Around 1.5 billion people globally experience some level of hearing loss – that’s nearly 20% of the world’s population. Losing the ability to hear can be devastating, and navigating the potential treatments isn’t always straightforward.

What actually causes it? Are there new treatments that can restore hearing? Can it be reversed? How does air travel affect hearing loss?

Konstantina Stankovic, MD, PhD, professor of otolaryngology, helps readers navigate these questions and more as she explains the mechanism behind hearing loss, describes available and emerging treatments, and provides a glimpse into her research and efforts to understand and restore this core human sense.

What causes hearing loss? Are there different types? Is it genetic?

There are many causes of hearing loss. They include genetic factors, which are errors in the DNA, loud noise, aging, infection, head trauma, and some medications. Additionally, certain medical conditions, such as high cholesterol, high blood pressure, diabetes, rheumatoid arthritis, and autoimmune conditions are associated with increased risk of hearing loss.   

Hearing loss can be broadly grouped into two categories: conductive and sensorineural hearing loss. Conductive hearing loss implies that there is a problem with how the sound is conducted through the ear canal and the middle ear into the inner ear. This can occur due to a hole in the eardrum, fluid in the middle ear or a disease process that erodes or fixes the minute bones in the middle ear. Sensorineural hearing loss indicates that there is a problem in the inner ear, the hearing nerve that connects the ear with the brain, or the brain itself. Most commonly, sensorineural hearing loss originates in the inner ear, which contains very delicate sensory cells called hair cells. Mixed hearing loss is a combination of conductive and sensorineural hearing loss.

What are the treatment options for hearing loss? 

Treatment options depend on the cause of hearing loss. For conductive hearing loss, some options include repairing a hole in the eardrum, replacing missing, broken or malfunctioning tiny bones in the middle ear with a prosthesis, performing eustachian tube surgery, or placing a type of implant in the skull bone. For sensorineural hearing loss, the main treatment options include hearing aids and cochlear implants. Additionally, it is important to manage diabetes, high blood pressure, high cholesterol, and other chronic conditions to slow the progression of hearing loss.

Is hearing loss reversible, or can it be prevented?

Hearing loss can sometimes be reversible. For example, conductive hearing loss is often reversible. The intervention may involve the removal of earwax buildup, treatment of middle ear infections or surgery. While sensorineural hearing loss is typically irreversible, some forms can be reversible, such as those caused by certain medications. Sudden hearing loss can be reversible if treatment is sought shortly after the loss occurs. In that case, treatment typically consists of steroids taken orally or delivered through the ear drum.

Hearing loss can be prevented by protecting the ears from loud noise and loud music, eating a healthy diet, avoiding smoking, maintaining a healthy lifestyle that includes regular exercise, avoiding medications that are toxic to the ear, and controlling underlying health issues, such as diabetes or high blood pressure.

What should I do if I get sudden hearing loss? 

You need to see a doctor as soon as possible. If the cause is sudden sensorineural hearing loss, you may benefit from a short course of steroids taken orally or steroid injections through the ear drum. The treatment is most effective if given within two weeks of the sudden hearing loss. You should also avoid exposure to loud noise to prevent adding insult to injury.

What’s the difference between hearing aids and cochlear implants? 

Hearing aids are devices that amplify sound and require no surgery. They make sounds louder but do not necessarily make them clearer. They are most effective for people with mild to moderate hearing loss. Cochlear implants are devices that require surgery to insert an electrode array directly into the cochlea, which is the hearing organ of the inner ear. Cochlear implants bypass missing or nonfunctional cells in the inner ear and directly stimulate the hearing nerve. They are effective for people with severe to profound hearing loss and can improve the clarity of speech. 

How do I choose the right hearing aid? Why don’t they always work?

It is best to consult a hearing aid specialist. They can help you identify the best hearing aid for your type of hearing loss. One size does not fit all. Hearing aids do not work well if the main problem is poor understanding of speech. This is because hearing aids make sounds louder, which does not always result in clearer speech. In addition, hearing aids sometime don’t work because they are incorrectly fitted or inadequately adjusted.

Does air travel affect hearing loss?

In some people, air travel can exacerbate existing ear problems and hearing loss. For example, if you travel with an ear infection, changes in cabin pressure during takeoff and landing can exacerbate hearing loss and even cause a rupture of the eardrum. People with a specific genetic cause of hearing loss due to an enlarged vestibular aqueduct can experience pressure-related changes in hearing.

What are the prospects regarding stem cell therapy reestablishing hearing?

This is a very active area of research that is demonstrating significant advancements in laboratory settings. However, it has not yet reached prime time for human application. Continued research and clinical trials will be necessary to determine its efficacy and safety for human use.

What is tinnitus? What causes it and are there any new or existing treatments?

Tinnitus is a phantom sound that is typically produced by the brain in response to hearing loss. A common way to experience tinnitus is through acoustic trauma. The main treatments include hearing aids, cognitive behavioral therapy, and cochlear implants for those who qualify for this surgical procedure. Stress management can help if tinnitus is exacerbated by stress. For severe, disabling tinnitus, consultation with a neuropsychiatrist or psychologist is recommended, as anxiety, depression, and sleep deprivation can exacerbate tinnitus. Other treatments, such as transcranial magnetic simulation or bimodal neuromodulation, have shown some benefit for certain patients. Many more experimental treatments are currently being investigated. 

Are children with chronic ear infections more likely to have hearing loss?

Yes, they are. To minimize this risk and support normal language development, it is important to treat underlying infections and monitor hearing. A simple and effective treatment that helps many is the placement of a small tube through the eardrum. These tubes allow the middle ear to stay ventilated. They reduce the frequency and intensity of ear infections. 

What’s Stanford doing to advance hearing loss understanding and treatment?

Stanford Initiative to Cure Hearing Loss includes over 100 researchers and clinicians. We have deep expertise in a range of complementary areas, which include genetics, structural biology, stem cells biology, regeneration, electrophysiology, mathematics, and computational modeling. We work collaboratively to better understand hearing loss and develop novel and improved treatment options. The Stanford environment is built to translate research findings from the lab bench to the clinic and thereby help people everywhere.

Why do your ears “ring” after extended periods of loud noise?

The ears ring after loud noise exposure because the inner ear has been damaged. This damage can be temporary or permanent. The ringing, called tinnitus, can be the first and sometimes only sign of hearing damage. It is essential to safeguard your hearing by using ear protection in noisy environments, such as loud concerts or when using power tools.

Sometimes my hearing goes in and out. Why does this happen and should I be concerned?

Many people experience brief episodes when hearing becomes weak. If these episodes last only a few seconds and occur infrequently, they are not a cause for concern. However, if your symptoms persist or worsen, it is best to be evaluated by an ear doctor. There are many causes of intermittent hearing loss, including earwax buildup, Eustachian tube dysfunction, middle ear infections, noise-induced hearing loss, Meniere’s disease, autoimmune inner ear disease, and others.

Can headphones and earbuds cause hearing loss?

Yes, they can cause harm if used improperly, particularly at high sound levels for extended periods. A rough rule of thumb is that if someone standing next to you can hear the music you’re listening to through your headphones or earbuds, it’s too loud.

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This story was originally published by the Stanford School of Medicine.