The loss of hearing sensitivity in one ear can happen suddenly, gradually, or can be present at birth. The term unilateral hearing loss is used to describe a hearing loss in one ear. According to the American Speech Language and Hearing Association "Approximately 1 out of every 1,000 children is born with unilateral hearing loss." Onset as an adult can have a variety of causes. The presence of a unilateral hearing loss can be frustrating but knowing the symptoms and causes can help determine appropriate treatment and management strategies.
The first symptom of a unilateral hearing loss may be difficulty hearing in background noise or localizing sound. The brain uses information from both ears to separate speech from noise and to tell where sound is coming from, according to the journal "Ear and Hearing." A simple test to see if there is a difference between your two ears is to hold a telephone up to one ear, then switch to the other for comparison. Unilateral hearing loss may also be accompanied by ringing in the ears, a feeling of fullness or pressure, or in rare instances pain. Sudden decreases in hearing, or sudden sensorinerual hearing loss, is typically noted immediately.
There are three parts to the ear, the outer, the middle, and the inner ear. The ear canal is in the outer portion of the ear. Any obstruction in the ear canal can cause a hearing loss in one ear. Some possible culprits are: ear wax, a foreign object, a cyst, or a bony growth. The middle ear is an enclosed space with the three smallest bones in the body. Any damage to those bones, a growth such as a cholesteotoma, diseases such as otosclerosis, or an infection in the middle ear can cause a hearing loss. The inner ear contains the cells of hearing and the hearing nerve itself. Noise exposure, Meniere’s Disease, auto-immune inner ear disease, and acoustic neuromas can all cause damage to the inner ear and loss of hearing in that ear.
Loss of hearing in one ear should be evaluated by a health care professional. Sudden loss of hearing should be evaluated immediately. Evaluation will include questions about your symptoms, medical history, visual examination of the ear, and a hearing test. Depending upon those findings, other tests may be ordered such as a CAT scan, MRI or balance testing.
Treatment of unilateral hearing loss is as varied as the causes. Some treatments are as simple as removing wax from the ear. Others may require medication or surgery. Some sudden hearing losses can be successfully remedied with medication as long as they are treated immediately. Hearing aids are sometimes recommended if hearing cannot be recovered. Some unilateral hearing losses can use conventional and directional hearing aids, while others require specific devices such as CROS, or contralateral routing of signal, or Baha(r). CROS devices pick up sound arriving at the poorer hearing ear and deliver it to the better ear. Baha(r) is a surgically implantable device that allows the user to hear through direct bone conduction rather than receiving sounds through the air.
No matter what the cause, there are things you can do to compensate for a unilateral hearing loss. Always sit in the front of a lecture or meeting where you can see the speakers face and use lip reading cues. Always sit with your good ear toward the speaker. In a public venue, ask if Assistive Listening Devices, or ALD, are available. Most churches, movie theaters, and lecture halls have ALDs. Use a hearing aid if it is determined that you are an appropriate candidate.