Sensorineural Hearing Loss

What is sensorineural hearing loss?

Sensorineural (sen-suh-ree-NUR-uhl) hearing loss, also known as SNHL, occurs because of damage to your inner ear. It can happen suddenly due to an illness, injury or exposure to loud noise, like an explosion. Alternatively, SNHL can develop gradually over time as part of the aging process. And in some cases, people are born with it.

SNHL has a significant impact on your hearing ability. You may not be able to hear soft sounds, and even loud noises may seem muffled. That’s because tiny receptors in your inner ear called hair cells are damaged. These hair cells are responsible for converting sound waves into signals that your brain interprets as sound.

Unfortunately, these cells can’t repair themselves, making SNHL a permanent condition in most cases. But wearing hearing aids or other hearing devices can greatly improve your hearing and quality of life.

Types of sensorineural hearing loss

There are a few different types of sensorineural hearing loss:

• Unilateral sensorineural hearing loss affects one ear.
• Bilateral sensorineural hearing loss affects both ears.
• Asymmetrical sensorineural hearing loss affects both ears, but hearing loss is worse in one ear.
• Sudden sensorineural hearing loss is a medical emergency that happens within 72 hours of an injury, illness or exposure to loud noise (like fireworks or gunshots).

How common is sensorineural hearing loss?

Sensorineural hearing loss, particularly the age-related variant, is one of the most common types of hearing loss in adults. It often develops between the ages of 50 and 70.

Sudden sensorineural hearing loss — which happens immediately or over the course of a few days — affects between 1 and 6 out of 5,000 people every year.

What are the symptoms of sensorineural hearing loss?

If you have sensorineural hearing loss, you might notice:

• It’s easier to hear deep voices as opposed to high-pitched voices.
• It’s harder to hear in noisy environments.
• Other people sound like they’re mumbling.
• You have ringing in your ears.
• You have trouble following conversations with multiple people.
• Your hearing is muffled.

What causes sensorineural hearing loss?

Sensorineural hearing loss happens because of damage to your inner ear. Specifically, it occurs when the tiny hair cells in your cochlea or vestibulocochlear nerve get damaged or destroyed.

Some people are born with SNHL because of a lack of oxygen or other complications during fetal development. Others develop it later in life due to illnesses, trauma, exposure to loud noises or typical aging.

Risk factors

A risk factor is something that increases your chance of developing a certain condition. Diseases and conditions that raise your risk for SNHL include:

• Acoustic neuroma. This is a noncancerous tumor that affects your inner ear.
• Aging. Simply growing older increases your risk for hearing loss, as the tiny hair cells in your inner ear deteriorate over time.
• Ménière’s disease. This chronic ear disorder causes symptoms like vertigo and tinnitus (ringing in your ears).
• Ototoxicity. This is inner ear damage that results from taking certain medications.
• Systemic conditions. Some conditions — like diabetes and meningitis — can disrupt blood flow to your inner ear or inflame your vestibulocochlear nerve.
• Traumatic brain injury. Brain trauma can cause fractures, blood flow disruption and increased intercranial pressure — all of which can lead to SNHL.

In some cases, healthcare providers can’t identify an exact cause. When this happens, they call it idiopathic SNHL.

How is sensorineural hearing loss diagnosed?

A healthcare provider (usually an otolaryngologist) will start with a physical exam. They’ll gently feel around the outside of your ear. Then, they’ll look inside your ear with a lighted tool called an otoscope. This helps them find any abnormalities that might interfere with your hearing.

Your healthcare provider may also ask questions like:

• Did you lose your hearing suddenly or gradually?
• If it was gradual, when did it start?
• Do you hear better out of one ear?
• Have you had any recent illnesses or traumas?
• Do you have a family history of hearing loss?

What tests will be done to diagnose this condition?

An audiologist will run some hearing tests to determine whether you have SNHL. These tests might include:

• Acoustic reflex test, which measures how tightly your stapedial muscle (a small muscle in your middle ear) contracts in response to loud sounds.
• Auditory brainstem response, which uses electrodes to track your brain waves in response to sounds.
• Bone conduction test, which sends sound directly to your inner ear and helps determine which type of hearing loss you have.
• Otoacoustic emissions (OAEs), which measures sound-related vibrations from your inner ear and can show whether you have a blockage or hearing loss.
• Pure-tone audiometry, which determines the quietest sounds you can hear at different frequencies (pitches).
• Speech audiometry, which tests how well you understand words and records the softest speech you can repeat.
• Tuning fork exams, exams like Weber’s test and the Rinne test, which determine whether you have sensorineural or conductive hearing loss (can be done by your otolaryngologist).
• Tympanometry, which tells your healthcare provider how well your eardrum moves in response to sounds.

Your healthcare provider may also need to examine your cranial nerves or take imaging tests, like an MRI or CT scan.

How is sensorineural hearing loss treated?

Sensorineural hearing loss treatments include:

• Hearing aids. These devices amplify sounds like tiny speakers and make it easier for you to hear.
• Cochlear implants. These surgically placed devices bypass your inner ear and create a new pathway for sounds to reach your brain.
• Medications. If inflammation or disease causes SNHL, your healthcare provider might prescribe medications like corticosteroids.
• Bone-anchored hearing aids (BAHA). These surgically implanted devices use vibrations to send sounds to your inner ear. BAHA might be helpful if you have single-sided (unilateral) sensorineural hearing loss.
• Active surveillance. Your healthcare provider may recommend “watchful waiting.” This is especially true if you have mild sensorineural hearing loss.

Can sensorineural hearing loss be prevented?

You can’t always prevent SNHL because many factors are out of your control. But there are things you can do to reduce your risk:

• Discuss any medication side effects with your healthcare provider.
• Get your hearing tested regularly.
• Wear ear protection (like earplugs or earmuffs) in noisy environments. Hearing loss from noise exposure is 100% preventable.

What’s the outlook for sensorineural hearing loss?

Overall outlook depends on the underlying cause and severity of hearing loss. In most cases, SNHL is permanent. But hearing aids or cochlear implants can improve your hearing abilities and keep you from missing out on what’s happening around you.

If you have sudden sensorineural hearing loss, it’s important to seek medical treatment right away. Early intervention may result in better outcomes.

When should I see my healthcare provider?

You should tell your healthcare provider if you:

• Develop vertigo or other balance issues.
• Have trouble hearing in loud environments or when multiple people are speaking.
• Hear ringing in your ears.
• Need to turn up the volume on a regular basis.
• Notice a sudden change in your hearing.

What questions should I ask my doctor?

If you have SNHL, here are some questions you might want to ask your healthcare provider:

• What caused my hearing loss?
• Is there a chance my hearing could improve on its own?
• What are my treatment options?
• What kind of results can I expect from treatment?
• How often will I need to see you for follow-up visits?