Single-Sided Deafness

Often there are cases in which people have a hearing loss in one ear and don’t have any aidable hearing loss in the other. This condition is also known as single-sided deafness or unilateral hearing loss. Single-sided deafness or SSD is a condition in which a person has lost his or her hearing in one ear, and has anywhere from normal to profound hearing loss in that ear and no hearing loss in the other ear. SSD causes real problems even if the working ear or the better ear has excellent hearing. Often untreated single-sided deafness might lead to stress, anxiety and depression, and you might isolate yourself socially. Therefore, the CROS and the BiCROS digital hearing aids are introduced so as to help people with SSD to hear better by making use of the better ear.


How is Single-Sided Deafness Different from Asymmetrical Hearing Loss?

While single-sided deafness, as already mentioned, refers to the condition in which an individual has some degree of hearing loss in one ear and absolutely normal hearing in the other; asymmetrical hearing loss, on the other hand, refers to the condition in which a person has mild to moderate degree of hearing loss in one ear, and severe to profound degree of loss in the other. CROS hearing aids are generally recommended for people with single-sided deafness and those with asymmetrical hearing loss are recommended BiCROS hearing aids.


Why is Binaural Hearing So Important?

Our body is a ‘machine’ which is finely tuned and properly balanced. If anyone organ gets damaged it will ruin this balance. Similar is the case with our ears! We really need two ears to hear well and have a proper and correct perception of sound. If there is a loss of hearing in any one of the ears, the sounds from your surroundings won’t be picked up in the correct way - thus resulting in a wrong and often misguiding sound perception - which can be dangerous!

Binaural hearing or hearing with both the ears has advantages in ways more than one (otherwise why would you be gifted with two ears)! Our brain makes use of information received from both the ears. It is only after receiving information from both the ears will the brain be able to process the information about the sound signals correctly, thus enabling you to have a distortion-free sound perception.

Hearing with two ears definitely has great advantages over hearing with one in situations like -

  • Improved speech recognition and understanding even in noise.

  • Better sound localisation or better recognition of the direction of the sound.

  • With binaural hearing, you will have a clearer and a much more natural sound perception as you are able to hear sounds coming from all the directions. It is because you will be able to hear sounds approaching from a much wider range, thus enabling you to understand and comprehend sounds better.

  • ‘Stereo’ hearing or binaural hearing (hearing with two ears) is less strenuous than ‘mono’ hearing (hearing with only one ear). People with monaural hearing usually get tired more faster than those with binaural hearing.

  • Two ears will act as a cushion as the sounds are divided equally between the two ears. This characteristic of binaural hearing also enables you to tolerate louder sounds much better than you would have done with monaural hearing. That is you won’t have to face jarring effects if you face some sudden loud noises.

  • Children will learn speech and language skills better than those peers with mono hearing (due to unilateral hearing loss or single-sided deafness).

  • Individuals with binaural hearing respond in group discussions much faster than their peers with monaural hearing.

  • Children with binaural hearing are more self-confident than those with monoaural hearing.

  • Binaural hearing makes sure that you can have your peace-of-mind while performing your day-to-day activities.

So this is why you need to hear well with both the ears!


CROS Hearing Aid Systems

CROS and BiCROS hearing aids are usually recommended for people with single-sided deafness. The CROS (Contralateral Routing Of Signals) digital hearing aids are recommended for individuals who have lost their hearing in one ear and have normal hearing in the other. In other words, the CROS hearing aid device is recommended for those who have unaidable hearing loss in one ear and no loss in the other. This device takes the sound from the poor ear to the working ear to enable you to hear well with less strain. The CROS device is usually not considered a full-fledged hearing aid.

The CROS hearing aid has microphones and an amplifier chip, but no speaker. The transmission of sounds takes place wirelessly from the hearing aid on the poor ear to the receiving hearing aid on the better ear. Although it may seem strange to wear a hearing aid on the ear with normal hearing, it is just delivering the sounds from your bad ear, and not amplifying any sound.

CROS Hearing Aids

There is yet another case in which the person has hearing loss in both the ears - with aidable hearing loss in one ear and unaidable loss in the other. In such a case, BiCROS (Bilateral Microphones with Contralateral Routing of Signal) hearing aids would be helpful. This type is similar to the CROS system - a CROS transmitter is paired with an active hearing aid. It is suggested for people who have asymmetrical hearing loss, with one ear being better than the other, though both have some degree of hearing loss. For example, a person having mild to moderate degree of hearing loss in one ear, and severe to profound degree of hearing loss or even total hearing loss in the other - would qualify as an ideal candidate for BiCROS digital hearing aids.

A BiCROS hearing aid picks up sounds from the ear with unaidable hearing loss (that is from the bad ear), processes it and mixes it with its own input and then amplifies the mixed signal and delivers the resultant into the other ear with aidable hearing loss (the better ear). This whole process is done in such a manner that you would feel that you are actually hearing from your bad ear.

BiCROS Hearing Aids


The Conclusion

The goal of these CROS devices is to provide the person with a sense of binaural hearing when true binaural hearing aid fitting is not possible. The good news is, these digital hearing aids are introduced with advanced wireless technologies with which the user no longer needed to stay connected physically, and yet enjoy the listening experience seamlessly.

This type of set-up is made so as to enable you to have a clear sound perception from all the directions and from both the sides of your head - which is important. In other words, the CROS and the BiCROS digital hearing aids are designed to give you a feeling of binaural hearing.