Negative Rinne test. Hearing examination using tuning forks. Indications for research

Guaiac(sometimes they write quayak)try, or Weber test, or Weber-Van Deen test, or Almen–Van Deen test or hemoccult test(English) guaiac fecal occult-blood test, gFOBT) is the historically first laboratory biochemical study of feces, which makes it possible to identify hidden blood in it. It is based on the appearance of a blue color when a solution of hydrogen peroxide reacts with an alcohol solution of guaiac resin in the presence of blood pigments.

First proposed by van Deen in 1864*.

Guaiac gum changes color in the presence of heme peroxidase, but this property of the gum causes it to react with other peroxidases that may be present in feces - such as peroxidases in red meat and some vegetables and fruits. This requires following a certain diet to avoid false positive results.

Currently used, among other things, for screening colorectal cancer. Methodology: a study is carried out with guaiac resin on two samples of each of three sequentially obtained portions of stool. Samples should not be specially wetted. The result is considered positive if traces of blood are found in at least one of the samples. If the test was carried out during screening for colorectal cancer, then a colonoscopy is required (Ivashkin V.T. et al.).

The guaiac test becomes positive in the stool when blood loss is 30–50 ml. When performing this procedure, 3–5 g of feces are ground with acetic acid in an amount sufficient to obtain a semi-liquid gruel, from which an ethereal extract is obtained. Then hydrogen peroxide is added to it and titrated with a freshly prepared tincture of guaiac resin. In the presence of blood, a blue or purple color appears. The main advantages of the guaiac test are its simplicity of execution and relative low cost. Disadvantages are low sensitivity (less than 30% for colorectal cancer and 15% for adenomas) and a large percentage of false-positive results, which limits its widespread use in routine clinical practice (V.I. Chissov, N.S. Sergeeva, etc.** ).

The second important disadvantage of the guaiac test is the need for careful preparation of patients for testing. The patient must be on a diet for about three days, excluding meat and a number of other foods and medications.

It is also used to detect hidden blood in urine, gastric contents, etc.

Preparing the patient for the guaiac occult blood test

For three days before stool collection, avoid consuming more than 250 mg of vitamin C per day, including citrus fruits and juices and dietary supplements.

For three days before stool collection, avoid consumption of meat products such as beef, lamb and liver.

Also, false-positive test results can be a consequence of taking corticosteroids, butadione, reserpine, anticoagulants, antimetabolites and chemotherapy or antiseptic drugs containing iodine, as well as large amounts of alcohol.

Industrial tests for occult blood detection and colorectal cancer screening

It is believed that the Hemoccult Sensa test has better sensitivity than many other biochemical tests for detecting occult blood in the stool (

Rinne's test.

Patients with dizziness must undergo a hearing test. Each ear is checked separately; When testing one ear, masking noise is applied to the other. The patient is asked to repeat one or two syllable phonetically balanced words (for example, “many,” “frost,” “nets,” “cup,” “egg,” “chair”). The patient must hear and repeat at least 9 words out of 10.

The hearing test necessarily includes tests with a tuning fork (Weber and Rinne). These simple tests allow you to distinguish conductive hearing loss from sensorineural hearing loss.

Weber test

To perform the Weber test, the handle of a sounding tuning fork is placed in the middle of the patient's forehead.

• With unilateral conductive hearing loss, the patient hears sound in the affected ear, since the healthy one is drowned out or “distracted” by external sounds.
• Conversely, a patient with unilateral sensorineural hearing loss perceives sound with the healthy ear.
• If the subject hears equally in both ears, then he has either normal hearing or bilateral hearing loss (conductive or sensorineural) with uniform hearing loss in both ears.

Rinne test

Using the Rinne test, air and bone conduction of sound are compared. Normally, a person hears better when sound is conducted through air. A sounding tuning fork is placed on the mastoid process; you need to make sure that the patient hears sound with the ear being tested. Then the tuning fork is brought to the external auditory canal and the patient is asked in what position the sound was heard more clearly and longer.

• Patients with sensorineural hearing loss and people with normal hearing hear sound conducted through air longer (positive Rinne test).
• With conductive hearing loss, the duration of sound perception is longer with bone conduction (negative Rinne test).

prof. D. Nobel

"Hearing test for vertigo" and other articles from the section

Audiology studies the peculiarities of the functioning of the auditory organ. The clinical direction within which it occurs is called audiology.

The main research method is. Special electronic-acoustic devices are used for studying. With their help, the subjective reaction “I hear or I don’t hear” is assessed.

Another method is to study hearing through live speech. Speech is used for tests:

• conversational,
• in a whisper,
• loud,
• very loud.

When testing using whispered speech, it is recommended to pronounce words in a whisper after physiological exhalation using reserve air in the lungs.

When using normal speech, words are pronounced with average volume.

The evaluation criterion is the distance from the subject to the doctor. A person must confidently voice 8 out of 10 words.

Loud speech is made directly near the ear. This research method is used for third degree hearing loss.

Simple hearing diagnostics:

Indications

Hearing is required to be checked in newborn children using instrumental research methods, and in workers who work in noisy industrial conditions. The functioning of the hearing organ is also checked during the driver's examination.

In all these cases, diagnosis is mandatory even in the absence of any complaints. If there are problems, tests are carried out before and after treatment is prescribed.

Indications may be:

• adenoids,
• ear diseases,
• necessity ,
• pathologies of the central nervous system,
• appearance of signs,
• heads.

Hearing tests

There are several techniques that allow you to assess the level of functioning of the hearing organ. Among them:

• Weber,
• Rinne,
• Schwabach,
• acoustic emission.

Weber

The technique is used to determine in people who suffer from hearing loss. It allows you to determine the degree of neurosensory or. The study is carried out using a tuning fork. It is activated and applied to various areas of the head.

During the test, a person is asked to listen and answer a question about which ear hears better. A healthy person hears well in both ears. If there is deafness, the sound will be louder in the affected ear. To prevent the ear from adapting to sounds, it is brought up every 4-5 seconds.

Bone conduction testing is carried out using a bass tuning fork. Its leg is placed in the middle of the crown. The branches must oscillate in the frontal plane.

How is the Weber test performed?

Rinne

When performing such a test, a sounding tuning fork is placed at the site of the mastoid process. When the perception of sound stops, the device is brought to the external auditory canal. In a positive experiment, a predominance of air conduction of sound over bone conduction is noted. When negative, it’s the other way around. A positive experience indicates normal hearing.

During the test, the teeth of the tuning fork are set into oscillatory motion in the same way as during the Weber test. The patient is warned that they will hear two sounds: one in the bone behind the ear and one in the ear itself. You need to answer without thinking about which sound is louder.

How to perform the Rinne test

Schwabach

A tuning fork is also placed on the . In case of pathologies, it is revealed that the bone conduction time is reduced or equal to 0. If it is affected, then the bone conduction time increases.

The study is conducted on two subjects. A tuning fork is placed between them. If a healthy person hears vibrations, but the patient does not, then further research methods will be aimed at studying sensorineural hearing loss.

When a healthy patient cannot hear, but the examinee can describe the sounds received, then we are talking about conductive hearing loss.

This method has been used since 1948. It was found that the presence of OAE in people depends on the functioning of the sensitive cells of the hearing organ. If there is sensorineural hearing loss, then there is no otoacoustic emission.

There are two types of UAE:

Detained summoned. It occurs when cochlear cells make oscillatory movements in response to sound received in the form of a broadband sound click. Sound takes some time to travel to the inner ear and return in the opposite direction.

Emission at the frequency of the distortion product. It is excited by two pure tones. Since the cochlea has nonlinear properties, in addition to the transmitted tones, distortions appear.

This research is carried out using special equipment. To record the emission, a probe is inserted into the external auditory canal. A small microphone and telephone are built into its body. Research is carried out for each ear separately.

Otoacoustic emissions in newborns

Other methods

In audiometry, audibility is measured in decibels. Thanks to this, the specialist can compare the obtained indicators with the norm. The technique is used for:

• determining sensitivity to sounds,
• air and bone conduction analysis.

The procedure is completely painless and has no contraindications. The patient is given headphones. Through them he receives various signals. The result is an audiogram.

Can be used to assess diseases. It measures the pressure level in the middle ear as well as the mobility of the eardrums. Allows assessment of abnormalities and integrity of the auditory ossicles. The procedure has no contraindications.

It includes a whole range of diagnostic studies that make it possible to assess the condition of the auditory tube and middle ear. The peculiarity of the method is that the results do not depend on conditioned reactions.

Can be used for children from an early age. During the conduction process, pressurized air or sound is introduced into the ear canal.

Additionally, electrocochleography may be prescribed. It allows you to evaluate the electrical potentials of the nerve and. Sometimes the method of acoustic brainstem evoked potentials is used to confirm the diagnosis. In this case, the bioelectric reactions of subcortical structures are studied.

How is audiometry performed:

How to check in a child and an adult?

You can test your newborn baby's hearing yourself. If the baby is not yet a month old, then in response to a loud sound he may flinch or move his arms. At the age of 2-3 months, the functioning of the auditory organ is simply determined. The baby begins to respond to the mother's voice. The appearance of cooing is the first sign indicating that everything is fine with his hearing.

If you want to test your hearing yourself, then take a squeaky toy, jars with:

• buckwheat,
• peas,
• semolina.

Stand close to the baby. Shake the container with semolina at a distance of 10 cm from the ear. In response to such an action, the child should calm down or show another reaction. After 30 seconds, perform the same procedures with other cans and the toy. The child must react to every action. If there are no changes in behavior, repeat your study after a while.

For adults, the test can be done using a whisper or loud speech. The inspector moves away to a distance of about 6 meters. The subject closes one ear. It is normal if a person heard all the numbers mentioned without any problems.

If spoken phrases are not heard, then the distance between the two subjects decreases. If it is impossible to hear a whisper, a re-test begins with spoken speech.

In conclusion, we note that if due to pathology of the auditory nerve, then its restoration will be almost impossible. Therefore, it is important to carry out timely diagnosis in order to monitor the condition and prevent it from worsening.

Diagnosis of hearing impairment using a tuning fork can be carried out using different methods. Among them are samples or Rinne's experiments And Federici. These tests, named after the scientists who developed them, are carried out by specialists from our center.

Indications for research

Like the usual, classical, tuning fork study, the Rinne and Federici tests help diagnose and differentiate conductive and sensorineural hearing loss. Conductive hearing loss caused by disturbances in the sound-conducting structures of the outer and middle ear. Causes of sensorineural hearing loss- pathology of sound-conducting components, inner ear, auditory nerve. Sometimes sensorineural hearing loss is caused by diseases and damage to the auditory center of the cerebral cortex.

Differential diagnosis is based on determining and comparing air and bone (along the bones of the skull) sound conduction. Normally, with conductive and sensorineural hearing loss, the ratio of these indicators will be different. This is what functional tests determine.

Rinne test

They use a low-frequency tuning fork, C128, which generates low-frequency sound. After exciting the tuning fork (fingered, hit on the elbow or knee), it is applied with the stem to the mastoid process. The patient hears sound through bone conduction.

After the sound ceases to be heard, the tuning fork, without exciting it again, is brought to the ear, with its jaws towards the ear canal. Normally, the patient hears the sound again. Audibility is due to air conduction. In this case we speak of positive Rinne's test. This test is positive not only in normal conditions, but also in cases of sensorineural hearing loss.

True, in this case there is a synchronous shortening of the time of both air and bone conduction. But still, sound transmission through the air takes longer. With conductive hearing loss caused by changes in air-conducting media, air conductivity decreases compared to bone conduction. Rinne's test is negative.

Federici sample

Its principle is similar to the Rinne test. A C128 low-frequency tuning fork is also used here. Only its leg is placed alternately on the mastoid process of the temporal bone and on the tragus of the auricle at the entrance to the external auditory canal. In this case, the ear canal itself should not be completely blocked by the stem. The perception of sound from a tuning fork located on the mastoid process reflects bone conduction, and on the tragus - air conduction.

Normally and with sensorineural hearing loss, audibility from the tragus is better and lasts longer. Federici sample positive. A negative Federici test indicates conductive hearing loss. In this case, the sound is better heard when the tuning fork is placed on the mastoid process.

These samples mainly give qualitative characteristics (better or worse). This is especially true for the Federici sample. During the Rinne test, a stopwatch is still used for counting. At the same time, these tests are simplified versions of tuning fork testing. Most often, we use them as screening methods, and if abnormalities are detected, we move on to other, more in-depth diagnostic methods.

For research, a tuning fork with an oscillation frequency of 512 Hz is used.

A) . The Weber test is based on a binaural comparison of bone conduction. A vibrating tuning fork is applied with its stem to the skull in the middle of the crown. With normal hearing and with symmetrical hearing loss, the patient localizes the tone in the center of the head or equally with both ears.

With unilateral conductive hearing loss (middle ear damage), he hears the tone in the affected ear, while with unilateral damage to the inner ear, he hears the tone in the healthy ear.

Theoretical background of the test:
When the middle ear is damaged, the mobility of the chain of auditory ossicles decreases, so it conducts sound vibrations worse than under physiological conditions (Mach theory of sound extinction).
The pathological process in the middle ear increases the mass of the sound-conducting apparatus, so it affects the inner ear with greater force due to increased inertia, i.e. stimulation of the inner ear increases (inertial theory).

b) . This test is based on a monaural comparison of air and bone conduction. If air conduction predominates over bone conduction, the Rinne test is considered positive. This picture is typical for normal hearing and sensorineural hearing loss (damage to the inner ear).

If bone conduction predominates over air conduction, the Rinne test is considered negative. This picture is typical for conductive hearing loss when affected.

A vibrating tuning fork is held close to the ear and then, without resorting to re-activation, it is applied to the mastoid process and the patient is asked to say in which position he hears the sound of the tuning fork better. If the patient finds it difficult to answer, the period of tone decay is measured during air and bone conduction.

V) . The Jelle test is performed to determine the mobility of the auditory ossicles in otosclerosis and the degree of fixation of the incus. This test has now been replaced by impedance audiometry.

P.S. Determination of the auditory threshold using whispered and spoken speech in combination with research using a tuning fork provides valuable information about the location of the lesion in the organ of hearing. The tests described above still remain the main diagnostic methods for patients with hearing loss.