Archive for the ‘single-sided deafness SSD’ Category

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.

So a child has been diagnosed with a unilateral hearing loss (often known as one-sided or single-sided deafness). Should you be concerned? After all the other ear hears completely normally doesn’t it?

Well yes, the hearing in the other ear is fine and this is great. It means that most children will hear well enough in their early years to make good progress in their speech and language development. However, there is a large body of evidence now that suggests that although not all, a significant proportion of children with unilateral hearing loss fall behind with language development, require additional educational assistance and suffer perceived behavioural issues in the classroom. Why might this be?

Well, the ears might be doing the hearing, but it’s our brains that are doing the listening. It’s the brain that identifies sounds by analyzing their pitch, loudness, and duration. It then searches for and maps this information onto existing stored information. When a match occurs, we understand what is being said, or we recognise sounds that have meaning to us, such as words or the telephone ringing. And basically our brains are ‘wired’ to hear sounds from both ears. Hearing with both ears is known as binaural hearing. When the brain receives sounds binaurally it is able to filter out a lot of unwanted background noise and concentrate just on what we want to listen to. It is also able to distinguish the direction and distance of where sounds have come from (localisation). Being able to filter out background noise is a skill we use a lot of the time because the majority of the speech we listen to is not in perfectly quiet situations. Being able to localise sound means we can tell which direction important sounds come from, whether this is being called by a friend when playing or hearing a car approaching. It is also important in being able to follow a conversation in groups. Binaural cues that the brain uses include the effect of ‘head shadow’ (where the head physically blocks some sound that comes from the affected side so that the good side hears it at a reduced level), and intra-aural level and timing differences (where the brain is able to perceive differences in location of sound based on which ear gave it the information quickest and loudest). So a child with unilateral deafness is likely to have problems listening in some situations because their ability to use binaural listening cues are reduced.

So the situations where a child with unilateral deafness will find it more difficult to hear well include:

  • hearing sounds or speech on the side with the deafness because of the ‘head shadow’ effect
  • identifying the source of a sound, the direction a sound is coming from, or judging the distance the sound is coming from
  • understanding speech when there is background noise.

Incidental learning is learning that takes place informally and is not taught in formal situations such as school. Children learn language incidentally through play and by hearing things going on around them. A child with unilateral deafness may not naturally overhear what people are saying or events that are happening. This means that a child may appear ‘out of it’, as though they don’t know what is happening or appear unconnected to their environment. Some children may need to be taught directly skills that other children learn incidentally.

Unilateral deafness may therefore cause or contribute to speech or language delay, and difficulties learning and reading. Unilateral deafness may impact on any co-existing conditions or additional needs. such as:

  • children with learning difficulties
  • children with speech or language disorders
  • children with attention deficit disorder
  • children who use English as a second language.

Additionally, children with unilateral deafness may be using more energy concentrating on listening, particularly in noisy environments, and as a result may experience problems in concentrating, tiredness and frustration that affects their behaviour. They may prefer to play alone and experience more difficulties than other children in reading and learning.

There are a couple of other things that are important to mention with unilateral hearing loss. Firstly that it is important to teach your child to take extra care when crossing the road because they can’t tell which direction a sound is coming from and older children/adults will have difficulty judging speed from the sound alone. Secondly, remember that the other ear is hearing well but may not always be if it is damaged by infection or noise. If a child has an ear infection they should be seen by their GP as soon as possible. And like all children, make sure they aren’t exposed to very loud sounds over long periods (for example at pop concerts or listening to music with headphones at high volumes). Provide ear protectors where appropriate, for example during noisy leisure activities such as motor racing.

Next time I’ll write something about the different styles of hearing aid that can be used to help children with unilateral hearing loss in “Hearing aids won’t help”.


Lieu, J.E.C. (2004) Speech-Language and Educational Consequences of Unilateral Hearing Loss in Children, Arch Otolaryngol Head Neck Surg. 2004;130:524-530

Lieu, J.E.C., Tye-Murray, N., Karzon, R.K., Piccirillo, J.F. (2010) Unilateral hearing loss is associated with worse speech-language scores in children. Pediatrics. June 2010;125(6).

Most, T. (2004) The effects of degree and type of hearing loss on children’s performance in class, Deafness and Education International, 6(3), 2004.

Priwin, C., Jonsson, R., Magnusson, L., Hultcrantz, M., Granstrom, G. (2007) Audiological evaluation and self-assessed hearing problems with single-sided congenital external ear malformations and associated hearing loss, Int J of Audiology 2007; 46:162-171

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