Abnormal movement of the ear drum when introduced to subtle pressure may indicate fluid behind the ear drum, a hole or rupture in the ear drum, or Eustachian tube dysfunction.   

The Eustachian tube runs from the throat to the middle ear.  Its purpose is to equalize the pressure in your middle ear with the atmospheric pressure. For example, when you are on a plane ride and the pressure in the cabin changes, you may notice a “popping” sound. This is the sound of your Eustachian tube opening to equalize the pressure in your middle ear. Some individuals experience Eustachian tube dysfunction which can create positive or negative pressure in the middle ear; this can be measured and read on a tympanogram. 

For children that have had surgically placed tubes in their ears, the tympanometry can determine if the tube is properly opened in the ear.