CROS Hearing aids

From Otolaryngology Online


Cros is an acronym for Contralateral routing of signals. This type of hearing aid is very useful in treating patients with unilateral severe deafness. The principle behind this type of hearing aid is that the good ear is made use of to hear sounds from the bad ear.

In this type of hearing aid the microphone is placed in the bad ear to pick up sounds directed towards the bad ear. The receiver and amplifier is fixed to the good ear. The sound picked up by the microphone is transmitted to the amplifier fixed to the good ear, it is amplified and projected to the good ear.


1. Since hearing is in the good ear, amplification need not be maximum

2. There is virtually no feed back

3. Directionality of sound is not lost

Modifications of CROS hearing aids:


This type of aid is used to treat bilateral asymmetrical hearing loss.


This device is a recent innovation in cros technology. This type of hearing aid restores binaural hearing functionality of ear.

Figure showing the concept of cross hearing aid