One Ear Deafness
Approximately, 4,000 new cases of sudden deafness are reported annually according to the National Institute on Deafness and Other Communication Disorders (http://www.nidcd.nih.gov). The outcome associated with a sudden or even gradual change in hearing that renders an ear unusable is sound isolation and communication loss. Difficulty hearing soft speech, localizing voices and sound, hearing speech in noise, and speech at a distance are impaired. This is because two ear hearing combines and separates sound using signals from each ear. Central auditory processing is impaired for all functions that utilize two ears. In some cases, the change can be sudden, resulting in a cascade of auditory, physical, and functional deficits. Re-establishing the sense of hearing from the off side with electronics eases the functional loss.
The advent of the Wireless CROS or BiCROS has made a remarkable difference in the treatment of single sided deafness. Having a sophisticated remote microphone on the poor ear side that combines information with signals from the better ear, enhances important speech information. When combined with visual information, a signal can be perceived as if it were heard in the dead ear. This would be impossible, except for the fact that the visual information places the physical environment first and then hearing adjusts to meet the predominant sense, a true illusion.
Patients realize that even with normal hearing in one ear, hearing performance and skills are compromised. An inability to hear someone or sounds from a dead ear side causes communication loss and related issues. Using the CROS system restores information from the non-responding side of the head to the good ear. This makes an observable difference by reducing some the effects. This is because the wall of lost information is once again available and the interaction between the vision and auditory systems improves. The patient acceptance and use rate with this type of device is over 95% when custom fitting and the programming is set correctly, the prescription verified, and then validated by the patient’s improved hearing skills, especially hearing soft speech.
Another option is the surgical bone anchored hearing aids (BAHA) that uses a vibration type hearing device to send the signal through the skull to the opposite ear, making this is a remarkable cross hearing option and should be considered, but there are side effects. When fitted properly, the BAHA can achieve similar results to the wireless CROS devices or better. However, the wireless CROS/BiCROS option appeals to most patients, because surgery is not required.
The most important aspect of the CROS wireless hearing aid option is that it is designed for comfort and ease of hearing in typical daily activities at home, at work, and school. Most of the devices can improve hearing in mild to moderate noise. However, when encountering high noise situations or more severe levels of hearing loss in the remaining ear there are more challenges. Some of these can be even improved upon with the use of a t-coil or FM wireless system.