Puretone is a tried and tested method of testing hearing thresholds, and is a mainstay of audiology. We will play you a series of sounds – tones, at different pitches and volumes, through headphones. All you need to do is press a button whenever you hear something. We will also repeat the test using a bone conduction headset, the purpose of which is to bypass the outer and middle ear, and test the inner ear directly. This enables us to ensure that sounds transmit effectively through the entire auditory pathway.
Whilst effective, and useful for diagnostics, listening to ‘beeps’ isn’t a real-world concern for our clients. Most people with a hearing impairment have concerns regarding speech intelligibility, especially when conversing in background noise.
In Air Conduction (AC) testing, we are measuring the hearing mechanism as a whole, by testing the reception of sound signals transmitted via the outer, middle and inner ear. If there is dysfunction in any part of the hearing mechanism, it will show up as an AC hearing loss.
The AC test involves a series of high and low frequency tones, some loud and some quiet, being played through either insert or over-ear headphones. The client is provided with a response button, and encouraged to activate (and maintain) the switch every time they hear a tone, until the tone finishes. The resulting data is compiled into a audiological graph, known as an audiogram.
In Bone Conduction (BC) testing, the bones of the skull are vibrated using a mechanical transducer known as a ‘bone vibrator’. This stimulates the cochlea directly, by-passing the outer and middle ear, thus testing the sensory organs and neural pathways to the brain. If there is a dysfunction of the sensory or neural mechanisms, it will show up as both a BC hearing loss and an AC hearing loss. The procedure is carried out in the same fashion as AC testing, but instead of having headphones, the bone vibrator is used and situated on the mastoid bone.
Speech in Noise Audiometry (QuickSIN)
Hearing loss is normally categorised into two types; loss of audibility and loss of intelligibility. The latter is normally attributed to damage of the central auditory nervous system. Loss of intelligibility is distortion-based and cannot be remedied simply by additional gain (amplification). It can, however, be measured and quantified using Speech in Noise testing (SIN) which measures signal to noise ratio. Puretone testing and word recognition scores alone do not give an accurate insight into a client’s difficulties. QuickSIN testing was developed to create a more ‘real world’ simulation. Language has two types of redundancy; extrinsic and intrinsic. Extrinsic redundancy is the ability to decipher meaning from syntax and grammar, and fill in the blanks. If you miss a few words, your innate knowledge of the English language allows you to better understand simply from context. This extrinsic redundancy becomes more valuable as we age.
QuickSIN invites you to listen to a recording and identify words and phrases in the presence of an increasing level of background noise. This gives us an indication of how effective hearing aids will be, but more precisely, it tells us how loud speech volume needs to be above the background noise in order to have good speech intelligibility and comprehension. This can help us identify the best hearing aid technology to suit your lifestyle.
Testing of a client’s ability to filter out background noise helps us determine treatment options best suited to their needs.
Acceptable Noise Levels (ANL)
ANL is the calibrated measurement of an individual’s ability to follow the conversation, in a background of speech babble. The purpose of ANL is to assess the client’s ability to follow conversation in continuous background noise. This is used in combination with SIN testing. Similar to Speech in Noise testing, ANL uses stimuli and increasing background noise, however ANL is a continuous conversation rather than word identification. Fatigue effect, short burst of words, comprehension of continued conversation etc are all analysed.
For all clients who present with a conductive element to their hearing loss, we can perform a tympanometry examination. Tympanometry is an examination used to test the condition of the middle ear and mobility of the eardrum (tympanic membrane) and the conductive bones by creating variation in air pressure in the canal. The purpose of this test is to ascertain how large your ear canal is, how efficient the energy transfer is between the outer and inner ear, and to test the pressure difference between the outer and middle ear.
The procedure involves inserting a tympanometer, which has a small, rubber dome, into the ear canal. This creates a tight seal, which is essential for accurate recording. A small amount of air pressure is introduced into the ear and a pure tone is played, whilst recording the eardrum’s response. The data is then illustrated into a graph, known as a tympanogram. The test requires no client input, and takes a few seconds to perform.
Acoustic Reflex Testing
Acoustic Reflex Testing (ART) is designed to test the natural defense mechanism of the middle ear muscle, to high-intensity sound stimulation. The middle ear muscle (also known as the Tensor Tympani) responds to stimulation beneath the level of cognitive control; in other words, it is an involuntary contraction, in a similar way that you pull your hand away from a hot surface without having to think “wow, that’s hot!” A problem with the Tensor Tympani could indicate the possible presence of a lesion, but further diagnostic tests would need to be performed.
If our audiologists suspect that there may be a problem with the cranial nerves of the auditory pathway, then an acoustic reflex test may be performed.
The test is performed using a tymaponemeter, like with tympanometry, a small rubber tip is inserted into the ear canal. A small amount of air pressure is applied, and a series of loud sounds are played. The test requires no feedback from the client, and takes just one minute to perform.
Real Ear Testing (RET)
Real Ear Testing, or Real Ear Measurement (REMs) is a verification method used to ensure that hearing aids are providing the expected level of gain. It is also known as in-situ testing or probe-microphone measurements. The test analyses the acoustic properties of the clients ear canals, and measures the sound pressure delivered to the eardrum from the hearing aid.
REM is performed by placing a small thin tube into the ear, where it measures the sound pressure delivered to the eardrum. The test is performed with and without hearing aids, and enables us to identify the additional volume provided by the hearing aid to ensure that it follows the prescription formula chosen.
Phoneme Perception Testing
The Phoneme Perception test was designed by world leading hearing aid manufacturers Phonak. Its primary aim is to identify the areas of speech that cause confusion or misunderstanding. By identifying the problem areas, we can them implement the findings to improve people’s speech understanding. The test is conducted in our consulting room and takes 10-15 minutes to complete. The test involves identifying a sound that is “the odd-one-out” as well as identifying the correct consonant sound when sandwiched between ‘a’ sounds, e.g. aga, ada.
The results are then broken down and explained to you, using real world context where possible. The test can be performed with and without hearing aids to help show the improvement the aids are making.
Tone Decay (Acoustic Reflex Decay)
This test is performed by introducing a continuous puretone stimulus at 10dB above the client’s Acoustic Reflex threshold, for 10 seconds. In a normal ear, the reflex should stay contracted for the entire duration. This is to test the cochlear function and if there is a lesion present.
Red Flag Matrix
To evaluate the client’s ability to hear in speech in noise situation and their tolerance to loudness levels. Uses the data from SIN, and ANL to predict the client’s improvement with amplification, in everyday speech-in-noise situation.
To evaluate the client’s ability to discriminate single word speech. The test is performed using live, spoken voice from the audiologist. The audiologist will then use a list of homonyms (words that sound the same), and record the accuracy of interpreted words.
Algorithm Suitability Testing
Our audiologists program hearing aids using complex algorithms that interpret your hearing test results, and prescribe an advised amount of gain based on the data. These algorithms are designed to produce different sound qualities and prioritise elements of speech/sound. There are two main algorithm types in use today; NAL and DSL. Hearing aid manufacturers often produce variations on these primary algorithms. Some people respond better to one algorithm over another; people with mild hearing loss may find DSL too loud, whereas a person with profound hearing loss may find NAL algorithms too soft.
That is why we will work with our client s to ensure we use an algorithm that produces the most comfortable and clear sound.
Uncomfortable Loudness Levels (ULLs)
Uncomfortable Loudness Levels are an assessment used to identify the level of sounds that cause discomfort. Just like minimal hearing thresholds, everybody has different thresholds and sensitivities to loud sounds. Some people find 80dB loud, whilst others can listen to 110dB sound with no problems at all.
ULL’s are an important diagnostic tool for identifying conditions such as hyperacusis or recruitment.
Hyperacusis being the increased sensitivity to sounds, for example a person with hyperacusis can find passing traffic intolerable.
Recruitment is the abnormal growth of loudness, meaning that sounds go from being very soft to very loud in a short scale of volume. Recruitment is a symptom associated with certain types of hearing loss.
ULL testing takes 2-3 minutes to perform, you are asked to respond when sounds become uncomfortable. The test is not a test of tolerance or assessing how much you can cope with, but simply a test to identify the volume at which you wouldn’t want to listen for very long. The result of the ULL’s can then be entered into the hearing algorithm to ensure sounds do not cause the user any discomfort.
Hearing Loss Simulation
You cannot recreate a hearing loss by simply blocking ones ears. Whilst a person with normal hearing can hear sounds at a range of volumes and frequencies with good clarity, a hearing impaired person may have difficulties with a specific range of (normally high) frequencies, but be perfectly able to hear other (low) frequencies. Women’s and children’s voices are often the most difficult to hear and comprehend.
Software designed specifically to replicate hearing loss, can be calibrated and programmed to show the family and friends of a hearing impaired individual what they are experiencing. This is a particularly useful test, as a hearing impaired person’s family is often unaware of the extent of the difficulties involved. It can be a useful tool to help reduce loved ones’ frustration.
At Hearing Healthcare Centre, we have undergone training which enables us to perform basic balance testing. This allows us to quickly identify any balance problems relating to inner ear, and quickly identify the need for onward referral. There are two main types of balance testing; Romberg and Unterberger Testing.
The Romberg Manoeuvre is used to exam a person’s neurological function. It uses the principle that a person requires at least two of the three following senses to maintain balance while standing;
- Proprioception (ability to know one’s body in space)
- Vestibular function (the ability to know one’s head position in space)
- Vision (ability to monitor and adjust for body position changes)
In a similar fashion to the “drunken driver” test, a client is asked to stand, with their feet together, arms by their side, and their eyes closed. The client is observed for 1 minute, and any resulting loss of balance/instability can be interpreted as a positive Romberg test. This could be due to a loss of motor coordination.
The Unterberger test is used to diagnose the presence and site location (left or right) of potential lesions.
A client is asked to walk on the spot for 1 minute with a high step, in a quiet environment, with both their eyes open, and then both their eyes closed. Any resulting loss of balance/instability can be interpreted as a positive Unterberger test, and could indicate an issue with the client’s vestibular system.
Audiologists at Hearing Healthcare Centre have been using video otoscopy since the late 1990’s.
A key-part of our service, is to ensure that ears are clear and healthy – a service we perform as standard in every appointment. The purpose of otoscopy is to check the health of the ear canal and the eardrum. Otoscopy is performed using an otoscope. We have access to a range of otoscopes, including the handheld Welch Allyn, as well as video otoscopes such as the Alina and Delfino (with image and video capture capabilities).
We always try to make our appointments as informative as possible, and try to engage our clients wherever possible with the use of these otoscopes. We can talk you though the visible landmarks of the outer ear and in certain cases explain the pathologies of your ear.
The ability to take pictures of your ear allows us to record important information for future reference. We can compare these images of your ears after each visit, which helps identify potential areas of concern and allows us to monitor the pathology progression of the ear. If a pathology or referable condition is identified during otoscopy a picture can be taken and an image sent to your GP for their investigation/records.
The McGurk effect is a perceptual phenomenon that demonstrates an interaction between hearing and vision in speech perception. The illusion occurs when the auditory component of one sound is paired with the visual component of another sound, leading to perception of a third sound.
In-Situ Audiometry s essentially a hearing test performed through your hearing aids. Like the diagnostic hearing test, you are asked to respond whenever you hear a stimulus (tone). The purpose of the test is to verify that the hearing aids are delivering the intensity of sound that was recorded in the hearing test. The acoustic properties of hearing aids vary, for example some hearing aid styles allow low frequency sounds to escape the ear. By performing in-situ audiometry, you can assess what level of loss is present, as well as what levels of sound the hearing aids need to deliver, in order for a person to hear it.