This is achieved by transferring sound from the deaf side to the hearing ear. Generally, patients also must cope in other ways, such as finding the best possible sitting and listening positions and reduce background noise.
One hearing device option is the so-called contralateral routing of signal (CROS) hearing aids. A newer alternative is the bone-anchored hearing aid, BAHA which has been approved by the United States Food and Drug Administration, FDA.
CROS hearing aids can be wired or wireless. In essence, CROS hearing aids consist of a hearing aid shell, containing a receiver and another unit with a small microphone system. The receiver unit is in or behind the normal ear while a shell with the microphone system is located on the side of the deaf ear. The sound is "heard" through the microphone system located on the side of the deaf ear, and sent via a wired or wireless system to the normal ear.
People with hearing loss in the better ear, as well, can be treated with BI-CROS hearing aids. With the BI-CROS system, both ears have a microphone system in their shells, and again, the sound is perceived only on the side with the receiver, the better hearing ear.
However, performance, handling, and aesthetics of CROS and Bi-CROS systems have been considered poor by many professionals who have dispensed them, and by patients who have worn them. Most people offered CROS hearing aids do not purchase them, and of those who do, apparently only a percentage of the owners use them full-time, a year or two later.
The so-called BAHA system involves a small titanium implant placed in the bone behind the deaf ear and connected to a sound processor. The sound processor picks up sounds and transfers them to the good ear via the skull bone, allowing the wearer to hear and understand sounds originating from both sides.
The BAHA system has been regarded as a successful treatment option in Europe since the late 1970s. Currently, the BAHA system is worn by 15,000 people worldwide.
www.Audiologyonline.com, Single Sided Deafness: Issues and Alternatives, 5/31/2004, by Teri Sinopoli, M.A., CCC-A, AAA, and BBC News, 13 June, 2003.