Value Hearing founder Christo Fourie holds a monthly webinar on the first Wednesday of the month where you can have your questions answered. This month, Christo takes a deep dive into hearing test results, how the results relate to your specific hearing difficulties, and lastly how those results guide your hearing aid selection.
You can watch the full video or read through the edited transcript below:
Today is our fourth webinar I believe, and I'd like to take the time to discuss hearing test results.
We've developed a new tool that makes it really easy to explain, and in using that with clients, they often say they've never had their hearing loss explained this way. So I just thought to make this information public as it might be helpful to many of you.
The aim of today is really to have a few outcomes:
To do that I'm going to switch to our tool I've created this tool to use in clinic to help clients understand their loss.
I've created a false client here - J Doe - it could be male or female.
We'll just start with what an audiogram means. An audiogram is the graph that's created when you go for a hearing test and it essentially plots the softest sounds you can hear from very low pitch, or bass sounds, on the left hand side through to the very high pitched sounds on the right hand side of the graph.
The further down you go, the louder the sounds are. So essentially what the audiologist does, is they play you a tone, find the softer sound you can hear and make a mark where you've heard that and that's then plotted on your audiogram.
I’ve created a few audiograms to help you understand how they all work.
The first one is normal hearing, and you can see that here we've taken normal hearing as far as we currently classified is between -10 and 20 decibels for all these different frequencies.
For us, red is right ear and blue is left ear, and you can see this person's hearing loss for both ears falls in this green area which means it's normal hearing even though there's a great difference between normal hearing at -10 and normal hearing at 20.
Every 10 decibels down is a doubling in volume, so essentially ‘normal’ can be between simply hearing, and needing a sound to be 2, 4 or 8 times louder to hear and still being considered normal. It's a big range, so that's important to understand.
When we look at this we can see what sort of sounds this person can hear
When you do a hearing test, a comprehensive hearing test, part of your test will be your speech understanding in quiet where when they turn things up to see what the maximum amount of speech is you can understand.
It normally consists of single words you have to repeat, either with a hissing noise in the background or no noise, and that gives you a percentage speech understanding which is this one here.
You can also see that when we plot the actual intensity of speech sounds on here, it shows where the different speech sounds are produced. When we talk normally, and the further away from the mark, the louder the sound is. So for this person, a ‘u’ sound would sound very much softer than a ‘zed’ or ‘zee’ sound. And, even though they've got normal hearing, they might have trouble with some of these very high frequency sounds at times, particularly if someone's further away. For every two metres you travel away, the speech drops by half. So someone talking from another room could still be problematic for this person.
Important to keep that in mind as well. We can also see where music would fall.
This is a musical keyboard, and at normal level, music would be completely audible to this person. Even very soft music would be audible with only some of the details being lost, compared to someone who's got slightly better hearing. But essentially this is normal and they wouldn't really notice much of an issue even though they're starting to lose some of the hearing definition.
The other thing we look at is the Q-SIN test result which is a speech and noise test result.
A number of sentences are played to you through the earphones in the booth. With every sentence, there's an increasing amount of background speech babble - almost like party noise. Then after every sentence, you have to repeat what you thought you heard and we score the sentence giving you a signal-to-noise ratio loss.
So 7.5 decibel loss means this person, even though they've got normal thresholds and normal sensitivity for sound, the ability to interpret speech and noise is actually impaired.
They actually need the speech to be 137.8 times louder than the noise to be able to hear where a normal hearing person can hear. When speech noise is pretty much equal, or the noise just a little bit louder than the speech, they can still hear, so this person actually has a signal to noise ratio loss even though their (hearing) thresholds are normal.
My wife, for instance is an excellent case of this. She's got a similar score to that - actually, she's got better hearing than this - but she wears hearing aids and she finds them very beneficial because they increase the amount of speech relative to the noise and she can function much better.
So, the audiogram alone doesn't tell us whether or not you're going to benefit from hearing aids. We have to look at everything together and speech-in-noise testing is very important.
If we look at the next type of hearing loss - and there's various types of hearing loss - I'll make an offer later on if you want your own results explained to you.
What I've done here is shown you what a typical noise-induced high frequency hearing loss looks like.
It's one of the very common types we get. The perception of this from a person with this kind of hearing loss is ‘I can hear fine, I just can't hear clearly’, or 'if everyone would just stop mumbling, I'll be able to hear’.
This would be described as a high frequency sloping moderately severe high frequency sensorineural hearing loss. We’ll plot speech on this graph so what you can see here.
This explains exactly what's going on.
This person can say they can hear someone talking, because these low pitched sounds give us the volume of speech, but they can't distinguish what's being said because the ability to hear the clarity is impaired.
This person would say, ‘I’m fine, everyone's just mumbling' or 'I'm fine if I can look at someone’. We can see that when someone talks about two metres away, they can hear about 66% of what's being said.
If you add someone looking at them we automatically get between 40 and 50% from the lips so that would give them a 100%.
If someone's talking at this sort of distance to them, they think their hearing's fine, but should that person move out of the room - suddenly things get a lot worse and there's a lot of sounds they can't hear.
So, they basically tell you, ‘don't talk to me with your head in the cupboard’ or ‘don't talk to me from another room’.
It's quite a common one and there's also a difference between how well they can hear male voices, which are a bit deeper, because you can see more of the sounds here fall in the white area then they could hear female voices when more of the sounds fall in the shaded area.
So for this person, a male voice would be fine, or better than a female voice. They can hear the volume of speech, which is low pitch, fine but they can't hear the clarity.
Often these people think, ‘oh there's nothing wrong with my hearing, it's someone else's problem’ but that's because part of your hearing is impaired and other parts are pretty normal and it's still something a hearing aid can help with quite a lot.
When we look at the next loss here, a flat hearing loss, this one would be described as a moderate hearing loss.
Again this might differ between male and female, but not as much as you can see.
So they wouldn't really point that out as being a difference but certainly they say, ‘if someone whispers or speaks too quietly I can't hear them, but if they talk normally, I'm fine’. Most people then might say, ‘my hearing's fine’, which is not the case for them.
Then music starts being a problem if it's anything than moderate to loud.
They say, ‘when it's very soft, I can't hear soft music’ but when they turn their music nice and loud, they can hear all the pieces of music beautifully and they say, ‘I just need to turn the telly up or turn the radio up and I'm fine’.
This person also has more difficulty in background noise, not that this figure here relates to your audiogram. There's no relationship between your speech in noise result and your hearing test result. That's why it's a different test.
For this person, when we turn things loud enough, they can hear very well as we saw with the speech sound, so there's no distortion going on in the brain. The brain is ready and waiting - it's just the ear not delivering enough sound but they do need the speech to be 217 times louder than the noise before they can hear. That’s quite a bit louder than a normal hearing person would need even, when we've turned things up through hearing aids, so that's important to keep in mind.
Another loss which is not as common is when there's an asymmetry. So there's a difference between the right (red) which is better than the left ear (blue).
All the hearing aid is doing is taking the sound from the outside and amplifying it according to the loss. Different levels get different levels of sound but it cannot fix the brain's inability to process properly. On the right ear they do a bit better, but even with the right ear there's still about 23% of speech that's going to be missed.
This means if you're not looking at someone, and not getting the lip reading cues from that person speaking, you'll still miss out some sounds, so it's important to measure that, but also important to have the clinician discuss it with you so you understand what you may expect from the hearing aids.
In this person's case they need the hearing the speech to be 19.5 decibels or 851 percent times louder so that's eight and a half times louder than noise for them to be able to hear.
The best hearing aids we've got today can probably make the speech about two or three times louder, so they might have difficulty even with the best hearing aid.
This is good to know, because at least then your expectations are: ‘if I invest all this amount of money in a hearing aid, I'll do much better in quiet because I can hear speech which I couldn't in my left ear. If we do it that way, I couldn't even hear it in my right ear there but the hearing aid will bring it up and I can hear those sounds yet I will still have trouble with clarity in some situations, and if someone's talking from the left in this background noise I won't hear them as well as from the right with background noise’.
So again, very important to relate this to the hearing test result.
Lastly we've got another common type of hearing loss which is called the cookie bite hearing loss, where the low pitch the volume is fine and the very high pitch is close to normal or normal but most of the speech impediments here are in the mid frequencies.
And the mid frequencies is where a lot of energy of speech lies, so you can see this person at normal speech ranges 2 metres away without facing them will only get between 35% and just under 50% of the speech correct without hearing aids.
With hearing aids you can see a lot more of the speech is in and with hearing aids, essentially what will happen is these sounds will be boosted more.
These sounds will be boosted according to the amount of hearing loss. So another way to show that is if I just split it between left and right just to clear it up.
Soft sounds will be brought closer to normal, and medium level sounds will be brought a lot louder. So even if there's normal speech, you should be able to hear most of the speech fine with some hearing aids and we can do the same for the right ear so you can see a hearing aid will help a lot with understanding speech in quiet.
Speech in noise for the person is not as bad. They just need the speech to be 68.2% louder than the background noise to be able to hear and they find it is pretty close to normal.
That means we need a hearing aid to boost that amount of sound, but the hearing aid itself doesn't need to clean up the sound as much as for someone who's got a much poorer signal-to-noise ratio score. This person could actually do very well for more much more basic, much less expensive hearing aid, and do as well as they would have done with a top end hearing aid because their brain doesn't need as much help.
So again that (speech in noise) score, which is often not done, is very important making sure you're getting the right hearing aid without paying for things you don't need.
So what I'd like to do now is just go through these different kinds of losses and show you a few more things, particularly with how much a hearing aid helps.
As you can see, a hearing aid is not going to give you normal hearing but it can make things a lot better than it was. In this case there might still be sounds you can't hear in the high pitch, even if we boost those soft sounds a lot, but what we can do is use technology to take these high-pitched soft sounds and move them down in pitch to the low pitch sounds we can hear.
Different hearing aids have different features so we'd be looking at those different features to decide what's going to work.
Another thing to understand here is when there's noise, there's different effects that happen.
So essentially hearing aids, to be able to hear in noise, needs two microphones, (apart from the newer AI type hearing aids like the Oticon More which can separate speech and noise into the component parts, rebalance them to bring up speech, drop noise and then put them back together).
But traditionally, hearing aids needed two microphones to separate speech from noise.
So if we look at a dinner party type noise, this is the normal level without the influence of the hearing loss, so anything in the gray you can't hear.
At a dinner party which is a noisy cocktail-type party, even someone of normal hearing would have trouble hearing because most of the speech is actually blocked out.
Male voices might be easier to hear because there's more of it in the non-noise area than female voices, so yeah everyone's going to have some difficulty there.
Typically what happens in background noise is everyone speaks louder which then brings more of the speech into the noise. But if you've got hearing loss, this amount of loudness isn't going to be the same.
So if your hearing was up there, the sound say, for a ‘f’, ‘t’, ‘h’ would be just audible, and when it's louder it would be a lot louder, and you will actually hear a lot more. But when you've got hearing loss, you'd still be left with areas you can't hear, even when we boost those sounds, so you'll still have more difficulty in background noise than someone with normal hearing.
Then hearing aids themselves have different technologies. So for instance, this kind of loss, the person needs the speech to be twice as loud as the background noise.
When you look at a hearing aid with more advanced noise reduction, you can see there's a big change here.
All the low pitch noise is dropped and more of the speech becomes audible just by that directional microphone and obviously, looking at the person you want to hear, so more of the speech in front of you is boosted than the sound behind you.
And then you get more advanced noise reduction which has a bigger effect. It gives you a separation between speech and noise, and that's why it's correlated the signal to noise ratio loss there. The more the speech needs to separate from the noise, the better the hearing aid can do it with a better directional microphone. And typically those with better directional microphones tend to be the more advanced hearing aids.
In this case the noise is made about five times softer than it was, and then if the speech remains the same, that can give you a five times louder speech and noise for instance.
In that case, and it varies with different kinds of noise, you can see some noise is a lot louder. So if I take off the microphone effect you can see that a busy food court is even louder than a dinner party and then a train station.... there's different kinds of noise so there's more low frequency some of the high frequency noises so even in a library there's a little bit of noise which is that top one there.
So, how does a hearing aid help us determine what kind of hearing aid you need?
In this case we need to consider a few things. We need to consider that your ability to hear the low pitch sounds, in this case, is normal and we don't want to take any normal hearing away by sticking a hearing aid in, because when it blocks the ear, all the natural sound that came to the ears is stunted and all the sound has to go through the hearing aid be processed and then put into your ear.
And a hearing aid, no matter what technology it has, it’s never going to be - well, never say never - but currently isn't as good as the brain is at separating the speech and noise.
When the brain receives a signal from both ears, it likes to compare notes between the two ears, so any speech is then boosted, any noise is subtracted which is why we typically do the speech in noise test through both ears at the same time.
In this case if we were to stick a hearing aid inside the ear - a very tiny type of hearing aid - what would happen is we would cause a hearing loss in the low pitch - something similar to that (illustration above). Your hearing would go from there-to-there and suddenly speech you were able to hear would be blocked, while speech you weren't able to hear in the high pitch would become audible. So it would essentially just flip your hearing loss around.
The other thing is when you've only then got one microphone running, it doesn't do anything to separate the speech from noise. It just makes everything louder, your ability to hear speech in noise won't be improved.
So typically for this kind of loss it's very hard, particularly if you've got a poorer than normal Q-SIN results, speech in noise result, to fit a very tiny hearing aid without you feeling blocked off or without causing an insertion loss whereby the fact of putting it in the ear even with a hole running through, we still stunt some of the sounds coming through.
With this kind of loss, we typically want to fit the ear with a more open hearing aid, so we don't block the natural sounds. We just want to add the missing sounds, which means a hearing aid behind the ear connected via fine little wire, which isn't particularly visible, sitting in the ear.
When we look at a loss like this one here, our options become greater as you can see the blocked feeling caused by a little hearing aid isn't really an issue because you can't hear it. Your hearing sensitivity is not there, and the hearing aid will boost those sounds for you quite well. Not quite as good as as normal, but you'll be around that sort of level there.
Look at all the speech sounds, you'll be able to hear those soft speech sounds although volume overall will still be a quite bit quieter for you than normal. A closed hearing aids not so much of an issue, but a hearing aid with a single microphone is still an issue because you need the speech to be a lot louder than the noise.
When you've got that single microphone, as I showed you earlier with the noise, it doesn't do anything to separate the speech from noise. So, if you chose a very discreet hidden hearing aid with that kind of loss, and with this kind of score, you'll find that your ability to hear in noise is still impaired.
However if this score was normal, then we could happily fit you with a tiny hearing aid and you'll do perfectly fine. You'll be very happy with it in fact so that that's another consideration there.
If we look at this kind of hearing loss, we can see that here the two ears are very different.
One thing we'll have to look at in this kind of hearing loss, which isn't plotted here, is these are the individual scores for each ear separately. So, we can see there's a good 27% difference between how well the right ear can do at 77% versus the left ear at 50%. The question is because the brain wears works binaurally, and it's comparing both ears, if the left ear is so distorted, does that distorted signal cause further difficulty for the right ear to understand? Or does the combination of the two make your overall understanding better?
It's important for the audiologists in this case to play you sound through both ears, then correct it for each ear and see whether the score for both ears together is better than the right, or at least no no worse than about 10% worse than the right ear which means actually by putting something in the left ear we're distracting from the right which might not be a good thing.
In which case, we might want to look at a CROS or BICROS type fitting where you've got a microphone on your left ear, the bad ear in this case, which simply picks up the sound and puts it in the good ear.
This means if someone's talking from your bad side, you can still hear them, but you'll be hearing them in your right ear which is better able to understand speech in noise so that's another indicator.
As I said, we can also then not expect you to understand more than about 77% of speech in noise. We can also not expect a hearing aid, no matter what the directional microphone or the technology inside the hearing aid itself, to come close to giving you the speech in noise understanding.
You'd still expect with a poor speech and noise score like that to have difficulty in the more noisy situations. A small group around a dinner table at home might be fine, but out in the street or the shops, will still be problematic.
Fortunately we also have things like remote microphones which could help for this loss. This is a microphone you can place closer to the person speaking.
So as I said, for every two metres someone travels away from you, their voice drops by half. If you pick up the sound closer to the source, then it's louder than the noise which is all around and that can give you a good separation. But that does mean a separate device connected to your hearing aids.
So a decision in that case, might be best to not buy the most expensive hearing aid but rather use the savings to buy a separate microphone to help you in those difficult situations.
If you are comfortable using a device like that, which is obviously a personal choice, but at least understanding it this way will give you some realistic expectations as to what a hearing aid may or may not do for you
Unrealistic expectations is one of the biggest reasons for failure of hearing aids.
If you're expecting something to work as marvellously as the brochures say and it doesn't, then you will be very disappointed. Yet if you understand what you're going into before you go into it, and it does the same or better, then it's a positive experience.
So it is important to understand your own results as it relates to the hearing aid choice very well before you make the decision.
This person here will probably want to keep the hearing aid open, even though a smaller device might be okay. With that sort of speech in noise result, we don't want to create a blocked effect, which takes away what this person's heard for a long time. So again, an open fit might be a better option for this person.
The person with the reverse slope is interesting.
It's not such a common loss but they essentially have the reverse of the the high frequency, or noise induced kind of hearing loss, where they can hear the high pitch sounds but they can't hear the volume.
Typically, this person finds hearing male voices are a lot worse than our female voices. You can see more of the speech sounds for female voices are in the audible area where the male voice is more in the inaudible area.
With this kind of hearing loss, if that (speech in noise) score is good then it's typically a good option to fit a invisible in the ear canal as long as the ear canal is big enough but also we could get loss in the high frequencies, so we've got to be careful not to bring these down too much. But certainly in the ear tends to be a potentially more suitable option for a reverse slope in some cases.
Again it's very individual. I'm just talking in generalised terms. It's important you understand and have your audiologist go through this so you get a better understanding of what's going to work, what your options are and why that recommendation hasn't been made for you specifically.
It's not something we do to you, it's something we work with you to help you find something that first of all you're comfortable wearing, comfortable be seen with - or not seen with for that matter - and is comfortable.
Obviously if you have to pay for it yourself, using it regularly as well as being a comfortable fit in your ear is a big consideration. Typically the ones that go deep in the air might not be as comfortable as the ones that just sit lightly in the ear.
Hopefully that has given you a clearer understanding of how hearing aids work, and your hearing loss relates to hearing aids, and how hearing aids might impact your speech in noise.
It's a little tricky trying to explain five different kinds of hearing losses as part of what I've done today, so I'd like to invite you to simply email us. Send us a copy of your results, I can enter it on our system and explain it to you in detail, using our tools and record a video to you and send that to you.
So hopefully, I've answered all those questions to an extent. We always have all our various resources we've got our YouTube channel. We've got our knowledge base which you can visit. There the Value Hearing website which is just valuehearing.com.au, your own hearing specialist of course, and soon to be released our 2021 Hearing Aid Buyer's Guide.
That discusses many of these things and other things that are important to understand when it comes to buying hearing aids, but also we've extended it to describe or explain in more detail how to be successful with hearing aids.
Once you've bought it and then as I mentioned, you're welcome to email us with a copy of your results which I'll enter into the system, I'll make a video recording as I explain it and send that to you so you've got a copy of that to look at your own leisure, and hopefully gain a better understanding of how your hearing loss relates to hearing aid options as well.