UK Single-Sided Deafness: Comprehensive Guide to Causes, Treatments, and CROS Hearing Aid Trials with Tragus – The Ear Specialists

Single-sided deafness (SSD), also known as unilateral hearing loss (UHL), is more than simply losing hearing in one ear. In SSD, one ear experiences significant hearing impairment—from severe to profound loss—while the other functions normally. This imbalance not only hampers the ability to localize sound but also affects speech understanding, particularly in noisy environments. For many, the lack of binaural input means the brain struggles to filter out background noise, which can impact everyday communication, safety, and overall quality of life.

Understanding Single-Sided Deafness

SSD disrupts essential auditory functions. With only one functional ear, individuals often lose the natural cues needed for pinpointing where sounds come from. This “head shadow” effect makes it hard to hear high-frequency sounds from the impaired side. Over time, the increased mental effort required to listen can lead to fatigue and even affect cognitive focus and motivation.

Prevalence in the UK

Determining the exact number of people affected by SSD in the UK is challenging. Traditional estimates often merge SSD with broader unilateral hearing loss, making direct comparisons difficult. Early figures—once citing rates of 12 to 27 per 100,000 adults per year—were later questioned for methodological reasons. More recent data suggests that roughly 9,000 new cases are diagnosed annually, with some sources reporting up to 7,500 cases per year. Although lifetime prevalence estimates hover around 1%, these numbers underscore that SSD is a significant health concern requiring further research and clearer diagnostic definitions.

Who Is Affected?

SSD spans all ages, but trends differ by life stage:

• Children: Congenital cases affect approximately 0.6 per 1,000 births in England. Early detection through newborn hearing screening is critical to ensure timely intervention.

• Adults: In the UK, age-related degeneration often leads to acquired SSD, with research indicating that older adults—especially those over 60—experience higher rates. In the US, data suggests that SSD is most common in the 60–79 age group.

• Across the Lifespan: Besides age-related causes, SSD can result from infections, head trauma, or tumors. Its impact, however, is not limited to hearing alone—it can influence cognitive function, concentration, and energy levels.

Causes and Underlying Conditions

The causes of SSD are broadly classified as:

• Congenital: Genetic factors, cochlear nerve abnormalities, or complications during pregnancy and birth can lead to SSD from birth.

• Acquired: Conditions such as sudden sensorineural hearing loss (often linked to viral infections), acoustic neuroma, head trauma, or exposure to ototoxic medications can cause SSD later in life. In many adults, the exact cause remains unknown, leaving the hearing loss classified as idiopathic.

Understanding the root cause is essential, especially since treatment options may vary based on whether the loss is congenital or acquired.

How Does Normal Hearing Work—and What Happens in SSD?

Normal hearing relies on the complex process of binaural hearing. Sound waves travel through the outer ear, vibrate the eardrum, and are transmitted via tiny bones to the cochlea, where they are transformed into electrical signals. These signals then travel along the auditory nerve to the brain. With two functioning ears, the brain compares input from each side, enabling sound localisation, improved speech perception, and enhanced overall sound quality. In SSD, the loss of one ear’s input disrupts these processes. Without interaural cues, tasks like detecting the source of a sound or separating speech from background noise become challenging.

The Diagnostic Pathway

Diagnosis of SSD typically begins with a consultation with a GP or ENT specialist. A physical examination is followed by:

• Audiological Tests: An audiogram and speech discrimination tests help assess the level and pattern of hearing loss.

• Imaging: CT or MRI scans may be ordered, especially in cases of sudden hearing loss or when a tumor is suspected.

• Specialised Pediatric Testing: For children, tests like the auditory brainstem response (ABR) help diagnose SSD early.

A thorough diagnostic evaluation not only identifies the cause but also guides the appropriate treatment plan.

Treatment Options

Treatment strategies for SSD vary widely and are chosen based on the severity, underlying cause, and individual needs:

• Hearing Aids: In cases with some residual hearing, conventional hearing aids or specialised devices like CROS (Contralateral Routing of Signal) systems may be used. CROS devices capture sound from the impaired side and transmit it to the better hearing ear.

• Bone-Anchored Hearing Aids (BAHA): These devices use bone conduction to relay sound directly to the functioning ear, thereby mitigating the head shadow effect.

• Cochlear Implants: Increasingly used for SSD, cochlear implants directly stimulate the auditory nerve and offer the best chance of restoring binaural hearing. They are particularly promising in improving speech understanding in noisy environments and reducing tinnitus.

• Additional Options: For specific situations—such as sudden sensorineural hearing loss—medical treatments like steroids might be administered, and remote microphone systems can help in challenging listening environments.

Comparative Insights: CROS, BAHA, and Cochlear Implants

Each treatment option has its strengths and limitations:

• CROS Systems: They are non-surgical and help overcome the head shadow effect, but they do not restore true binaural hearing.

• BAHA Devices: Often preferred for their cosmetic and practical benefits, BAHA devices transmit sound through the skull but similarly fall short in restoring spatial hearing.

• Cochlear Implants: They stand apart by offering the possibility of re-establishing binaural processing, significantly improving sound localisation and speech perception. However, successful outcomes depend on factors like the integrity of the cochlear nerve and the duration of deafness.

Ongoing Research and Emerging Therapies

Advancements in technology and surgical techniques continue to improve SSD treatment. Current research focuses on:

• Optimising the timing and methods for cochlear implantation.

• Refining surgical techniques to preserve residual hearing.

• Exploring emerging therapies such as gene and drug treatments, which may further enhance outcomes in the future.

The Daily Impact of Living with SSD

Beyond the technical and clinical aspects, SSD imposes real-world challenges:

• Sound Localisation: Difficulties in pinpointing sound direction can affect safety, such as when crossing the street.

• Communication Challenges: Understanding speech, especially in noisy environments, can be exhausting and frustrating, leading to social isolation.

• Tinnitus and Fatigue: Many experience bothersome ringing or buzzing, compounded by the extra mental effort required to listen with one ear.

For children, these challenges may extend to academic performance and social interactions, emphasizing the importance of early intervention and supportive strategies.

Steps to Effective Management and Recovery

Living with SSD requires a multifaceted approach:

• Timely Medical Intervention: Early diagnosis and treatment can improve outcomes, particularly in cases of sudden hearing loss.

• Collaborative Treatment Decisions: Working with ENT specialists and audiologists helps tailor the best treatment strategy, whether it’s a hearing aid, BAHA, or cochlear implant.

• Adaptive Strategies: Simple changes—such as facing the speaker in conversations, reducing background noise, and using visual cues—can make daily communication easier.

• Support Networks: Engaging with support groups or online communities provides both emotional support and practical tips.

Final Thoughts

Single-sided deafness is a complex condition that affects much more than just one ear. Although determining its exact prevalence in the UK remains challenging, the significant number of new cases each year highlights its importance as a public health issue. Advances in treatment—especially cochlear implantation—continue to offer hope for restoring binaural hearing and enhancing quality of life. At Tragus – The Ear Specialists, we are committed to exploring every avenue to improve hearing outcomes. That’s why we offer CROS hearing aid trials, allowing patients to experience firsthand the potential benefits of this technology. With timely diagnosis, personalized treatment plans, and innovative trial options, we empower individuals to navigate daily life with greater confidence and improved hearing.