Sensorineural hearing loss (SNHL) is caused by damage to the structures in your inner ear or your auditory nerve. It is the cause of more than 90 percent of hearing loss in adults. Common causes of SNHL include exposure to loud noises, genetic factors, or the natural aging process. Show A spiraling organ inside your inner ear called your cochlea contains tiny hairs known as stereocilia. These hairs convert vibrations from sound waves into neural signals that your auditory nerve carries to your brain. Exposure to sounds louder than 85 decibels can damage these hairs. However, you might not experience hearing loss until 30 to 50 percent of these hairs are damaged. Eighty-five decibels is roughly equivalent to heavy traffic noise heard from inside a car. SNHL can range from mild hearing loss to complete hearing loss depending on the degree of damage.
SNHL isn’t a life threatening condition, but it can interfere with your ability to communicate if not properly managed. Keep reading to find out what causes SNHL, how you can prevent it, and your treatment options if you’re currently dealing with it. SNHL can occur in one ear or both ears depending on the cause. If your SNHL onsets gradually, your symptoms might not be obvious without a hearing test. If you experience sudden SNHL, your symptoms will come on within several days. Many people first notice sudden SNHL upon waking. Sensorineural hearing loss can lead to:
SNHL can be congenital, meaning that it is present a birth, or acquired. The following are potential causes of SNHL. CongenitalCongenital hearing loss is present from birth and is one of the most common birth abnormalities. It affects about 1 to 3 babies per 1,000 births. About 50 percent of children born with congenital hearing loss develop it from genetic factors and the other half develop it from environmental factors. More than 100 genes have been linked to genetic hearing loss. Infections and a lack of oxygen can all lead to hearing loss. Loud noisesExposure to sounds over about 85 decibels can lead to SNHL. Even one-time exposure to sounds like gunshots or explosions can cause permanent hearing damage. PresbycusisPresbycusis is another name for age-related hearing loss. About 1 in 3 people between the ages of 65 and 74 in the United States have hearing loss. By the age of 75, about half have some type of hearing loss. Damage to your auditory nerve or the structures of your inner ear can lead to SNHL. This type of hearing loss leads to problems converting sound vibrations to neural signals that the brain can interpret. Conductive hearing loss occurs when sound can’t pass through your outer or middle ear. The following can cause conductive hearing loss.
Both types of hearing loss can cause similar symptoms. However, people with conductive hearing loss often hear muffled sounds while people with SNHL hear muffled and distorted sounds. Some people experience a mix of both sensorineural and conductive hearing loss. Hearing loss is considered mixed if there are problems both before and after the cochlea. It’s important to get a proper diagnosis if you’re dealing with hearing loss. In some cases, it’s possible to regain your hearing. The quicker you receive treatment, the more likely you are to minimize damage to the structures of your ear. SSHL is a hearing loss of at least 30 decibels within 3 days. It affects roughly 5 to 20 in 100,000 people and usually only affects one ear. SSHL leads to deafness either instantly or over a few days. It often only affects one ear and many people first notice it after waking in the morning. Medical Emergency The following causes can all lead to sudden deafness. The most common treatment option for sudden hearing loss is the prescription of corticosteroids. Taking corticosteroids within 2 weeks of the onset of SSHL gives you the best chance of regaining your hearing. Sensorineural hearing loss may affect one ear or both ears depending on the cause.
Doctors use several types of tests to properly diagnose sensorineural hearing loss. Physical examA physical exam can help differentiate SNHL from conductive hearing loss. A doctor will search for inflammation, fluid or earwax buildup, damage to your eardrum, and foreign bodies. Tuning forksA doctor may use a tuning fork test as an initial screening. Specific tests include:
AudiogramIf a doctor expects you have hearing loss, they will likely send you for a more accurate audiometer test performed by an audiologist. During the test, you’ll wear headphones in a soundproof booth. Tones and words will be played into each ear at different volumes and frequencies. The test helps find the quietest sound that you can hear and specific frequencies of hearing loss. Right now, there’s no surgical option to treat SNHL. The most common options are hearing aids and cochlear implants to help you compensate for hearing loss. Gene therapy for hearing loss is an expanding field of research. However, at this time it’s not clinically used for SNHL. Hearing aidsModern hearing aids can match specific hearing loss symptoms. For example, if you have problems hearing high-frequency sounds, a hearing aid can help dial in these sounds without affecting other frequencies. Cochlear implantsA cochlear implant is a device that can be surgically implemented to help with severe SNHL. A cochlear implant has two parts, a microphone you wear behind your ear and a receiver inside your ear that sends electrical information to your auditory nerve. The outlook for people with SNHL is highly variable depending on the extent and cause of hearing loss. SNHL is the most common type of permanent hearing loss. In cases of sudden SSHL, the Hearing Loss Association of America says that 85 percent of people will experience at least a partial recovery if they’re treated by an ear, nose, and throat doctor. About 32 to 65 percent of people regain their hearing spontaneously within 2 weeks. Does sensorineural hearing loss get worse?SNHL often progresses over time if it’s caused by age-related or genetic factors. If it’s caused by a sudden loud noise or environmental factors, symptoms will likely plateau if you avoid the cause of hearing damage. SNHL is a natural part of the aging process for many people. However, exposure to loud noises can also cause permanent damage to your inner ear or auditory nerve. Following these healthy hearing habits can help you avoid noise-related ear damage:
Author Stephanie A Moody Antonio, MD Associate Professor, Department of Otolaryngology-Head and Neck Surgery, Eastern Virginia Medical School Stephanie A Moody Antonio, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, Virginia Society of Otolaryngology-Head and Neck Surgery, American Neurotology Society, American Medical Association Disclosure: Nothing to disclose. Coauthor(s) Barry Strasnick, MD, FACS Chairman, Professor, Department of Otolaryngology-Head and Neck Surgery, Eastern Virginia Medical School Barry Strasnick, MD, FACS is a member of the following medical societies: Alpha Omega Alpha, American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, American Auditory Society, American College of Surgeons, American Medical Association, American Tinnitus Association, Ear Foundation Alumni Society, Norfolk Academy of Medicine, North American Skull Base Society, Society of University Otolaryngologists-Head and Neck Surgeons, Vestibular Disorders Association, Virginia Society of Otolaryngology-Head and Neck Surgery Disclosure: Nothing to disclose. Specialty Editor Board Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference Disclosure: Received salary from Medscape for employment. for: Medscape. Ted L Tewfik, MD Professor of Otolaryngology-Head and Neck Surgery, Professor of Pediatric Surgery, McGill University Faculty of Medicine; Senior Staff, Montreal Children's Hospital, Montreal General Hospital, and Royal Victoria Hospital Ted L Tewfik, MD is a member of the following medical societies: American Society of Pediatric Otolaryngology, Canadian Society of Otolaryngology-Head & Neck Surgery Disclosure: Nothing to disclose. Chief Editor Arlen D Meyers, MD, MBA Professor of Otolaryngology, Dentistry, and Engineering, University of Colorado School of Medicine Arlen D Meyers, MD, MBA is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, American Head and Neck Society Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Cerescan, Ryte, Neosoma, MI10<br/>Received income in an amount equal to or greater than $250 from: , Cliexa;;Neosoma<br/> Received ownership interest from Cerescan for consulting; for: Neosoma, eMedevents, MI10. Additional Contributors B Viswanatha, DO, MBBS, PhD, MS, FACS, FRCS(Glasg) Professor of Otolaryngology (ENT), Sri Venkateshwara ENT Institute, Victoria Hospital, Bangalore Medical College and Research Institute, India B Viswanatha, DO, MBBS, PhD, MS, FACS, FRCS(Glasg) is a member of the following medical societies: Association of Otolaryngologists of India, Indian Medical Association, Indian Society of Otology Disclosure: Nothing to disclose. |