[The variation of the vestibular response vs. the variations of the auditory threshold after administration of glycerol in patients with Meniere's disease].

Vestibular and auditory functions after glycerol intake were assessed correlated in twenty-eight patients diagnosed as menieric according to AAOO criteria. All patients had unilateral Ménière's disease confirmed by monolateral hypoacusia and labyrinthine hypofunction. Hearing thresholds were tested by tone-audiometry, according to the standard glycerol test. Variation in vestibular response were assessed comparing the VOR during the rotatory sinusoidal test as well as the caloric test, before glycerol intake and 2 hours after drug administration. Slow phase angolar velocity, directional preponderance percentile and percentile variation between basic and control observation were calculated. The audiometric glycerol test was positive in 58% of the cases. The vestibular glycerol test was positive in 30% of the cases and no correlation between and individual results hearing threshold result was found. The findings reported by other Authors regarding auditory and vestibular responses to glycerol intake were verified. Possible reasons which may account for variation with regard to reaction patterns in the acoustic and non acoustic labyrinth after glycerin administration are discussed. In the Authors' view, incoherence between vestibular and cochlear response might be linked to differences in the physiology of the fluid in the two labyrinths. In the vestibular district, glycerol might induce an early depletive effect and a later paradoxal effects due to mechanical modification of the ampulla function.