Learn how the Sonic CROS Solution can help your patients with Single Sided Deafness

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As a hearing care professional, you are proficient at managing a variety of types, degrees, and configurations of hearing loss every day. However, there may be one category of hearing loss that you don’t see on the regular – Single Sided Deafness (SSD). Here’s a quick refresher about causes, prevalence, and treatment options, including the new CROS solution from Sonic.

SSD Facts
SSD is defined as “unaidable hearing in one ear and either normal hearing or an aidable hearing loss in the other ear”.1 In other words, a person with SSD suffers from a unilateral hearing loss where traditional amplification will not provide any benefit in the poorer ear. There are many possible causes of SSD including trauma, infection, autoimmune disease, ototoxicity, Meniere’s disease, stroke, or a tumor on the eighth nerve. Additionally, sudden sensorineural hearing loss most commonly occurs unilaterally and is idiopathic in most cases. The prevalence of SSD is approximately 1 percent in the US, which affects about 60,000 Americans a year. 

Challenges of SSD
Persons with SSD may hear well in quiet listening situations. However, demanding listening environments can become significantly more challenging and put them at a greater disadvantage. For instance, hearing in background noise can become more difficult, listening effort can increase and cause mental fatigue, and sound localization can become problematic.1,2

Treatment Options
It is important for persons with SSD to seek treatment for this type of hearing loss. These are the three main options to consider for your patients’ needs:

  • Bone Anchored Hearing Aid (BAHA): This option requires a minimally invasive surgery and works by wearing a device that stimulates hearing in the better ear from the poorer ear via bone conduction.
  • Cochlear Implant (CI): This option requires a non-reversible, invasive surgery to electrically stimulate the hearing nerve on the poorer side via an implanted electrode array. Note that a cochlear implant has a variety of drawbacks and is not common as a treatment for SSD.
  • Contralateral Routing of Signal (CROS) Transmitter: This option is non-implantable and is a common first choice for patients with SSD. It consists of wearing a transmitter hearing aid on the poorer hearing ear and a receiving hearing aid on the better hearing ear. A CROS Transmitter can also be configured in a BiCROS (Bilateral Contralateral Routing of Signal) set-up if the better ear has hearing loss.


How a CROS Works
The basic principle of a CROS solution is that it aims to overcome the head shadow effect resulting from SSD – allowing the person to become a two-sided listener rather than a one-sided listener. It does this using a transmitting device placed on the poorer ear. The transmitter typically has one or two microphones that pick up sounds from the environment from the poorer side. These sounds are then wirelessly transmitted to a receiver hearing aid on the normal hearing ear where the sounds are perceived by the cochlea with better hearing. A BiCROS system does essentially the same. However, a BiCROS is relevant for people who also need amplification on the better hearing ear. This means that in addition to receiving sounds from the poorer ear, the receiving device also provides amplification based on the hearing loss in the better ear.

The Sonic CROS Solution
Sonic is excited to offer our first CROS Transmitter for patients with SSD. The Sonic CROS solution uses the latest EXTEND platform technologies for advanced speech processing and noise management – highly relevant for people who are affected by the challenges of SSD noted above. The CROS also features the Dual-Radio System that offers dual-streaming, allowing users to enjoy wireless streaming from their smartphones to the better ear without being excluded from the surroundings. For more information, register for our CROS course on AudiologyOnline or visit the Sonic website at www.sonici.com. With Sonic, Everyday Sounds Better.

  • Taylor, B. Contralateral Routing of the Signal Amplification Strategies. Seminars in Hearing. 2010. Vol. 31 (4): 378-392
  • Voelker, C. C. J. and Chole, R. A. Unilateral Sensorineural Hearing Loss in Adults: Etiology and Management. Seminars in Hearing. 2010. Vol. 31 (4): 313-325
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