What are CROS and BiCROS hearing aids?
Updated: Oct 4
SSD or single-sided deafness refers to a condition when a patient has profound hearing loss in one ear only. Continue reading to learn more about this type of hearing loss and learn how CROS or Bi-CROS hearing aids can help.
In this article you will learn about:
What is single-sided deafness (SSD)?
What could cause single-sided deafness (SSD)?
What does the audiogram look like for patients using CROS and BiCROS?
How can single-sided deafness be managed?
What are CROS and BiCROS hearing aids?
How are CROS hearing aids different from other hearing aids?
What benefits can CROS and BiCROS hearing aids bring to the patient?
What are the shortfalls of a CROS or BiCROS hearing aid?
What to consider when selecting a CROS or BiCROS hearing aid?
Is a manufacturer's CROS hearing aid different from the other? What about BiCROS?
What can I do to improve my chance of adjusting well with a CROS hearing aid?
I used CROS hearing aids for a while but now hearing on my better side has declined, do I need to purchase a BiCROS?
What is single-sided deafness (SSD)?
A unilateral hearing loss may also be called a one-sided hearing loss or a single-sided hearing loss.
If a unilateral hearing loss is severe or profound, it is often called single-sided deafness (SSD), as there is practically no hearing left. Single-sided deafness is defined as a hearing loss with normal or near-to-normal hearing in one ear (“the good ear”) and severe to profound hearing loss in the other. If the unilateral hearing loss is severe or profound, the person affected more or less only hears with one ear (monoaural hearing). Single-sided deafness may also be called unilateral deafness.
A unilateral hearing loss can both be a sensorineural hearing loss and a conductive hearing loss. A unilateral hearing loss can occur in both adults and children.
Children with unilateral deafness may have sensorineural deafness which is caused by a fault in the inner ear (cochlea) or conductive deafness, which is often caused by microtia and/or atresia. The deafness may be permanent or temporary.
What could cause single-sided deafness (SSD)?
A unilateral hearing loss can occur as a result of many causes.
It can be inherited (as other types of genetic hearing loss).
It can occur as a result of trauma or injury to the head.
An acoustic neuroma often results in unilateral hearing loss.
It can be a result of viral or bacterial infections.
It can also be caused by maternal illnesses, microtia, Ménière’s disease and mastoiditis.
What does the audiogram look like for patients using CROS and BiCROS?
The audiogram for a person with single-sided deafness would be something similar to the below sample. As you can see the left side has normal hearing thresholds (lower than 20 dB) while the hearing on the right side is almost or completely deaf. It is a poor chance that an Ultra-Power (UP) hearing aid can have a meaningful benefit to the hearing on the right side of this patient but s/he may want to try it first before considering CROS hearing aids.
The audiogram for a patient that could benefit from BiCROS would be similar to the below image. As you can see the hearing on the right side (in red) is deaf, but the left side (in blue) also has mild to moderate sloping sensorineural hearing loss (SNHL).
