Hearing Loss In One Ear: Causes, Diagnosis And Treatments (2024)

The ear follows a complex series of steps to ultimately deliver sound information to the brain in a way that it can be interpreted. The process can be divided into the following stages:

• The outer ear, which includes the ear canal up to the eardrum, collects sound.
• The middle ear conducts and amplifies that sound from the eardrum to the inner ear via three tiny bones (the malleus, incus and stapes).
• The inner ear includes a snail-shaped organ called the cochlea, in which mechanical sound waves are converted into electrical signals.
• The auditory nerve then transmits these electrical signals to the brain.
• The brain assembles the delivered information and interprets what the sound means.

“Anything that impedes the sound wave in the atmosphere from getting to the inner ear is categorized as a mechanical or conductive disorder,” says Sujana Chandrasekhar, M.D. an ear, nose and and throat physician in the New York and New Jersey region. “[Hearing loss stemming from] the cochlea to the brain would be what we call sensorineural—‘sensory’ means the cochlea, and ‘neural’ means nervous tissue like the nerve or the brain.”

Unilateral hearing loss occurs when the process of hearing described above is disrupted in one ear only.

Unilateral hearing loss can also occur suddenly or gradually over time. Clinicians define sudden hearing loss as one that happens over no more than 24 hours, though a person may not realize they have diminished hearing until they try to use the affected ear. Sudden hearing loss in one or both ears is considered a medical emergency—the sooner a person gets to a doctor, the better their chances of recovering their hearing.

Some instances of unilateral hearing loss can be reversed quite quickly, such as in the instance of earwax buildup (a common cause of conductive hearing loss), according to Dr. Chandrasekhar. Meanwhile, middle ear infections can be treated with corticosteroids, decongestants or antibiotics (for bacterial infections), after which dampened hearing often returns. In the event that a medication is causing hearing loss as a side effect, stopping the drug as soon as hearing loss is noticed can help remedy the situation.

Some hearing loss is permanent, such as cases associated with noise damage to the inner ear or arthritic changes in the tiny bones of the middle ear.

In order to streamline hearing health exams, doctors and audiologists divide hearing loss into two categories: conductive, which involves the mechanical workings of the outer and/or middle ear, and sensorineural, which affects the inner ear or brain. People often have a little of both. Determining the cause of hearing loss can help hearing health professionals advise a patient on whether the loss is likely to be permanent, reversible or treatable.

Explore the various potential causes of unilateral hearing loss below, including whether experts would consider them reversible or permanent. Note: Consult your doctor for your particular circ*mstance to determine both the cause of your hearing loss and what you can expect from recommended treatment.

Conductive Hearing Loss

Earwax buildup is a common cause of one-sided hearing loss. Infections can cause the Eustachian tube to swell, preventing fluids from draining from the middle ear, increasing pressure in the middle ear and preventing the three middle ear bones from amplifying and/or transmitting sounds from air to the cochlea. If the pressure lasts long enough, it can cause permanent damage to one’s hearing. In this situation, exposure to a very loud noise, a poke with a cotton swab in the ear, infection or trauma can rupture the eardrum.

Sensorineural Hearing Loss

Hearing professionals worry about single-sided sensorineural hearing loss because it can indicate a rare but serious problem like a tumor, injury or neurological disease. If the inner ear is damaged, it cannot turn vibrations into electrical signals. If the auditory nerve stops working, it cannot transmit signals to the brain.

Loud sounds usually damage both ears, but sometimes a person is exposed to loud sounds on one side of the body while their head protects the other ear. For example, a machinist sitting all day with a loud machine to their right might find the noise damages their right ear more than their left ear.

Having two working ears allows a person to locate and interpret sound. If a sound comes from the right, the right ear hears it first. The left ear hears the sound with a tiny delay, since it’s farther from the sound, and hears it a little muffled, since the head is between the left ear and the sound source. The brain compares the two sounds to figure out where the sound is likely to have originated. If one ear isn’t working, the brain cannot compare timing and loudness, nor determine the sound’s origin, and such inability can be destabilizing and disorienting.

The inner ear serves another important function: balance. Its semicircular canals are responsible for telling the brain where the head is in space, how fast it’s moving and in what direction. The inner ear is attached to the cochlea, so some problems with the cochlea can disturb both hearing and balance. For instance, symptoms of Ménière’s disease include dizziness, ringing in the ears (tinnitus) and loss of hearing.

First, a doctor or audiologist asks about a patient’s general state of health, how quickly their perceived hearing loss occurred, possible exposures to loud noises or ototoxic drugs, injuries and recent infections.

From there, they examine the ear, using an otoscope to look at the external ear, ear canal and eardrum. Dr. Chandrasekhar says she starts her otoscope exam by removing earwax, taking a look at the eardrum and making sure there’s no infection or hole in the eardrum and that there’s no fluid behind the ear, which would be a sign of infection. If the middle ear cannot be drained through the Eustachian tube, fluid can build up and dampen the movements of the middle ear’s bones, preventing sound from being transmitted to the inner ear.

The doctor may also conduct a tuning fork test to see if both ears hear equally—and if they don’t, whether the problem is likely conductive or sensorineural.

To check the function of the middle ear, hearing professionals conduct a tympanometry test. Part of the testing instrument blows puffs of air onto the tympanic membrane (eardrum), and the other part measures the reactivity of the membrane and middle ear bones. If the eardrum doesn’t react normally, that deficiency could be the source of the hearing loss.

Audiologists also conduct a hearing test to chart how well the patient hears at each frequency in each ear. In making that chart, or audiogram, they test both hearing and cognitive responses to sounds. The test is conducted in a very quiet sound booth with headphones.

Explore the various potential treatments of unilateral hearing loss below, depending on its cause. Note: Consult your doctor for your particular circ*mstance to determine what you can expect in the way of recommended treatment.

When nothing more can be done medically, turn to an audiologist who can provide treatments to mitigate hearing loss and improve overall quality of life. For instance, audiologists can fit a patient with unilateral hearing loss with a special kind of hearing aid called a Contralateral Routing of Signals (CROS) that emulates two-sided hearing.

“A CROS is for someone who has normal hearing on the unaffected side,” explains Sheila Pack, Au.D., CEO of The Hearing Center at ENTA in Atlanta. In that case, sound is received by a microphone in a hearing aid on the affected side and then transmitted to a hearing aid on the unaffected side.

If a person has hearing loss in both ears but one ear is more severe than the other, they may be eligible for a Bilateral Contralateral Routing of Signals (BiCROS).

“All of a sudden, you feel aware that sounds are coming, and you can lateralize where the sound is coming from,” says Dr. Pack about people who use CROS and BiCROS. “When you have single-sided deafness and you’re not treating it, it’s very hard to tell where sounds are coming from unless they’re directly beside you on your good side.”

It’s also common for the cause of one-sided hearing loss to remain unknown, but many conditions improve with oral corticosteroids and the use of some sort of hearing assistance device like CROS or BiCROS.

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Some hearing loss occurs gradually. If you notice that people seem to be mumbling more often or you cannot understand what people are saying to you, it’s best to visit your doctor. If you have trouble hearing in one ear or hear a constant hum or ringing in one ear, those symptoms are also worth a trip to your doctor’s office.

Loss of hearing in one ear can have serious consequences, from an increased risk of falling to decreased cognitive health, but it’s especially important to seek help for sudden hearing loss. “It’s not normal to wake up with hearing loss,” says Dr. Pack. “Any type of sudden loss, whether it’s unilateral or bilateral, is not normal. Don’t wait [to seek help], because time is of the essence in treatment. So many people come in six months later, and we kind of miss the window at that point.”