What is damaged when hearing loss occurs?

Inner ear hearing loss, deafness and deafness

Inner ear hearing loss(Sensorineural hearing loss, cochlear hearing loss): Hearing impairment due to impaired sound sensation. The causes of inner ear hearing loss are often unexplained, e. B. in the widespread age-related hearing loss. However, there are known causes for some forms of inner ear hearing loss, but their exact assignment is not always easy for the doctor. This is to be distinguished from Conductive hearing loss (Middle ear hearing loss) due to impaired sound conduction in the outer ear or middle ear.

Deafness(severe hearing loss, severe hearing impairment): Significant loss of hearing. Although 97% of deaf people still have residual perceptions that can be amplified with a hearing aid, it is called deafness.

Deafness: Complete loss of hearing, no more acoustic perception.

Leading complaints

  • Gradual or rapid hearing loss or loss of hearing
  • Infants do not respond to the mother's voice at 3–6 months of age, later language development is delayed.

When to the doctor

In the next days,

  • when hearing loss occurs.
  • Infants do not respond to loud noises or the mother's voice.

The illness

Causes and Risk Factors

There are various diseases behind the ENT medical key finding "inner ear hearing loss":

  • The chronic noise-related hearing loss is one of the most common forms of bilateral inner ear hearing loss. The trigger is long-term exposure to noise, e.g. B. at work, but increasingly also with younger people through loud music (headphones or disco). Decisive for the occurrence of noise-induced hearing loss are volume, tone frequency (high tones are more harmful than low tones), duration of noise exposure and personal sensitivity to noise. Consistent noise protection is essential for prevention.
  • Causes of a traumatic inner ear hearing loss are sudden direct or indirect injuries. Direct injuries include B. a fracture of the petrous bone, in which the inner ear can also be damaged. Indirect injuries to the inner ear occur, for. B. in bang trauma, which is triggered by an explosion or another short sound pressure wave, or in barotrauma, which leads to damage to the inner ear when diving or flying due to considerable negative pressure in the middle ear.
  • About 1 in every 1,000 newborns has an inherited form of hearing loss at birth (e.g. Usher syndrome). Other forms of congenital inner ear hearing loss develop only in the first years of life. Some inner ear damage in children is also acquired during pregnancy (e.g. alcohol abuse or rubella in the mother), during childbirth (e.g. forceps delivery) or after birth (e.g. severe otitis media) (inner ear hearing loss acquired in early childhood).
  • Causes of a Inflammatory hearing loss in the inner ear (Labyrinthitis) are infections and other inflammatory processes of the inner ear or its surroundings. They occur when pathogens reach the inner ear via the bloodstream, e.g. B. as a result of Lyme disease, mumps or measles. Acute or chronic otitis media can also damage the inner ear.
  • Some drugs have ear-damaging (ototoxic) side effects in high doses and long-term use and thus impair the functions of the inner ear (inner ear hearing loss caused by toxicity). Aminoglycoside antibiotics such as gentamicin and streptomycin destroy the sensory cells of the auditory and equilibrium organs. This effect is even used therapeutically in the treatment of Menière's disease. Commercial poisons (e.g. nitrobenzene compounds in solvents or heavy metals) as well as addictive and luxury goods (e.g. alcohol or heroin) are harmful to the inner ear.
  • If the unilateral hearing loss slowly worsens and tinnitus occurs, one is suspected Acoustic neuroma Near. It is a benign tumor of the auditory and balance nerves. In the further course there is unspecific dizziness, unsteady gait, facial pain and one-sided facial paralysis.

Division into degrees

  • Minor: Normally loud speech can still be understood from a distance of more than 4 m; Hearing loss: 10–40% (equivalent to 20 dB)
  • Moderate: Normally loud speech is understood from a distance of 1–4 m; Hearing loss: 40–60% (equivalent to 40 dB)
  • High grade: Normally loud speech is only understood from a distance of 0.25–1 m; Hearing loss: 60–80% (equivalent to 60 dB)
  • Bordering on deafness: Normally loud speech is only understood from a distance of less than 25 cm; Hearing loss: 80–95% (equivalent to 80 dB).

Diagnostic assurance

Diagnosis of congenital or early childhood forms

Unfortunately, inner ear hearing loss from birth is often only recognized in children around the age of two, namely when speech development is absent or lagging behind.

However, the foundations for language acquisition are laid in the first twelve months, when the nerve pathways are formed in the brain - therefore, early recognition is important. With objective measurement methods such as otoacoustic emissions or brainstem audiometry, doctors can examine newborns for hearing loss, as they function even without the child's cooperation. The cost of the Hearing screenings of newborns are covered by health insurances.

Diagnosis of hearing loss in adults

In adult patients, the ENT doctor determines the degree of hearing loss with the help of hearing tests (tone audiogram and speech audiogram).

treatment

In most cases there is still some residual hearing that can be strengthened with hearing aids (see under age-related hearing loss). In the case of completely deaf people, the use of a cochlear implant is an option in order to enable the affected person to have an auditory perception again or for the first time.

Cochlear implant

The Cochlear implant (CI system) can even enable deaf people to have an auditory perception, provided their auditory nerve is functioning. It bypasses the damaged inner ear and forwards the auditory impressions as electrical impulses directly to the auditory nerve.

Structure and principle. The CI system consists of an inner and an outer part.

  • During an operation under general anesthesia, the doctor implants a receiving coil and a magnet in a milled recess in the skull bone and from there inserts electrodes into the cochlea.
  • The outer part consists of a microphone, a signal processor that converts speech into electrical impulses and a transmitter coil. With modern cochlear implants, it is worn behind the ear like a normal hearing aid and held by the magnet. Some cochlear implants have a separate housing for the signal processor that is worn on the belt.

Chances of success. The auditory impressions transmitted with a cochlear implant differ greatly from the sensory impressions of a person with normal hearing. This is why rehabilitation centers practice recognizing sounds and speech. After a few months of training, this usually goes so far that language is understood again. Some patients receive an implant only on one side, some also on both sides. With two implants, speech understanding is better in restless situations and directional hearing is usually better. The success also depends on the duration of the deafness, the language competence, the condition of the auditory nerves and the motivation to train and learn the unfamiliar auditory impressions, or for speech sounds in general. The treatment is therefore particularly successful in adults who have recently become deaf and who are promptly treated with cochlear implants. Adults born deaf hardly benefit from an implant treatment.

Care of young children. Deaf parents, who are also deaf, often doubt that deaf toddlers should be provided with cochlear implants. The success is greatest when they are implanted in the first two years of life. From a medical point of view, this is the best. If the parents themselves are deaf, they often fear that sign language and their own deaf culture will be marginalized by concentrating on spoken language. As a compromise, these children often grow up "bilingual", i. H. they first learn the sign language and later the spoken language. Accordingly, they do not receive cochlear implants until later.

Complications with cochlear implants. Cochlear implant recipients are particularly at risk of developing otitis media, which can develop into life-threatening meningitis. To prevent this, the STIKO (Standing Vaccination Commission) recommends cochlear implant users vaccinations against the most common pathogens causing otitis media and meningitis, i.e. Haemophilus influenzae type B, streptococci, pneumococci and meningococci.

Further information

  • www.schwerhoerigen-netz.de - German Association for the Hard of Hearing V., Berlin: Contains a good and very detailed guide (can also be ordered as a CD) as well as addresses of self-help groups throughout Germany.
  • www.dcig.de - German Cochlea Implant Society e. V., Illertissen: With addresses of self-help groups and specialized clinics. Further information on the association magazine "Schnecke" can be found at www.schnecke-ci.de.
  • O. Fritsche; K. Kestner: Diagnosis hearing impaired. What parents of hearing impaired children should know. Karin Kestner Verlag, 2006. Recommended by the Federal Association of German Hearing Impaired Pedagogues.
  • G. Batliner: Supporting hearing-impaired children through play: A parents' book for early hearing and language acquisition. Ernst Reinhardt Verlag, updated in 2016.

Authors

Prof. Dr. med. Gerhard Grevers; Dr. Ute Koch; Thilo Machotta; Dr. med. Arne Schäffler in: Gesundheit heute, edited by Dr. med. Arne Schäffler. Trias, Stuttgart, 3rd edition (2014). Revision and update of the sections "When to see a doctor", "Confirmation of diagnosis", "Treatment" and "Further information": Dr. med. Sonja Kempinski | last changed on at 11:31


Important note: This article has been written according to scientific standards and has been checked by medical professionals. The information communicated in this article can in no way replace professional advice in your pharmacy. The content cannot and must not be used to make independent diagnoses or to start therapy.