1. Pressure and Inflammation Equals PAIN
Middle ear infections hurt. They often cause children to awaken in the middle of the night, screaming in pain. Inflammation of the ear drum and pressure that stretches the drum are the cause of the pain caused by fluid from infection in the middle ear. When children have many ear infections, that fluid can remain within the middle ear and cause not only further ear infections but hearing loss as well. Tympanometry is a test that evaluates how well the ear drum (tympanum) moves. This in turn is an indication of how much built up pressure there is in the middle ear and how well the middle ear's pressure valve-, the eustacean tube, is working.
2. How the Ear Drum Moves
Basically, tympanometry measures the movement of the ear drum when a given amount of air pressure (in the form of sound waves) is applied to it. A hand held device that looks like an otoscope (the tool used to look inside the ear) is inserted within the ear canal. A flexible plug establishes a tight connection at the end of the ear canal. Within the tympanometer are three tubes. One contains a loudspeaker, one contains a microphone and one contains a pump. The loudspeaker delivers a tone while the pump changes the pressure within the canal. The microphone then measures the amount of sound reflected by the eardrum.
3. Tympanogram
Documentation of tympanometry is in the form of a "tympanogram." This is a graph whose pattern estimates whether there is fluid in the middle ear, how well the eustacean tube is working, whether there is a hole in the ear drum, and if the middle ear has a negative pressure (pressure sucking the ear drum in).
4. Of Course, There is the Problem of Cooperation
Unfortunately, there are a number of factors that can alter the validity of the test. These include crying, movement, and ear wax. Trying to remove ear wax often causes crying and movement. This catch-22 is a scenario familiar to any parent. Tympanometry in infants is often inaccurate because of it. If a child is old enough to understand an explanation, prepping them te day before the test may be helpful. Offer them reassurance that the test won't hurt because it won't.
5. Amazing!
Tympanometry was recently verified a very rare condition, myoclonus of the middle ear. Myoclonus is the involuntary, rhythmic contraction of a muscle or a group of muscles. There are muscles attached to the ear drum that act to relax or tighten it (to protect against loud sounds). A doctor examining a patient complaining of ringing of the ear heard what appeared to be a clicking sound. Tympanometry revealed the contraction/relaxation pattern associated with myoclonus, causing the clicking sound heard by the doctor and the ringing heard by the patient. Muscle relaxants cured the problem.
