Impedansometriya

The acoustic impedansometriya is a complex of diagnostic procedures which carry out for assessment of a condition of the middle ear which is responsible for transfer of sound air vibrations.

The anatomy of an ear is arranged so that the existing acoustical reflex plays a role of the protective mechanism: as a result of strong sound vibrations muscles of a drum cavity strain, the chain of acoustical stones and a tympanic membrane is deformed and there is a resistance to fluctuations of a sound protecting sensory voloskovy cells. Impedansometriya gives the chance to check degree of this resistance. The impedansometriya based on acoustic stimulation of a middle ear allows to estimate objectively a condition of a tympanic membrane, acoustical pipes and stones, pressure on average to fish soup, to find out if in a tympanic cavity hems or liquid.

Besides, the impedansometriya of an ear gives the chance to record reduction of acoustical muscles and to estimate a threshold of an acoustic reflex, including a discomfort threshold, to differentiate diseases of an inner and middle ear: otitis, a tubo-otitis, an otosclerosis to confirm or disprove a disease of an acoustical nerve.

Impedansometriya methods

Impedansometriya fish soup includes the tympanometry and a research of an acoustical reflex.

The impedansometriya method – the tympanometry is meant as check of mobility of a tympanic membrane under pressure of air in acoustical outside pass. Appoint the tympanometry at diseases an adenoide, pathologies of a tympanic membrane and acoustical pipes, diseases of a middle ear, deterioration in hearing, after the postponed otitis.

The doctor the audiologist after survey of ears, removal of sulfuric masses (if necessary) and explanations to the patient of an essence of the test carries out the tympanometry. This procedure of an impedansometriya takes place as follows: the doctor inserts the small rubber probe into acoustical pass and turns on the device – импедансометр which by means of the special pump changes pressure in an ear and forces to move a tympanic membrane. Pressure is measured in acoustical pass by means of the small microphone connected to the probe entered into an ear. The procedure is painless, the patient feels the same pressure in an ear as at rise to mountains or during air flight, and hears peep. During the acoustic test it is impossible to chew, move and talk. The tympanometry of only 5-10 minutes lasts, the doctor the audiologist for the analysis of a condition of the patient receives results instantly.

The second method of an impedansometriya – studying of an acoustical reflex, is based on giving in an ear of a loud sound incentive. The sound moves directly in acoustical pass, via the earphone, the microearphone or the probe. The incentive passes through a middle ear, reaches a snail. From here information on intensity and frequency of a sound is transferred to a brainstem through the eighth nerve where sufficiency of intensity of a sound incentive for the reflex answer is defined. At sufficient intensity there is a bilateral reflex answer: the impulse passes on the seventh nerve from two parties to muscles of a stirrup and causes their reduction. The sound incentive for a research of a reflex is equal 85 dB in one ear.

If there is no reflex answer, the level of loudness is increased gradually, po10 the dB will not occur the reflex answer yet – muscles of a stirrup will be reduced on 0,05sm.

The acoustic impedansometriya is used not only for diagnosis of diseases of ears and pathologies of hearing, but also for selection of the hearing aid, performing cochlear implantation. In these cases inspection of a condition of a middle ear is combined with a tone audiometriya. Use an impedansometriya of an ear and for control inspection in therapy of a myasthenia and paralysis of a facial nerve.