Abstract
The influence of external auditory canal pressure on the activity of the vestibular nerve was studied in normal guinea pigs and in those with experimental endolymphatic hydrops. Vestibular nerve action potentials were continuously monitored when a pressure of 300mmH2O above or below atmospheric pressure was applied to the external auditory canal. Activity changed significantly during positive pressure application in 19% of the normal group and in 73% of the hydrops group, whereas 35% of the normal and 20% of the hydrops group responded to negative pressure. Responses of normal guinea pigs were reversed according to the polarity of the pressure, and their sensitivities to the pressure correlated to their coefficients of variation. In the hydrops group, polarity of the pressure did not reverse the responses and the correlation between the sensitivity and the coefficient of variation was not apparent.
