Question
We have a patient with 30dBHL unilateral conductive loss RIGHT ear (type B tympanogram) and a 67% Caloric weakness on the RIGHT. We know that otitis media and other middle ear abnormalities limit the effectiveness of caloric stimulation and accurate interpretation. However, using the theory of "better" heat transfer through a fluid medium, can we accurately interpret this right ear asymmetry as truly reduced caloric response?Answer
This is really an excellent question since middle ear fluid can result in labyrinthine impairment in the extreme which would be observed in the results of the bithermal caloric testing. At present we don't know whether a UW on the affected side is due to inadequate heat transmission or disease. The answer might come from a comparison of the results from the caloric test and the results of rotational testing. A normal rotational test (i.e. normal phase and gain and symmetry) especially at the lowest frequencies (i.e. .01 Hz and .02 Hz) might argue against labyrinthine impairment, whereas the reverse (UW on the affected side with phase leads, gain reduction and asymmetry in the low frequencies) would argue for the presence of labyrinthine impairment. To my knowledge that study has not been done. Sounds like a dandy Capstone project.
Dr. Gary Jacobson is a Professor at Vanderbilt University, Director of the Division of Audiology, and Co-director of the Division of Vestibular Sciences at the Vanderbilt Bill Wilkerson Center at Vanderbilt University Medical Center. He is past editor of the American Journal of Audiology and incoming editor of the Journal of the American Academy of Audiology. Dr. Jacobson is co-editor of the textbooks "Handbook of Balance Function Testing" and "Balance Function Assessment and Management." He is recipient of both the Honors of the American Speech-Language Hearing Association, and the Jerger Career Award for Research in Audiology from the American Academy of Audiology.
