常，而第一次结果异常的受试者中3例转为正常。 结论： 冷热气试验中不同方向吹气可影响试验结果，向后下方向吹冷热气是有效刺激，试验过程中吹气方向的标准规范是冷热气试验质量控制的重要指标。.