Hearing

Although sight is the most important co-ordinating sense, hearing is a most valuable sense for human beings because it is through hearing that we learn language and are able to communicate with each other. A child or person who cannot hear is cut off from other people and this will affect his ability to make relationships, as well as the way he learns, unless prompt help is offered and maintained.

The ears work by collecting sounds from the environment and channelling them down into the inner ear via the eardrum. The sounds make the eardrum vibrate, and these vibrations are converted by the organs of the inner ear into electrical impulses which are then passed along the auditory nerve to the brain. The brain converts these impulses into meaningful information just as it does with the light waves coming through the eyes. We take the skills of the brain so much for granted we do not always appreciate what an impressive performance it is to turn sound vibrations into the lines of a poem, or rays of light into patterns, shapes and designs, but this is what your baby's brain is equipped to do. And as with vision, his brain will set to work on the task of learning to interpret sounds right from birth.

Your Newborn Baby

Once the newborn baby's ears are drained of fluid which is left over from his life in the womb, his hearing is acute and it will get even better as he grows older. If he hears a sudden noise he will be startled. He may also move his head in response to noise, but he cannot yet tell exactly where a sound is coming from and look towards it. He learns to do this more accurately at around five or six months. New babies soon learn to recognise their own mother's or special caretaker's voice. If your baby is crying and hears you speak to him, he may stop and listen. A strange voice will not be so reassuring. Babies are also sensitive to the sound of other babies. If your baby is in a ward or a nursery with other mothers and babies and one baby starts crying, it is not long before your baby and all the others begin as well.

Many sounds seem to have a special quality for soothing babies - especially rhythmic sounds. Lullabies are an age-old way of sending a baby to sleep and so is rhythmic rocking. We do not quite know why this should be, but since the ear controls the sense of balance as well as hearing there is an obvious connection between rhythmic movement and rhythmic sound. You will probably notice you quite automatically sway backwards and forwards when holding your baby, you will pat his bottom rhythmically, and you will say simple phrases over and over: `There, there. What's the matter?' and so on.

By about seven months your baby will be well able to recognise and discriminate between different sounds: for instance, the sound of a spoon in a dish will mean food to him; the door opening will mean someone is coming; he can tell angry from cheerful voices, will be most upset if you speak crossly and will perk up if you speak brightly. So although he cannot understand words or sentences or speak them yet, he is well on the way to linking meaning with sound - an important part of learning to talk.

Sound Play

Being able to hear is vital in order to learn to talk, but we do not express ourselves only through speech. Language can also be expressed in signs and gestures (as used by deaf people) and of course through print and the written word. For more about language and its development click here.

During his first year your baby will learn to distinguish words from other sounds he hears and to associate them with meaningful things, but he will also enjoy being talked to. As you talk to your two- or three-month-old, you will notice he responds by waving his arms and kicking his legs and smiling and gurgling. Babies enjoy being sung to as well, no matter how unmusical you think your voice is, so do sing and hum to your baby, and let him hear other music too.

However, babies can be upset by too much noise. Sudden loud sounds can startle them and make them cry. They may get very upset by the vacuum cleaner or the washing machine. We all have a mechanism known as habituation which enables us to screen out unnecessary sounds once we have heard them a few times: although the noise may be continuing we simply do not hear it. Babies learn to do this in the first few days of their lives, but new sounds may still have to be introduced gently.

Babies and young children in today's cities live in a very noisy environment with cars roaring past and perhaps the radio or television as continual background noise. You do not want your child to screen out all sounds, so once he is old enough it is sometimes good to be quiet and encourage him to listen for particular noises: leaves rustling; a dog barking; a train passing; a car in the distance getting nearer. Talk about the noises as you hear them and tell him what they mean. As he gets older you can use his hearing skills to introduce important ideas such as loud/soft or high/low. There are plenty of ways of introducing sound play around the home - although most adults find it hard to habituate to sounds such as saucepans being banged! Five minutes will probably be as much as you can stand.

Most toys are designed to encourage hand eye activities, but remember babies play and learn through their ears too. Once your child is talking, sound remains crucial. This is especially true for blind or partially sighted children who have to learn everything through hearing, touch, smell and taste.

Hearing Tests

New babies do not have many ways of letting us know whether or not they can hear. If you have any hearing problems in your family, however, or if you had German measles or any other illness during early pregnancy, you should tell the hospital paediatrician or your own doctor.

Your newborn baby may be tested using an `acoustic cradle' to see if his hearing is working. Different hospitals vary in their policy, but this is especially likely if there is anything in his medical history which might cause impaired hearing. During one type of test the baby wears a special belt and lies in the acoustic cradle, which looks like an ordinary cradle, so that any changes in his breathing in response to a variety of sounds can be detected and recorded. A newer test for hearing called the `cochlea echo' is now more common. The cochlea is the snail-shaped organ in the middle ear which is full of fluid, sound receptors and membranes and is able to covert the vibrations of the eardrum into nervous impulses which send messages to the brain. In this test a probe bounces sound into the ear and a fraction of a second later is able to pick up an echo bouncing back from the cochlea. If there is no echo, this may indicate that the complicated hearing mechanism is not working properly. If your baby does not pass these screening tests a `brain stem response' test will be arranged to measure the hearing more accurately, and find out if there is really a problem.

Different health authorities operate slightly different community health screening programmes, but most see babies at six weeks and then again between about eight to nine months. At the first check, which may be done by your GP or at a health centre, hearing can only be tested in a fairly elementary way to see if the baby responds to a loud level of sound. At eight to nine months the hearing test usually consists of sounding a high frequency rattle and whispering low frequency words to see if the baby makes a turning response. A baby with a history indicating a greater chance of hearing impairment would be observed more carefully.

The test at eight to nine months involves you sitting with your baby on your lap while the health visitor or her assistant makes test sounds behind him, to his right and then to his left. If the baby turns towards the sound, it is assumed his hearing is all right. If he does not turn, then it does not necessarily mean he is deaf - he may have caught sight of something more fascinacing across the room. Bear in mind also that hearing can be temporarily affected by colds and illness. If he does not respond to this first test, you will be asked to bring him back again.

If you are sure that he responds to sounds, for instance, you know that you have only to tiptoe across his bedroom floor for him to leap up in his cot, then tell the health visitor. A parent's own reports on the child are usually taken very seriously, because as one paediatrician with years of experience of testing has put it, `The mother is usually right.' Of course, if you are worried about your child's hearing, perhaps because he does not respond to the soothing noises and sounds in the way described above, if he startles when he sees you as if he has had no warning from footsteps or the door opening, and if he is not woken by sounds, then be persistent in getting his hearing properly checked. Your worries will usually have some foundation as you know your child best and you will be well aware if he does not seem to be developing in the same way as other babies you know.

Your child will also usually be tested as part of a community screening programme at the local health centre or GP's surgery before he goes to school, when more sophisticated electrical equipment will be used to measure how well he hears high and low tones. The age when this is done varies according to regional health authority policy, but most see children between three and four. Some children have `high tone deafness' and cannot hear consonants properly; the speech they hear will seem blurred and will affect their own speech. If your child does seem to have difficulty hearing some sounds, or if he is prone to ear infections and colds which also affect his hearing, ask for the test and tell his playgroup leaders and teachers so that they sit him near the front of the group and make allowances for it. If he says `What?' all the time or ignores half of what you say, he may not be being difficult. Never rule out the possibility that he cannot hear properly and make sure he is tested by an audiologist - a specialist whose job it is to check hearing.

The Child with Reduced Hearing

Some children are deaf from birth through an inherited disorder of the inner ear or through damage during pregnancy, for example, from rubella, or from a shortage of oxygen at birth. Other children may become deaf later, perhaps because of a severe illness, such as meningitis, or from other childhood diseases such as mumps. Many children suffer some temporary deafness during their childhood from middle ear infection (otitis media) or by a build-up of wax in the ear, but do not use ear bud cleaners, as they stimulate wax production. If in doubt ask your doctor to check hearing - occasionally the ear may be blocked by something your child has inserted, such as a glass bead.

As mentioned above, good hearing is very important for the proper development of speech. It follows that poor hearing may affect social relationships, so always be aware of the possibility of hearing loss if your child suffers from any of the illnesses mentioned above or from subsequent coughs and colds. Also consider it if his behaviour seems absent-minded or indifferent, or if his speech is slow to develop. Few children have total hearing loss, and what hearing they have can be the basis for very specialised speech and language training. Once hearing loss, whether partial or severe, is diagnosed, it is important for this treatment to begin straight away.

Hearing Aids

As with glasses, parents usually find the idea of a hearing aid for their child much harder to accept than he does. It is important to keep such feelings from the child and to take a positive and optimistic view of the hearing aid as a real benefit. All hearing aids work on the same principle: they are amplifiers which make the sounds around louder. In this amplification there is a risk of distortion, but the quality of aids is improving all the time.

Small hearing aids worn behind the ear consist of an individually made ear mould in the ear which connects to a small box containing amplifier and micro battery. Under long hair it is invisible. Babies and young children will normally be given bilateral (two) aids. Young babies easily accept a hearing aid, but more tact and encouragement is required between the ages of eighteen months and three years when many children can be uncooperative about almost anything, ranging from putting on their coat to taking it off again!

Overcoming Deafness

Parents of children who cannot hear properly have to work much harder to stimulate them, drawing their attention to objects and events and associating them with language. You cannot just throw casual remarks over your shoulder you have to look at the child and speak very carefully so that he can also learn to read your lips.

Together with advice from audiologists, medical specialists, specialist teachers of hearing-impaired children, and specialist speech therapists, early language training at home is vital with regular help from the teacher. We all use language in our thought processes and it is important that hearing-impaired children are able to develop an inner language to use in this way. Specialists feel that both oral language and sign language should be used to communicate with a profoundly deaf child. There is some evidence that babies of deaf parents who learn sign language early on do better at reading and writing later than do deaf children who only have limited oral language by the time they learn to read. Young children have a greater facility than adults for learning language - children of bilingual parents are able to absorb both languages easily, while an adult finds tackling a foreign language for the first time far more difficult. In this way the mastering of what is two languages - sign language and oral language may be easier than an adult imagines for a young child.

Depending on where you live and the degree of handicap, a child with hearing impairment may attend a special school for the deaf to which transport is provided. Alternatively, he may go to a special unit for hearing-impaired children attached to the local primary school. This allows him to live in a hearing community and helps hearing children to be aware of the problems of the deaf. Many partially hearing children go to ordinary infant schools, but they need a great deal of specialist teacher help if they are not to miss out.