Hearing Aids Can Help Single-Sided Hearing Loss

Single-sided hearing loss, or “unilateral hearing loss,” is relatively common. If the hearing loss is profound, it is called single-sided deafness (SSD). Hearing loss is considered to be SSD when a person has normal or near-normal hearing in one ear, and severe or profound hearing loss in the other.

People can be born with single-sided hearing loss, or may acquire it in childhood or adulthood. It often happens very suddenly. A person may hear a loud screeching sound in one ear for a moment, and then that ear will stop picking up sound. If a person develops a sudden hearing loss in one ear, whether it be mild or profound, it should be treated immediately. It is not always possible to reverse the hearing loss, but the chances are greater if treatment is applied as soon as the hearing loss occurs.

How Does Single-Sided Hearing Loss Affect Hearing?

Humans have two ears so that our brains can compare the information coming from each ear in order to find the location of sounds around us. Having sonic information from both ears also helps to improve speech intelligibility in noisy environments, and increases our range of hearing. The way in which our brains use both of our ears to interpret the environment is known as binaural hearing.

Single-sided hearing loss presents a unique set of challenges. While the difficulties associated with single-sided hearing loss and SSD may not be as troublesome as bilateral hearing loss (hearing loss in both ears), there are still a number of changes in the way you perceive sound.

• Sound Localization – Our brains are able to pinpoint the location of a sound in space by identifying the microseconds of difference between when the sound reaches one ear, and then the other. This process cannot occur when sound is only taken in by one ear.
• Background Noise – While our brains localize sound using our two ears, the same principle helps our brains focus on just one sound amidst a din of other sounds. When we localize a sound in space, it’s easier to focus on it. When only one ear is taking in sound, the voice of the person you wish to listen to is less differentiated from other sounds in the environment. It’s similar to the way that losing vision in one eye makes it more difficult to perceive depth.
• Loudness Recognition – Binaural hearing is also partially responsible for loudness recognition. While some sounds will still appear louder than others to a person with single-sided hearing loss, the breadth of potential volume recognition may be reduced.
• Head Shadow Effect – High-frequency sounds are more directional than low frequency ones. When we have single-sided hearing loss, lower sounds coming into the poorer ear will “bend” around the head and be heard by the good ear. High frequencies, however, will be blocked by the head. This makes it more difficult to understand speech coming from the poorer ear’s side, even when it can be heard at a reasonable volume by the good ear.
• Attention Span and Fatigue – The three concerns above add up to an increased cognitive load on the brain. As less information comes in, the brain works harder to try to make sense of the information it does have. Speech may be harder to focus on, and the extra work the brain has to put into interpreting sound means you may become tired sooner in busier sonic environments.

Treatment for Single-Sided Hearing Loss

When single-sided hearing loss is mild or moderate, a hearing aid can be helpful for restoring binaural hearing capability. When the loss is more profound, other options may be considered.

A CROS (contralateral routing of signals) hearing system uses a microphone and transmitter on the poorer ear to send sound to a hearing aid worn on the good ear. This allows you to hear sound from all 360 degrees, though still only in your one good ear. It can help increase awareness of sound in the environment and help you feel more at ease. You’ll be less likely to be oblivious to sound coming from the poorer ear’s side.

CROS systems are available from the Phonak hearing aid company that can be of great help to people with SSD. If you feel a CROS system might be right for you, make an appointment for a hearing test today and try a CROS system for a trial period.