Diagnosis and following up of Ménière's disease using multifrequency tympanometry-Cutoff values and temporal changes in measurements.

Objective: This study aimed to verify cutoff values for G width (the width of bimodal peaks for the waveform obtained when measuring conductance at 2000Hz) in Japanese individuals diagnosed with Ménière's disease (MD) using multifrequency tympanometry (MFT) and to determine the relationship between the G width and ability to hear low-pitched sounds using measurements over time.

Methods: The study included 51 patients with clinically diagnosed MD, who had not undergone endolymphatic sac surgery, but had no other known ear disease (57 ears in patients aged 22-80 years were affected, and 45 ears in patients aged 18-83 years were unaffected; mean age: 53.3±16.9 years). We also enlisted 80 healthy controls with no prior history of ear disease (160 ears, aged 22-76 years, mean age: 40.8±15.7 years). MFT was used to measure the bimodal peak width of the waveform obtained when measuring conductance at resonance frequency of 2000Hz. For patients who had G width measured several times over multiple outpatient visits, we used initial test data to analyze cutoff values. In nine cases with four or more measurements over time, we evaluated a possible correlation between G width and the sum of the hearing threshold for three low-pitched frequencies (125Hz, 250Hz, and 500Hz). We used Student's t-test to determine significance.

Results: The both ears in the MD patients had a G width wider than the distribution in the control group. There was a significant difference between G width in the control group and in affected ears with MD (p=0.00026) and there was also a significant difference between G width in the control group and in unaffected ears of MD patients (p=0.0056). The cutoff value set with a specificity of 95% was 200daPa, with a sensitivity of 35.1% and specificity of 95.6%. The cutoff value set with a sensitivity of 50% was 140daPa, with sensitivity of 50.9% and specificity of 78.8%. There was no significant difference between resonance frequency of ears in the control group and ears with MD (p=0.41). In nine cases with four or more measurements over time, a case showed a statistically significant positive correlation between the G width and hearing ability threshold for low-pitched sounds (125Hz, 250Hz, and 500Hz) (p=0.03), while an another case showed a tendency toward a positive correlation, which was not statistically significant (p=0.08). Further, there were cases that did not show significant differences in the present study, but might have shown a negative correlation if the number of measurements had been increased.

Conclusion: Measurement of G width using MFT may have accuracy as the traditional endolymphatic hydrops test. MFT is non-invasive, causes little discomfort for patients, requires little time to perform, and can be performed by paramedics. MFT was shown to be useful in screening for MD and it is effective in diagnosing MD to measure the change over time of G width using MFT.