CROS and BiCROS Hearing Aids

CROS and BiCROS systems solve a problem standard hearing aids cannot: a hearing loss too severe on one side to benefit from amplification at all. Rather than trying to make an unaidable ear hear again, these systems reroute sound from that side to the ear that can still use it.

The Problem They Are Built to Solve

When one ear has too little usable hearing to benefit meaningfully from a conventional hearing aid, whether from sudden hearing loss, long-standing single-sided deafness, or a severe asymmetry between the ears, that side effectively goes dark. Sound arriving from that direction, or from anyone seated on that side, gets blocked by the head before it can reach the working ear, an effect called head shadow. The result is a very specific and disruptive kind of difficulty: an inability to locate sound, and real trouble hearing anyone positioned on the affected side. See one-sided hearing loss for the full picture of what this costs day to day.

How CROS Works

A small microphone device is worn on the poor-hearing ear. Rather than amplifying sound into that ear, it picks up sound on that side and transmits it wirelessly to a receiver worn on the better ear. The good ear then receives both its own natural hearing and the transmitted signal from the affected side.

This does not restore true two-ear hearing or the ability to localize sound, since both signals still ultimately arrive at one ear. What it does solve directly is the head shadow problem: someone speaking from your affected side becomes audible again, rather than lost entirely.

How BiCROS Differs

BiCROS is built for a different but related situation: one ear has too little hearing to aid at all, and the better ear also has some hearing loss of its own. In this arrangement, the better ear wears a full hearing aid rather than a simple receiver, providing amplification for its own loss while also receiving the transmitted signal from the poor side. It is essentially a CROS system combined with a conventional hearing aid in one device.

How This Works With the Brands We Carry

Each of the three manufacturers we carry offers a current CROS and BiCROS solution built around their newest platform. Phonak pairs its CROS I-R transmitter with the Audéo Infinio family. Starkey offers a CROS and BiCROS system built for Omega AI, its current flagship. Signia’s CROS IX solutions, including the CROS Active Pro IX, pair with its Integrated Xperience platform. Which manufacturer fits best depends on which hearing aid ultimately gets paired with the transmitter on your better ear, and that decision follows from your hearing evaluation rather than a brand preference.

Who Is Typically a Candidate

• Single-sided deafness from sudden sensorineural hearing loss that did not recover
• Long-standing severe to profound loss in one ear from any cause
• Significant asymmetry between the ears where the poorer ear cannot be adequately aided on its own
• Patients who have been told a conventional hearing aid will not help their affected ear

Candidacy always follows a full hearing evaluation and, where the loss appeared suddenly, a medical workup ruling out treatable or urgent causes. See one-sided hearing loss for why that medical step matters before any device decision.

What CROS and BiCROS Cannot Do

It is worth being direct about the limits. Neither system restores hearing in the affected ear itself, and neither fully restores the ability to localize where sound is coming from, since both ears’ information is ultimately processed by a single working ear. Patients considering CROS or BiCROS should understand it as a solution to the head shadow problem specifically, not a full restoration of two-ear hearing.

Other Options for Single-Sided Hearing

CROS and BiCROS are not the only path. Bone conduction devices route sound through skull vibration to the working inner ear, and for appropriate candidates, cochlear implantation of the deaf ear is an established option that can restore some genuine two-ear hearing, including partial localization ability, which CROS systems cannot provide. Gwen Cantrell, BC-HIS discusses all reasonable options based on your specific situation rather than defaulting to one.

What to Expect If You Try One

Adjustment takes some time, since the brain has to learn a new way of processing sound arriving through a single ear via two different paths. Most users find the improvement in awareness of their affected side is immediate and significant, even while full adaptation continues over several weeks. We schedule follow-up visits specifically to fine-tune the balance between the transmitted signal and the ear’s own natural hearing as you adjust.

Frequently Asked Questions

Will a CROS system let me hear normally out of my deaf ear?
No. It routes sound from that side to your working ear rather than restoring hearing in the affected ear itself. It solves the head shadow problem, not the underlying hearing loss.

How long does it take to adjust to wearing a CROS system?
Most patients notice immediate benefit for awareness of their affected side, with full adaptation to the new way of processing sound typically continuing over several weeks.

Can children use CROS or BiCROS systems?
Yes, with appropriate pediatric evaluation and fitting. Single-sided hearing loss in children benefits from early intervention given the impact on speech development and classroom listening.

Is a CROS system covered by insurance?
Coverage varies by plan. See hearing aid insurance benefits for how to check what your specific plan covers.

What if my hearing loss on the poor side happened suddenly?
Sudden hearing loss warrants prompt medical evaluation before any device decision, since some causes are time-sensitive and treatable. See sudden hearing loss.