Sudden sensorineural hearing loss (SSHL), also known as sudden deafness, occurs when you lose your hearing very quickly. It can happen instantly or over a span of several days. During this time, sound gradually becomes more muffled or faint. SSHL typically only affects one ear.
Frequencies measure sound waves. Decibels measure the intensity, or loudness, of the sounds we hear. Zero is the lowest decibel level and is close to complete silence. A whisper is 30 decibels, and normal speech is 60 decibels. A loss of 30 decibels in three connected frequencies is considered SSHL. This means that a hearing loss of 30 decibels would make normal speech sound like a whisper.
There are about 4,000 cases of SSHL diagnosed every year in the United States. The condition most commonly affects people between ages 30 and 60.
Most people with SSHL recover quickly when the condition is diagnosed and treated promptly. However, about 15 percent of people with the condition have hearing loss that gradually gets worse over time. Advances in technology used for hearing aids and cochlear implants are helping to improve communication for people affected by hearing loss.
SSHL is a serious medical condition and requires prompt medical attention. Call your doctor right away if you think you’re experiencing SSHL. Early treatment can save your hearing.
SSHL happens when the inner ear, the cochlea in the inner ear, or the nerve pathways between the ear and the brain become damaged.
There are more than 100 causes of SSHL, so most people can’t pinpoint the exact cause of their hearing loss. Some of the possible causes include:
- malformation of the inner ear
- head injury or trauma
- prolonged exposure to loud noise
- neurologic conditions, such as multiple sclerosis
- an immune system disease, such as Cogan’s syndrome
- Meniere’s disease, which is a disorder that affects the inner ear
- Lyme disease, which is an infectious disease that’s often transmitted through tick bites
- an ototoxic medication, which can harm the ear
- venom from a snake bite
- blood circulation problems
- abnormal tissue growth or tumors
- blood vessel disease
Babies can be born with SSHL. This may happen as a result of:
- infections that pass from the mother to the child, such as rubella, syphilis, or herpes
- Toxoplasma gondii, which is a parasite that passes through the womb
- genetic, or inherited, factors
- low birth weight
To diagnose SSHL, your doctor will ask you about your medical history and perform a physical exam. Make sure to tell your doctor about other medical conditions you may have and about any over-the-counter and prescription medications you’re taking.
During the physical exam, you may be asked to cover one ear at a time while listening to various sounds at different volumes. Your doctor may also perform some tests using a tuning fork, which is an instrument that can measure vibrations in the ear. These tests can check for damage to the parts of the middle ear and eardrum that vibrate.
Audiometry tests may be done to check your hearing more thoroughly and precisely. During these tests, an audiologist will test your hearing ability using earphones. A series of different sounds and volume levels may be sent to each ear individually. This can help determine the level at which your hearing begins to fade.
An MRI scan may also be ordered to look for any abnormalities in your ear, such as tumors or cysts. The imaging test will take detailed pictures of your brain and inner ear, which can help your doctor find the underlying cause of SSHL.
Hearing loss can develop in children as a result of infections at birth or damage caused by ototoxic medications. It may not always be easy to know if your child is hearing correctly. You should have your child’s hearing tested if they:
- don’t seem to understand language
- don’t attempt to form words
- don’t appear to startle at sudden noises or respond to sounds in a way you would expect
- have had numerous ear infections or problems with balance
You may notice hearing loss right after you wake up in the morning. You may also become aware of it when you use headphones or hold a phone to your affected ear.
Sudden hearing loss is sometimes preceded by a loud popping sound. Other signs include:
- trouble following group conversations
- muffled conversation sounds
- inability to hear well when there’s a lot of background noise
- difficulty hearing high-pitched sounds
- balance problems
- tinnitus, which occurs when you hear ringing or buzzing sounds in your ear
Nine out of 10 people with SSHL experience hearing loss in only one ear.
Early treatment may increase your chances for a full recovery. However, your doctor will try to find the cause of your hearing loss before starting treatment.
Steroids are the most common treatment. They can reduce inflammation and swelling. This is especially helpful in people who have diseases of the immune system, such as Cogan’s syndrome. Your doctor may also prescribe antibiotics if your SSHL was caused by an infection.
In some cases, a cochlear implant can be surgically inserted into your ear. This implant doesn’t completely restore hearing, but it can amplify sounds to a more normal level.
SSHL often improves on its own when it’s treated promptly. The symptoms usually go away within the first few days after you experience hearing loss. This is called a spontaneous recovery. Sometimes, it may take up to two weeks for your hearing to return to normal.
Although a complete recovery is likely, about 15 percent of people who experience SSHL don’t recover and continue to lose their hearing over time. Hearing aids and telephone amplifiers can help if your hearing doesn’t improve. Sign language and lip reading can also improve communication for people with severe hearing loss.