[A study of the effect of hot and cold gas perfusion sequence on caloric test results]

Objective: To study whether the warm/cold air injection sequence affects the test results in the caloric test, and provide a basis for the specification and quality control of the caloric test. Methods:Video nystagmography and warm and cold air stimulation apparatus were applied for caloric test. Thirty healthy volunteers （60 ears） were divided into two groups of 15 （30 ears） each. The first group was given cold air stimulation followed by warm air stimulation, and the second group was given heat followed by cold. The differences in nystagmus maximal slow phase velocity （SPV）, semicircular canal paresis （CP） and dominant preponderance （DP） were compared between the two groups of subjects under different perfusion sequences of caloric test. Results:The intensity of nystagmus evoked by subjects in group 1 （cold first and then warm） and group 2 （warm first and then cold） were similar. Paired t-test showed that intra-group analysis of the SPV values of the two groups, comparison of the intensity of nystagmus evoked by different temperatures of the same ear or different sides of ear with the same temperature, the difference was not statistically significant （all P>0.05）. Independent samples t-test showed that between-group analysis of SPV values of two groups, the intensity of nystagmus induced by the same and different temperature stimuli in the ipsilateral ear, the difference was not statistically significant （all P>0.05）. Independent samples t-test showed that the CP values of the two groups were analyzed between groups, and the difference was not statistically significant （all P>0.05）. Independent samples t-test showed that DP values of both groups were in the normal range and the difference was not statistically significant （all P>0.05）. Conclusion:Different perfusion sequences of warm and cold air do not affect the results of caloric tests, and the order of warm and cold air stimulation is not the normative and quality control research direction of caloric test.