SNHL occurs when you lose the ability to hear certain sounds. It can affect one or both ears. Symptoms include:
Your ear is covered in tiny hair cells that change sounds into electrical signals for your brain to process. Sensorineural hearing loss happens when these hair cells get damaged.
Causes
Sensorineural hearing loss, or SNHL, occurs when the tiny hair cells of your inner ear are damaged. These cells are responsible for converting sound waves into nerve signals that your brain can interpret as sounds. They can be damaged or destroyed by many things, including prolonged exposure to loud noises, a physical injury that disrupts blood flow to your inner ear (such as from a car accident), certain medications (such as aminoglycosides), and aging.
This type of hearing loss can affect one or both ears, and it can happen gradually over time or suddenly. It may also be more severe in one ear than the other. Depending on the cause, it can be reversible. Your healthcare provider will perform a physical exam of your ears and a detailed history of your symptoms. They will gently feel around the outside of your ears and look inside your ear canal using a lighted tool called an otoscope. They will ask about your past illnesses and injuries, whether you have trouble hearing out of only one ear or both ears, and whether the symptom is sudden or gradual.
They will also ask about the frequency and intensity of your SNHL symptoms. The severity of your symptoms helps them determine the cause of your SNHL. Then they can decide what treatment is best for you.
Typical symptoms include difficulty understanding people on the telephone or in noisy environments, feeling like other people are mumbling, having trouble distinguishing deep voices from high-pitched ones, and a general feeling of muffledness. People with SNHL often find that they are less likely to participate in social activities, which can lead to depression and isolation.
A complete audiometric evaluation should be performed to identify SNHL, such as a pure tone audiogram and tympanometry. Other tests may be needed to distinguish it from conductive hearing loss, such as tuning fork tests, oto-acoustic emissions, and acoustic stapedial reflexes. If the results of these tests indicate that you have SNHL, your doctor will recommend a hearing aid to help you communicate more easily. In some cases, surgery to remove fluid or repair a perforation can also be beneficial.
Symptoms
The sound waves in your ears travel through the ear canal and vibrate the ear drum. The ear drum is connected to three middle ear bones (malleus, incus, and stapes), which transmit the vibrations to the inner ear (cochlea). The cochlea transforms the wave into a nerve signal that the brain interprets as sound. When you have sensorineural hearing loss, the ear cells that convert sound into electrical signals are no longer working properly. This can lead to a sudden or gradual loss of hearing. SNHL can affect one ear or both ears and can range in severity from mild to severe.
Symptoms include difficulty hearing low or high-pitched sounds, muffled sound, and trouble following conversations with multiple people. You may also experience ringing in the ear (tinnitus), or experience changes in balance and vertigo. SNHL can make it harder to recognize speech, but it is possible to learn new ways to communicate and adapt to the change.
Causes of SNHL include genetic or age-related conditions, loud noise exposure, certain medications or chemicals, and certain diseases. The most common cause of SNHL is exposure to loud noises over time, which can damage the hair cells in the cochlea and damage the nerve pathways that send sound from the ear to the brain. Often, this type of hearing loss is reversible if you remove yourself from noisy environments and use ear protection when listening to music or attending a live event.
Other causes of SNHL include the inflammatory condition otosclerosis, which can lead to the boney attachment of the eardrum to the tympanic membrane, which in turn can inhibit the movement of the fine mechanisms involved in hearing. Cytomegalovirus infection can also lead to SNHL in infants, especially when the mother contracted it during pregnancy.
During an exam, your healthcare provider will perform tests to determine the type and severity of your SNHL. They will gently touch around the outer ear and look inside your ears with a lighted tool called an otoscope to see if there are any problems that could interfere with your hearing. Then they will ask you questions about your symptoms and when they started. They will also do a few simple tests, like the Weber test and the Rinne test, to help them discover the cause of your hearing loss.
Diagnosis
If you experience a sudden and permanent hearing loss in one or both ears, it’s important to see an otolaryngologist for a thorough exam. In addition to a complete medical history, your doctor will perform a full audiometric evaluation. These tests will reveal whether the hearing loss is conductive, sensorineural or a combination of both types. They’ll also test for tinnitus and vertigo.
The symptoms of conductive and sensorineural hearing loss are similar, but it’s important to know the difference between them. Conductive hearing loss affects the outer or middle ear, while sensorineural causes problems with your inner ear. If you have a mix of the two, your hearing loss is referred to as mixed hearing loss.
Generally, if your hearing loss is caused by an underlying condition that can be treated, the outcome will be better than if the problem is permanent. Luckily, most of the causes of SNHL can be addressed.
Your healthcare provider will recommend a treatment based on the cause of your hearing loss. If the loss is due to an infection, antibiotics might help. If the loss is due to aging, there are ways to improve your hearing like wearing hearing aids.
In some cases, you can get back some of your hearing if you act quickly. For example, if your hearing loss is due to earwax buildup, your healthcare provider might remove it and you’ll be able to hear again for a short time.
But most SNHL is permanent. It can affect your quality of life and make it harder to engage in the world around you. It’s important to talk to a healthcare provider about the best treatment options for you, including hearing aids and cochlear implants. With the right treatment, you can enjoy your life again.
Treatment
As with conductive hearing loss, there are times when sensorineural hearing loss can be reversible if you act quickly enough. For example, sudden SNHL due to loud noise or environmental factors is often reversible if you immediately see an ear, nose and throat doctor. Symptoms of this type of hearing loss usually plateau within two weeks, and most people find that their hearing returns to normal.
Unlike conductive hearing loss, which occurs when sound waves cannot reach your inner ear, SNHL affects the sensory cells and nerve pathways inside your inner ear and brain. It happens when hair cells in the cochlea are damaged, or if your brain no longer receives signals from the ear. You may notice that sounds are muffled or soft, and it is more difficult to understand speech.
The first step in determining whether you have sensorineural hearing loss is a physical exam. Your healthcare provider will gently feel around the outside of your ear and look inside with a special lighted tool called an otoscope. This allows them to look for inflammation, fluid or earwax buildup, and damage to the ear drum. They will also ask about your symptoms.
Do you have a family history of hearing loss? Have you had any head trauma or illnesses in the past that might explain the onset of your hearing loss? Your healthcare provider will then perform a full audiologic assessment, including pure tone audiometry and speech audiometry. A tympanometry test will be performed to measure your eardrum and middle ear function, and a head computed tomography scan may be performed if they suspect an underlying condition such as mastoiditis or cerebellopontine angle tumor. In some cases, laboratory tests such as erythrocyte sedimentation rate, antinuclear antibody and rheumatoid factor are performed to check for an autoimmune cause of your SNHL.
If your healthcare provider can’t identify the cause of your SNHL, it’s considered idiopathic. In these cases, hearing aids are the primary treatment option. Today’s advanced hearing aid technology can stimulate your inner ear and fill in the Sound Voids of your SNHL, so that you can enjoy life again.
