Monothermal caloric test its value in assessment of vestibular function

Abstract

Background: The usefulness of either cool or warm caloric stimulation alone has been suggested as a screening tool for unilateral vestibular weakness. Previously researchers have reported false-negative rates ranging from 0% to 52% for either cool or warm stimulation depending on variable failure criteria. Objective: To re-evaluate the monothermal caloric test before it can be routinely used in clinical settings. Methods: Data were collected retrospectively from 97 patients who had a complete electronystagmography (ENG) examination including alternate binaural bithermal caloric test (ABBT). The cut-off values of unilateral weakness (UW) for the monothermal (MT) caloric test are 27% and 30% for cool and warm stimulation, respectively. Results: There was a significant positive correlation between bithermal and monothermal unilateral weakness. Specificity of both MT caloric tests was 87.7% while sensitivity levels were 62.5% and 56.3% for cool and warm MT caloric test, respectively. The false-negative rates were correspondingly and unacceptably high for both MT caloric tests. Conclusion: There is always a substantial risk of significant vestibular pathology being missed when MT caloric test, either cool or warm, is used.