Single-Sided Hearing Loss: Understanding CROS and BiCROS

Solutions

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Hearing well with only one ear can be more challenging than many people realize.

A person with single-sided deafness may hear clearly when speech reaches the better-hearing ear but struggle when someone speaks from the poorer-hearing side. Busy restaurants, meetings, vehicles, classrooms, and group conversations can be especially difficult.

 

Modern CROS and BiCROS systems offer a nonsurgical way to improve access to sounds arriving from the side with little or no usable hearing.

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What Is Single-Sided Deafness?

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Single-sided deafness, often abbreviated as SSD, generally describes severe or profound sensorineural hearing loss in one ear with normal or near-normal hearing in the other.

 

A related condition called asymmetric hearing loss occurs when hearing is significantly worse in one ear, but the better ear also has some degree of hearing loss.

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Possible causes include:

• Sudden sensorineural hearing loss

• Viral or bacterial infections

• Head trauma

• Ménière’s disease

• Acoustic neuroma or vestibular schwannoma

• Congenital hearing differences

• Genetic conditions

• Circulation or vascular problems

• Ototoxic medications

• Noise-related damage

• Ear surgery or other medical conditions

Sometimes the cause remains unknown even after a medical evaluation.

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Sudden Hearing Loss Requires Immediate Attention

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A sudden decrease in hearing in one ear should be treated as a medical urgency.

Do not assume that the ear is simply blocked with wax, fluid, or congestion. Contact a physician or ear, nose, and throat specialist promptly. Early evaluation and treatment can be important in cases of sudden sensorineural hearing loss.

A hearing device should not be used as a substitute for appropriate medical evaluation.

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Why Is Hearing With One Ear So Difficult?

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The brain normally compares information arriving from both ears. These two inputs help us determine where a sound originated, separate speech from competing noise, and follow conversations in complex environments.

When one ear has little or no usable hearing, several difficulties can occur.

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The Head-Shadow Effect

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Your head physically blocks and weakens some sounds before they reach the opposite ear. This effect is particularly significant for higher-frequency speech sounds, including many consonants that contribute to speech clarity.

 

If someone speaks from the poorer-hearing side, their voice may sound quieter or less distinct by the time it reaches the better ear.

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Difficulty Locating Sound

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Two normally functioning ears provide the brain with timing and loudness differences that help identify where a sound originated.

 

With only one usable ear, localization may be reduced or absent. A person may hear a voice, alarm, vehicle, or other sound without being able to identify its direction quickly.

This can affect convenience, communication, and personal safety.

 

Difficulty Understanding Speech in Noise

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Single-sided hearing loss is often most noticeable when:

• Several people are speaking

• Speech comes from the poorer-hearing side

• Background noise is near the better ear

• The speaker is at a distance

• Visual cues are limited

• The environment has significant echo

 

Someone may perform well in a quiet room but struggle considerably in a restaurant, meeting, social gathering, or vehicle.

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Increased Listening Effort

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Trying to compensate with one ear can require significant concentration. People may turn their head repeatedly, choose seats strategically, watch faces carefully, or mentally fill in portions of a conversation.

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This extra effort can contribute to:

• Listening fatigue

• Frustration

• Reduced concentration

• Headaches or tension

• Avoidance of social situations

• Difficulty participating in groups

 

Tinnitus

 

Single-sided deafness may also be accompanied by tinnitus in the poorer-hearing ear. CROS and BiCROS systems are not direct tinnitus treatments, but improved environmental awareness may help some people feel less focused on their tinnitus.

 

Anyone with new, persistent, or one-sided tinnitus should receive an appropriate medical and hearing evaluation.

 

What Is a CROS Hearing System?

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CROS stands for Contralateral Routing of Signal.

A CROS system is generally considered when one ear has little or no usable hearing and the opposite ear has normal or near-normal hearing.

 

The system uses two devices:

1. A transmitter with a microphone is worn on the poorer-hearing ear.

2. A receiving device is worn on the better-hearing ear.

 

The transmitter collects sounds arriving from the poorer-hearing side and sends them wirelessly to the device on the better-hearing ear.

The goal is to make sounds from the poorer side more accessible without requiring the person to turn their head continually.

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What Is a BiCROS Hearing System?

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A BiCROS system is designed for someone who has:

• Little or no usable hearing in one ear, and

• Aidable hearing loss in the better ear

 

Like a CROS system, a transmitter on the poorer side sends sound to the better side. The difference is that the device worn on the better ear also amplifies sound according to that ear’s hearing loss.

 

A BiCROS system therefore performs two functions:

1. It routes sound from the poorer-hearing side to the better ear.

2. It amplifies sound for the hearing loss in the better ear.

 

A complete hearing evaluation is necessary to determine whether CROS, BiCROS, or another approach is most appropriate.

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What Can CROS and BiCROS Systems Improve?

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Depending on the person and listening environment, a properly fitted system may provide:

• Better awareness of sounds from the poorer-hearing side

• Easier conversation with someone seated on that side

• Less need to turn or reposition the head

• Improved participation in meetings and groups

• Reduced listening effort in certain situations

• Greater awareness of environmental sounds

• Amplification for the better ear when using BiCROS

• Wireless connectivity and rechargeable options, depending on the model

 

The benefit is often greatest when important speech comes from the poorer-hearing side.

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What CROS and BiCROS Systems Cannot Do

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CROS and BiCROS systems do not restore hearing in the unaidable ear. They send sound from that side to the better-hearing ear.

 

Because both sides of the environment are ultimately being processed through one functioning ear, these systems generally do not restore true binaural hearing or normal sound localization.

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They also may not improve every noisy environment. For example, if unwanted noise is coming from the poorer-hearing side while the desired speaker is near the better ear, routing that noise across may not be helpful. Modern controls, directional processing, and listening programs may help manage these situations, but expectations should remain realistic.

 

Benefits vary considerably. A professionally supported trial is often the best way to determine how the technology performs in your daily life.

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Will a Regular Hearing Aid Work on the Poorer Ear?

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That depends on how much usable hearing and speech understanding remain.

If the poorer ear still has aidable hearing, a traditional hearing aid may provide benefit.

 

When hearing thresholds are extremely poor or word understanding remains very limited even with appropriate amplification, making sounds louder may not make them clearer.

Testing each ear separately helps determine whether the poorer ear may benefit from conventional amplification or whether a routing system should be considered.

 

Are CROS and BiCROS Systems Available From Different Brands?

 

Yes. CROS and BiCROS technology is available through multiple major hearing-aid manufacturers.

 

Available features may include:

• Rechargeable batteries

• Disposable batteries

• Smartphone controls

• Direct audio streaming

• Hands-free calling on compatible devices

• Automatic environmental adjustments

• Directional microphones

• Remote professional adjustments

• Television and remote-microphone accessories

• Multiple technology and pricing levels

 

No single manufacturer is automatically best for every patient. The appropriate system depends on hearing results, physical comfort, smartphone compatibility, desired accessories, listening environments, insurance benefits, and budget.

 

Nova Hearing Center works with every major hearing-aid manufacturer, allowing us to compare available systems rather than limiting patients to one brand.

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Other Options for Single-Sided Deafness

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CROS and BiCROS hearing aids are not the only possible approaches.

Depending on the cause, severity, medical history, age, hearing in the better ear, and individual goals, additional options may include:

 

Communication Strategies

 

Some people manage effectively by positioning the better ear toward speech, selecting seats carefully, reducing background noise, and using visual cues.

 

Remote Microphones and Assistive Technology

 

A remote microphone can transmit a speaker’s voice directly to a hearing device. This may be particularly helpful in meetings, classrooms, lectures, restaurants, or conversations at a distance.

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Bone-Conduction Devices

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Bone-conduction systems route sound through vibration of the skull to the functioning inner ear. Options may include nonsurgical devices and surgically implanted systems.

 

Evaluation by an appropriate medical and hearing professional is required to determine candidacy.

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Cochlear Implants

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Cochlear implantation is now an approved treatment option for some adults and children with single-sided deafness.

 

Unlike CROS and bone-conduction systems, which reroute sound to the better cochlea, a cochlear implant stimulates the auditory pathway on the poorer-hearing side. In appropriately selected candidates, this may provide benefits for speech understanding in noise, sound localization, tinnitus, and overall hearing quality.

 

Cochlear implantation requires medical and surgical evaluation, and outcomes vary. Patients interested in this option should be referred to a qualified cochlear-implant center.

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No Device

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Some individuals may decide not to use a hearing device after reviewing the expected benefits, limitations, and alternatives. An informed decision should be based on accurate testing and a clear understanding of available options.

 

How Is a CROS or BiCROS System Evaluated?

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A comprehensive evaluation may include:

• Review of hearing and medical history

• Examination of the ear canals

• Pure-tone hearing testing

• Speech-recognition testing for each ear

• Testing in background noise when appropriate

• Review of tinnitus symptoms

• Assessment of communication difficulties

• Discussion of work, family, and social environments

• Smartphone and accessory compatibility

• Consideration of medical or cochlear-implant referral

• Demonstration or trial of appropriate technology

The goal is not simply to determine whether you can hear a sound. It is to understand how each ear processes speech and how the hearing difference affects your everyday life.

 

Questions to Ask Before Choosing a System

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Before selecting CROS or BiCROS technology, ask:

• Is the poorer ear truly unaidable?

• Would a traditional hearing aid provide any useful speech understanding?

• Is my better ear normal, or does it also need amplification?

• What improvement should I realistically expect?

• Will the system help in my most difficult environments?

• Can I try it before making a final decision?

• Does it work with my smartphone?

• Are rechargeable and disposable-battery models available?

• What accessories may help me at work, home, or in groups?

• What follow-up care and adjustments are included?

• Should I consider a bone-conduction device or cochlear-implant evaluation?

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Find the Right Single-Sided Hearing Solution

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Living with hearing loss in one ear does not mean you have to continue missing every conversation that occurs on that side.

 

At Nova Hearing Center, we evaluate both ears independently, explain the available treatment pathways, and help you compare solutions from every major manufacturer. If a medical, bone-conduction, or cochlear-implant evaluation may be appropriate, we will discuss the next step with you.

 

Schedule your FREE hearing evaluation or call 833-687-8324 to speak with our hearing-care team.

 

Results with CROS, BiCROS, bone-conduction systems, and cochlear implants vary. An individual evaluation is necessary to determine candidacy and expected benefit.

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