By Rex Banks, M. A. CCC-A. Reg. CASLPO
Single-Sided Deafness (SSD), or unilateral sensorineural hearing loss, refers to significant or total hearing loss in one ear. The hearing loss is usually permanent and may be the result of a variety of conditions including:
• Sudden deafness – can occur at any time, often for unknown reasons
• Physical damage to the ear
• Pressure on the hearing nerve
• Inner ear problems including infections (viral or bacterial)
• Diseases such as measles, mumps, meningitis
• Tumours in the ear or brain
• Disorders of the circulatory system
• Severe Meniere's disease
• Trauma – e.g. head injury
The above health conditions that cause SSD can be quite stressful to manage. But in addition, the individual must also cope with having no hearing on one side. Being deaf in one ear presents a variety of challenges, most notably difficulty in determining the direction of sound. Another issue which affects communication is the “head shadow effect." Sounds that originate from the side of the deaf ear actually fall in the shadow of the head. Vowel sounds which have longer wave lengths may still travel from the deaf side to the hearing side, but consonants which have a shorter wavelength and carry the most meaning for speech and conversation, don’t do as well in terms of making their way from the deaf ear around the head to the hearing ear. This can cause a great deal of frustration for the individual with SSD especially when trying to communicate in the presence of background noise.
Directionality (or sound localization) is an important aspect of managing communication and environmental cues. When you’re unable to hear out of one ear, crossing the street, cycling and jogging can all become difficult and even dangerous. Unexpected communication challenges arise in situations such as:
- Communicating in the car (deaf side facing driver)
- Interacting in circular group meetings (can be difficult even if participants are speaking one at a time and even worse if distance is a factor for large circular discussions)
- Whispered communication into the deaf ear in quiet environments such as church, lectures, movies or training
All of the above can greatly affect day-to-day life. As a result, some people with SSD find themselves exhibiting irritability and jumpiness, have frequent headaches (due to stress), feel socially isolated and experience chronic interpersonal communication difficulties. Undetected SSD in children may even be misdiagnosed as ADHD.
In cases of SSD, the deaf ear receives no clinical benefit from amplification. This means that no matter how loud we make things through a hearing aid, speech is not clear or usable in that ear. The other ear often has typical or regular hearing ability, but not always.
As with any hearing loss, we cannot restore the hearing once it has been lost. For SSD, there are treatments available which can restore the sensation of hearing to the deaf side. The two main treatment options available for SSD are the BAHA (a bone anchored hearing device) and the CROS or BiCROS hearing aid systems.
In this article, we’ll focus on the CROS (contralateral routing of signal) and BiCROS (bilateral contralateral routing of signal) hearing aid systems. But first, you may be asking - what is the difference between a CROS and BiCROS hearing aid system?
CROS hearing aids systems are worn by individuals with one deaf ear and one ear that is unaffected by hearing loss. With a CROS hearing aid system, a transmitter (which looks like a behind the ear hearing aid) is worn on the deaf ear. The transmitter’s microphone picks up sound from the deaf ear and sends it to a receiver (hearing aid) that is worn in the ear that has hearing.
BiCROS hearing aid systems are worn by individuals with hearing loss in both ears, but one ear is deaf and unaidable. In this case, a transmitter is worn on the deaf ear. The transmitter’s microphone picks up sound from the deaf ear and sends it to a receiver/hearing aid that is worn in the better ear. But as the better ear still has hearing loss, amplification is provided to that ear along with the information coming from the deaf ear.
If you have SSD and want to learn more about the Unitron Tandem wireless CROS/BiCROS hearing aid or other similar products on the market, contact one of CHS’ Hearing Clinics Plus locations. A CHS audiologist will be able to test your hearing and educate you on both the benefits and limitations of CROS/BiCROS technology in to help ensure the best possible outcome for your individual case and communication needs.