Sudden Hearing Loss

What is sudden hearing loss? Sudden hearing loss is characterized by the sudden onset of hearing difficulty in one ear. It often resolves on its own, but can sometimes lead to permanent hearing damage.

At a Glance:

Sudden hearing loss is typically unilateral (affecting one ear) and of unknown cause.
It can manifest as a sensation of pressure or ear blockage and may be accompanied by tinnitus (ringing in the ears) and dizziness.
The exact cause of sudden hearing loss is usually not identifiable.
Many patients recover their hearing, but long-term and permanent hearing damage can occur.
There is no specific treatment due to the unknown causes, but anti-inflammatory cortisone preparations might increase the chance of recovery.
If an underlying condition is identified, it should be treated if possible.
Note: The information in this article cannot replace a doctor’s examination and should not be used for self-diagnosis or treatment.

What is Sudden Hearing Loss?

Sudden hearing loss is the abrupt onset of hearing loss, usually affecting one ear, though rarely it can affect both ears. Often, the exact cause remains unknown.

In cases of sudden hearing loss, the ability to hear decreases to varying degrees and can sometimes lead to deafness in the affected ear. Typically, the hearing loss occurs suddenly over a few minutes or hours. The more severe the initial hearing loss, the higher the likelihood of permanent hearing damage.

Many people experience transient episodes of sudden hearing loss that resolve on their own within seconds or minutes. If the hearing loss persists, medical attention should be sought. Individuals experiencing acute hearing loss should consult an ear, nose, and throat (ENT) specialist immediately. Generally, the chances of recovery are quite high.

What are the Symptoms of Sudden Hearing Loss?

The typical symptom of sudden hearing loss is the sudden onset of hearing difficulty in one ear. Some individuals wake up realizing they can no longer hear or can barely hear out of one ear. In about 3 out of 100 cases, both ears are affected. Tinnitus often accompanies the hearing impairment.

Other individuals may initially feel only a sensation of fullness or blockage in the ear before noticing the hearing loss. Additional symptoms of sudden hearing loss can include dizziness and sensory disturbances around the outer ear.

What are the Causes of Sudden Hearing Loss?

In over 90% of cases, the cause of hearing loss lies within the inner ear. Doctors refer to this condition as acute idiopathic sensorineural hearing loss or sudden hearing loss. Possible causes include viral infections or circulatory disorders in the inner ear, as well as autoimmune reactions where antibodies attack the body’s own cells. The connection to stress is not scientifically proven.

Specific causes of acute hearing loss are rarely identifiable. Potential causes include:

Tumors in the vestibular or auditory nerves, inner ear, or brain
Disorders in the production of inner ear fluids (Meniere’s disease)
Various viral diseases like flu, mumps, and measles
Autoimmune diseases such as systemic lupus erythematosus
Hemorrhages in the inner ear
Leaks of inner ear fluid
Neurological disorders such as multiple sclerosis
Metabolic diseases like diabetes
Vascular diseases
Side effects of certain medications
Head injuries
Noise exposure
Barotrauma from significant positive or negative pressure changes

What Factors Trigger Sudden Hearing Loss?

Few factors have been proven to increase the risk of sudden hearing loss. These include:

Smoking
Alcohol abuse
Various hereditary changes that increase blood clotting risk
Certain anti-inflammatory painkillers

How Common is Sudden Hearing Loss?

In Turkey, an estimated 160 to 400 out of every 100,000 people experience sudden hearing loss each year. The exact number is difficult to determine because many people do not seek medical help if symptoms resolve quickly on their own.

Sudden hearing loss can occur at any age but is particularly common in adults over 50. The likelihood of occurrence is roughly equal between men and women; children are rarely affected.

How is Sudden Hearing Loss Diagnosed?

If sudden hearing loss is suspected, ENT specialists will conduct an examination (anamnesis) and hearing tests. The ENT doctor will use a specialized microscope to examine the ear and ear canal to rule out other causes of hearing loss, such as ear drum, middle ear, or ear canal diseases, or earwax blockage.

Various tuning fork tests are also used, where a tuning fork is held in front of the ear or on the head. This helps distinguish between sensory impairment of the inner ear and sound transmission issues in the middle or outer ear.

A pure-tone audiogram provides the most precise measurement. For this test, different pitches are played through headphones at increasing volumes, allowing the threshold at which tones can be heard at specific frequencies to be determined.

The ENT doctor may conduct additional tests to more precisely identify the degree and location of the hearing impairment. This might include measuring brainstem potentials via electroencephalogram (EEG).

If dizziness is a symptom, the function of the balance organ is typically assessed. Further diagnostics such as magnetic resonance imaging (MRI) or blood tests may be necessary.

For instance, MRI can determine if a tumor like a vestibular schwannoma is present.

How is Sudden Hearing Loss Treated?

If a specific trigger for hearing loss is identified, it will be treated accordingly. However, in most cases, no specific cause can be determined, and treatment is based on experience. No treatment reliably restores hearing in all affected individuals, so the best course of action should be decided in consultation with a doctor.

Initially, anti-inflammatory glucocorticoids like cortisone are commonly used. These can be administered as tablets, intravenously, or directly injected into the middle ear, either alone or in combination.

The choice of administration method depends on:

The severity of the hearing loss
Which sound frequencies are affected
The presence and type of underlying conditions

If the hearing loss is minimal and does not interfere with communication, the natural course of the condition can be observed without treatment.

Sometimes, hyperbaric oxygen therapy is offered, where pure oxygen is inhaled in a pressure chamber, potentially in combination with cortisone medication. However, its effectiveness in relieving or curing symptoms is not yet conclusively proven.

What Can Be Done After Sudden Hearing Loss?

After treatment, it is beneficial to conduct a follow-up hearing test immediately and approximately 2 to 3 and 9 to 12 months later. In some cases, a rehabilitation measure (rehab) can also be helpful.

If the hearing loss is permanent, a hearing aid or, if that is insufficient, a hearing implant (cochlear implant) can help.

Tinnitus and dizziness usually diminish as hearing improves but can sometimes persist longer and be treated in rehabilitation.