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[Aural fullness and endolymphatic hydrops]
E Gossow-Müller-Hohenstein1, A Hirschfelder, G Scholz
1Hals-Nasen-Ohrenklinik der Charité, Campus Virchow-Klinikum, Humboldt-Universität zu Berlin.
Background:
Low-frequency modulated DPOAEs were registrated to investigate whether the subjective symptom of aural fullness can indicate an endolymphatic hydrops.
Method:
The cochlear partition is periodically moved towards scala vestibuli and scala tympani by a low-frequency suppressor tone. The level of simultaneously registrated DPOAEs is modulated depending on the phase of the suppressor. This modulation may be reduced when the displacement of the organ of Corti is inhibited by mechanical stiffening of the basilar membrane (e. g. in endolymphatic hydrops).
Subjects:
Low-frequency modulated DPOAEs were registrated in 15 patients with Menière's disease, in 8 patients with aural fullness and tinnitus, but without vertigo, and in 21 normal hearing adults.
Results:
In both patient groups the modulation depth is high significantly lower than in the control group. The results do not differ significantly in the patients with and without vertigo.
Conclusion:
The reduction of the modulation depth can be interpreted as a sign of an endolymphatic hydrops. In the group of patients with aural fullness a cochlear hydrops can be assumed. The measurement of low-frequency modulated DPOAEs is a new tool to diagnose and monitor the course of endolymphatic hydrops and to evaluate the effectiveness of therapeutic methods.