Unilateral hearing loss (UHL) is the medical term for reduced hearing ability in one ear. Medical professionals sometimes refer to the condition as one-sided hearing loss or single-sided hearing loss.

This type of hearing loss may develop suddenly or gradually and may be temporary or permanent, depending on the cause. In many cases, treatments are available to help improve or restore a person’s hearing.

This article describes the effects of UHL in adults and children and provides information on UHL symptoms, types, and causes.

We also outline procedures for testing, treating, and managing UHL and offer tips on how to help children with this condition.

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UHL may be temporary or permanent, and the condition can be mild to severe.

Medical professionals refer to severe UHL as unilateral deafness. A person with this type of hearing loss has normal or near-normal hearing ability in their functioning ear but cannot hear in their affected ear.

Unilateral hearing loss can affect a person’s ability to communicate with others. This can have a detrimental effect on the person’s mental health and overall quality of life.

A person with UHL may experience difficulties with the following:

  • social interaction
  • relationships
  • education
  • employment

How common is this condition?

UHL is common among adults in the United States.

Based on a study from 2018, the prevalence of UHL is 7.2%, with 5.7% of people having mild UHL and 1.5% having moderate-or-worse UHL.

Unilateral hearing loss can develop at any age. A 2016 study reported that around three or four in every 1,000 children had some degree of hearing loss in one or both ears. Medical professionals refer to hearing loss in both ears as “bilateral hearing loss” (BHL).

According to the study, children with UHL or mild BHL are over four times more likely to need special assistance in school. However, it may be difficult for parents and caregivers to tell whether a young child or infant has either condition.

Fortunately, screening programs are identifying children with milder forms of hearing loss sooner, which lessens the impact of hearing loss on language development.

Some people may develop UHL gradually over time, while others may experience the condition suddenly. The type of UHL a person develops depends on the underlying cause.

Sudden sensorineural hearing loss (SSNHL) is a type of sudden hearing loss that often affects only one ear. It can happen immediately or may develop over several days. Some people hear a loud pop immediately before losing their hearing.

A person may first notice the hearing loss when they wake one morning or try to use a cell phone with the affected ear. As many as 9 in 10 people with SSNHL do not discover the cause of their hearing loss.

SSNHL is an ear, nose, and throat (ENT) emergency. If a person experiences sudden hearing loss, they should contact a doctor as soon as possible.

A person with UHL may experience the following issues with hearing:

  • Localization: A person may have difficulty identifying where sounds are coming from, such as who is talking at a given time.
  • Understanding: A person may have difficulty understanding another person’s speech in a noisy environment.
  • Volume: A person may struggle to hear a person call from another room or from outside.

People with UHL may also experience tinnitus, which is the medical term for ringing, buzzing, or whistling sounds in one or both ears. The sounds occur inside the head or ears and have no relation to external stimuli.

UHL can be conductive or sensorineural, or a combination of the two.

A person with conductive UHL has an abnormality in the outer or middle ear. This abnormality impairs the ability of soundwaves to reach the cochlea, which is a spiral-shaped, hollow bone in the inner ear that helps a person to hear.

A person with sensorineural UHL has an abnormality in the neural pathway that carries information between the inner ear and the auditory cortex, which is the part of the brain that processes sounds.

Some potential causes of UHL include:

  • genetic factors
  • head injury or trauma
  • viral or bacterial infections, such as mastoiditis, which is an infection of the bone behind the ear
  • an acoustic neuroma — a benign tumor on the vestibular or cochlear nerve
  • Ménière’s disease — an inner ear condition that causes sudden bouts of inner ear pressure, tinnitus, and vertigo
  • certain illnesses during pregnancy
  • microtia — a condition in which the outer ear is not fully formed at birth, resulting in abnormalities in the inner ear
  • atresia — when the ear canal and middle ear structures are absent or underdeveloped
  • perforated eardrum
  • noise-induced hearing loss that affects one side

Other causes include:

  • impacted ear wax
  • the presence of a foreign body in the ear
  • middle ear infection

In order to diagnose UHL, a doctor may refer a person to an audiologist or ENT specialist.

An ENT or otolaryngology specialist can check for the presence of fluid in the ear and may recommend additional tests to determine the underlying cause of UHL.

An audiologist can conduct hearing tests to determine the extent of the hearing loss.

The type of treatment a person receives for UHL depends on the underlying cause of their symptoms, as well as the severity of their hearing loss.

We outline some treatment options below.

Speech and language therapists

In some cases, UHL may have associations with speech delays.

People can contact speech and language therapists. These medical professionals may perform tests to check speech and language development in a child with UHL.

They may recommend an early intervention (EI) program to assist speech and language development in children under 3 years old or suggest home-based activities to help develop these skills in older children.

Devices

Devices such as hearing aids, hearing implants, and bone conduction devices may help to improve a person’s ability to hear. The type of device a person receives will depend on the cause and severity of their hearing loss.

Hearing aid

A person with some degree of hearing in the affected ear may benefit from a regular hearing aid to amplify sounds.

If a person has little to no hearing ability in their affected ear but normal hearing ability in their other ear, they may benefit from a contralateral routing of sound (CROS) hearing aid. This device picks up and amplifies sounds from the affected ear and sends them to the good ear.

Cochlear implant

A cochlear implant uses electrical signals to directly stimulate the nerve that carries sound from the cochlea to the brain. This type of hearing device may be beneficial for people with severe to profound deafness.

Auditory brainstem implant

An auditory brainstem implant may be an appropriate choice for a person who has experienced trauma to their auditory nerve.

The device works by directly stimulating the auditory brainstem to provide the sensation of hearing.

Bone anchored hearing aid (BAHA)

These hearing devices amplify sound via vibrations through the bones of the skull. These vibrations then stimulate the cochlea in the ear.

A person will not need to insert BAHA devices into the ear canal. Instead, they attach them to a soft band that a person can wear on their head.

Alternatively, they can come in the form of a metal implant that a surgeon inserts into the skull.

Steroids

Some people with sudden sensorineural UHL may benefit from oral steroid medications or steroid injections into the middle ear.

A person with sudden sensorineural UHT may partially or fully regain their hearing with steroid treatment. However, the more time that passes before the treatment, the less effective the treatment is likely to be.

Early intervention programs

Children who have UHL and are below 3 years of age may take part in an early intervention (EI) program to help them develop their speech and language skills.

A parent or caregiver can consider speech therapy through the school, hospital, privately, or through EI hearing specialty services.

It is important to remember that in the U.S., each state has its own qualifications for EI hearing specialty services, so not all children will qualify.

Unilateral hearing loss can affect a child’s behavior, especially the way they interact with their parents, peers, and other people.

Some tips that parents, carers, and teachers can follow to help children with UHL understand and learn include:

  • looking at the child before and while speaking to them so that the child can see a person is communicating with them
  • talking about activities while doing them to help the child learn words and sentences
  • minimizing background noise while having conversations with the child, such as turning off the television during mealtimes
  • managing the volume while the child watches screen-based media or listens to audio to prevent further damage to their hearing

A person who experiences any level of hearing loss should discuss the issue with their doctor, who will work to determine the cause.

It is important that a person sees their doctor as soon as symptoms develop. In many cases, early diagnosis and treatment can help to slow down or prevent further hearing loss. In some cases, prompt and appropriate treatment may fully restore hearing.

A person who experiences sudden hearing loss in one ear should seek medical help as soon as possible for the best chance of recovery.

Unilateral hearing loss is the medical term for reduced hearing ability in one ear. Depending on the cause, the condition may come on suddenly or gradually and may be temporary or permanent.

Potential causes of UHL include genetic factors, infections, and head trauma. The treatment will depend on the underlying cause and may include hearing devices or steroid medication.

A person should see their doctor if they are concerned about any changes to their hearing. In many cases, prompt diagnosis and treatment can help to slow or prevent further hearing loss.