Sudden hearing loss: getting to the bottom of it
Imagine you woke up one morning and couldn’t hear out of one ear. Would you know what to do? Would you seek treatment? Unfortunately, for most people the answer to both of these questions is a resounding no.
Every year, one out of every 5000 adults experiences sudden onset hearing loss. Also known as sudden sensorineural hearing loss, or SSHL, sudden onset hearing loss occurs all at once or over the course of several days. For most people, the immediate assumption is that they are suffering from allergies, an earwax blockage or sinus infection, so they might decide not to seek treatment. But here’s what you need to know: Sudden onset hearing loss is considered a medical emergency, and prompt treatment might just save your hearing.
But how do you know you have it? SSHL doesn’t always manifest itself in the same way. Some people notice when they wake up first thing in the morning that their hearing is different. Others don’t notice a difference until they hold the phone up to that particular ear or try to listen to headphones. In some cases SSHL is preceded by a very noticeable “pop," which can be quite alarming. Afterward, some patients report a feeling of fullness in the affected ear or a strange feeling on that side of the head, possibly accompanied by tinnitus and dizziness.
SSHL differs from other types of hearing loss in a couple of important ways. Aside from its rapid onset, it is often idiopathic, meaning the cause is usually unknown. As a matter of fact, a cause can be identified in only 10 to 15 percent of diagnosed cases. Some possible known causes, however, include:
- Tumors (e.g. acoustic neuroma)
- Neurologic diseases or disorders (e.g. multiple sclerosis)
- Bacterial infections
- Head injury or trauma
- Inner ear disorders (e.g. Meniere’s)
- Autoimmune diseases (e.g. rheumatoid arthritis)
- Ototoxic medications
- Circulation issues (e.g. vasculitis)
One of the most common theories, however, is that SSHL is caused by a viral infection of the hearing nerve. The swelling that occurs in the affected nerve causes it to effectively become strangled in the narrow, bony canal that leads to the ear (the internal auditory canal). If it stays in that state for too long, the nerve dies. That is why it is so important to seek immediate treatment; the window of time during which hearing can be saved in these cases is very narrow.
Nine out of 10 occurrences of SSHL are unilateral, meaning the hearing loss only occurs in one ear. It is thought that SSHL affects about one in 5000 people every year, though that number could be much higher due to the number of cases that go unreported and undiagnosed. Men and women are affected equally, and the average age of first occurrence is typically mid-40s to mid-50s.
If you suspect you might have SSHL, the first step is to make an appointment with a hearing healthcare professional. She may conduct a hearing test called pure tone audiometry in order to see whether hearing loss exists. The test can distinguish between two things: whether the sound is reaching the ear or whether the ear is processing the received sound. The test can also determine the range of hearing loss in decibels. SSHL will be diagnosed in the case of a hearing loss of at least 30 decibels in at least three connected frequencies. After diagnosis, she may order further tests in an attempt to determine an underlying cause. Blood tests, MRIs and balance tests are just a few examples that might help get to the bottom of your hearing loss.
Although treatments for SSHL are still fairly limited, they are important; 85 percent of those who receive prompt medical attention regain some or all of their hearing. Corticosteroids are the most common treatment for SSHL. They work by helping the body fight illness, decreasing swelling and reducing inflammation. Usually administered in pill form, the steroids can also be given through an injection behind the eardrum. This treatment via injection, called intratympanic corticosteroid therapy, is recommended for those who are unable to take oral steroids. Both treatments are equally effective, although the injections are known to be somewhat uncomfortable. Additional treatments may be necessary to treat the underlying cause, i.e. antibiotics for an infection.
Although 50 percent of those who experience SSHL spontaneously recover all or some of their hearing within one to two weeks, it is vital to seek treatment as soon as possible; indications are that the window for treatment closes two to four weeks after the onset of the hearing loss, meaning the hearing loss will then become permanent and irreversible.
If you experience sudden onset hearing loss, whatever you do don’t ignore it in the hopes that it will go away. Seeking treatment from a hearing professional immediately could make all the difference.