Age-Related Central Auditory Processing Disorder (CAPD): Could It Be Causing Your Hearing Issues?

When retired biologist, Dr. Peter Spencer Davies, 83, of Bearsden, Scotland, began to experience hearing loss in his 60s, he made an appointment with his general practitioner (GP) who arranged for a hearing assessment. An audiogram revealed moderate age-related sensorineural hearing loss, and he was fitted with hearing aids. Though the hearing aids helped to some extent, Dr. Davies realized there were some situations that he continued to find challenging. He began to wonder whether something else might have been affecting his ability to process sound. 

What is Central Auditory Processing Disorder (CAPD)?

When researching his hearing issues, Dr. Davies had come across descriptions of Central Auditory Processing Disorder (CAPD) which seemed to describe what he was experiencing. CAPD, also referred to as APD, is a condition that affects the way the brain processes sound and speech. For people with CAPD, the ears and brain don’t coordinate well. While the ears can hear well or well enough with assistance, the brain has trouble processing and understanding the sounds. As the auditory system ages, these issues can become more pronounced.

You may have heard of CAPD in relation to children. In fact, it is often referred to as a childhood learning issue. But adults can also have this condition.

To learn more, HearingTracker spoke to Rodolfo Sardone, AuD, MPH, Head of Population Health Research Unit, IRCCS Saverio De Bellis (a medical research center in Italy), who is researching age-related CAPD.

Symptoms of CAPD

Among the most common indicators of CAPD are the following:

• The inability to understand speech in a noisy setting or what’s known as a reverberant environment (more on that below)
• Difficulty understanding what’s said in the presence of competing speech
• Difficulty following multi-step or complex directions

For people with CAPD, complex listening environments can be difficult to navigate. A key factor is reverberation, which refers to sound waves reflecting off hard surfaces like walls, ceilings, floors, and furniture, causing echoes.

Dr. Davies began to realize the impact of reverberation on his ability to converse with his family.

“When I visit my grandchildren, who live in a modern house with a lot of glass and hard furnishings, there’s a good amount of reverberation that can stop me from hearing,” he said.

The reverberation issue also interfered with his being able to hear in public spaces, whether at church or in a lecture hall.

Diagnosis of CAPD

For those who are experiencing this kind of hearing loss, it can be challenging to get the right diagnosis. There is no universally accepted method for CAPD screening.

According to Dr. Sardone, “One of the fundamental limitations of this disorder is that diagnosis is often late or never occurs because pure-tone audiometry [a standard hearing test] cannot detect CAPD.”

To diagnose CAPD, testing must focus on the way the brain processes sound. Evaluations may include the following:

• Identifying small changes in sounds
• Filling in missing parts of words
• Memory tests
• Testing with electrodes to measure how the brain reacts to sound
• Listening to speech when background noise is present

Testing for CAPD is generally concentrated on diagnosing children, where early diagnosis is key to limiting the impact on learning. It can take some legwork to locate an audiologist skilled in diagnosing CAPD among adults. Dr. Davies shares that he is self-diagnosed with CAPD; he has as yet been unable to find a local audiologist who has the expertise to evaluate him for CAPD.

Complications of age-related CAPD

While Dr. Davies has been proactive about understanding his auditory issues, that is not always the case among older people.

Research findings have identified two fundamental concerns linked to age-related CAPD:

• Those affected are usually not aware of their deficits and tend to minimize the handicap. They often don’t speak about it and avoid situations that could trigger it, such as noisy or crowded places. This predisposes them to social isolation that can negatively impact cognitive status.
• The incidence of age-related CAPD may be underestimated. Age-related CAPD is often associated with other forms of cognitive impairment. This could mask the coexistence of the condition and delay diagnosis and treatment.

Treatment of CAPD

Treatment of CAPD typically concentrates on auditory training, which consists of activities to improve listening and concentration.

A frequency modulation (FM) system (radio aid) can also help people hear better in noisy listening situations. This device works in conjunction with hearing aids or cochlear implants (CIs); it can also be used on its own. The FM system is a two-part assistive device. It picks up the voice of the conversation partner through a microphone, which the listener then hears through the FM device’s receiver, thereby cutting out background noise. There’s a wide range of price points for these devices, typically starting in the $150 range.

Another treatment angle: Adapting the communication environment to be more conducive to hearing well. Dr. Davies is passionate about making public meeting spaces more accessible and enjoyable for people with age-related CAPD. In a blog post for hearing-access specialists, he highlights the need to address this in acoustic requirements for building regulations. Until such changes become common, a person with CAPD can work towards meeting with friends, family, and colleagues in spaces that have minimal background noise and reverberant surfaces to optimize their ability to hear well.

Looking forward

One of the key ways to support people with age-related CAPD is better diagnosis.

“We have to start with the diagnosis. Screening tests for central-auditory functioning should be implemented in the clinical audiology practice, not only of the elderly but every individual,” Dr. Sardone told HearingTracker.

Another avenue: state-of-the-art hearing aids. Assistive devices that use artificial intelligence (AI) to optimize sound for the surroundings can make a positive impact. An example of a company pioneering this technology is Whisper. Algorithms in the Whisper hearing system determine the voice the wearer is trying to focus on and amplifies it above the ambient noise, which could be a game-changer for people with CAPD.

Further research is also vital. As Dr. Sardone remarked, “Age-related CAPD is one of the most important risk factors for dementia and cognitive and functional decline.” Though only a few studies have confirmed this association, more research is essential to increase awareness of this disorder and its impact on daily life.