Tympanometry is a test that measures the movement of the eardrum in response to changes in air pressure. It is commonly used to evaluate the function of the middle ear and diagnose conditions such as middle ear infections and eustachian tube dysfunction. Here are the different types of tympanograms:
Type A: A normal tympanogram with a peak in the middle of the graph indicates normal middle ear function. The pressure at which the peak occurs is called the "tympanometric peak pressure" and should be around -100 to -200 daPa.
Type B: A flat tympanogram with no peak indicates that there is little or no movement of the eardrum, which may be due to a blockage in the ear canal, a perforation in the eardrum, or fluid in the middle ear.
Type C: A tympanogram with a peak shifted to the negative pressure side of the graph (i.e., to the left) indicates negative middle ear pressure, which may be caused by eustachian tube dysfunction or an upper respiratory infection.
Type As: A tympanogram with a peak that is shallow or reduced in height indicates stiffness or decreased mobility of the eardrum, which may be due to ossification of the middle ear bones or other conditions that affect middle ear function.
Type Ad: A tympanogram with a peak that is unusually high or steep indicates increased compliance or mobility of the eardrum, which may be due to a perforation in the eardrum or the presence of fluid in the middle ear.
It's important to note that the interpretation of a tympanogram should be done by a qualified hearing healthcare professional, such as an audiologist or hearing instrument specialist, who can determine the appropriate course of treatment based on the individual's test results and symptoms.