To Analyze The Clinical Value Of Vestibular Monothermal Caloric Tests

ObjectiveCaloric test is the most important inspection item in the functional evaluation of vestibule,and there is no other reliable inspection approach to identify the injured side of vestibule up to now.The bithermal caloric tests(BCT) are frequently used in clinical at present.But BCT are tedious,time consuming and uncomfortable.A lot of scholars tried to apply monothermal caloric tests(MCT) to predict BCT results during the past few years,because MCT could decrease examination time and increase patient comfort.But there were arguments to the findings.We did vestibular function examination for vertigo patient who visit our department.We considered the possible influential factors of the caloric test sequences,directional preponderance(DP) and spontaneous nystagmus(SN) to MCT.The aim of this study was to investigate the screening value and the reliability of MCT in evaluating vestibular function.MethodWe considered the vertigo patients 1406 cases who visited our department between October 2006 and June 2008 as study objects.They were divided into two groups.705 cases were stimulated by different temperature air from cold to warm.The caloric test sequence of other 701 cases was opposite.We used Video- Nystagmography (VNG) to trace the spontaneous nystagmus and did the caloric test routinely.The first stimulated cold or warm air test was regarded as monothermal cold caloric test (MCCT) or monothermal warm caloric test(MWCT).The unilateral weakness(UW₂) and DP of the BCT and the UW₁ of the MCT were calculated.By defining the BCT results as the standard,the sensitivity,specificity,Youden's index and kappa were calculated.Result1 The group stimulated from cold to warm428 showed abnormal BCT and MCCT.145 showed normal BCT and MCCT. 85,47 showed isolated abnormal BCT and abnormal MCCT respectively.The sensitivity of the MCCT was 83.4%,specificity was 75.5%,false negative rate was 16.6%,false positive rate was 24.5%,Youden's index was 0.589 and kappa was 0.555(P＜0.01).â‘ The sensitivity of the MCCT was 86.9%,specificity was 77%,false negative rate was 13.1%,false positive rate was 23%,Youden's index was 0.639 and kappa was 0.631(P＜0.01) when cases accompanied by SN were excluded.â‘¡The sensitivity of the MCCT was 89.3%,specificity was 78.6%,false negative rate was 10.7%,false positive rate was 21.4%,Youden's index was 0.679 and kappa was 0.685(P＜0.01) when cases with abnormal DP were excluded.â‘¢The sensitivity of the MCCT was 91.5%,specificity was 79.2%,false negative rate was 8.5%,false positive rate was 20.8%,Youden's index was 0.707 and kappa was 0.714(P＜0.01) when cases with abnormal DP and SN were excluded.2 The group stimulated from warm to cold429 showed abnormal BCT and MWCT,130 showed normal BCT and MWCT. 82,60 showed isolated abnormal BCT and abnormal MWCT respectively.The sensitivity of the MWCT was 84%,specificity was 68.4%,false negative rate was 16%,false positive rate was 31.6%,Youden's index was 0.524 and kappa was 0.505 (P＜0.01).â‘ The sensitivity of the MWCT was 86.9%,specificity was 69.5%,false negative rate was 13.1%,false positive rate was 30.5%,Youden's index was 0.564 and kappa was 0.568(P＜0.01) when cases accompanied by SN were excluded.â‘¡The sensitivity of the MWCT was 88.1%,specificity was 73.7%,false negative rate was 11.9%,false positive rate was 26.3%,Youden's index was 0.618 and kappa was 0.625(P＜0.01) when cases with abnormal DP were excluded.â‘¢The sensitivity of the MWCT was 90.5%,specificity was 74.1%,false negative rate was 9.5%,false positive rate was 25.9%,Youden's index was 0.646 and kappa was 0.653(P＜0.01) when cases with abnormal DP and SN were excluded.ConclusionThe high false positive and false negative rate of the MCT limit the usefulness as a screening test due to the influence of DP and SN.