Sensorineural Hearing Loss: Causes and Treatment
- Approximately one in three adults between 65 and 74 has hearing loss.
- Sensorineural is the most common form of hearing loss, and it's not reversible.
- Sensorineural hearing loss can be caused by illness, some medications, age, or exposure to loud noises.
- It typically cannot be fixed by medications or surgery.
- Hearing aids and cochlear implants may help your ability to hear.
Sensorineural hearing loss (SNHL) is the most common type of permanent hearing loss, affecting approximately 48 million people in the United States. It occurs from damage to the inner ear and cannot be reversed. If you have SNHL, most soft sounds will be difficult to hear. Even loud noise can be muffled or difficult to understand.
Two other types of hearing loss are conductive hearing loss and mixed hearing loss.
Conductive hearing loss is caused by something that stops sound from getting through the outer or middle ear. Mixed hearing loss occurs when you have both SNHL and a form of conductive hearing loss.
What Causes Sensorineural Hearing Loss?
"To understand sensorineural hearing loss," says Shoup, "you first have to understand how a sound is heard. Sound waves travel from the outer ear, through the ear canal to the eardrum. The eardrum vibrates, causing three connected bones in the middle ear to vibrate, which in turn passes along vibrations to the fluid-filled inner ear. Within the inner ear, there are thousands of hair cells laid out, kind of like the keys on a piano. These hair cells code the information and send the message to the hearing nerve, which then transmits information about the sound to the brain."
According to Shoup, sensorineural hearing loss occurs when something damages the hair cells, hearing nerve, or brain pathways of hearing. Approximately 15% of adults 18 or older in the United States have varying degrees of hearing loss, as reported by The National Center for Health Statistics. As you age, you are more likely to have hearing loss. An estimated 30 to 35% of people between 65 and 75 years old have some degree of hearing loss, increasing to 40 and 50% if you're over the age of 75.
Sensorineural hearing loss tends to be gradual and worsens over time. There are a few common causes for this type of hearing loss:
- Illnesses like mumps, meningitis, or multiple sclerosis
- Medications that are toxic to hearing
- Hereditary hearing loss
- Injuries or sharp blows to the head
- Problems with how the inner ear is formed
- Listening to loud noises
You may slowly realize it's difficult to hear conversations if there's background noise, or you may find it difficult to understand a child's softer voice.
Conductive vs. Sensorineural Hearing Loss
When something is blocking the transmission of sound waves from reaching the inner ear, conductive hearing loss is occuring. Some examples of conductive hearing loss include:
- Excessive ear wax in the ear canal
- Fluid from ear infections or bones stiffening in the middle ear
"Conductive hearing loss can often be treated successfully medically or surgically," says Shoup. "If hearing persists, amplification may be an option. Sensorineural hearing loss is caused by damage or loss of the sensory cells of hearing, the hair cells, or changes in the hearing nerve or brain networks that process sounds. Sensorineural hearing loss is typically treated with amplification devices, such as custom fit hearing aids."
Sudden Sensorineural Hearing Loss
While SNHL is typically gradual, there is a variation of SNHL that can result in sudden deafness: sudden sensorineural hearing loss (SSHL). With SSHL, there is rapid, unexplained loss of hearing. It can occur all at once or over several days. SSHL may affect only one ear. Health care professionals consider SSHL to be a medical emergency.
How Is Sensorineural Hearing Loss Diagnosed?
If you suspect you are experiencing SNHL, it's important to schedule a visit with an audiologist or otolaryngologist. A diagnostic test for hearing loss includes the following:
- Physical exam: Using an otoscope, a medical device used to look into the ears, the doctor will look for any physical problems or obstructions.
- Air conduction test: During this test, you'll wear headphones, and the doctor will play different tones and pitches. You'll signal when you hear certain sounds.
- Speech recognition test: Similar to the air conduction test, the speech recognition test involves playing words or sentences at different volumes.
- Bone conduction test: With a bone conduction test, the doctor will fasten a metal band with an attachment known as a bone oscillator to the bone behind the ear. The device will send sounds to the inner ear through the bone.
The results of your diagnostic hearing test are available quickly and will be mapped out on an audiogram. The audiogram will depict what you can typically hear at different pitch and volume levels. Volume is measured in decibels, while pitch is measured in hertz. The audiogram results will show if your hearing is normal or if it shows mild, moderate, moderately severe, severe, or profound hearing loss.
Treatment Options for Sensorineural Hearing Loss
Unfortunately, SNHL is not a hearing condition that can be cured or reversed. However, it can be treated.
Hearing aids are wearable devices that amplify sound. The hearing aid's microphone receives sound and converts it into a digital signal. The device's amplifier increases the strength of the digital signal, sending the amplified sound into the ear. Some devices have different settings you can use to customize the level of amplification needed for your surroundings.
However, the cost of hearing aids can be prohibitively expensive, and not all insurance plans will cover the cost. According to Consumer Reports, the average out-of-pocket cost for a pair of hearing aids is $2,691.
Unlike hearing aids, which are removable devices, cochlear implants are surgically implanted. They are small electronic devices that stimulate the cochlear nerve. Cochlear implants can provide greater clarity of sound than hearing aids, but they require rehabilitation and training after surgery to achieve the best results.
The cost of cochlear implants is significant, typically exceeding $40,000. Some insurance companies provide coverage for the implants and surgery, so check your policy documents to see the available options.
Is Sensorineural Hearing Loss Preventable?
While SNHL can be caused by genetics and illness, there are some ways to decrease your risk of developing hearing loss.
If you are around loud noises—such as a construction site or concert—wear hearing protectors like earplugs or protective earmuffs. If you listen to loud music, lower the volume to protect your hearing.
When prescribed any medications, ask if hearing loss is a potential side effect. If it is, talk to your doctor about possible alternatives.
If you feel like your hearing problems are worsening, visit a health care professional to get tested and discuss treatment options.
Kat Tretina is a journalist and copywriter with expertise in personal health and personal finance. Her content has been featured on sites such as Everyday Health, HuffPost, Forbes, Investopedia, and Credit Karma. Kat calls Orlando, Florida home.