Hearing Changes in Normal Individuals after Glycerol Intake

Abstract

In this investigation of possible changes in hearing after glycerol intake, puretone thresholds were measured before and 1, 2 and 3 hours after glycerol intake in 23 normal subjects and 27 patients with Meniere's disease. Pure-tone thresholds were also measured before and after saline intake in 12 normal subjects as controls.
There was a change in hearing after glycerol intake in 19% of normal subjects and in 58% of patients with Meniere's disease. Only 4% of the control group had a positive reaction after saline intake. Improvement of hearing was observed in the middle frequencies after glycerol intake more frequently in patients with Meniere's disease, while in normal subjects improvement was noted more often in the low frequencies. The hearing threshold for high frequencies was raised by glycerol intake; this phenomenon was more prominent in normal subjects than in patients with Meniere's disease. This study reveals that hearing changes after glycerol intake can be demonstrated in normal subjects. The effect of glycerol on inner ear function seems to be more complicated than postulated previously.