Hearing Loss in One Ear: What CROS Hearing Aids Are and Who They Help

AudiologyOctober 6, 20265 min read

Hearing loss in one ear, often called single-sided hearing loss, means one ear hears well or reasonably well while the other has significant hearing loss. A CROS hearing aid system is one option for people whose poorer ear cannot benefit from a regular hearing aid: it picks up sound on the poorer side and sends it wirelessly to the better ear.

A CROS does not restore hearing in the poorer ear. Instead, it helps you hear sounds and speech coming from that side without having to turn your head. Whether it suits you depends on your hearing test results, the cause of the hearing loss and your daily listening needs.

What is single-sided hearing loss?

Single-sided (or unilateral) hearing loss affects one ear while the other ear hears within the typical range or close to it. It can be present from birth or develop later. Possible causes vary and include problems in the outer or middle ear as well as the inner ear or hearing nerve, which is why a medical evaluation is important.

Important: if hearing in one ear drops suddenly, treat it as urgent and see a doctor promptly. Our article on sudden hearing loss in one ear explains why timing matters. One-sided tinnitus, dizziness, or ear pain with discharge also need a medical check.

How does single-sided hearing loss affect daily life?

People with hearing loss in one ear often notice that:

conversations are harder when the speaker is on the poorer side;
noisy places, such as restaurants, gatherings or offices, are much more tiring;
it is difficult to tell where a sound is coming from, such as a phone ringing or someone calling your name;
they choose seats carefully, for example sitting with the better ear towards the group;
driving conversations are harder when a passenger sits on the poorer side.

These challenges are real even though the other ear hears well, and they are a good reason to have an assessment.

What is a CROS hearing aid?

CROS stands for "contralateral routing of signal", which simply means sending sound from one side to the other. A CROS system usually has two parts:

A transmitter worn on the poorer ear. It looks like a hearing aid and picks up sound from that side.
A receiving hearing aid worn on the better ear. It receives the sound from the transmitter and plays it to the better ear, together with sound from its own side.

When the better ear also has some hearing loss, a related arrangement, often called BiCROS, can both route sound from the poorer side and amplify sound for the better ear.

As an authorised Danavox (GN Hearing) dealer, our hearing aid catalogue includes a CROS option. Your audiologist will explain whether this type of system is suitable for you.

Who might a CROS help?

A CROS may be considered for people who:

have very limited hearing in one ear that is unlikely to benefit from a regular hearing aid;
have good or aidable hearing in the other ear;
find conversations on their poorer side, or in noise, difficult in daily life.

Other approaches may also be discussed, depending on the cause and type of hearing loss, and some of these involve assessment by an ear, nose and throat (ENT) doctor. If the poorer ear can still benefit from amplification, a regular hearing aid on that side may be more suitable; see one hearing aid or two.

How is it assessed?

Medical check to look for the cause of hearing loss in one ear.
A full [hearing test](/en/services/hearing-test) measuring each ear separately.
Discussion of daily challenges and what you hope to improve.
Fitting of the recommended option during a Danavox hearing aid fitting appointment, followed by fine-tuning; ask about trial arrangements when you discuss options.

When to see a specialist

Book a hearing assessment if you rely on one ear, often ask people to move to your "good side", or struggle in noisy places. You can arrange a hearing aid fitting consultation to discuss CROS after your hearing test by booking online or contacting us. No referral is needed for a hearing assessment.

See a doctor promptly, before any hearing aid appointment, if hearing in one ear changed suddenly, or if you have one-sided tinnitus, dizziness, or pain with discharge.

Frequently asked questions

Is a CROS a hearing aid for the deaf ear?

Not exactly. A CROS does not make the poorer ear hear again. The device on the poorer ear acts as a microphone that sends sound to the better ear, so you can hear what is happening on your poorer side through your better ear.

Do I need a medical check first?

Yes, a medical check is usually advised. Hearing loss in one ear can have different causes, and some need medical assessment or treatment. If the change was sudden, see a doctor promptly, as sudden hearing loss is treated as a medical emergency.

Does CROS help with direction of sound?

A CROS mainly helps you hear sounds and speech from your poorer side. Because the sound from both sides reaches only one ear, it usually does not restore the ability to tell where sounds come from. Your audiologist can explain what to expect realistically.

Sources

This article is general information and does not replace advice from a qualified professional.

Hearing Aid Selection, Fitting, Programming & Follow-up Ashfeera Ashraf