From Big Medical Encyclopedia

DEAFNESS (surditas) — full loss (full G.) or the sharpest extent of defeat of hearing, at a cut remain the remains of hearing allowing to perceive very loud nonverbal sounds (a whistle, beep etc.) or well familiar words pronounced by a loud voice about an ear (incomplete G.). Legible perception of the speech at G. is impossible. Full G. meets seldom. More considerable remains of hearing allowing it is legible to perceive the speech, speak about existence relative deafness (see).

Happens bilateral or unilateral. Usually unilateral G. disturbs patients and a little sometimes, arising in the early childhood, is noticed later accidentally., come for the first time at advanced age, especially suddenly, immediately causes acoustical discomfort. Very seldom G. is temporary. Patients with bilateral G. need the special surdologichesky help.

Accuracy of statistical data on G.'s prevalence is doubtful because the accurate gradation of G. and relative deafness often is not carried out. Data on incomplete G. are based hl. obr. on results of the separate researches conducted in various countries on the basis of attendance surdol. or audiol. offices. By data Ya. S. Temkina (1957), 1 — 3% of the population has a hearing disorder in such degree, at Krom social communication is complicated. According to Mulonge (And. Moulonguet, 1966), such degree of a hearing disorder is noted at 4,9 — 6% of the population.

Distinguish the inborn and acquired G. Vrozhdennaya G. can be hereditary and caused by diseases in the anti-or perinatal periods, and also reception by mother of ototoksichesky substances during pregnancy, a Rhesus factor conflict, a birth trauma. The acquired G. can be caused nek-ry infectious or somatopathies, diseases and an injury of an ear etc. According to P. Ya. Darzniyeks (1972), the bilateral G. which arose in the pre-natal period is noted at 13,3% of deafs, at the time of delivery — at 1,9% and after the birth at 59,8%. At 25% of deafs it was not succeeded to determine the moment of emergence of G. Among persons at whom G. arose in the antenatal period in 84,4% of cases it was hereditary, and on a recessive character was inherited in 68% of cases, and on dominant — in 32%. At mass inspection of the population in the USA (1940) 1,25% of persons with inborn hereditary deafness, in England (1947) — 4%, in Denmark — 6% are revealed. Inborn G. meets much less often than acquired. Both forms G. are a consequence of irreversible changes in a receptor, nerve pathways, kernels or cells of a cerebral cortex. An exception is hysterical, or psychogenic, G.


was widely adopted the incomplete G.'s classification by the nature of dysfunction (sound carrying out or sound perception) having practical value in definition of a method and efficiency surdol. help. On this classification distinguish sound carrying out (conductive) and sound perceiving (perceptual, neurosensory) incomplete G.'s forms; at their combination speak about the mixed form. This classification, however, does not define character patol, process and the exact level of its localization.

At a conductive form of incomplete G. elements of the sound carrying out system — an outside ear, a tympanic membrane, acoustical stones, a window of a threshold and a snail (a window of a labyrinth), a perilympha, an endolymph and a basilar plate are surprised. On a usual threshold tone audiogramma note high thresholds of hearing at air carrying out sounds and normal perception of kostnoprovodimy sounds. In cases of defeat of both windows of a labyrinth incomplete G. can be the mixed type: on an audiogramma note increase in thresholds both on bone, and on air sound carrying out, but between curves the interval remains. At defeat of fluid mediums of an inner ear, secondary or main membranes define equally high thresholds of hearing at air and bone and fabric carrying out sounds.

At a perceptual form of incomplete G. the sound perceiving system — spiral (kortiyev) body, a spiral node of a snail, nerve fibrils, front and back cochlear kernels, central routes is surprised. On a threshold tone audiogramma coinciding curves of threshold sizes (at a low level) of air and bone conductivity will come to light at the same time.

Defeats of the sound perceiving system in domestic literature designate the term «cochlear neuritis» (see. Eighth cranial nerve ), though it is inexact and collective since it is used not only for designation of an inflammation of an eighth cranial nerve, but also for all other forms of defeat both the nerve, and various departments of all sound perceiving nervous device of an acoustic organ. At the mixed incomplete G.'s form the sound carrying out and sound perceiving systems at the same time are surprised, the exception makes G. at defeat of both windows of a labyrinth.

G. I. Greenberg (1962) allocates three groups of the defeats of the acoustic analyzer calling incomplete G.: 1) diseases of an inner ear, 2) cochlear neuritis (defeat of a spiral ganglion and other ways of a mostomozzhechkovy corner), 3) central defeats (defeat of a trunk and cerebral cortex). This classification characterizes the level of defeat of an acoustic organ, but is a little suitable for definition of an etiology and a pathogeny of the diseases leading to incomplete G.

An etiology, a pathogeny and clinical manifestations

G. — a symptom of a large number of diseases, various on a pathogeny and the reasons causing them.

Conductive incomplete G., according to Yu. M. Nikitina (1973), meets less often (20%), than perceptual (80%). Usually it is noted in cases of full obstruction of outside acoustical pass (cerumen impaction, a foreign body, a furuncle, a cicatricial atresia, anomaly of development etc.). Sometimes diseases are the reason middle ear (see), especially inflammatory character (hron, tubotimpanit, hron, purulent average otitis), which can be independent or a complication of any infectious disease of a nose, nasopharynx. At the same time in process it can be involved and inner ear (see) owing to infection, influence of toxic products of an inflammation or medicines through windows of a threshold and a snail. A wedge, by observations it is established that as a result of any form of average otitis sensitivity of spiral body to noise influence increases. In such ear easier and earlier senile deafness develops.

Disturbance of sound carrying out owing to a peculiar osteodystrophic process in the bone capsule of a labyrinth can be incomplete G.'s cause — otosclerosis (see).

Fig. 1. The scheme of a part of outside acoustical pass, a middle and inner ear with the center of an otosclerosis (in a section): 1 — outside acoustical pass; 2 — a hammer; 3 — an anvil; 4 — a stirrup; 5 — an ampoule of semicircular channels; 6 — a projection of an underfoot plate; 7 — a snail; 8 and 10 — the center of an otosclerosis (8 — in Perilymphangeal space, 10 — in a drum cavity); 9 — a round window; 11 — a tympanic membrane.

The centers of an otosclerosis can be localized in various sites of a labyrinth, acting in a tympanic cavity, is more rare in perilymphangeal space (fig. 1). In the first case the hearing disorder on the sound carrying out type is noted, in the second — also sound perception suffers.

Fig. 2. Audiogramma of the healthy person — is given for comparison: a dashed line — bone sound transmission, continuous — air sound transmission; the circle with a cross designated the curves characterizing a condition of both ears.
Fig. 3. Audiogramma of the patient suffering from a timpanalny form of an otosclerosis: bone sound transmission normal, air sound transmission is lowered (a dashed line — bone sound transmission, continuous — air sound transmission; crosses designated the curves characterizing a condition of hearing of the left ear, a circle — the right ear, by a circle with a cross — both ears).
Fig. 4. Audio of grams and the patient suffering from a timpanalno-cochlear form of an otosclerosis: curves of bone and air sound transmission are reduced and almost parallel (a dashed line — bone sound transmission, continuous — air sound transmission; crosses designated the curves characterizing a condition of hearing of the left ear, circles — the right ear; a circle with a cross — both ears).

N. A. Preobrazhensky and O. K. Patyakina (1973) depending on the level of hearing on bone conductivity distinguish the timpanalny, cochlear and mixed forms of an otosclerosis. At a timpanalny form hearing on bone conductivity is not broken (fig. 2 and 3), at a cochlear form on an audiogramma there is no bone and air interval, both curves of thresholds of hearing go almost in parallel. At mixed, timpanalno-cochlear, hearing is considerably reduced in various degree (fig. 4).

Incomplete conductive G. can be result of inborn malformations of various departments of an ear. At slukhouluchshayushchy operations the inborn underdevelopment of a window of a threshold and the basis of a stirrup or the Liquorrhea as a result of anomaly of development of a water supply system of a snail sometimes is found. Incomplete conductive G. can be also a consequence of tumors of a middle ear.

Perceptual G. is subdivided on peripheral (cochlear, or cochlear, labyrinth) and central (retrolabyrinth or cortical). Most often meets cochlear. In spite of the fact that the snail with acoustical nervous cells is deeply in a dense bone pyramid, it is highly sensitive to many ekzo-and internal causes of influence (disturbance of blood circulation, toxins, a viral infection, a noise injury etc.). Under their influence the dystrophic changes in receptor cells of spiral body bringing to full or partial G. Prakticheski most often develop the cochlear G. caused by defeat of one spiral body or in combination with defeat of overlying nerve acoustical pathways meets. The purulent labyrinthitis — timpanogenny or meningogenny can be cochlear G.'s cause. Meningogenny, unlike timpanogenny, as a rule, bilateral and, arising at early age, leads not only to G., but also to a surdomutism.

Dystrophic and inflammatory processes of a trunk of an eighth cranial nerve are sometimes observed at typhus, flu, scarlet fever, measles, epidemic parotitis and other infectious diseases. Dystrophic changes can then extend also to spiral body (the descending dystrophy), but sometimes arise at the same time or begin with a snail, and then extend to an acoustical nerve and its kernels (the ascending dystrophy). Existence of noise in an ear and bystry development of is characteristic of such neuritis. Infectious cochlear neuritis comes to an end with full or incomplete G. for rather short time term. In process of subsiding of inflammatory changes the exhausting noise in an ear disappears.

The spiral body can be exposed to dystrophic changes under the influence of a number of toxicants (gasoline, hydrogen sulfide, aniline, fluorine, mercury, arsenic, quinine, nicotine, salicylates etc.) and microbic poisons. Usually process begins in voloskovy (touch and epithelial) cells, nerve fibrils or cells of a spiral ganglion, then it extends also to cells of the supporting device therefore it is possible to speak about dystrophy of all spiral body.

Fig. 5. Audiogramma of the patient having «cochlear neuritis» after introduction of Neomycinum: curves of bone and air conductivity are sharply lowered, their break is characteristic (a dashed line — bone sound transmission, continuous — air sound transmission; crosses designated the curves characterizing a condition of hearing of the left ear, a circle — the right ear, by a circle with a cross — both ears).

Cases of dystrophy of spiral body and acoustical nerve became frequent in connection with broad use of ototoksichesky antibiotics (streptomycin, Neomycinum, Monomycinum, etc.) at various inflammatory diseases. Especially often «cochlear neuritis» develops at use of antibiotics at diseases of kidneys since removal of antibiotics from an organism is complicated that leads to their cumulation in liquids of a labyrinth. At children among the reasons of defeat of the acoustic analyzer ototoksichesky antibiotics figure prominently. The «Cochlear neuritis» developing at long introduction of massive doses of these drugs is more often bilateral, is followed by an intensive sonitus and quite often continues to develop even after cancellation of antibiotics. On an audiogramm (fig. 5) curves of bone and air carrying out are sharply lowered and their break (lack of perception of sounds of high frequency) is characteristic.

Stabilization of process and consequently also the termination of further decrease in hearing, comes, as a rule, in several years after its emergence.

The injury of a skull can be the cause of «cochlear neuritis». At the same time dystrophy of an acoustical nerve develops as a result of a break or a prelum of a nervous trunk, and dystrophy of spiral body — from disturbance of blood circulation, hemorrhage in an inner ear or a direct injury.

In development of «cochlear neuritis» impact of noise and vibration is of great importance (see. Acoustic injury , Vibrotrauma ), which can be the reason professional. Duration of impact of the noise and vibration, age and the general state working individual sensitivity of an acoustic organ etc. exerts impact on professional G.'s development. Professional G.'s development is promoted by inflammatory diseases of a middle ear, the changes in nerve acoustical pathways which are not connected with noise.

The combination of noise and vibration causes damage to an acoustic organ approximately by 2,5 times more often than impact of one noise. Pulse noise lead to G. quicker, than a constant noise background. The changes in an acoustic organ caused by impact of noise are very diverse, they cover a tympanic membrane, a middle ear (first of all muscles), an inner ear (vessels, membranes and nervous cells), an acoustical nerve, kernels and a cortical acoustical zone.

Changes in an inner ear are most frequent and more expressed. At short influence of audibles signal the acoustic analyzer adapts to them, as if becomes less sensitive (see. Adaptation acoustical ); after the termination of sound influence hearing soon is returned to initial. At long impact of noise after adaptation the exhaustion develops. Adaptation and exhaustion of hearing at different persons are expressed unequally. Long noise influence gives l to emergence by a rack of.

Fig. 6. Audiogramma of the right ear of the patient suffering from professional defeat of hearing: bone and air sound transmissions are sharply reduced at sounds of high frequency; characteristic «tooth» in the field of the frequency of 4000 Hz is expressed (a dashed line — bone sound transmission, continuous — air sound transmission).

Thus, in professional G.'s development it is possible to allocate two stages: the first — adaptation and exhaustion of the hearing aid (functional changes), the second — permanent decrease in hearing (organic disturbances). At firm professional G. in and an audiogramm (fig. 6) characteristic «tooth» in the field of the frequency of 4000 Hz is visible, i.e. sharp disturbance of perception of sounds of high frequency is noted.

Defeat of an acoustic organ at fluctuations of barometric pressure meets seldom. At the same time comes owing to disturbance of blood supply and hypostasis of a labyrinth. Can develop at local or general irradiation radioactive materials when disturbance of permeability of capillaries leads to hemorrhages of a labyrinth with the subsequent dystrophy of spiral body, a ganglion and higher ways.

Owing to vascular changes in an inner ear it is observed at atherosclerosis, a hypertension, an angioneurosis. Long spasms of the main branch or smaller arteries of a labyrinth can come at persons with a vegetodistoniya. Short-term disturbance of blood circulation quite often is followed by temporary functional changes in an inner ear. In a pathogeny of organic and functional vascular lesions of an acoustic organ the large role is played by anatomic feature of a cochlear branch of an artery of a labyrinth — it has no anastomosis. Narrowing of its gleam leads to considerable defeat of spiral body. As a result dystrophy of receptor and ganglionic cells and nerve fibrils develops.

In the mechanism of development of perceptual G. because of syphilis and tuberculosis into the forefront changes in vessels also act. The labyrinth and nerve acoustical pathways up to cortical department of the acoustic analyzer are surprised.

Can lead noninflammatory diseases of an inner ear in connection with quantitative and qualitative changes to firm full or incomplete G. peri-and an endolymph, napr, an edema of a labyrinth (see. Menyera disease ). Its origin, probably, is closely connected with disturbance of an innervation of capillaries of a labyrinth and permeability of their wall, i.e. straining action and resorption of liquid. Usually these phenomena are observed in one ear.

One of the reasons of G. are age changes of an acoustic organ. All sites of the hearing aid, however the greatest changes, by data Ya. S. Temkina (1957) are exposed to involution, come to light in the field of a kortiyev of body and a vascular stripe. According to Shuknekht (H. Schuknecht, 1964), at age G. atrophic changes in nerve fibrils, kernels and a cortical zone develop. With age elasticity and mobility of acoustical stones, a basilar plate and secondary tympanic membrane decreases. Given B. S. Preobrazhensky (1966), age changes arise more earlier in those departments of an acoustic organ in which there were once organic changes. Fiziol, aging of an acoustic organ considerably differs from patol., at Krom of change in an acoustic organ are more expressed as a result of capillary angiopatiya, early atherosclerosis and other changes under the influence of long influence of adverse factors (household and production noise, effect of alcohol, nicotine, etc.). Emergence of signs of senile G., rate of its development are individual, as well as process of the general aging (see. Presbyacusis ).

The central G. is caused by defeat of the carrying-out nerve pathways, kernels and cells of an acoustical zone of a cerebral cortex. Tumors, arachnoidites, hemorrhages etc. happen the most frequent reason. Arachnoidites in the field of internal acoustical pass are observed as an effect of otitises and their complications. Localization of tumors in a mostomozzhechkovy corner is noted quite often; the eighth cranial nerve, and in particular its cochlear part, at the same time suffers from a prelum. The special form is represented by acoustic neurinoma which lead not only to decrease in hearing, but also to vestibular frustration. The isolated damages of the central conduction routes and kernels almost do not meet, usually they make a part of more extensive process.

Functional G. — hysterical or contusional belongs to central.

Hysterical G. is more often observed at young women at difficult life situations; at the same time also a number of the general hysterical reactions comes to light. At treatment of a basic disease of G. disappears, but without treatment can long keep.

At strong acoustic irritation, as a result of development of guarding braking in a cerebral cortex contusional G. develops, sometimes it is followed also by dumbness. Changes in an inner ear at contusional G. come down to destructions of receptor cells and hemorrhages.

The central G.'s elements can come to light at shumovibratsionny long influence, atherosclerosis, typhus, etc. It is characterized by deterioration in legibility of the speech. The understanding of words, and also perception of sounds in time suffers.

The incomplete or full G. connected with inborn uglinesses usually has no dynamics and is noted since the early childhood. Because of acute and hron, average otitises in connection with destruction or an anchylosis of acoustical stones, occlusion of windows of a labyrinth, penetration into a labyrinth through a membrane of a round window of products of an inflammation and toxins the progressing conductive relative deafness can develop and be broken legibility of the speech. Professional «cochlear neuritis» steadily progresses if impact of noise and vibration does not stop. At toxic defeat of the perceiving elements of an acoustic organ dystrophy of nervous tissue slowly accrues, and even after the termination of influence of toxicant; at the same time especially painful is an intensive sonitus which can proceed within several years. The hearing loss at an acoustic neurinoma progresses in process of increase in the sizes of a tumor in connection with destruction of internal acoustical pass; at the same time there are symptoms of damage of nearby cranial nerves and increase in intracranial pressure. Quite often progressing current with increase of acoustical disturbances is characteristic of influenzal neuritis. Slow decrease in hearing, fading in of signs of the central G. is characteristic of G. because of atherosclerosis — at first perception of high-pitched sounds, then average and low-frequency is broken. The similar current has G. at hron, infections or intoxications that, probably, is connected with vascular changes. Sometimes G. can suddenly come; early recognition of its etiology and timely treatment can lead to recovery or considerable improvement of hearing as at an early stage of a disease there is no organic lesion of nervous elements still. The vascular disorders (more rare — contusional) leading to disturbance of blood supply of a kortiyev of body happen sudden G.'s reason more often, I will swell also to increase in intra labyrinth pressure. Arising at typhus, flu, appears quickly and almost always reaches considerable degree; At cerebrospinal meningitis usually full and bilateral.

The diagnosis

full G.'s Recognition is usually simple. Difficulty is caused by contusional G.'s diagnosis and identification of simulation of. G.'s simulation is revealed in several ways: reading with muting (to the patient in earphones suggest to read aloud, sound intensity in earphones is gradually increased; at G. the loudness of reading does not increase), a repeated audiometriya (tone and speech), objective audiometriya (see), based on identification various reflex (unconditional, conditional) reactions in response to sound irritation, and also registration of biopotentials of a cerebral cortex. Use definition tests and uro-palpebral reflex (see), auro-pupillyarny reflex (see), and also study vasomotor and galvanic skin response (see) at influence by sounds. It is better to carry out G.'s diagnosis in the conditions of a hospital since its identification requires the special equipment and overseeing by behavior of patients. The game audiometriya is applied to G.'s identification or definition of the remains of hearing at small children along with registration of the biopotentials of a cerebral cortex caused by acoustic irritants.

In a wedge, practice often should carry out differential diagnosis of diseases of certain sites of the acoustic analyzer, i.e. to specify the level of its defeat. For this purpose along with assessment of anamnestic data, an otoskopichesky picture hearing is investigated by means of various methods. Defeat of the sound carrying out and sound perceiving systems in typical cases is differentiated usually on the basis of a ratio of level of hearing at bone and air carrying out sounds. The best perception of sounds at bone carrying out indicates conductive incomplete G.'s presence that it is observed at an atresia of acoustical pass, different diseases of a middle ear and the timpanalny or mixed form of an otosclerosis.

Specification of level of defeat of the sound perceiving device and character patol, process presents certain difficulties. The diagnosis is made on the basis of the analysis a wedge, pictures of a disease, with the help audiol. receptions or additional research of a vestibular mechanism, cranial nerves etc. Quite often it is necessary to differentiate such diseases as the mixed and cochlear forms of an otosclerosis, a disease (or a syndrome) Menyer, an acoustic neurinoma and other diseases at which «cochlear neuritis» develops. At diagnosis of these diseases it is necessary to consider a wedge, development of symptoms, their causal relationship with adverse factors (an injury, noise, the postponed flu, reception of antibiotics, etc.). In the absence of instructions in the anamnesis on adverse factors, vestibular frustration and the progressing hearing impairment usually speak about «cochlear neuritis» of not clear etiology at young people or about early presbyacusis (see) — at persons of more advanced age. Assume what at such sick G.' most is result of a «pure» cochlear form of an otosclerosis. On a tone audiogramma both at «cochlear neuritis», and at a cochlear otosclerosis curves of thresholds of hearing on air and bone conductivity will be coincident — descending or bent. A distinguishing character of patients with an otosclerosis is the normal or slightly increased perception of ultrasound. At «cochlear neuritis» patients or do not perceive ultrasound, or they have high thresholds of his perception. Identification of the centers of an otosclerosis in the capsule of a labyrinth, definition of normal legibility of the speech, lack of a phenomenon of a rekruitirovaniye (the accelerated increase of loudness) matters also rentgenol, at superthreshold audiometriya (see) and anamnestic data (existence of an otosclerosis at relatives, etc.). At an otosclerosis can be so deep that on an audiogramma only islands of hearing are defined. In such cases speak about far come conductive G.'s form, at a cut otosklerotichesky process extends to all capsule of a snail, sometimes to internal acoustical pass, a window of a snail, narrowing intra labyrinth space.

Audiol. the characteristic of the mixed incomplete G.'s form at an otosclerosis, at adhesive and purulent hron, average otitis has common features: on an audiogramma the bone and air interval is defined at low (more often descending) the level of perception of the bone carried-out sounds.

At an inflammation of a middle ear rechetonalny dissociation (discrepancy of a speech and tone audiometriya), high thresholds of hearing at bone carrying out sounds, the raised thresholds of perception of ultrasound sometimes come to light that indicates more profound changes in the receptor device. In these cases it is possible to think of secondary structural changes in spiral body.

At G. of a cochlear origin patol, process can be finished or progressing. Seldom it is isolated, takes also more often a vestibular analyzer which suffers less. There is a number of the general audiol. cochlear G.'s signs, and also distinction characteristic of its separate types. Sometimes the spiral body is involved in process at an inflammation of a middle ear. At the same time there can be an intra cochlear disturbance of transformation of a sound, disturbance of blood circulation or a labyrinthitis (serous, purulent). Clinic of a purulent labyrinthitis acute and accurate; the clinic of a serous labyrinthitis can be sluggish and be followed only by decrease in perception of high-pitch tones. The research of hearing on bone conductivity at one - or bilateral process, but with different degree of a hearing impairment on both ears requires muting by noise better than the hearing ear.

Fig. 7. Audiogramma of the patient having Menyer's disease: bone and air sound transmission of the left ear are lowered (a dashed line — bone sound transmission, continuous — air sound transmission; crosses designated the curves characterizing a condition of hearing of the left ear, krukochka — the right ear).

Ulitkvvy G. is characteristic of Menyer's disease (see Menyer a disease), and also vascular and toxic damages of an inner ear. In an initial disease of Menyer of stages a unilateral hearing impairment is followed by low thresholds of differentiation of sound intensity, balance upsets of loudness and legibility of the speech. Lateralization of a sound of a tuning fork of C512 will be in better the hearing ear, and ultrasound — in worse hearing. On a threshold audiogramma coinciding curves of bone and air conductivity in the affected ear (fig. 7) are defined. At vascular (acute) defeats (a spasm, thrombosis) of spiral body lateralization of all sounds will be in better the hearing ear. Vascular disorders either regress, or are stabilized, bringing to partial or full.

Toxic defeats of a snail more often bilateral, progress slowly, at defeat of spiral body symptoms of initial irritation are replaced by symptoms of oppression. In the period of irritation the phenomenon of a rekruitirovaniye is expressed, legibility of the speech is broken, the speech is sometimes perceived «doubled» and loud or as said in the big empty hall. At a kamertonalny research of hearing the sound of C512 is perceived by a sore ear as more high-pitched sound (diplacusis). Depending on the nature of process, the events in a snail, the period of irritation has various duration and degree of manifestation. The period of oppression is characterized by disturbance of perception of sounds. Toxic defeat of spiral body happens owing to use of himiopreparat, napr, ototoksichesky antibiotics more often. In these cases the coinciding descending curves of thresholds of hearing on both ears are characteristic. The phenomenon of a rekruitirovaniye with sharp falling of legibility of the speech y an intensive sonitus can come to light. Toxic defeat of spiral body often is followed by simultaneous or subsequent defeat of nerve fibrils and kernels.

Acoustic damages of a snail at long impact of noise are various and depend on individual sensitivity of an acoustic organ, duration and the nature of noise. The tooth at a frequency of 4000 Hz is originally characteristic of defeat of a snail on an audiogramma, retraction at a frequency of 8000 Hz, and later — and at low frequencies joins Krom then. Ultrasound is perceived normally, the phenomenon of a rekruitirovaniye is sometimes noted. Audiol. displays of an acoustic injury have big polymorphism since damage is seldom limited only to a snail.

The acoustic neurinoma, usually unilateral, is characterized by flat curves of thresholds of hearing, high thresholds of differentiation of sound intensity.


At early treatment of acute perceptual G. sometimes is never possible to improve hearing, at late — almost. At slowly developing perceptual G. treatment pursues the aim of stabilization of level of hearing and reduction sometimes of the exhausting sonitus. The medicamentous means applied to perceptual G.'s treatment are ineffective since there are no clear ideas of the changes happening in nervous cells or fibers. Positive takes of treatment can be at functional changes in kortiyevy body. Studying of origins of functional and organic disturbances will give the chance of carrying out purposeful therapeutic influence. Drug treatment of «cochlear neuritis» usually comes down to purpose of vitamins A, In 1 , B 6 , B 12 , E, PP and their derivatives. At senile G. improvement of legibility of the speech from use of vitamins A, E and sex hormones is noted; widely use ATP, cocarboxylase in combination with vitamins and nicotinic to - that; appoint prozerin, Galantaminum, etc. Efficiency of these means is noted at professional.

At sudden G.'s treatment along with vitamins appoint depending on alleged vascular changes either vasodilating, or spasmolytic and anti-coagulating means, and also sedative, dehydrational and desensibilizing. The effect at use of strychnine and echinopsine, and also an aloe is possible, pyrogenal and, a vitreous, novocaine, hormonal drugs, etc. The effectively earliest purpose of a complex of these means. The same means are applied to elimination of a sonitus or vagosympathetic blockade, a pleksotomiya of a drum cavity, etc.

Krom of pathogenetic is carried out, carry out a symptomatic treatment of. It includes operations, the improving hearing and correction of hearing with the help hearing aids (see) or artificial prosthetics of elements of a middle ear (see. Hearing aid ). Slukhuluchshayushchy operations (see) are widely applied at an otosclerosis and adhesive average otitis.

As at adhesive average otitis of change on average to fish soup of a polimorfna, and operation are in character various. They can be same as at an otosclerosis, or to include prosthetics of an anvil, a myringoplasty (see. Myringoplasty ), recovery of passability of an acoustical pipe, etc. At big destructions of elements of a middle ear (a cholesteatoma, radical operation of an ear) slukhuluchshchayushchy operation (see) provides creation of a small drum cavity with a kolumellization of one of windows of a labyrinth (see. Tympanoplasty ).

One of important points in assistance at G. is training to understand the speech from lips. Deaf children go to special facilities where along with the general education they are learned to understand the speech speaking from lips (cm, Surdomutism , Surdopedagogika ) and. to use the corresponding equipment (see. Surdoterapevtichesky equipment ).


plays the Large role in G.'s prevention prevention of infectious diseases, especially at children, timely and rational treatment of an acute inflammation of a middle ear (see. Otitis ), sanitation of a nose and nasopharynx. In perceptual G.'s prevention at hron, purulent average otitis the large role is played by sanitation of a middle ear, the prevention of exacerbations of otitis or its complications, and also periodic purpose of the stimulating therapy,

the Means used in gerontol. to practice, can be applied also to the prevention presbyacusis (see).

A specific place is held by prevention professional. On productions where noise and vibration take place, there are obligatory preliminary medical examinations for arriving and periodic — for working. Elimination or weakening of production noise is important (carrying out of the equipment making noise and vibration to the certain room, the organization of distance steering, sound insulation and vibration absorption etc.). Also individual means of protection are used: the vibroextinguishing gloves and footwear, ear helmets and antiphons (see. Protivoshuma ), by means of which it is possible to reduce noise level by 10 — 15 dB. Reduction of negative influence of noise is carried out y at the expense of breaks in work with an exit to the quiet room. For working in such conditions the organization of balanced and systematic diet with inclusion of vitamins, first of all groups B is necessary. At identification of signs of relative deafness treatment is appointed, leave is granted, and at its progressing — work out of noisy rooms.

See also Surdomutism .

The short characteristic of the typical diseases and morbid conditions causing deafness

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D. I. Tarasov; author of the tab. V. T. Palchun.