SENSORINEURAL HEARING LOSS: CAUSES, SYMPTOMS, TREATMENT AND PREVENTION
Medically Reviewed by Dr. Sony Sherpa (MBBS) - September 02, 2024
Sensorineural hearing loss (SNHL) is a classification for hearing loss that occurs in response to auditory nerve damage or damage to the hair cells in the inner ear. This type is irreversible, although scientific advances may give rise to a cure soon.
This blog summarizes the causes, symptoms, and treatment options for SNHL, including recent breakthroughs in SNHL treatment.
What is Sensorineural Hearing Loss?
SNHL emerges when sufficient damage occurs to the auditory nerve that connects the ears to the brain or the inner ear hair cells.[1]
These hair cells change sound waves into electrical nerve impulses that the brain can interpret. Ear hair cell damage causes the brain to receive fewer or improper signals, resulting in hearing loss.
This condition is distinct from conductive hearing loss, which is a condition of faulty sound transmission affecting the outer or middle ear.
SNHL impacts one or both ears and ranges from mild to severe. Classifications of SNHL include bilateral (affecting both ears), unilateral (affecting one ear), or asymmetrical (affecting one ear more than the other).
Types and Causes of SNHL
There are several types of SNHL, including:
- Age-related (presbycusis): This type of SNHL is caused by the natural aging process and is the most common type of hearing loss in adults.
- Noise-induced: Exposure to loud noises over a long period can damage the inner ear's hair cells, leading to SNHL.
- Genetic: Some people are born with genetic mutations that can cause SNHL.
- Acquired: In this type of SNHL, auditory nerve damage results from various factors, such as head trauma, viral or bacterial infections, autoimmune diseases like Meniere’s disease, and ototoxic medications (also known as ototoxic hearing loss).
- Sudden (SSHL/sudden deafness): A type of acquired SNHL that occurs suddenly and without warning.
Symptoms of SNHL
The symptoms of SNHL can vary due to the severity or cause of hearing loss.[2] Some common symptoms include:
- Difficulty understanding speech, especially in noisy environments
- Muffled or distorted sound perception
- Difficulty hearing high-pitched sounds
- Tinnitus (ringing or buzzing in the ears)
- Difficulty hearing on the phone
- Difficulty following conversations
- Difficulty hearing in group settings or social situations
If you experience any of these symptoms, it is necessary to confer with a hearing specialist for a proper diagnosis and treatment plan.
Diagnosis of SNHL
If you are experiencing symptoms of SNHL, your audiologist will likely execute a series of tests to diagnose the condition. These tests may include:
- Audiogram: This hearing test measures your ability to hear different pitches and volumes.
- Rinne and Weber tests: These tests use tuning forks to determine if the hearing loss is conductive or sensorineural.
- MRI or CT scan: These imaging tests can help identify structural abnormalities in the inner ear.
- Blood tests: These tests can help identify any underlying medical conditions that may be causing the hearing loss.
Treatment and Management of SNHL
Unfortunately, SNHL is not reversible. However, there are several treatment and management options available to help improve hearing and quality of life for those with SNHL.[3]
Steroids
Audiologists may temporarily prescribe corticosteroids in cases of sudden hearing loss until they reach a definitive diagnosis. Similarly, corticosteroids are often part of the treatment plan for individuals with autoimmune hearing loss due to their effectiveness in suppressing inflammation.
Hearing Aids
Hearing aids are a standard treatment for SNHL. These devices amplify sound and can help improve hearing in both quiet and noisy environments. There are many different types of hearing aids available, including behind-the-ear, in-the-ear, and in-the-canal options.
Your audiologist can help you determine the best hearing aid for your needs.
Cochlear Implants
For those with severe or profound SNHL, cochlear implants may be an option. These surgically implanted devices bypass the inner ear's hair cells and can directly engage the auditory nerve. Cochlear implants can provide significant improvement in hearing for those with severe SNHL.[4]
Bone Conduction Implants
Bone conduction implants are sensorineural hearing loss (SNHL) treatment that bypasses the damaged cochlea and transmits sound vibrations directly to the inner ear. This surgery involves the implantation of a gadget that vibrates the skull bone, stimulating the inner ear. Bone conduction implants can benefit individuals with SNHL who have a damaged cochlea but have a functioning auditory nerve.
Assistive Listening Devices
Assistive listening devices (ALDs) can also be helpful for those with SNHL. These devices can improve hearing in specific situations for those with hearing aids, such as watching TV or talking on the phone. ALDs can also be used in group settings or social situations to help improve speech understanding.
Auditory Rehabilitation/Speech Therapy
For those with SNHL, auditory rehabilitation and speech therapy can be beneficial. These therapies can help improve communication skills and teach strategies for better understanding speech in different environments.
Tinnitus Management Techniques
For those with tinnitus, several management techniques can help reduce the symptoms. These may include sound therapy, cognitive behavioral therapy, and relaxation techniques.
Prognosis of SNHL
The prognosis for SNHL varies depending on the cause and severity of the hearing loss. In some cases, SNHL can be managed with hearing aids or other assistive devices, while in others, more invasive treatments may be necessary.
A hearing specialist is essential for determining the best treatment plan for your needs.
Prevention of SNHL
Some causes of SNHL, such as age-related and genetic factors, cannot be prevented. As for the rest, you can safeguard your hearing and lessen your chances of noise-induced SNHL by[5]:
- Wearing earplugs or noise-canceling headphones in loud environments
- Limiting exposure to loud noises
- Taking breaks from loud noises
- Avoiding ototoxic medications when possible
- Getting regular hearing check-ups
Future of Hearing
These advancements offer a glimpse into a future where hearing loss becomes a treatable condition and the soundscape becomes accessible to everyone. The relentless pursuit of scientific breakthroughs promises a symphony of hope for millions struggling with hearing challenges.
1. Regenerative Medicine for Ear Hair Cell Rebirth: Scientists are actively exploring ways to regrow damaged hair cells within the inner ear, potentially reversing sensorineural hearing loss. One promising approach uses stem cell therapy, transplanting healthy cochlear stem cells into the inner ear to stimulate hair cell regeneration. Animal studies have shown success, and early human trials are underway.[6]
2. Gene Therapy for SNHL: Gene therapy offers a targeted approach for genetic hearing loss caused by specific mutations. Researchers aim to restore normal hair cell function and hearing abilities by injecting non-defective genes into inner ear cells. Successful preclinical trials for Usher syndrome, a common genetic hearing loss condition, pave the way for future human applications.[7]
3. AI-Powered Hearing Aids and Smart Sound Enhancement: Traditional hearing aids amplify sound while struggling to distinguish speech from background noise. Artificial intelligence (AI) changes the game by enabling real-time noise cancellation and personalized sound adjustments. AI-powered hearing aids can learn an individual's listening preferences and adapt to their environment, providing a more precise and comfortable listening experience.[8]
4. Bionic Ears with Brain-Computer Interfaces: The ultimate frontier in hearing technology lies in brain-computer interfaces (BCIs) that directly connect auditory implants to the auditory cortex in the brain. This revolutionary approach bypasses the damaged inner ear entirely, translating sound waves into electrical signals that are interpreted directly by the brain. While still in the early stages, BCI-based hearing offers immense potential for restoring natural hearing perception for individuals with profound hearing loss.[9]
Conclusion
Sensorineural hearing loss can have a sudden or gradual onset and significantly impact daily life. While it is not reversible, many options are available to help improve hearing and the quality of life for those with SNHL. Those with intact hearing can help to prevent SNHL and improve outcomes by remaining informed and opting for early diagnosis and treatment. If you are experiencing symptoms of SNHL, consult a hearing specialist for a proper diagnosis and treatment plan.
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