Abstract
The caloric test is an important tool for the assessment of labyrinthine function.Objective: To compare the nystagmus response in the caloric tests with air at 50°C and 24°C and with water at 44°C and 30°C. Study Design: Randomized crossover clinical trial.Materials and Methods: 40 healthy individuals were submitted to a neurotological evaluation, including caloric tests with air at 50°C and 24°C and water at 44°C and 30°C.Results: Comparing the air and water caloric tests, there were no significant differences among the post-caloric nystagmus slow-phase velocity in relation to the stimulation order, between ears and between the values of unilateral weakness and directional preponderance. The slow-phase velocity values were higher with water (p = 0.008, p < 0.001), and cold stimulation produced stronger responses (p < 0.001).Conclusion: Comparing 50°C and 24°C air caloric test and 44°C and 30°C water caloric test, we observed similar slow-phase velocity values for both ears, higher responses in the cold temperature and in the test with water, and similar results of unilateral weakness or directional preponderance for post-caloric nystagmus in both tests.
Highlights
The caloric test is usually the most informative part of vestibular evaluation
Comparing the air and water caloric tests, there were no significant differences among the post-caloric nystagmus slow-phase velocity in relation to the stimulation order, between ears and between the values of unilateral weakness and directional preponderance
There were no statistically significant differences when we compared the responses from the right ear with those from the left ear in the stimulations at 50°C and 24°C in the caloric test with air and at 44°C and 30°C with water, to what has been reported by other authors[17,23]
Summary
The caloric test is usually the most informative part of vestibular evaluation It is the only procedure which assesses each labyrinth separately, it informs about the affected side and enables characterization of the vestibular lesion intensity[1,2], despite having large intra and inter-individual variability in its evaluation parameters[2,3]. Heat stimulation of the labyrinth causes endolymphatic current in the semicircular canals, polarizing or depolarizing the sensorial cells of the ampule crest, triggering the vestibular-ocular reflex. The stimulus generates an ampule current, towards the utricle, exciting the stimulated lateral semicircular canal and causing nystagmus in the same direction of the labyrinth being tested. The cold stimulus results in a current in the opposite direction of the utricle, inhibiting the stimulated semicircular canal and nystagmus in the opposite direction of the assessed labyrinth[2,3,4,5].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
