In most cases, hearing loss happens gradually over a period of years. But sudden sensorineural hearing loss, sometimes called sudden deafness, is an unexplained, rapid hearing loss that may happen all at once or over a few days, and it is considered a medical emergency.
According to the National Institute on Deafness and other Communication Disorders (NIDCD), sudden hearing loss strikes between one and six people per 5,000 per year, but the actual number of cases may be higher because it often goes undiagnosed. It can happen to anyone at any age, but most often it affects adults in their late 40s and early 50s.
Sudden hearing loss happens because something is wrong with the inner ear. It often affects only one ear, not both, and individuals may notice the hearing loss when they wake up first thing in the morning. Others note a loud “pop” just before their hearing disappears. People with sudden hearing loss may also notice one or more of these symptoms: a feeling of ear fullness, dizziness, and/or a ringing in their ears, such as tinnitus.
Sometimes, people with sudden hearing loss put off seeing a doctor because they think their hearing loss is due to allergies, a sinus infection, earwax plugging the ear canal, or other common conditions. However, sudden hearing loss symptoms should be considered a medical emergency. Visit a healthcare professional, such as an audiologist or ear, nose and throat specialist, immediately.
Although about half of people with sudden hearing loss recover some or all their hearing spontaneously, usually within one to two weeks from onset, delaying diagnosis and treatment may reduce treatment effectiveness. Receiving timely treatment greatly increases the chances that at least some hearing will return.
What causes sudden hearing loss?
A variety of disorders affecting the ear can cause sudden hearing loss, but only about 10 percent of people diagnosed with it have an identifiable cause. Some of these causes can include:
- Head trauma
- Autoimmune diseases
- Exposure to certain drugs that treat cancer or severe infections
- Blood circulation problems
- Neurological disorders, such as multiple sclerosis
- Disorders of the inner ear, such as Ménière’s disease
Most of these causes are accompanied by other medical conditions or symptoms that point to the correct diagnosis.
Diagnosing sudden hearing loss
If you have sudden hearing loss symptoms, your healthcare professional should rule out problems such as an obstruction in the ear, like fluid or ear wax. For sudden hearing loss without an obvious cause, your healthcare professional should refer you to an audiologist as soon as possible for a diagnostic hearing evaluation including pure tone audiometry.
With pure tone audiometry, an audiologist can measure how loud different frequencies, or pitches, of sounds need to be before you can hear them. One sign of sudden hearing loss could be the loss of at least 30 decibels in three connected frequencies within 72 hours. This drop would, for example, make conversational speech sound like a whisper. Patients may have more subtle, sudden changes in their hearing and may be diagnosed with other tests.
If you are diagnosed with sudden hearing loss, your healthcare professional may order additional tests to try to determine an underlying cause for your sudden hearing loss. These tests may include blood tests, imaging (usually magnetic resonance imaging, or MRI), and balance tests.
Can sudden hearing loss be treated?
The most common treatment for sudden hearing loss, especially when the cause is unknown, is corticosteroids. Steroids can treat many disorders and usually work by reducing inflammation, decreasing swelling, and helping the body fight illness.
Treatment should be started as soon as possible for the best result. Delaying treatment for more than two to four weeks is less likely to reverse or reduce permanent hearing loss. Additional treatments may be needed if an underlying cause of the sudden hearing loss is discovered.
Associated Audiologists is equipped to help treat sudden hearing loss with a protocol for immediate testing and referrals to several specialists in the area who might be able to help.