Would a middle ear prosthetic device alter caloric test results?
A review of the literature did not reveal any specific information related to this question. Theoretically, as long as the tympanic membrane is intact, a middle ear prosthesis should have no significant effect on the temperature change induced by caloric irrigation. However, the titanium used in middle ear implants likely has different heat transfer properties than surrounding bone and skin. Any situation where there are anatomical differences between the two ears increases the chance of invalid results in a test already fraught with potential technical error.
Bottom line: In a patient with a middle ear prosthesis, you could surely determine if that labyrinth is responsive to caloric stimulation. I would be cautious about placing too much emphasis on a mild caloric asymmetry if that was the only abnormality.
Alan Desmond, Au.D. is the director of Blue Ridge Hearing and Balance Clinic in Bluefield and Princeton, WV, and is the author of Vestibular Function: Clinical and Practice Management, 2nd edition, Thieme, (2011)