The human auditory system is designed in such a way that when any sound vibration is affected, an auditory reflex occurs.
Muscle of the tympanic membrane begins to strain, creating resistance to sound. Such a reaction allows unhindered passage of air through the ear canal, creating the necessary audibility for a person.
What is acoustic impedance measurement
Impedanceometry of an acoustic type is a special set of procedures, the purpose of which is to diagnose and assess the condition of the middle ear, audibility, the presence of possible inflammation and damage.
However, in most cases this procedure is aimed at determining the level of hearing.
The peculiarity of the procedure is its evolutionary universality. Due to its carrying out, a person can diagnose the onset of a variety of diseases, such as otitis media, tubo-otitis, otosclerosis and others.
As the procedure proceeds, the patient is examined the middle ear cavity, the membrane of the tympanic membrane, the eustachian tube, and the auditory ossicles.
Indications for the
study Acoustic impedance measurement is assigned to children and adults, regardless of age. First of all, the diagnosis and suspicions regarding the possible disease are taken into account. The procedure is carried out without special preparations and preparations.
Differential diagnosis is assigned in the following cases:
- dysfunction of the auditory tubes;
- inflammation in the middle ear;
- catarrhal otitis media of the middle ear;
- exudative otitis media of the middle ear;
- Adhesive otitis media of the middle ear;
- rupture of the auditory ossicles;
- eardrum damage;
- damage to cranial nerves;
- hearing loss of any degree;
- lesion of the facial nerve.
The procedure is applied not only for more accurate diagnosis of diseases. Impedanceometry has effectively demonstrated itself as the most accurate method for recording recovery.
The accuracy of the device allows you to prevent a possible relapse of the pathology of the middle ear, which will help in time to begin treatment.
A similar examination helps in the early stages to identify a patient with an existing hearing loss or deafness. This manipulation is especially useful in diagnosing children of small age.
Already after the first procedure the doctor can assert about the presence of this or that pathology and about possible methods of its cure.
Basic tests of
Acoustic impedance measurement consists of several tests. The device itself is a small device with headphones and a special module. This newest development has made it possible to greatly simplify the work of doctors and speed up the treatment of patients with ear pathologies.
Timpanometry is the procedure for measuring acoustic vibrations within the external auditory canal. Manipulation allows you to record even minor changes in acoustic admittance, namely the ease of passage of a sound wave through the auditory meatus. All the results obtained are displayed graphically on the device and are called a tympanogram.
The parameters of ease of passage directly depend on the sharpness of the pressure drop inside the external ear canal. The most acceptable and normal pressure is considered to be when the pressure on the tympanic membrane is the same on both sides.
When this pressure is increased or decreased, the graph on the monitor of the apparatus signals a violation with the help of special conditional tympanograms.
The photo shows the results of a hearing test before treatment( A), during treatment( B), after treatment( C)
Auditory function of the auditory tube
If the functioning of the Eustachian tube is impaired, it is also diagnosed by impedance measurement. The auditory tube is a kind of anatomical canal connecting the middle ear with the throat of the human body.
If the work of this body is disrupted, there is a violation of air exchange, namely, there is a sharp drop in external and internal pressure. If you do not normalize the work of the auditory tube, very soon the occurrence of otitis media occurs.
When the Eustachian pipe is broken, it closes completely or partially. It is this deviation that leads to an incorrect air distribution. Often this is due to the appearance of infection, inflammation, less swelling.
The device is diagnosed three times. This is necessary to obtain three different results at different degrees of pressure, which provides the necessary indicators for detecting the deviation.
- Primary tympanogram is done at normal pressure in the nasopharynx. In this procedure, the initial indicators are recorded.
- A secondary tympanogram is performed at elevated nasopharyngeal pressure. For this person, they intend to ask for a tangible breath with closed mouth and nose. This is a prerequisite for obtaining accurate data.
- Tertiary tympanogram is done under reduced pressure in the nasopharynx passage. To perform the procedure, the patient swallows with the nose and mouth closed.
Principle of the
The procedure allows to identify acoustic response to sound. Acoustic sensitivity is the ability of the auditory canal to perceive a minimum level of sound, which, when tested, is set artificially. In the aftermath, this sound causes contraction in the stremna muscle. It is these indicators that are fixed on the apparatus during diagnosis.
Acoustic reflex is an involuntary reflex reduction of the middle ear's stentive muscle that does not depend on the person .With excessively loud sounds, the tympanic membrane can not always protect the passage from negative influences. In this way, the inner ear can be overloaded.
Reflexonometry is performed to reveal the acoustic reflex. It allows you to identify violations from two sides, even without looking at the isolation of stimulation of one ear.
The procedure is carried out in two ways:
- An ipsilateral-acoustic pulse is applied to the same ear where an acoustic reflex was detected before.
- Contralateral - sound with the help of the device is fed directly to the opposite ear, where an acoustic reflex was detected.
Sound stimuli are frequencies from 500 to 4000 Hz. The device independently raises the sound level to the permissible level, and finds a zone of sensitivity, namely, an acoustic reflex.
Hearing Acuity Study:
Diagnostic Value of
Acoustic impedance measurement is an incredibly important procedure that allows detailed diagnosis of hearing loss of various types. Also, the device can detect the presence of lesions of the facial and auditory nerve, as well as the brain.
Impedansometry is actively used not only to treat ear disease and pathologies associated with them. The device makes it possible to select a hearing aid and to carry out cochlear implantation phenomenally and unerringly.