How is the peak of a Type C tympanogram characterized?

A Type C tympanogram is characterized by a peak that occurs at negative pressure. This type indicates that there is a significant pressure difference between the external auditory canal and the middle ear space, which generally suggests that Eustachian tube dysfunction may be present. In the case of Type C, the negative pressure reflects that the middle ear pressure is lower than atmospheric pressure, leading to the tympanic membrane being retracted. This condition typically occurs during or after a cold or upper respiratory infection when the Eustachian tube may not be functioning properly, preventing adequate ventilation of the middle ear space.