Hearing loss is often seen as a simple inability to hear sounds, but it actually manifests itself in many different ways. It can vary in severity, in the types of sounds that become inaudible, in its symptoms, and in how quickly it sets in.
The most common form develops slowly, over time, and affects both ears. It usually appears between 40 and 50 years of age, or even later. While this is the most frequent scenario, some people may experience sudden hearing loss in only one ear.
Here's an overview of sudden hearing loss and unilateral hearing loss, how they can occur together, and the possible causes of each.
Sudden Hearing Loss
Sudden hearing loss is a form of hearing loss that appears quickly and noticeably, unlike typical hearing loss. A gradual decline in hearing is normal and often linked to aging. However, sudden hearing loss can be concerning.
Here's a detailed examination of sudden hearing loss and its possible underlying causes. This information will not diagnose your specific case, but it can be helpful to know the possible causes. If you experience sudden hearing loss, consult a doctor to rule out any potentially dangerous underlying causes and get a diagnosis.
An Auditory Nerve Problem
One possible cause of sudden hearing loss is compression of the auditory nerve. The auditory nerve is the part of the ear that transmits signals from the ear to the brain. If it is compressed or damaged, it can allow fewer signals to pass to the brain and thus reduce the extent of hearing.
Since the auditory nerve acts as an information highway from the ear, any compression or injury to this nerve can lead to sudden and noticeable hearing loss.
A Perforated Eardrum
The eardrum is a thin membrane located at the end of the ear canal; it vibrates in response to sound. A perforated eardrum occurs when it tears. A perforated eardrum conducts sound less effectively, which can cause sudden hearing loss.
Sudden hearing loss in both ears due to a perforated eardrum is likely caused by an extremely loud sound, trauma, or a sudden change in pressure. Scuba diving, for example, can cause both eardrums to rupture. Without precautions, diving and similar activities can subject the ears to extreme pressures.
An Infection
At one time or another, we all get sick. Whether it's the flu or a common cold, you've most likely encountered a few infections in your lifetime. While most of them are either fought off by the immune system or effectively treated with medication, some can cause lasting damage.
Some sudden hearing loss of undetermined origin is thought to result from infection. Although very rare, it is possible for a virus to reach the components of the ear and cause sudden, lasting sensorineural damage. COVID-induced hearing loss, a rare complication, is one example.
Diseases that can cause sudden deafness or hearing loss in general include mumps, measles, and rubella. Vaccines help the body fight the disease and prevent these conditions in general. Sometimes, allergies or sinusitis can also lead to hearing loss.
Unilateral Hearing Loss
Many people associate hearing loss with a general decrease in hearing in both ears, but a difference in hearing between the two ears is perfectly normal.
Many people who have never even seen an audiologist to diagnose their hearing loss identify their "good ear" themselves. They then tend to orient this ear towards what they are trying to listen to.
Here are some possible causes of unilateral hearing loss and what can be done about them.
A Cotton Swab Perforation
For decades, cotton swabs have been misused by many people to clean their ears. In the vast majority of cases, ears clean out earwax on their own. Using a cotton swab can instead promote earwax buildup by pushing it deeper into the ear.
In addition to being unnecessary, cotton swabs can be dangerous. Their small size and the act of using them blindly in the ear can cause a perforated eardrum or even other physical damage to the ear. Injuries from cotton swabs usually result in unilateral hearing loss, as most people stop after injuring one ear.
Earache
Earache most often corresponds to an ear infection caused by bacteria or a buildup of fluid. One of the most common types of infection is otitis media. In otitis media, the middle ear cavity, called the tympanic cavity, can fill with fluid.
This is called otitis media with effusion (glue ear) and it can reduce your ability to hear in one ear. Sounds perceived are then muffled, almost as if you were underwater. Fortunately, if the infection is treated within a reasonable time, hearing can be restored.
Both ears can be infected, but earaches most often affect only one side and cause temporary hearing loss in that ear.
Sudden Unilateral Hearing Loss
Sudden hearing loss and unilateral hearing loss can occur at the same time: this is called acute unilateral hearing loss. This form of hearing loss is not particularly common. However, it is essential to be aware of it and to consult a doctor if you suddenly lose hearing in one ear.
Here's a detailed examination of this particular form of hearing loss and what can cause it.
Sudden Sensorineural Hearing Loss
Sudden sensorineural hearing loss, also called SSNHL or sudden deafness, is a condition in which a person experiences the sudden onset of sensorineural hearing loss.
Sensorineural hearing loss is a form of hearing loss caused by a problem with the inner ear, the auditory nerve, or the auditory cortex of the brain. This inner ear disorder is characterized by a loss of at least 30 decibels over at least three contiguous frequencies within 72 hours.
SSNHL can be long-lasting, or it can be temporary and disappear as quickly as it appeared. In the vast majority of cases, it occurs without any identifiable cause. This idiopathic nature makes it a difficult form of hearing loss to manage and live with.
Blood tests, MRIs (magnetic resonance imaging), and balance tests can be used to diagnose SSNHL or similar hearing conditions. Common treatments include steroids (mainly corticosteroids) in case of infection.
Other treatments may consist of medications for an autoimmune disease that may have caused the hearing loss. Neurological diseases, circulatory disorders, and inner ear conditions (such as Ménière's disease) can all be the cause.
Acoustic Neuroma
Another possible cause of acute unilateral hearing loss is acoustic neuroma. This is a relatively rare condition, caused by the development of a non-cancerous tumor on or around the structures of the ear.
An acoustic neuroma can cause hearing loss by compressing the auditory nerve or by somehow interfering with the functioning of the inner ear. Tumors normally take some time to develop.
This is why a large proportion of acoustic neuroma cases cause progressive hearing loss and tinnitus. While this is true most of the time, it is estimated that about 5% of patients with an acoustic neuroma experience acute unilateral hearing loss.
How is Hearing Loss Diagnosed?
While a sudden loss of hearing in one ear is usually obvious, the exact cause and extent of the hearing loss are more difficult to pinpoint. This is where diagnostic tools and the audiologist come in.
Learn how hearing loss is diagnosed and how it is quantified.
Visual Examination
The first tool an audiologist has is a device called an otoscope. An otoscope is essentially a specialized magnifying glass that allows them to observe your ear canal and eardrum.
This is usually the first thing the audiologist does. They want to make sure the eardrum is intact and check for any earwax buildup that might be affecting your hearing.
Pure-Tone Audiometry
The most useful diagnostic tool an audiologist has is the audiogram. The test consists of headphones and a device that allows them to transmit different tones at different volumes.
You wear the headphones and signal whenever you hear the sound. Each ear is tested separately. At the end of the test, they get a clear graph illustrating your degree of hearing loss for each ear.
Based on the audiogram results, they can prescribe hearing aids for you. This is convenient, but there are many options when it comes to hearing aids. Comparing offers can save you money and allow you to get an excellent product at a fraction of the price, like the CLARIA EV1.
Act Quickly in Case of Sudden Hearing Loss
Sudden hearing loss should absolutely be investigated. Several conditions can cause it, including acoustic neuroma or sudden deafness (SSNHL). In these cases, getting treated as soon as possible can make a huge difference to your long-term hearing ability.
Sources
Otitis media with effusion | MedlinePlus
Sudden sensorineural hearing loss in adults: Evaluation and management | UpToDate
Acoustic Neuroma: Symptoms | Johns Hopkins
Ruptured eardrum (perforated eardrum) - Symptoms and causes | Mayo Clinic
Sudden Sensorineural Hearing Loss (SSHL) | NIDCD
