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Bilateral Sensorineural Hearing Loss - Causes, Symptoms, Diagnosis and Treatments

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Bilateral Sensorineural Hearing Loss - Causes, Symptoms, Diagnosis and Treatments

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Sensorineural hearing loss refers to a condition where there is a hearing loss due to the hair cells of the inner ear being damaged.

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iCliniq medical review team

Published At September 26, 2018
Reviewed AtApril 22, 2024

What Is Sensorineural Hearing Loss?

The ears have three portions, namely the outer, middle, and inner ear. Sensorineural hearing loss (SNHL) occurs when the inner ear is damaged. It is referred to as sensorineural because the inner ear and hearing nerve need to work together for proper hearing. SNHL accounts for around 90 percent of hearing loss cases. It might be permanent and can be mild, moderate, severe, and total.

Sensory hearing loss is usually a consequence of damaged cochlear hair cells. These hair cells can be abnormally formed at birth or damaged after birth. Some of the causes include infections, certain drugs, and genetic mutations. Neural hearing loss is a consequence of a damaged cochlear nerve. This nerve is responsible for the transmission of impulses to the brain. SNHL usually results in a gradual deterioration of a person’s hearing over many years and can be accompanied by symptoms such as tinnitus (ringing in the ears) and vertigo. SNHL can be either:

  1. Unilateral - Affecting only one ear.

  2. Bilateral - Affecting both ears.

The common kinds of sensorineural hearing loss are presbycusis (age-related) and noise-induced hearing loss. The frequent symptoms of SNHL include the inability to distinguish voices in a noisy environment, difficulty following a conversation over the phone, a few sounds that are very loud, feeling that people are mumbling, and difficulty following and understanding speech. The symptoms are common to all types of hearing loss, so it is important to consult a doctor and run necessary tests to rule out other causes and conditions.

Diagnosis is generally made by an audiologist with the help of an audiogram, tympanometry, and speech audiometry. As of now, there is no cure for SNHL, and treatment is done with the help of hearing aids. In severe cases, a cochlear implant is indicated.

What Are the Different Types of Sensorineural Hearing Loss?

There are three types, these are

  • Bilateral Hearing Loss: This can be caused due to genetics, exposure to loud noises, or diseases like measles.

  • Unilateral Hearing Loss: This condition usually affects only one ear. This can be caused by a tumor, Meniere’s condition, or loud sounds.

  • Asymmetrical Hearing Loss: In this condition, both ears will be affected, but one ear will be worse than the other.

What Causes Sensorineural Hearing Loss?

There are many different conditions which can damage the inner ear, but they are broadly grouped into two types:

Congenital: Congenital SNHL is a type of hearing loss seen at birth. Reasons include -

  • Low birth weight.

  • Premature birth.

  • Inherited deafness.

Acquired Hearing Loss: Acquired SNLH is developed at a later stage in life, unlike the congenital type. Reasons include -

  • Presbycusis (Age-Related Hearing Loss) - It usually affects both ears in people between the ages of 65 and 74 years.

  • Noise-Induced Hearing Loss (NIHL) - Prolonged exposure to loud noise higher than 85 decibels or exposure to a single loud noise like gunfire or explosion.

  • Viral Infections - Such as measles, meningitis, and mumps.

  • Other Disorders - Such as Meniere’s disease, bacterial meningitis, diabetes, and inflammatory ear conditions.

  • Acoustic Trauma - Due to exposure to loud sounds such as firearms or explosions.

  • Medicines - Ototoxic drugs such as certain antibiotics, chemotherapy drugs, and anti-inflammatory drugs.

  • Tumors - Ear tumors and growths may also affect hearing health.

What Are the Signs and Symptoms of SNHL?

  • Those with sensorineural hearing loss can hear muffled sounds but not understand the context of what is being spoken, and this leads to gradual isolation.

  • Problems with hearing in a noisy environment.

  • There is reduced sensitivity to soft sounds. This causes problems with communication and interpersonal skills. It also affects learning and school performance in young children.

  • Balance problems.

  • Perception of loud sounds is altered, causing social withdrawal and loneliness.

  • Tinnitus (ringing or buzzing sound in the ear).

  • Brain stroke.

  • Iodine deficiency and hypothyroidism (underactive thyroid).

  • Dizziness.

What Is the Pathophysiology of Sensorineural Hearing Loss?

The abnormal formation or function of the hair cells present in the inner ear results in sensory hearing loss. Any damage to the vestibulocochlear nerve or the eighth cranial nerve results in neural hearing loss.

When Is the Right Time to Test The Child’s Hearing?

It is not easy to know if a child has hearing problems or not. Children can develop hearing loss due to infections at birth. In the following situations, it is best to get the children tested for hearing loss:

  1. If the child does not look like they understand the language.

  2. If they do not attempt to form words.

  3. If they develop frequent ear infections.

  4. If they have balancing problems.

  5. If they do not get startled by sudden noises.

How Is Sensorineural Hearing Loss Diagnosed?

The specialist will ask you questions to understand the symptoms and medical history. Then, the specialist will perform a physical examination and ask about any previous medical conditions and the medications that the child is currently taking. The tests include:

  • Physical Examination - The child will have to cover one ear at a time while the doctor plays sounds at different volumes. They will also conduct tests using a tuning fork, which measures the vibrations in the ear.

  • Audiometry - This test can detect hearing loss more accurately. Here, a number of different sounds at different volume levels are sent individually to each ear.

  • MRI - To check for any abnormalities in the ear, such as cysts or tumors.

How is Sensorineural Hearing Loss Treated?

A thorough evaluation of the extent of the hearing loss must be conducted by a hearing health professional who can diagnose the actual type of hearing loss and suggest appropriate treatment.

In the case of bilateral hearing loss, which is mild to moderate, hearing aids may help. However, in case of severe hearing loss, even using hearing aids will not help as they would just amplify the distorted sounds, and in the presence of background noise, it would lead to more confusion and frustration.

In that case, cochlear implants may be the solution. A cochlear implant is an electronic device that is placed in the ear surgically and stimulates the hearing nerve by converting sound waves directly to electrical impulses.

Is This Condition Permanent?

Unfortunately, Sensorineural hearing loss is permanent because it is impossible to repair or replace the hair cells in the inner ear. Hearing does not recover over time on its own. The percentage of hearing that has already been lost will remain permanent. Some types of sudden sensorineural hearing loss (SSHL) can be cured with immediate medical help.

What Is the Prognosis of SSHL?

The prognosis of SSHL depends on the extent and cause of the condition. This is a very common form of permanent hearing loss.


SSHL is a natural part of aging in many people, but some loud sounds can damage the inner ear or the auditory nerve permanently. Some causative factors of this condition are loud sounds, genetics, tumors, or the aging process. It is not a serious condition, but it can impact a person's normal life.

Frequently Asked Questions


Is Wearing a Hearing Aid Considered as a Disability?

Some people cannot hear at all the frequencies. So they are advised to use hearing aids. Using a hearing aid is not a disability. It is an adaptation to a different hearing frequency. A good hearing aid will help in the proper hearing. When a hearing aid does not have the potential to provide proper functioning, then it can lead to disability. Only total deafness is considered as a disability.


What Are the Different Levels of Hearing Loss?

Hearing loss can be mild, moderate, and severe. Severe cases result in total deafness. This might be due to the damage of the auditory nerve. Genetics might be the reason for it. You should consult your doctor to identify which level you are in to know the prognosis rate.


What Is the Prognosis for Sensorineural Hearing Loss?

Early treatment has a good prognosis. Medical or surgical procedures can treat sensorineural hearing loss. Sensorineural hearing loss leads to reduced quality of life and isolation. You should contact your doctor and ask for the treatment options.


Do You Need a Hearing Aid for Sensorineural Hearing Loss?

If sensorineural hearing loss is mild or severe in one ear, then using a conventional hearing aid is the usual treatment method. However, hearing aids need some degree of useable hearing. Therefore it is not useful in complete hearing loss cases.


How Does Sensorineural Hearing Loss Affect Speech?

Sensorineural hearing loss not only reduces the ability to hear mild sounds but also the ability to listen clearly. The function of understanding the speech is also lost. Sensorineural hearing loss is caused by a birth injury, diseases, genetic syndromes, and drugs that are toxic to the auditory system.


What Are the 4 Levels of Deafness?

Four different levels of deafness are mild, moderate, severe, and profound. It is necessary to identify the cause for that particular degree of deafness. With proper treatment plans and aids, it is possible to cope up with a hearing loss. With modern medicine, hearing loss is not a very big complication.


What Is Considered a Severe Hearing Loss?

Severe hearing loss can be categorized based on the severity level, as follows:
- Mild hearing loss - Hearing loss ranging from 20 to 40 decibels.
- Moderate hearing loss - Hearing loss ranging from 41 to 60 decibels.
- Severe hearing loss - Hearing loss ranging from 61 to 80 decibels.


How Long Should a Hearing Aid Last?

Typically, hearing aids have an estimated lifespan of around two to seven years. Depending on the style and quality, some may have a longer life. The lifespan also depends on the type. In-the-ear hearing aids last for four to five years, while behind-the-ear hearing aids have a five to six years lifespan.


What Vitamins Help With Hearing Loss?

If hearing loss is because of exposure to loud noise, then supplementation with vitamins A, C, and E with magnesium is a remedial treatment. Folic acid helps to keep your ears sharp if your hearing loss is due to aging. To minimize noise-induced hearing loss, vitamins A, C, and E, coupled with magnesium, is the best treatment option.


Can You Pass a Hearing Test With Tinnitus?

When you try to attend a hearing test with tinnitus, it might be difficult to understand certain words, pitches, and sounds. There are certain other protocols to be followed for tinnitus patients. Please inform the health care provider about your condition before beginning the test.
Source Article IclonSourcesSource Article Arrow
Dr. Vasantha. K. S
Dr. Vasantha. K. S



hearing aidcochlear implantbilateral sensorineural hearing lossnoise-induced hearing loss
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