Schallempfindungsschwerhörigkeit/ Innenohrschwerhörigkeit: Ursachen, Symptome, Behandlung

Sound-induced hearing loss or sensorineural hearing loss

What is sensorineural hearing loss/internal ear hearing loss?

Acoustic hearing loss or sensorineural hearing loss is characterized by irreparable dysfunction in the inner ear. An initial sign may be limited speech understanding. The cause of the symptom is that the eardrum and ossicular chain transmit sound waves, but they are not properly transmitted and processed. This type of hearing loss can be divided into sensory, neural and sensorineural sensorineural hearing loss

In addition, depending on the type of sensorineural hearing loss, there are four subtypes:

  • Basocochlear sound sensorineural hearing loss - high-frequency hearing loss
  • Mediocochlear sensorineural hearing loss - midrange hearing loss
  • Apicocochlear sensorineural hearing loss - low frequency hearing loss
  • Pancochlear sensorineural hearing loss - broadband hearing loss

Causes of sensorineural hearing loss/ sensorineural hearing loss

The cause of sensorineural hearing loss/ sensorineural hearing loss is due to damage to the hair cells in the inner ear. Such damage prevents the hair cells from doing their job of amplifying and converting electrical signals. Possible causes of sensorineural hearing loss include presbyacusis, noise damage, hearing loss, poisoning, and skull injury. However, hearing impairment may also be due to pre-existing conditions (metabolic disease, diabetes, circulatory disorder,..) and hereditary factors. Accordingly, sensorineural hearing loss/ sensorineural hearing loss is present in both congenital and acquired forms.

Other possible causes that can lead to a corresponding impairment are:

  • Morbus Meniere (vertigo disease)
  • Atherosclerosis (vascular disease that leads to narrowing and hardening of the arteries)
  • Drugs such as
    • Chinine
    • Acetylsalicylic acid
    • Diuretics (diuretic medications)
    • Cytostatics (chemotherapeutic drugs)
  • Infections such as
    • Mumps
    • Measles
    • Typhoid
    • syphilis
    • Brain infections
    • AIDS
    • Toxoplasmosis
    • Borreliosis
    • Labyrinthitis
  • Acoustic neuroma (a benign growth that constricts the auditory nerve)

Acoustic hearing loss/ sensorineural hearing loss in children

In children and babies, sensorineural hearing loss is the most common form of acoustic impairment. It can be congenital or acquired in childhood. Congenital damage is due to hereditary processes, but maternal illness during pregnancy and complications in the birth process can also cause hearing loss. Infections and illness during childhood - these include, in particular, classic childhood diseases such as mumps, measles and rubella - are also a possible cause of sensorineural hearing loss. If hearing loss is suspected in children and babies, a paediatrician should be consulted for clarification and to initiate possible treatment using children's hearing aids.

Symptoms of sensorineural hearing loss/ sensorineural hearing loss

The symptoms of sensorineural hearing loss/ sensorineural hearing loss mainly refer to hearing loss. That is, spoken words are more poorly understood. A first indication of sensorineural hearing loss is therefore when conversations are difficult to follow, especially in noisy environments. In addition, there are often noises in the ear such as tinnitus. In some cases, sufferers also complain of balance problems as well as dizziness, which may be caused by the location of the vestibular organ in the inner ear.

Diagnosis of sensorineural hearing loss/ sensorineural hearing loss

If hearing loss is suspected, an otolaryngologist should be consulted as soon as possible, because if treatment is not received, further undesirable consequences may develop. A diagnosis is made by the ear, nose and throat specialist after taking a medical history and clarifying the patient's medical history. In the diagnostic process, various tests provide information about the type and severity of the hearing loss and whether it is unilateral or bilateral.

  1. Otoscopy: Otoscopy is an external examination that excludes earwax blockage, injury, and other external impairments of the ear.
  2. Audiometry: A hearing test is performed through headphones, which allows for the creation of an audiogram. The audiogram maps the hearing threshold, which is the volume level above which sounds are audible to the patient. A measurement takes place for both air and bone conduction. With the help of the resulting graph, different types of hearing loss can be distinguished from each other.
  3. Fowler test: In the case of unilateral hearing loss or severely different damage to the ears, the Fowler test, also ABLB test (Alternate Binaural Loudness Balance Test), can be used. The aim is to compare the ears with regard to their loudness perception. From the result, conclusions can be drawn about the location of the hearing loss in the case of sensorineural hearing loss.
  4. Weber test: To determine whether the hearing loss is to be assessed as unilateral (one-sided) or bilateral (two-sided), the Weber test is used. This involves placing a tuning fork on the mastoid (the bone behind the ear) and checking how long the resulting sound is heard by the patient. The test is then repeated on the other ear.
  5. Gutter test: For the gutter test is also used with the tuning fork, which is placed on the mastoid until the patient no longer hears any sound. The fork is then placed next to the ear. Here the sound should be heard again. If not, the attempt is considered negative and can be attributed to a conductive disorder. Both the Rinne test and the Weber test help differentiate a sensorineural versus a conductive-hearing-disorder.

Sound conduction hearing loss/ sensorineural hearing loss: audiogram

In the audiogram, a sensorineural hearing loss or sensorineural hearing loss is manifested by closely spaced bone and air conduction curves. A tolerance of 15 decibels applies here. In this example audiogram, you can see a bone conduction curve (line with arrows) that deviates only minimally from the air conduction curve (line with circles), suggesting sensorineural hearing loss.

Acoustic hearing loss/ sensorineural hearing loss: therapy

After a detailed examination and a differentiated diagnosis, therapeutic measures are derived. A congenital or chronic form of hearing loss is usually not curable, but only treatable. Support is usually provided in the form of a hearing aid. If the performance of a hearing aid is insufficient for the degree of hearing loss or the fitting is not possible for anatomical reasons, a cochlear implant can take over the function of the inner ear.

In the case of sensorineural hearing loss caused by inflammation, medication or surgery can provide partial relief. In the case of disease-related restriction, the impairment is usually curable and disappears after overcoming the disease. It is to be considered that a non-treatment can entail serious consequences, which is why a clarification should not be renounced under any circumstances.

Acoustic sensorineural hearing loss vs. conductive hearing loss: differences at a glance

Sound conduction hearing loss

Sound conduction hearing loss

  • Involves the inner ear

  • affects mainly speech comprehension

  • high frequencies are particularly affected

  • Causes include: Infections, noise exposure, hearing loss, extreme stress

  • Treatment by hearing aids or cochlear implant

  • Involves transmission from middle to inner ear

  • influences v.a. the volume

  • all pitches are affected

  • Causes include: Inflammation, swelling in the ear canal, blockage

  • Treatment by hearing aids, cochlear implant or bone-conduction hearing aid