Hearing loss in one ear

Most people with hearing loss have what's known as "binaural" hearing loss, meaning both ears are affected. But some people only experience hearing loss in one ear. 

This is known as unilateral hearing loss or single-sided deafness, depending on the severity of the hearing loss. It's generally referred to as "single-sided deafness" (SSD) when the degree of hearing loss is profound or near-profound.

Let's take a closer look at symptoms of hearing loss in one ear, why it happens, and what your treatment options are.

What are the signs of unilateral hearing loss?

We were designed to have two ears for a reason—the brain uses both ears to locate where sound is coming from and to hear more clearly. 

Having diminished or no hearing in one ear can present unique challenges that can be more pronounced the more severe the hearing loss is. Hearing loss in one ear may mean:

• You can't always pinpoint where a sound is coming from: Your brain knows where a sound is coming from by which ear receives the sound first, known as sound localization or directional hearing. When a person can only hear well from one ear, he or she may have difficulty figuring out where the sound originated.
• You may struggle to hear in noisy environments: Your brain is in charge of selective listening, meaning, filtering out noises that aren't useful. This is tougher to do without the aid of a second ear. In a noisy environment, a person with with unilateral hearing loss or SSD can struggle to focus on a single person’s voice.
• You may have a harder time telling how loud a sound is: The brain “hears” a sound more loudly when it’s perceived through both ears than if the same sound at the same decibel were only perceived through one ear. This is because the brain receives signals from the nerves located in both ears and uses this information to process sounds.
• You may struggle to multi-task: Because of all of the above, single-sided deafness increases cognitive load on the brain, leading to listening fatigue. The more noise there is, the longer it takes your brain to focus on the tasks at hand. If you're also trying to listen to someone speak, you may miss a significant amount of what is being said.

What is the 'head shadow effect'?

If you have single-sided deafness, you will likely experience something known as the "head shadow" effect. Due to the way sound waves travel, high-frequency sounds don't "bend" around to the side of the functional ear, meaning a person who can only hear in one ear never hears them.

"The head essentially acts as a shield, blocking sounds from the poorer hearing ear from reaching the better hearing ear," explained Cleveland Clinic audiologist Sarah Sydlowski.

The end result is that speech can sound muffled, because a person can't hear high-frequency sounds like "s" or "f."

Can single-sided deafness cause tinnitus?

Yes. Patients with hearing loss in one ear, and specifically those with single-sided deafness, commonly experience tinnitus in one ear. Research indicates that anywhere between 54-84% of those with SSD "may have debilitating tinnitus in the deaf ear."

This occurs frequently because the brain receives little to no sound input from the affected ear and may generate “phantom” sounds in response. Tinnitus is also commonly associated with hearing loss in general, so people with mild to moderate hearing loss in one ear may experience ringing or buzzing as well. However, it is typically less severe than in those with SSD.

Causes of hearing loss in one ear

There are a number of potential causes of hearing loss in just one ear, including but not limited to:

• Meniere’s disease
• acoustic neuroma
• viral or bacterial infections
• physical damage to the ear and head trauma
• circulatory system disorders
• genetic or inherited disorders

Sometimes a cause can't be identified, or is due to a combination of factors.

Can hearing loss in one ear go away?

Depending on the cause, hearing loss in a single ear can sometimes be temporary. Common reversible causes include earwax blockages, middle-ear fluid from an infection, or sudden pressure changes (like when flying). Identifying and treating the cause quickly usually restores your hearing back to normal.

Sudden hearing loss in one ear

Hearing loss in one ear can develop quickly, and when it does it's known as sudden sensorineural hearing loss (SSHL). It’s important to act fast if you or a loved one notice any change. You might also experience “double hearing,” known as diplacusis, as the loss develops.

You should always seek medical care ASAP if you experience sudden hearing loss.

The sooner you seek treatment, the better your chances of a full recovery. Steroid treatment, when started early, can often restore at least some hearing.

Treatment options for single-sided hearing loss

Treatment options for mild to moderate unilateral hearing loss will be different than those for severe hearing loss or single-sided deafness. Thankfully, there are multiple options depending on the results of your hearing test.

• Hearing aids. For people with mild to moderate hearing loss, a hearing aid in the affected ear may be all that's needed to amplify the sounds you're not hearing.
• CROS. A contralateral routing of sound (CROS) hearing aid system helps people with almost total hearing loss in one ear and normal hearing in the other. It picks up sounds on the deaf side and sends them to the functional ear. This requires two devices: a transmitter on the non-functional ear and a receiver on the functional ear. The sound isn't amplified in the receiver as the user has normal hearing in that ear.
• BiCROS. BiCROS hearing aids work the same way, except they're designed for people whose functional ear has moderate-to-severe hearing loss. This means the functional ear not only receives sound from the transmitter on the other ear, it is also receives amplified sound via a typical hearing aid.

It's important for patients to realize these devices re-route sound, but do not "restore" hearing to the deaf ear, according to Erika Woodson, MD, Medical Director of Cleveland Clinic’s Hearing Implant Program, in an online discussion with patients about the devices. "You will not hear in stereo. The benefits of these hearing strategies are to improve awareness of sound from 360 degrees, but you will not be able to localize sound."

Learn more: What are CROS and BiCROS hearing aids?

Other treatment options

• Bone-anchored hearing systems. Some people don’t find CROS hearing aids helpful. An alternative is a bone-anchored hearing system, which requires surgical implantation. These devices, also called bone-anchored auditory implants, transmit sound vibrations through the skull directly to the inner ear. This is especially useful when ear canal or middle-ear problems block sound, making standard hearing aids ineffective. Here's how to know if a bone-anchored hearing system will help your single-sided deafness.
• Cochlear implants. A cochlear implant is a small electronic device that can provide a sense of sound for people with severe to profound hearing loss. It bypasses the inner ear and directly stimulates the auditory nerve. While not normally used for single-sided deafness, both the MED-EL Cochlear Implant Systems and the Cochlear Nucleus System are FDA approved to treat SSD.

Finding a hearing specialist

If you notice hearing loss in one ear, the first step is to get a thorough evaluation. For mild to moderate loss, a qualified audiologist can help find the right hearing aid.

If you’re in need of treatment for SSD, and want information on CROS devices, bone-anchored systems, or cochlear implants, look for an audiologist or ENT who specializes in single-sided deafness.

You can check out our provider directory to find a trusted professional near you and take the next step toward better hearing.