Hearing Aids for Severe and Profound Hearing Loss

Navigating the world of audiological rehabilitation becomes significantly more complex when addressing severe and profound hearing loss. Unlike mild or moderate impairments, where a wide array of discreet devices might suffice, severe and profound losses demand highly specialised, powerful amplification strategies. At Buckinghamshire Hearing, an independent private audiology clinic in High Wycombe, we recognise that individuals with this degree of hearing loss face unique daily challenges that require expert, individualised care. This comprehensive guide explores the specific requirements for power hearing aids, the critical importance of precise fitting techniques, and the realistic expectations necessary for successful auditory rehabilitation.

In clinical audiology, hearing loss is categorised by the quietest sounds an individual can detect, measured in decibels (dB) across various frequencies. A severe hearing loss is defined as having hearing thresholds between 71 and 90 decibels. Individuals with severe hearing loss cannot hear conversational speech without amplification and rely heavily on visual cues, such as lip-reading, to communicate. A profound hearing loss is defined as having thresholds of 91 decibels or greater. At this level, individuals may only hear very loud environmental sounds, such as a motorcycle engine or a fire alarm at close range, and speech is entirely inaudible without powerful intervention.

These degrees of impairment are most commonly associated with sensorineural hearing loss, which involves damage to the delicate hair cells within the cochlea or the auditory nerve pathways. Because the damage is typically permanent and extensive, the amplification required must not only be exceptionally loud but also meticulously shaped to match the individual's residual hearing profile without causing discomfort or further damage.

When treating severe to profound hearing loss, the physical style of the hearing aid is dictated by acoustic physics rather than cosmetic preference. While Receiver-in-Canal (RIC) or completely-in-the-canal (CIC) devices are popular for milder losses, they are generally insufficient for profound impairments. The standard of care for this demographic is the Behind-The-Ear (BTE) power or super-power hearing aid, coupled with a custom-made full-shell earmould.

A BTE device houses all the electronic components—the microphone, amplifier, and receiver (speaker)—within a robust casing that sits behind the pinna (the outer ear). This separation of components allows for larger, more powerful amplifiers and larger batteries to sustain the high energy demands of significant amplification. The amplified sound is then directed down a thick acoustic tube into a custom earmould that completely seals the ear canal.

The custom earmould is a critical component. It must provide an acoustic seal tight enough to prevent the highly amplified sound from leaking out of the ear canal and reaching the hearing aid's microphones. If sound leaks, it creates a feedback loop, resulting in a loud, high-pitched whistling sound. For severe and profound losses, the earmould is typically made of a soft, medical-grade silicone to ensure a tight yet comfortable fit that moves with the jaw during speech and chewing, maintaining the acoustic seal at all times.

A frequent observation at our High Wycombe clinic is that patients with severe hearing loss often struggle with feedback when using poorly fitted generic domes. We always emphasise that for high-gain requirements, a deeply fitted, custom silicone earmould is not an optional extra; it is a fundamental necessity for delivering the prescribed amplification without constant, disruptive whistling.

Not all hearing aid manufacturers dedicate the same level of research and development to the super-power category. However, certain brands have established themselves as leaders in providing robust solutions for severe and profound hearing loss. At Buckinghamshire Hearing, we offer access to the most advanced power devices on the market, ensuring our patients benefit from the latest technological innovations.

The Phonak Naída series has long been recognised as a gold standard in power amplification. The latest iterations incorporate advanced frequency-lowering technology (SoundRecover), which shifts high-frequency sounds that the patient cannot hear into a lower frequency range where they have better residual hearing. This is particularly beneficial for distinguishing consonant sounds like 's' and 'sh', which are crucial for speech intelligibility.

Similarly, the Oticon Xceed is a formidable option, built on a platform designed to provide 360-degree access to speech while rapidly reducing background noise. Unlike traditional directional microphones that simply focus forward, the Xceed analyses the soundscape multiple times per second to preserve speech cues from all directions, which is vital for individuals who rely heavily on spatial awareness. Furthermore, many of these modern power devices are now available as rechargeable hearing aids, offering convenience and eliminating the need to frequently change large batteries, which can be challenging for those with dexterity issues. You can explore our full range of hearing aids to understand the breadth of technology available.

Providing a powerful hearing aid is only half the solution; ensuring that the device delivers the exact amount of amplification required at every frequency is where clinical expertise becomes paramount. This is achieved through Real Ear Measurement (REM), an objective verification process that is absolutely critical when fitting power hearing aids.

Every ear canal has a unique shape and volume, which significantly alters the acoustics of the sound delivered by a hearing aid. If a clinician relies solely on the manufacturer's predictive software, the actual sound pressure level reaching the eardrum could be vastly different from the prescription. In cases of severe and profound hearing loss, the margin for error is incredibly narrow. Under-amplification means the patient will continue to struggle with communication, while over-amplification can cause physical pain and potentially exacerbate the hearing loss.

During REM, a tiny probe microphone is inserted into the ear canal alongside the hearing aid. The audiologist plays calibrated speech signals and measures the exact sound pressure level at the eardrum. This allows the clinician to make precise, real-time adjustments to the hearing aid's programming, ensuring that soft sounds are audible, conversational speech is comfortable, and loud sounds are safe. For high-gain fittings, REM is not merely best practice; it is an essential clinical requirement to guarantee safety and efficacy.

Acoustic feedback—the high-pitched whistling caused by amplified sound leaking from the ear canal and re-entering the microphone—is the nemesis of power hearing aid fittings. Because severe and profound losses require immense amounts of gain (amplification), the risk of feedback is exponentially higher than with milder losses.

Managing this challenge requires a multi-faceted approach. As previously mentioned, a perfectly fitted custom earmould is the first line of defence. However, even the best earmould can occasionally leak sound, especially during jaw movement. Therefore, modern power hearing aids employ sophisticated digital feedback cancellation algorithms. These systems continuously monitor the sound entering the microphone; if they detect the specific acoustic signature of feedback, they instantly generate an opposing sound wave (phase inversion) to cancel the whistle before it becomes audible to the user.

The clinical challenge lies in balancing feedback cancellation with optimal amplification. If the feedback manager is set too aggressively, it may inadvertently reduce the gain for high-frequency speech sounds or musical notes, compromising speech clarity and sound quality. An experienced audiologist must carefully calibrate these systems to provide maximum stable gain without sacrificing the fidelity of the amplified signal.

It is crucial to establish realistic expectations when embarking on auditory rehabilitation for severe and profound hearing loss. Hearing aids, no matter how advanced or powerful, cannot restore normal hearing or repair a damaged auditory system. They are aids, designed to provide access to sound and improve communication, but they do not offer a cure.

Individuals with profound impairment may find that even with optimal amplification, speech remains distorted or difficult to understand, particularly in noisy environments. The goal of amplification in these cases is often to provide environmental awareness, improve lip-reading capabilities by providing auditory cues, and facilitate one-on-one communication in quiet settings.

Therefore, successful rehabilitation must incorporate comprehensive communication strategies alongside amplification. This includes:

• Ensuring optimal lighting to facilitate lip-reading and visual cues.
• Gaining the listener's attention before speaking.
• Speaking clearly and at a moderate pace, rather than shouting, which can distort the sound further.
• Reducing background noise by turning off televisions or radios during conversations.
• Utilising assistive listening devices, such as remote microphones or FM systems, which transmit the speaker's voice directly to the hearing aids, bypassing environmental noise.

We discuss these strategies extensively during the process of auditory rehabilitation, ensuring that both the patient and their family are equipped with the tools necessary for effective communication.

There are instances where even the most powerful hearing aids, fitted with precision using REM, fail to provide adequate benefit. When the damage to the cochlear hair cells is so extensive that amplifying sound merely results in distorted noise rather than intelligible speech, a cochlear implant may be considered.

Unlike a hearing aid, which amplifies acoustic sound, a cochlear implant bypasses the damaged portions of the inner ear and directly stimulates the auditory nerve with electrical impulses. Candidacy for a cochlear implant is determined through a rigorous assessment process by a specialist multidisciplinary team.

If our clinical assessments indicate that a patient meets the preliminary criteria for a cochlear implant, we will facilitate a referral to a specialist implant centre for further evaluation. We remain involved in the patient's care, providing ongoing support and advice throughout their journey. For information on the costs associated with our private audiology services, please review our pricing structure.