Which tympanogram type is characterized by normal middle ear pressure with reduced tympanic membrane mobility?

Type As tympanograms are characterized by normal middle ear pressure but exhibit reduced tympanic membrane mobility. In this scenario, the peak of the tympanogram is present, indicating that the pressure in the middle ear is normal, yet the height of the peak is lower than what would typically be seen in a Type A tympanogram. This reduced mobility often suggests a stiffening of the tympanic membrane or other areas of the middle ear system, which can occur in conditions such as otosclerosis or other types of middle ear performance issues.

A Type A tympanogram shows normal middle ear function with both normal pressure and mobility, while a Type C tympanogram indicates negative middle ear pressure but normal mobility, typically seen in cases where there is Eustachian tube dysfunction. A Type Ad tympanogram is characterized by normal pressure but an excessively high peak, indicating increased mobility of the tympanic membrane, which can occur in situations such as a disarticulated ossicular chain. Understanding these distinctions is crucial for correctly interpreting audiological assessments.