Hearing tests for all
Written by Dr Lynzee McShea
Senior Clinical Scientist (Audiology)
Clinical Lead for Complex Adults and Balance Assessment / Rehabilitation
When I tell people that I work in Audiology, I usually receive one of two responses. Either “What’s Audiology?” or “Is that something to do with hearing?”
Audiology is an exciting profession, with fantastic technology and assessment techniques. The problem is, most people don’t know about this. Most people are shocked when I tell them that I routinely carry out hearing tests on people whilst they are asleep. It is perhaps surprising, but it is possible.
Those who have had experiences of Audiology often describe the hearing tests they have had; sitting in a small soundproof room in silence, wearing a pair of headphones and pressing a response button every time they hear a sound. Yes, this is the most common way of testing hearing, but it is by no means the only way. The problem is, many people do think this is the only way and if a person is not able to do this, then they cannot have their hearing tested.
Unfortunately it is something my colleagues and I hear all too often; “You wouldn’t be able to test their hearing, they have learning disabilities”.
The fact is, many people with learning disabilities can complete a routine hearing test successfully with no adjustments whatsoever. And for those that can’t, we must make reasonable adjustments. Most of the time, these adjustments are small and easy to make, and it is our responsibility to do this.
Sometimes the little things can make all the difference. I have seen many people with learning disabilities complete a routine hearing test with one or more of the following adjustments:
♦ Allowing the person to sit in a larger test room
♦ Giving the person more time to respond
♦ Playing sounds through speakers first to allow a person to become acclimatised, before rushing to put headphones over their ears
♦ Instead of insisting the person press a button in response to sound, trying an alternative such as raising their hand or saying “Yes.”
Just recently I tested the hearing of a man with Down’s syndrome who was thought to be “untestable” because he wasn’t able to use a response button. However, we completed an easy and fun hearing test, because he was able to clap his hands every time he heard a sound.
We should not define people by what they can’t do, instead we should spend time finding out what they can do.
Alternative hearing assessments
Of course, there will be some individuals who are unable to complete a routine hearing test even with reasonable adjustments.
I am clinical lead in my Audiology department for these adults and we have a specialised service available where we use a range of alternative hearing test techniques. There are many similar services in Audiology departments across the country.
I am Chair of the national Hearing and Learning Disabilities Special Interest Group; a group of professionals who are interested in hearing loss and people with learning disabilities. As a group, we recommend having specialised services like this in place, in order to ensure we meet the needs of those with even the most severe or profound learning disabilities.
However, if your local Audiology department doesn’t have such a service in place, they still have a duty of care and can provide an appropriate assessment as required, using alternative methods.
Visual Reinforcement Audiometry (VRA)
VRA, as the name suggests, involves combining sounds with a visual stimulus. Sounds can be played via speakers into a test room, or through headphones or earphones directly to the person:
Each VRA assessment begins with a conditioning phase. A sound is played at a volume that is expected to be clearly audible to the individual. At the same time, a visual stimulus is presented, which is pointed out to the person. In our clinics, this is a short video clip. The process of playing the sound and the simultaneous visual stimulus is repeated several times until it appears that the person being assessed has made the connection between the sound and the visual stimulus.
Next, the test phase begins. This time the sound is played, but the visual stimulus is only presented once the person has responded without prompting (usually by turning their head to the monitor, glancing with their eyes or pointing to the monitor). Gradually the volume of the sound is decreased which allows us to determine the quietest sounds that person responds to. The full range of sounds used during a conventional hearing test can be tested in this way.
With VRA testing, the individual does not need to be consciously aware of how the test works. The response is almost like a reflex – an instinctive response to the sound, with a visual “reward” for responding. The test is most successful if this reward is interesting to the person. We use a variety of video clips to maintain interest and can tailor them to an individual’s likes and preferences. In some cases, we observe a person’s responses to sound (Behavioural Observation Audiometry) to watch for subtle changes in behaviour, movement or facial expressions that only occur when a sound is being played.
Objective hearing tests
We also have a range of tests that do not rely on a person responding to sound in any way. A simple ear examination is very valuable and allows us to check ears for signs of wax, infection or other abnormalities.
Tympanometry tells us about the middle part of the ear and can be completed in a matter of seconds. It is not painful or uncomfortable and involves placing a soft tip in the entrance of the ear canal:
Tympanometry can tell us if there is fluid and congestion in the middle part of the ear, which people with Down’s syndrome are particularly prone to. We can also check there are no holes in the eardrum (perforations).
Oto Acoustic Emission (OAE) testing is another quick and painless assessment, performed in a similar way to tympanometry. This time, sounds are sent along the hearing pathway to the organ of hearing (cochlea). If the cochlea is working well, when it detects a sound it emits an “echo” in return which can be recorded. Although it is not a test of hearing as such, OAE assessment is often used in hearing screening, and is offered to every baby born in England as part of the Newborn Hearing Screen.
Increasingly, electrophysiological hearing assessments are being used in Audiology, and again require no active participation from an individual. The most common types used are:
♦ Auditory Brainstem Response (ABR)
♦ Auditory Steady State Response (ASSR)
♦ Cortical Evoked Response Audiometry (CERA)
Each of these tests check hearing pathways using electrical responses. A person has stickers placed on the head and behind their ears and are played sounds via an earphone.
Responses are detected by the stickers, which can be analysed on a computer. Some of these tests (e,g, CERA) work best when the person is awake and engaged in an activity (such as watching a television programme or looking at a magazine) but others (e.g. ABR) require the person to be still and relaxed. Such tests can be performed under natural sleep, sedation or general anaesthetic.
Which test is best?
There is no definite answer to this question, it depends on the individual, their capabilities and the information we need to gather.
In my clinical experience, most adults with learning disabilities can complete some form of hearing assessment in clinic, providing reasonable adjustments are made. Sometimes, we perform home visits if a person is unable to come to our clinic. We do perform hearing assessments under general anaesthetic, but only when all other options have been exhausted and only if it is in the best interests of the individual. We have good multidisciplinary links with other professions and coordinate care as much as possible. For example, last year we were part of investigations organised for a man with Down’s syndrome. With a single general anaesthetic, hearing tests, grommets, a biopsy and dental work were all completed. He was found to have a permanent hearing loss and is now a successful hearing aid user.
♦ Anyone can have their hearing tested- judgements and misconceptions should not prevent referral
♦ Many people with learning disabilities can complete a routine hearing test with minimal adjustments
♦ Hearing tests can be enjoyable and personalised to people’s strengths and abilities
♦ Audiology departments have a variety of assessment techniques available