Tympanometry is a test performed to diagnose disorders of the middle ear, the space behind the eardrum. During the test, a probe is placed inside the ear and an airtight seal is created. Air pressure inside the ear is then increased and decreased at intervals to detect how well the eardrum responds.

A healthy eardrum will contract and relax with changes in pressure. An eardrum that does not react well indicates a disorder of the middle ear, such as:

• Ear infection
• Fluid in the middle ear
• Perforated eardrum
• Impacted ear wax
• Inadequate contact between the middle ear’s conduction bones
• Tumor in the middle ear

Healthcare providers diagnose a patient’s ear problem after analyzing a readout called a tympanogram, which records the results of the tympanometry test. While some patients (particularly children) may be uneasy about a procedure that involves pressure changes inside the ear, tympanometry itself is painless, and most disorders uncovered during the procedure are highly treatable.

Some ear disorders – such as ear infections or fluid in the ear – may be the result of allergies. Allergic reactions can cause a variety of symptoms, including inflammation and blockage of the eustachian tube (connecting the nose to the middle ear). The tube is designed to allow air into the middle ear and to drain fluid from the ears into the nasal cavity. When the eustachian tube fails to work properly, a number of ear conditions can develop.

Tympanometry is a test used to evaluate hearing and detect disorders of the middle ear, the space behind the eardrum (tympanic membrane). The middle ear is frequently the site of ear infections in children.

Tympanometry involves the use of a small probe that resembles an ear plug. The probe has four functions:

• Creates an airtight seal around the ear
• Changes the air pressure inside the ear
• Produces a pure, continuous tone of sound
• Records the middle ear’s response to the pressure changes and sounds it creates

During the test, a gentle stream of air is pumped through the probe and into the ear, causing the pressure to increase and decrease at intervals to see how well the eardrum (tympanic membrane) responds. As pressure changes are introduced, the patient hears sounds resulting from the air pressure pushing on the eardrum. The eardrum transmits these vibrations to the bones of the middle ear. The probe inside the ear measures how much of the sound passes through the middle ear and how much is reflected back. This information is transmitted to a tympanometer, which then creates an information readout known as a tympanogram.

Most of the time, the eardrum will respond well to the test. A good reading on a tympanogram looks like an inverted “V” with the center point lining up directly over the “zero” mark on a chart. This indicates that the air pressure in the middle ear is identical to the pressure in the room.

An eardrum that does not move properly will result in a tympanogram that is either flattened (indicating that little sound is being reflected back to the tympanometer) or that shows the “V” shifted to the left (indicating that there is less pressure behind the eardrum than there is in the room). An abnormal reading can indicate a number of disorders, including:

• Ear infection (e.g., otitis media). Commonly found in children, it is triggered by a cold or other respiratory infection and produces symptoms of sharp pain and fever. Severe nasal allergies (e.g., allergic rhinitis) can cause recurrent ear infections.
  
  
• Blocked eustachian tube (connects middle ear space to back of nose and throat). Upper respiratory infections can cause inflammation and blockage of this tube. Severe nasal allergies produce mucus that can flow back into the eustachian tube, creating a blockage.
  
  
• Fluid in the middle ear space (otitis media with effusion). Often the result of an ear infection, cold or flu, it prevents the eardrum and middle-ear bones from moving properly.
  
  
• Perforated eardrum (hole in the eardrum). It can be caused by trauma or a sudden pressure increase, usually from an acute infection.
  
  
• Disruption in chain of three bones (ossicles) that propel sounds through the middle ear. This is often caused by a buildup of fluid that prevents the bones from moving properly. Over time, secretion due to nasal allergies can build up and stick to the ossicles, affecting a person’s ability to hear. This condition is known as chronic secretory otitis media, or “glue ear.”
  
  
• Stiffness in the eardrum or the bones of the middle ear. It may be caused by otosclerosis, a hereditary disorder that causes a bone in the ear to grow excessively.

Tympanometry also measures shifts in the stapedius muscle, which normally contracts in response to loud noises. This action – known as the acoustic reflex – reduces sound transmission and protects the inner ear. Neural hearing loss (which results from a problem with the auditory nerve) is suspected if the stapedius muscle does not properly contract. It often is the result of a benign tumor in the middle ear.

The tympanometry test may be performed after a pneumatic otoscopy. Pneumatic otoscopy is a test that allows a healthcare provider to visually examine a patient’s eardrum to see how well it moves in response to pressure changes inside the ear. Using these tests together improves the accuracy of the patient’s diagnosis.

The tympanometry test should be a part of hearing evaluation for all children, although the test may not be accurate in infants under seven months old. This is due to the fact that the ear canals of infants younger than seven months are highly compliant. In addition, children who are crying or uncooperative during the test may make it difficult or impossible to obtain accurate test results.

For adults, little preparation is necessary before a tympanometry test. However, parents of children scheduled to take the test should explain the procedure in detail. The more children know about the procedure beforehand, the less anxious they will be on the day of the test. They will also be less likely to become startled during the procedure. Smaller children will be allowed to sit on a parent’s lap.

Prior to the test, a healthcare provider examines the patient’s inner ear canal with a device called an otoscope. A clear pathway to the eardrum must be present. If there is a buildup of ear wax, the ear will need to be gently flushed and cleared before the procedure can continue. The appearance of the ear drum will also be noted. A healthy ear drum will appear smooth and symmetrical.

A small rubber-tipped probe that looks like an earplug is then placed inside the ear. This is painless, though it may cause minor discomfort in some patients. During the procedure, the probe causes pressure changes in the patient’s ear and creates sounds that may be loud or potentially startling. Patients must consciously try not to react to them, as well as to avoid speaking, moving, swallowing or startling. All of these actions can change pressure inside the middle ear, affecting the accuracy of the test.

Tympanometry requires no participation on the part of the patient. There are no significant risks associated with the test.

Upon completion of the test, a healthcare provider will analyze the results recorded on a tympanogram. A diagnosis of the patient’s condition then will be made. The course of treatment following a tympanometry test depends on the condition that is uncovered.

Many of the conditions detected during tympanometry – such as ear infections, blocked eustachian tube and fluid in the middle ear – have high cure rates and primarily are treated with antibiotics.

Otosclerosis may require removal of a middle-ear bone called the stirrup (stapes). An artificial replacement can be surgically implanted, restoring hearing in most cases.

Neural hearing loss usually is the result of a benign tumor. Once the tumor is surgically removed, hearing loss often stops.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to tympanometry:

1. Why are you recommending that I undergo a tympanometry test?
   
   
2. Can you explain the tympanometry test to me in detail?
   
   
3. Will I experience any pain during the test?
   
   
4. How long should I expect the test to take?
   
   
5. Does the test pose any danger to me?
   
   
6. How accurate is this test? Can I trust the results?
   
   
7. Are there any special steps I should take before, during or after the test?
   
   
8. How can I make the test easier on my child?
   
   
9. What did you discover about my ear during the test?
   
   
10. Now that a diagnosis has been made, what is the next step?