Otolaryngologists sometimes prescribe a procedure for tympanometry. It shows the functional ability of the human ear. The result of the examination is a tympanogram, the decoding of which gives a more complete picture of the pathology of the middle ear in the patient.
The structure of the human ear
People’s ears are complex and interesting.
The exterior is represented by the auricle, the shape of which allows better capture of sounds and protects the hearing organ from environmental influences. As well as the auditory meatus, which abuts against the eardrum, transmitting the sound wave further into the ear.
The secondary is located behind the membrane and is represented by the tympanic cavity, where the auditory ossicles do their work , passing the baton of sound into the inner ear. The hammer, anvil and stapes have grown together in a chain, flying over which the sound is amplified. The handle of the malleus is spliced ​​with the eardrum, and the stapes with its base enters the window of the inner ear. The latter, in the form of a maze, is hidden in the human head. It serves not only to recognize sounds, but also is the vestibular organ responsible for the balance and speed of movements.
Definition of tympanometry
Tympanometry is a pressure measurement technique that is created in the ear under the influence of sound vibrations and is recorded graphically, which is shown by the tympanogram. With the help of such an examination, otolaryngologists want to understand whether the pressure in the tympanic cavity is normal and whether there is fluid, whether the auditory ossicles are moving at full strength, whether the eardrum performs its function, whether it is whole.
Indications for the examination
There are a lot of them:
- Otitis media. This is inflammation that occurs due to the fault of bacterial and viral microflora, hypothermia, and a decrease in the body's immune defense. In this case, the patient is concerned about pain in the ear of varying intensity and hearing loss. Possible discharge from the ear canal. The inflammatory process in the ear, if untreated in a timely manner, goes into the chronic stage, and the disease can bother a person for years.
- Obvious or suspected damage to the tympanic membrane, which occurs both in case of a direct injury to the ear canal, and in an indirect blow to the head or in an inflammatory process that affects the membrane up to its perforation.
- Pathology or damage to the auditory tube, which is the connecting link between the middle ear and nasopharynx. Inflammation is accompanied by pain, congestion and hearing loss.
- Tumors of various nature (glomus, tympanic paraganglioma, hemangioma, osteoma) and cysts formed in the middle ear, making hearing difficult, causing pain and discomfort.
- Rapidly growing hearing loss that appeared for no apparent reason.
- Inflammatory changes in the behind-the-ear area: redness and soreness of the skin, an increase in behind-the-ear and submandibular lymph nodes, an increase in body temperature.
- Respiratory failure through the nose, snoring, combined with hearing impairment.
- The presence of sulfur plugs that impair hearing and cause an unpleasant sensation of change and distortion of your voice.
- Inflammation and degenerative processes affecting the auditory nerve.
- Frequent inflammatory processes in the nasopharynx in children, including adenoiditis.
To assess the effect of the treatment of chronic inflammatory processes of the middle ear, decoding the tympanogram will also be helpful.
Contraindications to the manipulation
Such an examination has a number of limitations. Here they are:
- The presence of profuse serous or purulent discharge from the ears.
- Pronounced redness and swelling of the tympanic membrane, accompanied by shooting pain.
- Foreign bodies (headsets, caps, balls, buttons, fragments of cotton buds, insects, etc.). Before the tympanometry procedure, they must be removed from the otolaryngologist.
- Volumetric sulfur plugs. They must also be removed in order to carry out the procedure safely and more effectively.
It is impossible to carry out manipulations on the insertion of the probe into the ear canal in case of serious disturbances in general well-being: fainting state, mental insanity or severe agitation, increased frequency of epileptic seizures in recent days.
Caution should be given to patients undergoing microsurgical operations of the middle ear and eardrum. This should only be done if decoding the tympanogram is important for further patient management.
Methodology in adults
After explaining to the patient all the stages of the manipulation and obtaining his consent, it is necessary to perform an otoscopy, that is, examine the auditory meatus for the presence of foreign components, sulfur plugs and secretions. If everything is in order, then you can proceed to the examination. No additional preparation, other than observing personal hygiene rules, is required from the patient.
The health worker conducting the procedure inserts a probe into the patient’s ear with a nozzle corresponding to the size of the ear canal to seal it tightly. The probe is equipped with a pump that changes the pressure in the ear canal, a sound generator - it delivers sound signals to the microphone, which is necessary to pick up the sound reflection. Signals with a frequency of 220 Hz and a noise intensity of 85 dB begin to enter the patient’s ear. They make the membrane vibrate, while the microphone reads the vibration. The device gives a graph for each ear according to the type of tympanogram, the decoding of which by a specialist will help to make a diagnosis.
Methodology for children
The child needs to be explained, and it is better to show on the mannequin all the moments of the examination. The most important thing that a small patient should understand is that this procedure, despite the introduction of a foreign object into the ear, is painless and passes quickly - about 10 minutes.
The baby should be told that during tympanometry you can’t spin, talk, kick, swallow saliva, chew, cry and laugh. The child should sit motionless all the time during the manipulation. Parents are encouraged to pick up small children. This examination, with the right approach, is absolutely safe and is carried out even for infants.
A probe up to four months of age is recommended with high-frequency indicators. Also, the size of the nozzles varies depending on the age of the child.
The interpretation of the tympanogram in children (normal and in pathological processes) is carried out by specialists in functional diagnostics or the otolaryngologists themselves. Only by prescribing and evaluating all the examination methods, the doctor can prescribe the correct treatment.
Decoding of the tympanogram
The result of the procedure is a schedule separate for each ear. It displays how the hearing organ perceives sounds of different frequencies, what pressure is fixed in the ears at the moment, how the sound signal is reflected and absorbed. The method is objective, that is, independent of the subjective sensations of the patient. The result depends only on the condition and functioning of the middle and outer ear of the person being examined.
The decoding of the results of a tympanogram is usually done by a functional diagnostician who is trained to understand this type of research. And then the otolaryngologist prescribes the necessary treatment or additional examination. In addition to tympanometry, audiometry should be done to clarify the presence of a disease.
Normal tympanogram
Normally, the decoding is similar to an isosceles triangle, which is located in the middle of the graph. This means that everything is in order with the pressure in the tympanic cavity and it is equal to atmospheric pressure. There is no fluid in the middle ear. The eardrum and auditory ossicles function normally. Sound is almost completely transmitted inside the ear structures.
Types of tympanograms
According to various authors, the interpretation of tympanometry can be carried out according to the number of types of graphs from three to fifteen. Most often, seven types of decryption are used.
Type A described above corresponds to the tympanogram normal.
Type B looks like a straight line on the chart. Therefore, the tympanic membrane practically does not respond to pressure fluctuations, which indicates either its damage or the presence of fluid in the tympanic cavity. Such changes are observed with otitis media.
Type C shows the shift of the graphic curve to the left along the abscissa (X) axis. This is interpreted as a violation of air passage through the Eustachian tube connecting the middle ear with the nasopharynx. Such violations are possible with inflammation of the auditory tube itself or pathology from the mouth (tonsillitis, abscess), tumor formations.
Type D on the graph gives a side sharp peak spike, which makes the pattern look like the letter “M”. Such a curve is characteristic of scars and tympanic atrophy.
Type E is displayed on the tympanogram at a high pulse frequency as a curve with one or more rounded additional peaks. This occurs when there is a violation in the chain of the malleus, stapes and anvil associated with inflammatory, traumatic or degenerative processes.
Type Ad shows such a high peak that its tip can go beyond the borders of the graphic image. This is due to the high lability of the eardrum as a result of cicatricial deformities, impaired tone of the membrane, rupture of the chain of bones in the middle ear or their abnormalities that are present from birth.
Type As looks almost normal, but the amplitude is lower than with type A. This is due to otosclerosis, a thickening of the eardrum due to cicatricial changes.
Pros and Cons of Research
The advantages are:
- Objectivity - the final conclusion will depend solely on the work of the elements of the hearing aid, and not on what the patient hears or does not hear.
- Efficiency - according to the chart, a competent doctor can make a preliminary diagnosis and determine the concept of treatment.
- Painless - the method does not cause discomfort and can be used even in newborn babies.
- Speed ​​- examination takes less than ten minutes.
Cons are that:
- The study is not always informative, since the type of curve can characterize several pathological processes.
- The presence of contraindications.
- Lack of equipment for tympanometry of all medical institutions.