Dynamics of hearing threshold alteration during the glycerol test in meniere’s disease
Abstract
Glycerol test is still the most popular non-invasive specific test in Meniere’s disease. There are too few reports in literature regarding dynamics of the hearing level alteration in the course of the glycerol test.
PURPOSE – to follow up dynamics of pure tone threshold alteration induced by glycerol in patients with defined Meniere’s disease, suspected Meniere’s disease and with cochlear hearing loss without vestibular deficits.
MATERIAL: Material constituted 58 persons, 32 female, 26 male, at mean age of 47,2, which was divided into 3 groups: (A) eighteen patients with defined advanced Meniere’s disease (AAO-HNS criteria), (B) patients with vestibulo-cochlear disorders under observation for having Meniere’s disease (n=20), (C) patients with cochlear hearing loss without vestibular disorders (n=20).
METHOD: Solution of 86% glycerol, 1,5ml/kg of body weight, dissolved 1:1 in physiological saline was taken orally. Pure-tone audiometry was performed in 4 series: as an initial examination before glycerol intake, 1, 2 and 3 hours after glycerol administration. The glycerol test was regarded as positive when the hearing threashold lowered at least 15dB at minimum 3 frequencies.
RESULTS: In group A there was significant hearing improvement after the third hour at 250Hz. Group B presented significant improvement appearing at the second and third hour and ranged over 500-2000Hz. Evident hearing deterioration was observed in group C at the second hour that turned back again to initial level at the third hour. Positive test was gained in 50% of group A, 45% of group B and 5% of group C. All subjects with positive glycerol test presented the most dynamic threshold decrease at the first hour, unchanged hearing level during the second hour and further improvement at the third hour.
CONCLUSIONS: Pure-tone audiometry results are at its best three hours after glycerol intake. The most significant hearing improvement is observed within the range of lower frequencies.