Understanding Sensorineural Hearing Loss

Hearing loss affects millions of people in the U.S., yet it remains misunderstood by many. Among the three types of hearing loss—conductive, sensorineural, and mixed—sensorineural hearing loss (SNHL) is the most common, accounting for over 90% of cases. Here we’re understanding sensorineural hearing loss, its causes, symptoms, and available treatments in greater detail.

A diagram shows the outer, middle and inner ear.

What Is Sensorineural Hearing Loss?

Sensorineural hearing loss occurs due to damage to the inner ear—specifically the cochlea—or the nerve pathways that transmit sound to the brain. Inside the cochlea are tiny hair cells responsible for converting sound vibrations into electrical signals. These signals travel along the auditory nerve to the brain, where they are interpreted as sound. Damage to these hair cells or nerve pathways disrupts this process, leading to reduced hearing clarity and volume.

Unlike conductive hearing loss, which involves physical blockages or structural issues in the outer or middle ear, SNHL results from issues deep within the auditory system. This type of hearing loss can vary in severity, ranging from mild to profound, and is often permanent due to the inability of hair cells to regenerate.

A Venn Diagram showing the types of hearing loss and their causes.

Causes of Sensorineural Hearing Loss

SNHL can result from a variety of factors. Understanding these causes is crucial for prevention and management.

1. Aging (Presbycusis)

As people age, natural wear and tear occur within the auditory system. Tiny hair cells in the cochlea become less effective, leading to a gradual decline in hearing. This age-related hearing loss often affects both ears and typically impacts higher frequencies first.

2. Noise Exposure

Prolonged exposure to loud sounds, such as machinery, concerts, or personal audio devices, can damage the hair cells in the cochlea. Sounds above 85 decibels, especially over extended periods, are particularly harmful. Sudden loud noises, such as explosions or gunshots, can also cause immediate damage, known as acoustic trauma.

3. Genetics

Inherited conditions can predispose individuals to hearing loss. Genetic factors may affect the development or function of the inner ear and auditory nerve, leading to congenital or progressive SNHL.

4. Infections

Certain viral and bacterial infections, such as meningitis, measles, or mumps, can damage the cochlea or auditory nerve. These infections can cause inflammation, disrupt blood flow, or directly harm the delicate structures of the inner ear.

5. Medications (Ototoxicity)

More than 200 medications are classified as ototoxic, meaning they can harm the inner ear. Common culprits include certain antibiotics, chemotherapy drugs, and high doses of aspirin. These medications can lead to temporary or permanent damage, depending on the dosage and duration of use.

Learn more about which medicines can cause hearing loss. 

6. Trauma

Head injuries can damage the cochlea, auditory nerve, or other parts of the auditory pathway. Physical trauma, such as fractures to the temporal bone, can disrupt the inner ear’s function. Sudden exposure to extremely loud noises, like an explosion, can also result in immediate hearing loss.

7. Systemic Conditions

Diseases like diabetes and autoimmune disorders can contribute to SNHL by affecting blood flow or causing inflammation in the inner ear. Meniere’s disease, a chronic inner ear condition, can also lead to sensorineural hearing loss alongside symptoms like vertigo and tinnitus.

Symptoms of Sensorineural Hearing Loss

Recognizing the symptoms of SNHL is key to seeking timely treatment. Common indicators include:

  • Difficulty understanding speech, especially in noisy environments.
  • A perception that people are mumbling or speaking unclearly.
  • Trouble hearing high-pitched sounds, like children’s voices or birdsong.
  • Ringing or buzzing sounds in the ears (tinnitus).
  • Increased sensitivity to loud noises.
  • Needing to turn up the volume on devices like TVs or radios.
  • A reduced ability to distinguish speech from background noise.

Diagnosing Sensorineural Hearing Loss

Diagnosing SNHL requires a comprehensive evaluation by a hearing care provider. Key steps include:

  • Medical History: Reviewing past illnesses, medications, noise exposure, and family history of hearing loss.
  • Physical Examination: Inspecting the ear for blockages or abnormalities.
  • Audiometry Tests: Measuring hearing ability across different frequencies and volumes.
  • Speech Recognition Tests: Assessing how well speech is understood in various conditions.
  • Imaging Tests: MRI or CT scans may be used to identify structural issues or tumors.

Schedule a free evaluation at your local American Hearing + Audiology center. 

How Sensorineural Hearing Loss Develops

The process of SNHL development often starts with damage to the inner ear’s hair cells. These cells play a vital role in converting sound vibrations into electrical signals. Damage may occur gradually, as with aging or prolonged noise exposure, or suddenly, due to trauma or infection. Once damaged, these hair cells cannot regenerate, leading to permanent hearing loss.

Additionally, disruptions in the auditory nerve’s ability to transmit signals to the brain can contribute to SNHL. This nerve damage may result from genetic conditions, systemic diseases, or ototoxic medications. In some cases, reduced blood flow to the inner ear—caused by cardiovascular conditions—can also impair hearing.

Treatment Options for Sensorineural Hearing Loss

Although SNHL is often irreversible, various treatments can enhance hearing and improve quality of life.

1. Hearing Aids

Hearing aids amplify sound and improve clarity, making it easier to communicate in different environments. Modern devices offer features like noise reduction and Bluetooth connectivity.

2. Cochlear Implants

For severe or profound SNHL, cochlear implants bypass damaged hair cells and directly stimulate the auditory nerve. These devices require surgical implantation and rehabilitation.

3. Assistive Listening Devices

Tools such as amplified telephones or personal FM systems can support specific hearing needs.

A palm holding several types of medication.

4. Medications

In cases involving inflammation or autoimmune conditions, corticosteroids may help reduce symptoms. However, this treatment is typically temporary.

5. Auditory Rehabilitation

Speech therapy and auditory training programs can help individuals adapt to hearing changes and improve communication skills.

Preventing Sensorineural Hearing Loss

While not all cases of SNHL are preventable, taking proactive steps can reduce risk:

  • Limit Noise Exposure: Avoid prolonged exposure to loud environments or use ear protection.
  • Maintain Cardiovascular Health: Conditions like high blood pressure can affect inner ear function.
  • Be Aware of Medications: Consult your doctor about potential ototoxic side effects.
  • Protect Against Infections: Stay up-to-date on vaccinations and seek prompt treatment for illnesses.
  • Regular Hearing Tests: Routine check-ups can catch early signs of hearing loss.

Living With Sensorineural Hearing Loss

Adjusting to SNHL involves using appropriate tools and seeking support. Hearing aids and cochlear implants can restore a sense of normalcy. Additionally, family, friends, and hearing care providers play essential roles in creating a supportive environment. Participating in social activities and seeking counseling can help reduce feelings of isolation.

Take Control of Your Hearing Health

If you’ve noticed symptoms of hearing loss, don’t wait. Contact American Hearing + Audiology to schedule a hearing evaluation. Our dedicated hearing care providers will guide you toward solutions tailored to your needs.