Distortion-product otoacoustic emissions and glycerol on the guinea pig hydropic ear

Objective: The aim of the present work was to investigate the therapeutic effects of glycerol on the distortion-product otoacoustic emissions in guinea pigs in which experimental endolymphatic hydrops had been surgically induced. Methods: Thirty albino guinea pigs were used. The experimental protocol considered three groups of guinea pigs (10 animals each). Group 1 received no drug treatment, while group 2 and 3 were given glycerol orally 0.75 and 0.50 g/kg of body weight once a day for 24 days. Results: The animals treated with glycerol showed an improvement of the distortion-product emission responses in the middle frequencies. This effect was not observed in the higher frequency region. This effect was evident 7 days after glycerol administration in the guinea pigs treated with a dose of 0.75 g/kg. The 0.50 g/kg dosage gave evidence of ameliorating effects 14 days after treatment. Conclusion: Glycerol given orally resulted in an improvement of distortion-product otoacoustic emissions in the guinea pig. Further studies are necessary before the effect of such a treatment can be assessed in humans.