Tympanometry : A Middle Ear Test And its Purpose, Risks & Procedure
- Last Updated: Jun 15th, 2018
- Posted by: admin
- Category: Hearing Test
There are many tests which makeup through evaluation and act like pieces of a puzzle which when put together helps to determine the type and cause of hearing loss. One such middle ear test is tympanometry. Tympanometry is a type of test which is helpful in determining if the hearing loss can be helped by hearing aid or any medical treatment is available to treat it.
The tymp test method is used to assess the functioning of the middle ear. Tympanometry represents its results in the form of a graph called a tympanogram. In this in-depth article, we have tried to answer every possible question related to tympanography, tympanograms as well as ear pressure test.
Tympanometry was developed by Terkildsen et al in 1950’s for measuring middle ear pressure. It has contributed a lot to clinical diagnosis and has become a routine part of the audiological test battery. The probe tone offered by tympanometer is 226 Hz, though it can give different results on other frequencies. This tone has some advantages when testing adult ear because it is stiffness dominated at this frequency. And also the effect of mass and friction will be minor.
What is tympanometry?
Tympanometry is the examination which is used to diagnose the condition of middle ear, the mobility of the tympanic membrane. The tympanic membrane is a thin tissue separating the middle and outer ear segments from each other. For your child tympanometry may be performed every week for several months to figure out the change in the fluid over time.
Tymp test is also used to examine the conduction bones by generating air pressure changes in the ear canal. It becomes easier for doctors to diagnose the problems in the middle of the ear. This is done to record the quantity of fluid your infant has collected in his middle ear over a period of time.
Tympanometry checks whether someone can be treated for the hearing loss by a hearing aid or not and whether the treatment will give relief or not. Tympanometer consist of the following; air pump, a probe with a loudspeaker, a microphone, and a manometer. There is no risk related to the tymp test. Therefore, parents who have children middle ear problem can easily take this test without giving a single thought.
This method is used to diagnose disorders which may lead to hearing loss, especially children. However, in kids the diagnosis of symptoms of middle ear is not an easy task. Thats why tympanometry is suggested as a additional diagnostic tool with a examining the amount of fluid present or not present in the middle ear.
This test helps in determining various factors. Some of the factors are –
- Presence of fluid in the ear,
- The tear in the eardrum or tympanic membrane perforation,
- Eustachian tube dysfunction, this tube connects the middle ear to the nasopharynx,
- Middle ear infection (Otitis media).
This test is used in conjunction with other test such as audiometry and otoscopy. Tympanometry is always performed after otoscopy examination. Although tympanometry is used simultaneously with pneumatic otoscopy when the kid is seven month old or has any kind of hearing or ear difficulty.
According to heath professionals tymp test and otoscopy can be complementary. The reason is pneumatic otoscopy gives a qualitative estimate of the mobility of the tympanic membrane whereas tymp test produces more quantitative information ( for example graphic and numeric data about taking of acoustic energy by the middle ear system, produced positive and negative pressures and ear canal volume).
It is also believed that otoscopy test with tympanometry enhance the reliability of the diagnosis as there are several ear canal and ear drum abnormalities that in some cases cause might cause different types of abnormalities which can easily be traced through tymphanogram. The graphic represntation of tymp test data is the tympanogram.
Tympanogram represents the relationship between air pressure in the ear canal and the movement of the eardrum, or tympanic membrane, and the tiny bones in the air-filled middle ear space.
As soon as the eardrums are disturbed with any type of voice, some part of it is absorbed and sent through the middle ear while the remaining sound is reflected back. Tympanometry provides some extra information Eustachian Tube Functioning.
For Further info:- What are Symptoms of Eustachian Tube Dysfunction?
How is Tympanometry performed?
Tympanometry is performed by a hearing healthcare professional or a doctor. The test can be performed in any hearing clinic by any of the audiologist/professional. Before start examining through hearing test, a doctor always make sure that your ear does not contain any type of earwax or any other thing which can affect your ear. The instrument used for this testing is otoscope. Firstly ear canal and eardrum are inspected visually and then using a lighted scope. It should be checked if there is no earwax or a foreign object obstructing the eardrum.
Then after performing otoscopy, your doctor will use another instrument which will be placed in the ear i.e. a probe with flexible rubber tip. The probe will cause a change in the air pressure of the ear canal as you hear some low-pitched tones. This pressure change feels similar to that of takeoff and landing of a plane, which may be uncomfortable. Measurement of your eardrum’s movement will be taken and recorded as the pressure keeps changing.
Moving, speaking, or swallowing during the test may give incorrect results. If a child is there for tympanometry, he/she should be explained about the test beforehand with the help of a dummy. This will prepare them for the loud noises and practice being still.
It will maximum take two minutes for both the ears. People from any ages bracket can have tympanometry, as there is no risk related it.
Working on tympanometry
Firstly, a professional will test the presence of earwax and other particles. Then they insert the earbud which tends to be soft to check the capacity of your eardrum by moving it and changing the air pressure of the ear. During the tymp test you will hear a dim noise, the voice is produced due to measurement of the capacity.
If the tympanogram is not normal then there will a fluid behind the eardrum. If the tympanogram is normal then there will be no fluid present in the middle ear. It shows the normal movement of the middle ear, eardrum, and the conduction bones. The tympanogram gives relief for both the children and adults.
Interpreting the Tympanometry Results
Tympanometry result indicates; ear canal volume (cm3), the max pressure (daPa) and the peak compliance (ml). The test plays a crucial role in distinguishing between conductive hearing loss and sensorineural hearing loss. And it also allows us to view the upper auditory pathways and the reflex contraction of the middle ear muscles.
- No fluid in the middle ear
- Smooth Eardrum
- Normal Pressure in the middle ear
- Normal movement of conduction bone and eardrum
This test can be performed on both adults and infants since no risk is involved in it. Even if the results are normal it can provide information regarding fluid or any middle ear concerns. Presence of fluid in middle ear space may not allow movement of eardrum and transmission of sound. The condition is temporary and can be treated medically. This condition may not require the use of hearing aid to correct the hearing loss but must consult a physician.
Normal pressure in the middle ear varies from +50 to -150 deca pascals (daPa). Decapascals is the measurement unit of air pressure.
- Presence of fluid in the middle ear
- Eardrum blocked by earwax
- Perforation of the tympanic membrane
- Scarring of tympanic membrane from the frequent ear infection
- Tumors in the middle ear
- Pressure beyond normal range in the middle ear
- Lack of contact in conduction bones of the middle ear
- Middle ear infection
- Some problem with the Eustachian Tube
Some other tests should also be performed to diagnose the condition. After getting abnormal test results, the doctor will conduct some additional tests as well as a follow-up appointment with a specialist.
Classification of Tympanogram
A tympanogram depending on the diagnosis gives results related to the compliance of the middle ear system, middle ear pressure and ear canal volume. Compliance is shown in a vertical manner on the tympanogram, and is measured in ml or mmho. In case the middle ear cavity pressure is same as the external auditory canal pressure then the tympanogram shows maximum compliance of the middle ear system.
The graphs obtained after conducting tympanometry are classified into following types based on the compliance and the peak of the graph:
Tympanogram Type A –
Type A resembles a teepee and shows a normal middle ear system which has no fluid and an intact tympanic membrane. It also indicates absence of any kind of physiological anomalies that usually prevent the entrance of sound in to the cochlea from the middle ear. an intact tympanic membrane. It shows compliance from 0.3-1.5 ml.
Tympanogram Type AD
Type AD shoes high Compliant middle ear system and compliance more than 1.5 ml. This type shows Scarred or Monomeric T/M, Loss of elasticity in T/M, and Ossicular Disarticulation such as Fractured Ossicles.
Tympanogram Type AS
Type AS indicates less Compliant middle ear system and compliance less than 0.3 ml. This type shows Scarred or Thickened EarDrum, Tympanosclerosis and Ossicular Fixation.
Tympanogram Type B –
Type B shows a flat line. It indicates a constant middle ear pathology which is build up of fluid or ear infection behind the ear drum. A flat tympanogram (type B) also indicates a stiff tympanic membrane. Some of the cases of type B shows –
- presence of hole inside the ear drum,
- the dissimilarity lies in the ear canal volume,
- a larger volume of the ear canal shows eardrum perforation.
- No identifiable peak in the graph
Tympanogram Type B-High
Type B – high indicates middle ear involvement from a perforation. It shoes no identifiable peak in the graph. This type shows normal limit exceeded by ear canal volume equivalently, much more than 1.5 cm3
Tympanogram Type C
Type C also resembles a teepee, although it is shifted negatively on the graph. This shows presence of negative pressure inside the middle ear space. This type of condition is usually shown in constant allergy congestion, or sinus. In some of the cases it also shows the end-stages of ear infection or cold, possible Tympanic Membrane retraction and eustachian Tube dysfunctions, just seen before or after effusion. It indicates compliance from 0.3 to 1.5 ml.
Types C1 and C2 tympanograms are usually noticed in kids who have runny nose. These types are the stage that are found in between which means they can also develop into a type A or type B tympanogram.
Development of Otitis Media
The above Tympanogram shows different stages during development of Otitis Media. Middle ear infectio is a type of inflammatory diseases of the middle ear.
A person should not perform tympanometry examination in case of any of the following cases –
- If he/she has recent ear surgery,
- In case his eardrum is red bulging and causing extreme pain,
- Presence of some foreign object in the canal such as grommets,
- If there is any kind of ear discharge,
- In case of perforated eardrum,
- Presence of moisture in the ear.
What the result mean?
In children, this test shows signs of middle ear problems such as the presence of the fluid, the hole in the middle ear, ear infections many more. There is a possibility of an error or incorrect result the fluid is present behind the middle ear as the fluid stops the movement of the eardrum and transmits the sound properly. This condition occurs temporary and is medically treatable.
The tympanometry generally used to check the capacity and the quality of your eardrum. This test checks other difficulties of the middle ear. It is most commonly used for the children but can be tested to all the different ages. It always provide the accurate result and should be done by the doctor only. Depending on the result of the tymp test your doctor will suggest other test also for further diagnosis of your ear condition. In case your test results are abnormal then book an appointment with a specialist for further examination.