Verification of a new test of endolymphatic hydrops.

J Laryngol Otol

MRC Institute of Hearing Research, Royal South Hants Hospital, Southampton.

Published: December 1989

A new objective test of endolymphatic hydrops has been described previously. The test uses auditory brain-stem response (ABR) techniques to estimate the basilar membrane travelling wave velocity (TWV). The underlying hypothesis is that raised pressure in the scala media will lead to an increase in the stiffness of the basilar membrane and that this will give rise to a travelling wave velocity that is greater than normal. It was considered that verification of the technique could be obtained by carrying out the new test before and during a glycerol dehydration procedure. Patients who required this procedure for verification of the diagnosis or as a prognostic indicator for sacculotomy, underwent the following tests. Prior to dehydration an audiogram, the ABR TWV test and a blood sample (for plasma osmolality) were taken. The patient was then given the appropriate amount of glycerol mixed with lemon juice and laid on a bed in a test room. The audiogram and a blood sample were repeated every hour and the ABR TWV test was repeatedly carried out every twenty minutes between the other tests. Six of these procedures have been carried out. In five of them the 0.5 and 1 kHz average threshold improved by at least 10dB and in all those cases the ABR TWV test showed an abnormal pre-dehydration result which moved towards the normal value following dehydration. One patient gave ABR TWV results that were within normal limits before and during the procedure and gave an audiometric change of only 5dB.(ABSTRACT TRUNCATED AT 250 WORDS)

Download full-text PDF

Source
http://dx.doi.org/10.1017/s002221510011120xDOI Listing

Publication Analysis

Top Keywords

abr twv
16
twv test
12
test endolymphatic
8
endolymphatic hydrops
8
basilar membrane
8
travelling wave
8
wave velocity
8
blood sample
8
test
7
abr
5

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!