Tympanic membrane displacement analyser tracing modifications induced by glycerol in Meniere's disease.

The aim of the study was to detect inner ear fluid pressure changes induced by glycerol in MeniÞre's disease (MD) by means of a tympanic membrane displacement analyser (TDA). The study group consisted of 25 MD patients. The Vi (maximum inward displacement of the tympanic membrane) and the Vm (mean displacement of the tympanic membrane) were measured at 10, 20 and 25 dB above the stapedial reflex threshold. Each patient received therapy based on glycerol. The control group consisted of 20 patients with non-hydropic sudden hearing loss. At 20 and 25 dB above stapedial threshold MD patients had lower Vi values before therapy. After glycerol, we observed a Vi increasing in the hydropic ears in 68-96 per cent of patients. Since a Vi improvement implies a reduction of perilymph pressure, our results confirm the effectiveness of Vi in detecting specific action of glycerol in MD.