Latest posts by Jeff Baller, Au.D., CCC-A (see all)
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There is a reason we have two ears. We have two ears to tell our brain from which direction sounds are coming from. But just because we have two ears doesn’t mean hearing conditions necessarily come in twos as well. When one ear becomes damaged and the other ear stay hearing healthy this is referred to as single-sided or unilateral hearing loss. The good news is that in many cases hearing loss in one ear can be improved through the other.
Why Two Ears?
We were designed with two ears for a reason; the brain uses both ears for elevated volume, to pinpoint the direction of a sound and for additional processing power.
- Sound localization: Your brain knows which direction a sound is coming from by which ear receives the sound first. When a person can only hear from one ear, they often have difficulty deciphering the origin of the sound.
- Hearing in noisy situations: Your brain is also in charge of selective listening, which is more of a challenge without the aid of a second ear. In a noisy environment, a person with single sided hearing can struggle to focus on a single person’s voice.
- Cognitive load: This refers to the act of listening while multi-tasking, which can be complicated even for a person with normal hearing. The more noise there is in an environment, the longer it takes the brain to focus and the person to complete the task. If the person is also trying to listen to someone speak while multi-tasking, often it’s easy to miss important information or keep up with the conversation at all.
- Binaural loudness summation: The brain can perceive a sound more clearly when it’s heard through both ears than if the same sound at the same decibel was only heard through one ear. The brain reads nerves located in both ears and uses this information to process sounds.
The Head Shadow Effect
The head shadow effect is the result of Single-Sided Deafness. When one ear has a hearing loss, then it’s up to the other ear to process the sound information from both sides of the head. That’s why it’s called a shadow: the head blocks sound in the same way that it would block sunlight. Low frequency, long-wavelength sounds bend around a person’s head, and are often perceived well even though the deaf ear may be turned in the direction of the sound. High frequency and short-wavelength sounds, however, are not as elastic and do not bend around to the side of the good ear. Many high-frequency sounds are lost to a person with SSD. Consonant sounds in speech occur as high-frequency sounds, so a person with SSD can often miss a significant amount of surrounding conversation.
Causes of Single Sided Hearing Loss
Unilateral hearing loss or single sided deafness, also known as SSD, is typically caused by viral infections, Meniere’s disease, a disorder of the inner ear that can lead to dizzy spells (vertigo) and hearing loss, head or ear injuries, or through surgical intervention to remove brain tumors.
How to Treat Unilateral Hearing Loss
Several options exist to address adult-onset severe-profound unilateral sensorineural hearing loss with normal contralateral hearing sensitivity.
- One approach is traditional amplification. This will be dependent on remaining function in the affected ear and ability to achieve audibility.
- A second approach is rerouting of the signal to the contralateral normal hearing ear. This may be accomplished by use of a contralateral routing of signal (CROS) hearing aid or through bone conduction. Bone conduction can be achieved in two ways, either a high-powered hearing aid or a bone-anchored hearing device.
- A third approach is to try to restore binaural hearing with the use of a cochlear implant.
Professional Hearing Services
Hearing loss in one ear or both isn’t just an ear issue; it’s a quality of life and health issue. Untreated hearing loss can have serious consequences. A decrease in hearing sensitivity is associated with diminished cognitive function, poorer mental health, and social withdrawal. If you suspect that you have single sided hearing loss don’t ignore it any longer. Contact us at Professional Hearing Services to set up a hearing test today. We can diagnose your hearing and help you find hearing aids that are perfect for you and your lifestyle.