Bone-Anchored Hearing Aids (BAHA): Who Benefits and How They Work

For most people with hearing loss, conventional hearing aids that amplify sound through the ear canal are the right solution. But for certain types of hearing loss — particularly conductive hearing loss, mixed hearing loss, and single-sided deafness — standard amplification simply does not work well enough. The problem is not that sound needs to be louder; it is that sound cannot reach the inner ear through the normal pathway. This is where bone-anchored hearing aids come in.

A bone-anchored hearing aid (BAHA) bypasses the outer and middle ear entirely, transmitting sound vibrations directly through the skull bone to the functioning cochlea (inner ear). First developed in Sweden in the 1970s and available on the NHS since the 1990s, these devices have helped thousands of people in the UK for whom conventional hearing aids are ineffective or physically impossible to wear. With modern wireless connectivity, discreet designs, and both surgical and non-surgical options, bone-anchored hearing systems are more versatile and accessible than ever.

Understanding Bone Conduction

To understand how a BAHA works, it helps to understand the two ways sound reaches your inner ear. The first and most familiar is air conduction: sound waves travel through the air, enter the ear canal, vibrate the eardrum, pass through the three tiny bones of the middle ear (the ossicles), and are transmitted to the fluid-filled cochlea, where hair cells convert the vibrations into electrical signals sent to the brain via the auditory nerve.

The second pathway is bone conduction. Sound vibrations can also travel through the bones of the skull directly to the cochlea, bypassing the ear canal, eardrum, and middle ear bones altogether. You experience bone conduction every time you hear your own voice while speaking — part of what you hear reaches your cochlea through the bones of your jaw and skull rather than through the air. A bone conduction hearing test uses this principle to assess how well the inner ear is functioning independently of the outer and middle ear.

A BAHA exploits this second pathway. By delivering processed, amplified sound vibrations directly to the skull bone, it enables people whose outer or middle ears cannot conduct sound normally to hear clearly through their functioning inner ear.

How Bone-Anchored Hearing Aids Differ from Conventional Hearing Aids and Cochlear Implants

It is important to understand where BAHAs sit in the spectrum of hearing devices, because they serve a different population from both conventional hearing aids and cochlear implants.

Conventional hearing aids amplify sound and deliver it through the ear canal. They work best for sensorineural hearing loss, where the inner ear is damaged but the outer and middle ear pathways are intact. If the outer or middle ear is blocked, malformed, or chronically infected, a conventional hearing aid may be uncomfortable, impractical, or simply ineffective because the amplified sound still cannot reach the cochlea efficiently.

Cochlear implants are designed for people with severe to profound sensorineural hearing loss — where the hair cells in the cochlea are damaged beyond the point where amplification helps. A cochlear implant bypasses the hair cells entirely, stimulating the auditory nerve directly with electrical signals.

BAHAs occupy the middle ground. They are ideal when the inner ear is healthy or moderately damaged, but the outer or middle ear cannot conduct sound. By vibrating the skull bone, a BAHA delivers sound directly to the working cochlea, sidestepping the problem entirely. They are also used for single-sided deafness, where one cochlea is non-functional — in this case, the BAHA transmits sound from the deaf side through the skull to the functioning cochlea on the opposite side.

The Three Types of Bone-Anchored Systems

Modern bone-anchored hearing systems come in three main configurations, each with distinct advantages. The choice depends on clinical factors, patient preference, and age.

1. Percutaneous (Abutment) Systems

The original and still widely used design. A small titanium screw (fixture) is surgically implanted into the skull bone behind the ear. After a healing period of several weeks, during which the bone fuses with the titanium in a process called osseointegration, a small post (abutment) protrudes through the skin. The sound processor clips directly onto this abutment, creating a direct mechanical connection between the processor and the skull bone.

Advantages: The direct bone connection provides the most efficient sound transmission, with minimal energy loss. Sound quality is generally excellent, and the processor is easy to attach and remove. Considerations: The skin-penetrating abutment requires daily cleaning to prevent infection and skin irritation. Some patients experience minor skin reactions around the abutment site, particularly in the first year. The visible abutment post may be a cosmetic concern for some users, though modern designs are small and can be concealed by hair.

2. Transcutaneous Active Systems

These newer systems eliminate the skin-penetrating abutment entirely. An internal implant is placed beneath the skin, and the external sound processor is held in place by a magnet aligned with the internal component. The processor transmits vibrations through the intact skin to the implant, which drives the skull bone directly. The Cochlear Osia 2 system is the leading example of this approach, using piezoelectric technology (converting electrical signals to mechanical vibrations) for powerful sound transmission without a through-skin connection.

Advantages: No skin-penetrating abutment means no abutment site care, reduced infection risk, and a more cosmetically acceptable result. The processor sits flush against the scalp and is easily concealed by hair. Considerations: There is some energy loss transmitting vibrations through intact skin, though modern active transcutaneous systems have largely overcome this limitation. The magnetic coupling means the processor may occasionally shift during vigorous activity.

3. Non-Surgical Bone Conduction Devices

These devices use a softband, headband, or adhesive adapter to press a bone conduction processor firmly against the skull without any surgery. The Cochlear Baha SoundArc and softband are common examples. Sound transmission is less efficient than with implanted systems because the vibrations must pass through skin and soft tissue, but for many users the benefit is still substantial.

Who uses them: Non-surgical options are particularly important for children under the age of five, who are generally too young for implant surgery and whose skull bones are still developing. A softband allows children to benefit from bone conduction hearing from as early as a few weeks of age, supporting critical speech and language development. Non-surgical devices are also used as a trial before committing to implant surgery — a patient wears the device on a headband for several weeks to evaluate the benefit before deciding whether to proceed with a permanent implant.

Who Benefits from a Bone-Anchored Hearing Aid?

BAHAs are recommended for people whose hearing loss cannot be adequately managed by conventional hearing aids. The three main groups of candidates are:

Conductive Hearing Loss

People whose outer or middle ear cannot transmit sound to the cochlea effectively. Common causes include:

• Chronic otitis media: Persistent middle ear infection or inflammation that makes wearing an ear mould uncomfortable or medically inadvisable.
• Atresia and microtia: Congenital absence or malformation of the ear canal and/or outer ear, meaning a conventional hearing aid physically cannot be fitted.
• Otosclerosis: Abnormal bone growth in the middle ear that fixes the stapes bone and prevents it from vibrating, blocking sound transmission. While surgery (stapedectomy) is an option for some, a BAHA is an effective alternative.
• Cholesteatoma: An abnormal skin growth in the middle ear that may destroy the ossicles and create a cavity unsuitable for conventional hearing aids.
• Previous ear surgery: Patients who have had mastoid surgery or radical mastoidectomy may have an altered ear canal that cannot accommodate a standard hearing aid.

Mixed Hearing Loss

Where there is both a conductive component (outer/middle ear problem) and a sensorineural component (inner ear damage). BAHAs can address the conductive element by delivering sound directly to the cochlea through bone, while the cochlea`s remaining function handles the sensorineural component. BAHAs are effective for mixed losses up to a moderate-to-severe sensorineural component (typically up to around 55-65 dB sensorineural threshold, depending on the device).

Single-Sided Deafness (SSD)

People with normal or near-normal hearing in one ear and severe to profound hearing loss in the other. In SSD, a BAHA worn on the deaf side picks up sound and transmits it through the skull to the functioning cochlea on the opposite side. This restores awareness of sounds from the deaf side, reduces the "head shadow" effect (where the head blocks high-frequency sounds from reaching the good ear), and can significantly improve hearing in group conversations and noisy environments. NICE guidance supports BAHA provision for single-sided deafness on the NHS.

The Assessment and Referral Process

The pathway to receiving a BAHA on the NHS involves several stages:

• ENT referral: Your GP or audiologist refers you to an ENT (ear, nose, and throat) consultant if a BAHA might be appropriate. Some NHS audiology departments can also initiate the referral.
• Audiological assessment: Comprehensive testing including air conduction and bone conduction audiometry, speech perception testing, and evaluation of current hearing aid performance (if applicable). The bone conduction thresholds are critical — they show how well the inner ear is functioning and predict the likely benefit from a BAHA.
• Trial period: Before any surgery, patients are fitted with a non-surgical bone conduction device on a headband or SoundArc for a trial period of several weeks. This allows the patient and the clinical team to evaluate the real-world benefit and ensure the patient is comfortable with the device before committing to implantation.
• Medical assessment: A review of the patient`s medical history, examination of the proposed surgical site, and sometimes imaging (CT scan) to assess skull bone thickness and quality at the intended implant location.
• MDT decision: A multidisciplinary team including the ENT surgeon, audiologist, and sometimes a speech and language therapist reviews the case and agrees on the most appropriate system and approach.

The Surgical Procedure

For patients proceeding with an implanted system, the surgery is straightforward and well-established:

For percutaneous (abutment) systems: The procedure is typically performed under local anaesthetic (with sedation if preferred) and takes approximately 30 to 60 minutes. The surgeon makes a small incision behind the ear, drills a shallow hole in the skull bone, and inserts the titanium fixture. For some systems, the abutment is attached at the same time; for others, a healing cap is placed and the abutment is fitted at a second appointment after osseointegration is complete (typically 6 to 12 weeks). The patient usually goes home the same day.

For transcutaneous active systems (e.g., Osia 2): The procedure may be performed under local or general anaesthetic and takes approximately one to two hours. The internal implant and actuator are placed beneath the skin, secured to the skull bone. There is no skin-penetrating component. The external processor is fitted after healing, typically four to six weeks later.

Complications from BAHA surgery are uncommon. The most frequently reported issue with percutaneous systems is minor skin irritation or infection around the abutment site, which usually responds to improved hygiene or topical treatment. Fixture failure (the implant not integrating with the bone) occurs in fewer than 5% of cases and is more common in children, whose skull bone is thinner.

NHS Provision and Lifelong Aftercare

BAHAs are available free of charge on the NHS for patients who meet the clinical criteria. The NHS covers:

• All assessment and trial costs
• The surgical procedure and hospital stay
• The implant and sound processor
• All follow-up appointments and processor programming
• Lifelong aftercare, including repairs, replacements, and troubleshooting
• Processor upgrades every five to seven years as new technology becomes available

Specialist BAHA centres are located across the UK, typically within NHS audiology departments at major hospitals. Referral pathways and waiting times vary by region, but once accepted, the NHS provides comprehensive, lifelong support at no cost to the patient.

Leading Brands and Devices

Two manufacturers dominate the UK bone-anchored hearing aid market, and both are available through the NHS:

Cochlear (Baha and Osia Systems)

Cochlear, the Australian company best known for its cochlear implant systems, is the market leader in bone-anchored hearing. Their current range includes:

• Baha 6 Max: The latest percutaneous (abutment) processor, featuring Bluetooth LE Audio connectivity for direct streaming from smartphones, rechargeable batteries, a companion smartphone app for adjustments and personalisation, and compatibility with both abutment and magnetic (Attract) coupling systems.
• Osia 2: The transcutaneous active system using Cochlear`s proprietary Piezo Power technology for powerful, clear sound transmission through intact skin. It offers the same Bluetooth LE Audio streaming and smartphone app connectivity as the Baha 6 Max, in a design with no skin-penetrating abutment.
• Baha SoundArc and Softband: Non-surgical options for trials and for children. The SoundArc is a lightweight, discreet band worn behind the head; the softband is an elasticated headband suitable for infants and young children.

Oticon Medical (Ponto System)

Oticon Medical, part of the Demant group, manufactures the Ponto range of percutaneous bone-anchored systems:

• Ponto 5 Mini: The smallest percutaneous bone-anchored processor available, featuring Bluetooth connectivity, direct streaming from smartphones, a rechargeable battery, and Oticon`s OpenSound Navigator technology for improved hearing in complex listening environments.
• Ponto Softband: The non-surgical alternative for trials and paediatric use.

The choice between Cochlear and Oticon Medical systems is made in consultation with the implant team, based on the patient`s hearing profile, the type of system most suitable (percutaneous vs. transcutaneous), lifestyle preferences, and connectivity needs. Both manufacturers provide excellent sound quality and ongoing support through the NHS.

Living with a Bone-Anchored Hearing Aid

Most BAHA users report a significant improvement in hearing and quality of life, particularly those who previously struggled with conventional hearing aids due to ear canal or middle ear problems. Modern processors are small, lightweight, and discreet — comparable in size to a conventional behind-the-ear hearing aid.

Daily Care

• Percutaneous systems: The abutment site requires daily cleaning with a soft brush and mild soap to prevent skin build-up and infection. Most users develop a quick, simple routine that takes less than a minute. Your BAHA centre will provide detailed hygiene instructions and ongoing support.
• Transcutaneous systems: No abutment site care is required. The skin over the implant should be kept clean and healthy as with any other area of the scalp.
• Processor care: Clean the processor regularly, charge the rechargeable battery daily (or replace disposable batteries as needed), and store the device in a dry, safe place when not in use. A hearing aid drying kit is recommended to remove moisture and extend the life of the processor.

Sport, Swimming, and Activities

The external processor should be removed before swimming, showering, and contact sports. The internal implant is unaffected by water and can withstand normal physical activity. Some manufacturers offer water-resistant accessories, though full submersion is not recommended with the processor attached. For non-contact sports such as running, cycling, and gym exercise, most users wear their processor without difficulty — retention clips and sport accessories are available for added security.

MRI Compatibility

Modern BAHA implants are generally MRI-compatible at 1.5 Tesla and, in some cases, at 3.0 Tesla. Your BAHA centre will provide an implant identification card detailing MRI compatibility and any precautions required. Always inform the MRI team about your implant before any scan.

Processor Upgrades

Sound processors are upgraded approximately every five to seven years as technology advances, provided free of charge through the NHS. New processors are designed to be compatible with existing implants, so the internal component does not need to be replaced. Each upgrade typically brings improved sound quality, better noise management, longer battery life, and enhanced wireless connectivity.

If you are living with conductive hearing loss, mixed hearing loss, or single-sided deafness and conventional hearing aids are not meeting your needs, ask your GP or audiologist about a referral for a bone-anchored hearing aid assessment. A hearing test including bone conduction testing is the essential first step in determining whether a BAHA could transform your hearing. Find an audiologist near you to get started.