A comparative study of responses obtained by supine and prone vestibular caloric testing

Vestibular disorders continue to pose a constant challenge today as they have in the past, not only for clinicians and researchers alike, but for those who suffer themselves from dizziness, imbalance, or any of the other symptoms stemming from what is a rather lengthy and complex list of vestibular pathologies. Though current vestibular tests are extremely important and provide valuable information, new research on possible ways to supplement these tests in order to ensure accurate results when findings are questionable or inconclusive, may also be of great value. One such possibility in caloric testing is to change head orientation from the ideal supine position to the opposite angle in the prone position. In this research study, the goal was to determine if significantly different responses were produced when head orientation was changed in this manner. A total of 20 subjects underwent a series of caloric irrigations for multiple conditions where position, irrigation temperature, and ear side were changed each time until all possible combinations were made, totaling eight irrigations/conditions per subject. The peak slow-phase velocity was measured in each condition and responses in all combinations were compared, with the primary comparison of interest being the response differences with respect to head position. Results showed that the supine position consistently yielded greater responses than the prone position, despite irrigation temperature and ear side. All results for these comparisons were statistically significant. Irrigation temperature, ear side, gender, age, and hearing loss were also addressed as possible influences on the caloric response, however none showed to significantly affect the response, indicating that the significant changes found were likely due to position changes only. In conclusion, these findings may serve as a supplement for future research on approaches for improving vestibular testing and creating ways to rule out technical error and to ensure accurate findings, which would be a valuable resource in itself.