Your Audiology Tutorial : CROS and BiCROS

In determining whether a patient is a candidate for amplification, the audiologist or dispenser will consider a patient's Word Recognition Score (WRS).  If a patient has a moderately severe or worse audiometric pure tone configuration and a markedly poor (say, 20% or below) WRS, a CROS (Contralateral Routing of Signal) or BiCROS (Bilateral Contralateral Routing of Signals) system may be a good choice.  

The CROS device is not a hearing aid, but may look exactly like one (Usually a Receiver-the-Canal or In-the-Canal style).  It contains a microphone that will wirelessly send signals from the "bad" or "worse" or even "dead" (profound hearing loss) ear to the "normal" ear, which will be fit with a hearing aid to receive the signals.  So if, as an example your right ear is not suitable for a hearing aid (because amplifying speech will merely sound like distortion), you can wear a CROS transmitter on that ear and have the hearing aid worn on the left, normal hearing ear process the sound.  You can have someone on your right side speak to you and be able to understand them because the hearing aid on the left is doing the work.  The hearing aid, by the way will have its microphones shut off as amplification is not needed on that side.

A BiCROS set-up is used when hearing loss is present bilaterally.  Let's say that left ear in the previous scenario does have some hearing loss, then the clinician will activate the hearing aid's mics (via the manufacturer's fitting software) in addition to those of the transmitter on the right ear.

 

Neither the CROS or BiCROS plan, however, will not help you localize (determine which direction) sounds.  But for many these options are very helpful.