CROS and BiCROS systems send sound from a poorer-hearing side to the better-hearing ear. They may help when an ordinary hearing aid cannot usefully support the poorer ear. They do not restore hearing in that ear or recreate normal hearing with two ears.
One-sided hearing loss does not automatically mean you need a routing system. An assessment should establish what each ear can hear, why they differ and whether medical investigation is needed.
What does one-sided hearing loss mean?
It means hearing is affected in one ear. If both ears are affected to different degrees, you may hear the term “asymmetric hearing loss”. Neither description explains the cause or selects the treatment.
Tell the clinician when the difference began, whether it fluctuates and whether you have tinnitus, dizziness, pain or discharge. NICE guidance identifies unexplained one-sided or asymmetric loss as a reason to consider further investigation. A device discussion should not replace that step.
How are CROS and BiCROS different?
Both use a device on each side, but the two devices have different jobs. One collects sound on the poorer side; the other delivers it to the better ear.
- CROS: routes sound to a better ear that does not itself need amplification.
- BiCROS: also provides amplification for hearing loss in the better ear.
The County Durham and Darlington NHS explanation describes this distinction. Ask your provider whether your better ear needs amplification and who can assess a routing system for you.
Is this the same as wearing two hearing aids?
No. A conventional pair supports two ears that can each benefit from amplification. A routing system brings sound from both sides into the better-hearing ear.
If the poorer ear can benefit from an ordinary aid, that may lead to a different recommendation. Ask what your results show and what each proposed device will do. Our one hearing aid or two guide explains that separate decision.
What can a routing system help with?
It can improve access to someone speaking from the poorer-hearing side. It does not make the poorer ear hear again, and locating sound can remain difficult. Background noise may still interfere with conversation.
UCLH's CROS and BiCROS guidance explains these limits. Discuss the situations you want to improve, rather than expecting every busy room to become easier.
Ask how you could compare a conversation from each side, a family meal and a walk outdoors. Confirm any demonstration, trial and return arrangements before buying; this guide does not promise a particular trial period.
What else is worth discussing?
Depending on the findings, options may include a conventional aid, communication changes, accessories or specialist assessment. Bone-conduction devices and implants are separate options for selected people, with their own assessment requirements.
Try facing the speaker, reducing competing noise and explaining which side you hear best from. Our communication guide and assistive-device guide cover practical support alongside a device recommendation.
What should I ask at an assessment?
Keep the conversation focused on your own results:
- Can the poorer ear benefit from an ordinary hearing aid?
- Does the better ear also need amplification?
- Is further medical or specialist assessment needed?
- What improvement is realistic, and what may remain difficult?
- Who would fit, review and support the recommended system?
Bring previous results if you have them. Our audiogram guide can help you prepare questions, without trying to diagnose the difference yourself.
Start with your hearing, not the device
Hear Better offers free adult hearing tests at home across North East England, with no obligation to buy hearing aids. Liam Robson, HCPC HAD03779, can discuss your findings and the appropriate next step.
If you are specifically seeking CROS or BiCROS, contact us to confirm whether we can meet your needs before booking. Explore the home hearing assessment; hearing aids, if suitable and chosen, are a separate paid purchase.