What You Need to Know About Sensorineural Hearing Loss

Causes

There are a number of causes of SNHL, including a blow to the head, reduced blood flow to the ear, certain medications that impact the inner ear, abrupt changes in air pressure, benign tumors — the list goes on. But the most common causes are age-related hearing loss (known as presbycusis) and noise exposure, whether that's ongoing exposure to, say, daily traffic, or a one-time exposure to something like a gunshot, a jackhammer or firecrackers.

“There are numerous causes of hearing loss, and many of them are not mutually exclusive,” says Collins. “For example, you can have both a genetic link to hearing loss, but also have noise exposure from being an avid hunter.”

Types of sensorineural hearing loss

Sensorineural hearing loss can come on gradually or suddenly, and can affect one or both ears, depending on the cause. For instance:

• Asymmetrical SNHL occurs when there’s hearing loss on both sides but one side is worse than the other.
• Bilateral progressive hearing loss happens in both ears over several months. Also diagnosed as autoimmune inner ear disease, this type of SNHL occurs when the body’s immune system mistakenly attacks the inner ear.
• Unilateral SNHL, or hearing loss in one ear, is commonly caused by a tumor, disorders such as Ménière’s disease, or sudden exposure to a loud noise.
• Sudden SNHL (also known as sudden deafness) is a rare, emergency condition leading to hearing loss of at least 30 decibels (the equivalent of normal speech sounding like a whisper) instantly or over the course of a three-day period, typically in one ear. Those experiencing symptoms of sudden SNHL should reach out to a medical provider promptly. While the majority of SNHL is permanent, sudden SNHL can be effectively treated by a physician with steroid treatment if done immediately after onset, Collins says.

How it’s diagnosed

Doctors use several types of tests to diagnose sensorineural hearing loss. A physical exam can help rule out conductive hearing loss, which is caused by something — like earwax buildup — that prevents sounds from getting through the outer or middle ear. Specific tests include:

• Weber test. The doctor softly strikes a 512 Hz tuning fork and places it near the midline of your scalp or on your forehead, nasal bones or teeth. If the sound is louder in your affected ear, the hearing loss is likely conductive. If it’s louder in your unaffected ear, the hearing loss is likely sensorineural.
• Rinne test. Your doctor strikes a tuning fork and places it against your mastoid bone behind your ear until you no longer hear the sound. The doctor then moves the tuning fork in front of your ear canal until you can’t hear the sound. If you have SNHL, you’ll be able to hear the tuning fork better in front of your ear canal than against your mastoid bone.
• Audiometer tests. You wear earphones and hear sounds and words directed to each ear. Each tone is repeated at faint levels to determine your hearing threshold and the degree of hearing loss.

Treatment

Although there is no treatment that will reverse hearing loss due to age or noise exposure, hearing aids can help to amplify sound at the frequencies you need. Proper programming, testing and fitting of hearing aids is important to ensure they address your unique hearing loss. If your hearing loss is profound, you may benefit from a cochlear implant, which works by bypassing the damaged hair cells and sending signals directly to the auditory nerve.

“There have been tremendous advancements in digital hearing aids as well as cochlear implants over the past five years,” says Collins. “Hearing aid features now utilize artificial intelligence to identify speech from background noise, help stream music or movies directly into your hearing aids, and some devices can even help alert a family member if they detect that the hearing aid user has experienced a fall.”

Kimberly Goad is a New York–based journalist who has covered health for some of the nation’s top consumer publications. Her work has appeared in Women’s Health, Men’s Health and Reader’s Digest.