KidsAudiologist

Archive for the ‘bone-anchored hearing aid’ Category

More than 9 out of every 10 chldren born with a hearing loss have hearing parents. It’s therefore entirely natural that early on they are going to ask “What can my child actually hear, what does it sound like for them?” They share a need to try and get to grips with this as part of the process of understanding what they need to do to help their child. It is a very difficult question to answer. Some of the things we know at this stage include the degree and type of deafness: we know how much volume is lacking for a mild (20-40dB), moderate (41-70dB), severe (71-95dB) or profound (95+dB) hearing loss, and we know that loss of hair cells in sensorineural hearing loss means that some natural processing that happens within the cochlea is lost – including the cochlea amplifier, pitch discrimination and the ability to recognise different sound levels (reduced dynamic range). We also know a good amount about the benefits and limitations of various types of hearing technologies that are used. Now more than any time in history, we know that almost all deaf children can perceive the full range of speech sounds with their hearing aids or cochlear implants. But we also know that they can’t do this as easily as hearing children and that no hearing technology can replace normal levels or quality of hearing.

So it’s relatively easy to mock up some simulations of what a hearing loss might sound like using some software to reduce the overall level of sound and filter out some of the frequencies that make up speech sounds. There are some good ones available online and my favourite is the Better Hearing Institute which has mild and moderate hearing loss in different situations. The NDCS also have a couple of examples that are specific to children in classrooms.

But there is a health warning about these simulations and that is that we don’t know, especially in the early days following diagnosis in young babies, what is happening beyond the ear and how well they can make sense of the sound they hear. Hearing, listening and understanding are sophisticated processes that are determined by a complex interaction between the physical properties of the ear as well as attention, memory and auditory processing (what happens when your brain recognises and interprets sound so that it becomes meaningful). The brain has the incredible power of plasticity in the early years and is continually moulding and learning from new experiences and sounds. As adults the brain is much less plastic and it takes much longer to adapt. This means that the experience of hearing and listening is hugely variable between individuals and is influenced by whether someone is born deaf or what age they became deaf, how long it was between developing a hearing loss and being fitted with hearing aids, their listening experience, and their cognitive and auditory processing abilities. Children born deaf and those who become deaf early in life experience deafness as the norm. Older children, teenagers and adults who become deaf have a very different experience of deafness to which they need to psychologically and physically adapt to. Much of what we understand hearing loss to sound like comes from adults who have previously experienced normal hearing levels. This is a particular issue when parents are considering a cochlear implant for their child for example. It is commonly reported that cochlear implants sound electronic, that they aren’t natural, and that voices sound like ‘a Dalek underwater’. This can be a devastating idea for parents considering this option but in fact when you speak to these same implanted adults later on they describe their implants as sounding very natural as their brain has acclimatised to the new sound. I recently chatted with a group of teenagers who all used cochlear implants and they agreed – “people think they sound like robots, but they don’t”. Just from listening to the voice quality of the thousands of implanted children, we can be certain that they do not experience this kind of ‘electronic’ sound. But to listen to this type of electronic simulation the best one I’ve found is Scientific American Frontiers.

Auditory Neuropathy Spectrum Disorder (ANSD) affects approximately one in 10 deaf children and causes distortion of sound and difficulty discriminating speech over and above what we would expect from the hearing loss alone. The level of distortion is highly variable from very slight to very severe and it is not measurable. So in young children we do not know early on how it will affect their speech and language development. Simulations of ANSD from mild to profound neuropathies can be heard here and make scary listening but again we know that with the right intervention children with ANSD are successfully using their hearing and using spoken language.

There are 10 million people in the UK have some degree of hearing loss and the majority of these people experience age-related deterioration of hearing. At the other end of the age spectrum there are just 45,000 under 18’s with a permanent hearing loss. Inbetween there are those adults who grew up with a hearing loss as well as those who have lost their hearing as an adult. My experience is that individuals (and their parents or family) use a wide variety of terms to describe their hearing level – deaf, hearing loss, partially hearing, hearing impaired, hard of hearing – and they rarely relate to their audiogram level. There are those people who associate themselves culturally with the Deaf community who we may traditionally think of as those who are profoundly deaf sign-language users. But there are also people who have developed a mild hearing loss for the first time who may tell their audiologist they are ‘stone deaf’ or ‘can’t hear a thing’ and this is their perception compared with their normal experience.

Every child’s hearing levels and hearing experience is unique and it is impossible for these types of simulations to represent how all deaf people process and experience sounds heard. But they are useful in giving the listener an understanding of the difficulties encountered and I particularly like those that can highlight the big differences experienced between listening in quiet and noisy environments and which are an important reminder of how much easier we can make life for children by improving their listening environments in school and elsewhere.

This weekend I had the priviledge to be invited to the final residential weekend for the current NDCS Youth Advisory Board (YAB) cohort. Wow, I mean just wow, what an amazing bunch of teenagers! I was doing some filming with them on retubing earmoulds, using radio aids with other equipment, and their experiences with cochlear implants, and the films will appear on the NDCS Buzz website soon. I had the chance to have a chat with some of them and had a read through their memory books of their year but you can have a read of their new blog for more details of the weekend.

But my main memory of the weekend will be about communication. These teenagers had a range of hearing losses from mild to profound; most were using a range of technology including hearing aids, cochlear implants and radio aids; and most had identified themselves as using one main communication preference prior to joining the YAB. In the last 20 years or so I have often walked into a room full of deaf kids signing with one another and this was no different. But some of these kids hadn’t signed a year ago at all – they had learnt it so that they could all communicate easier with one another. At the same time they almost all used spoken language and effortlessly switched depending on who they were chatting to. They were so flexible – it was much less about their own communication needs, as them adjusting to others communication needs! One of the teenagers had taken her mock oral GCSE in German last week, and another had passed both GCSE Japenese and BSL Stage II in the same year.

None of these kids are ‘mine’ or had been seen in my clinic but they all made me very proud to be an audiologist. There has never been a time in history when deaf children and young people had as many options, choices and opportunities available to them, thanks in part to the technology they’re using.

It’s almost a given. Sometime between their first and second birthdays your little one will start a new game with you – how many times can I get mummy or daddy to put my hearing aids back in my ears today (or cochlear implant back on my ear/head)? And they’ll be aiming for what feels like hundreds! Every day!!

First off – try not to worry too much – almost all kids will go through this phase. It’s just the same as the other games they like at this age, like throwing away their favourite toy from the buggy or dropping toys out of the high chair. In these situations we pick them up, say “oopsy, there you go” and smile at them. It’s a fantastic game that draws in mummy or daddy’s attention and they love it! After a few times though we find we have something more pressing to do and we break the cycle. With hearing aids though it’s easy to get very worried or stressed about them needing to keep them in and we keep the game going longer. Check for any physical reasons why your little one might be pulling at their hearing aids, such as any signs of discomfort with their ears. And it’s always advisable to mention changes in behaviour to your audiologist or teacher of the deaf so that they can ensure that the amplification settings of the hearing aids are still correct – too loud and they won’t want them in, too quiet and they won’t be perceiving any difference. But on the whole most children do this because they’re at that stage of development and they do it just because they can!

It can seem a long and frustrating phase (for you) but I promise it will usually pass! In the meantime concentrate on using the hearing aids when you’re together and they are distracted and busy doing something else, such as feeding, playing and reading together. Give yourself a break from them sometimes and put the hearing aids away for a short spell to help break the cycle. If you get more and more stressed by the situation then your little one will pick up on this and in the longer term that’s not positive for either of you, or your relationship with one another, or with the hearing aids. Eventually children will start leaving them alone again as other things become more interesting, and they have greater freedom and access to more exciting things to play with.

For some more tips from parents read the tips section of the NDCS booklet Hearing aids; Information for families. You might also like to try the Parents Place Forum. Type “keeping hearing aids in” in the search box and you’ll find loads of suggestions from other parents.

Christmas is that time of year when we traditionally eat too much, exchange presents, and get extended family and friends together. Whilst I’m not going to attempt any dietary or present buying advice, there may be readers who are going to be joining family or friends with a deaf or hearing impaired child in the family. You may not normally get to spend a lot of time with them or maybe they were very tiny the last time you saw them. The following tips will help make communication easier and more enjoyable for you both…

  • Most children who have hearing difficulty will use all kinds of visual clues to help them make sense of what is being said. They will watch your facial expressions and body language, and they may be watching your lips closely (lip-reading). So it’s really important to make sure you have the child’s attention before starting to talk, keep facing the child and try to maintain good eye contact. Try to get down on the same level as them so that they don’t have to look up to you all the time. And if you’re playing together allow some space so that they can see your face clearly. At Christmas the fairy lights can be very pretty and atmospheric but if a child has a hearing loss they won’t easily be able to follow what’s being said in a dark room so try to keep the lights on when you’re talking. And try not to stand with your back to a window as this creates shadow and makes it difficult to read your facial expressions or lipread.
  • Santa may be a lovely fellow who brings some great presents but with that bushy white beard he’s impossible to lip-read. If you’re sporting facial hair consider a festive trim. And don’t try to talk to the child at the same time as munching your way through the mince pies and Quality Street, or when hiding behind the Christmas edition of the Radio Times.
  • Background noise makes it really hard for a hearing impaired child to follow your speech and conversation in groups can be impossible. Since there’s probably going to be lots of conversation  going on around the dinner table try to make sure that any background noise that can be turned off, such as the looped CD of Christmas songs, is.  Make sure members of the group speak one at a time and visually indicate when a different person is speaking so that the child can keep up.
  • When you’re talking there’s no need to shout. This will distort your lip patterns but more importantly appear to the child that you are angry with them, potentially setting up yet another generation of traditional Christmas family feuding. So speak clearly, naturally and at a normal pace.
  • Mostly though, don’t give up! They may not know all the words you use so try a different word with the same meaning and use gestures to show what you mean. Encourage them to tell you if they don’t  understand.

However you celebrate, I wish you a very enjoyable festive period and happy New Year!

If you’re reading this after Christmas, why not contact the NDCS for a copy of their flyer or poster of tips Communicating with deaf children without references to slightly dysfunctional family dynamics (which may have more to do with the authors own rather than widespread experiences).

 

 

This week is Road Safety Week in the UK and so today’s post is inspired by our Benefits Appeals Advisers who support families with Disability Living Allowance tribunals and who are frequently challenged on what difficulties deaf children have and why they require additional supervision near traffic, especially as the majority are using hearing aids or cochlear implants and therefore have ‘corrected’ deafness.

Clearly, deaf teenagers and adults don’t remain a hazard in traffic and develop terrific coping mechanisms such as taking extra care to visually check for vehicles before crossing roads, and perhaps utilising their peripheral vision more effectively than hearing people. But these skills take time to develop so what do families need to know when their children are young?

Firstly are limitations of the hearing technology and what even the best hearing aids or cochlear implants can’t do. Parents often report that their child appears to be startled as if they didn’t notice a lorry or train approaching and this is probably an effect of the limitations of the microphone pick-up range, coupled with a reduced dynamic range. Microphones pick up sound at an optimal distance of just a few feet. This means that any sounds that have come from further away may have ‘bounced’ off other objects on the way (reverberation). This means that sounds can get distorted and makes it very difficult to judge distance or direction the sound is coming from. Hearing aids are programmed so that they amplify sounds within the wearers ‘dynamic range’ (the quietest sound a person can hear and the loudest sound they are comfortable with). However, because the dynamic range for most deaf people is reduced, the speed at which sounds grow from quiet to loud is quicker. Additionally, microphones are often affected by wind noise outside too obscuring what the wearer needs to listen to, but the programming of the hearing aids should prevent uncomfortably loud sounds getting through to the listener (eg lorries passing). Additionally, hearing aids are limited to the frequency ranges of speech and therefore sounds outside those ranges and heard by hearing people aren’t available (think for example about the restrictions on hearing music which has a much wider frequency range than speech). So what hearing and deaf people are hearing are quite different because of the features of the hearing loss and properties of the hearing aid.

Secondly is the limitations of the hearing nerve pathways – after all hearing isn’t all about the ears. It’s also very much about the brain and the clever things it does with the sound it receives and a hearing aid has almost no effect on this aspect. The brain can focus on what we want to hear and filter out alot of unwanted background noise but has a much harder time doing this when the sound input is not as good as normal. This means that the brain is going to have a harder time when sound has come via a hearing aid, the aid has amplified background noise, and the auditory pathways between the ear and brain are not be as developed as they should be due to the hearing loss and poorer input. The brain is also responsible for ‘localisation’ or working out which direction a sound comes from and this is important in judging speed and direction of traffic. To do this well the brain needs to have consistent and equal sound input from both ears and this would be the goal of programming and persuading deaf children to wear their hearing aids all the time. Filtering and localisation are skills which develop as we get older (young children are very bad at it and it normally naturally develops with age, deaf children may never fully develop them). More important reasons why early identification, good quality hearing aid fitting, and consistent hearing aid use are vital to enable deaf children to develop these skills well.

Following on from my earlier post “Don’t worry about it, the other ear will compensate” about unilateral hearing loss, the next myth is “hearing aids won’t help”.  The importance of providing hearing aids to children with deafness in both ears as early as possible is widely recognised. If you have a hearing loss in both ears then your audiologist is likely to recommend that you have a hearing aid in both ears. This is going to help keep the hearing balanced and help provide the brain with the binaural information it needs to distinguish direction of sound as well as effectively filtering out unwanted background noise. Hearing aids aren’t always helpful for every child with a unilateral hearing loss – a careful assessment should be done on an individual basis and will depend on their type and level of hearing loss as well as their particular needs. But if a child does need the support of a hearing aid then there are lots of options to think about:

Hearing aids

Conventional hearing aids work by amplifying (making louder) sounds going into the ear. Hearing aids come in a range of styles. Good-quality digital hearing aids are available free of charge for all children on the NHS. If there is some hearing in the poor ear then a hearing aid may help to balance the hearing in both ears.

CROS hearing aids

Children who have very little or no hearing in one ear may benefit from a special type of hearing aid known as a CROS aid. Although it is described as a hearing aid, a CROS aid does not amplify sound. It is simply designed to transfer sound from the ear with deafness to the ear with hearing. The main advantage of using a CROS aid is that it can help the child to hear sounds from all directions. A CROS aid includes two units which both look like ordinary behind the ear hearing aids. However, the unit worn on the ear with deafness just contains a microphone. It is connected to the other unit, sometimes with a lead and sometimes by a wireless radio link e.g. Unitron or Phonak.

Bone anchored hearing aids

A bone anchored hearing aid consists of a sound processor that clips on to a fixture, known as an ‘abutment’, attached to a small titanium screw that has been implanted in the skull just behind the ear. This allows sound to be conducted through the bone rather than through the ear canal and middle ear as it would normally. Through the abutment, the sound processor is directly connected to the skull bone, of which the cochlea (inner ear) is part. This allows sound to be transmitted more directly to the inner ear. The implant surgery cannot be done until the child has sufficient bone thickness and quality of the skull bone. In very young children, the skull bone may be too thin to firmly hold the fixture the sound processor attaches to. Younger children and children undergoing assessment before surgery are therefore offered a bone anchored hearing aid that is worn on a soft headband. Bone anchored hearing aids have recently been used for people who have unilateral hearing loss. The sound processor is worn on the poor hearing side and the sound vibrations will vibrate through the skull bone and be picked up by the cochlea on the better hearing side. This can help with understanding directionality of sound, as well as improving hearing of speech and other sounds that come from the poor side.

FM Systems

Children with unilateral hearing loss may benefit from using an FM system. FM systems help overcome problems of listening when

  • there is unwanted background noise;
  • sounds are echoing around the room (reverberation); and
  • there is a distance between the person who is speaking and the deaf child.

FM systems can be used with or without hearing aids. They consist of a transmitter, worn by a teacher, and either a receiver worn by your child or speakers. A system using a receiver (ear piece) worn by the child is known as the Phonak iSense. A system using speakers is known as a soundfield system. Both systems work by making the teacher’s voice clearer in relation to other unwanted noise. Children with unilateral deafness are likely to benefit from an FM system because it provides a consistent sound quality around the classroom enabling them to hear the teacher clearly in their good ear even if the teacher is moving around the classroom.

Classroom soundfield systems are increasingly popular and may already be fitted in your child’s classroom. They are designed to improve listening conditions for all children in the classroom as well as reducing vocal strain for the teacher.



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