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                                                                                               TESTING  BABIES



Early detection of hearing impairments in young babies is one of the most important tasks for the parents to ensure the baby’s normal
The integrity of sensory systems depends on external stimulation. External acoustic stimulus is needed for the structural development
of sensory neurons and their functional connectivity. Appropriate sensory stimulation, especially between the ages of 0 to 2 years, is
critical for a child’s normal development in
later years.

If the baby turns it's head towards the sound source, it means not only that they can hear, but also that the appropriate connectivity
between the hearing and motor neurons in the brain was established during the critical time. Missing on this critical time will later
result in the child’s delayed development, especially when the hearing loss was not detected early enough and corrected.

So far there is no efficient method for early detection of hearing loss in all babies in the given population. A lot of effort has been
given to screening of hearing for newborn babies in neonatal centers. Those babies who have not received neonatal screening or
who developed hearing loss at a later age, require effective and continued monitoring of their hearing behavior and language
development. Unfortunately there is no screening system developed for such purpose and usually these are the parents, who
worrying about their baby's poor reaction to the environmental sounds and their voices, bring the baby to the family doctor or
audiological center for hearing assessment.

This visit usually occurs too late when the baby has already passed the critical time for auditory pathway development and
establishment of it's connections with the other brain centers.
To organize the hearing test for those babies, who have been brought to the audiological center by parents, it involves a lot of
problems and effectiveness of such testing is still very poor in terms of the volume of babies tested.
The parents have to organize transport for their baby, incur the costs involved with this transport and at least one of them has to
dedicate minimum half a day for this testing. In an unfamiliar environment the baby seldom wants to cooperate with the tester, the
child often becomes fatigued or restless and nearly 50% of all babies tested require up to 3 visits to complete the test and to obtain
repeatable results. Often a wait for appointment is also long and it may take a few months before all testing is completed.  

With a new clinical method and inexpensive tool like mobile phone, now the parents can do the baby’s hearing test at home when the
baby is quiet but alert and repeat this test many times, to confirm results repeatability .


To conduct the hearing test at home the parents can load from the Internet a special program into their mobile phone which allows
them to use the complex sounds like the animals voices as the testing sounds.
It is well known from clinical practice that the young babies respond poorly to
the artificial sounds like pure tones or even warble tones, but they respond much
better to the complex environmental sounds.

With this test three frequency bands can be used:

low tones          -  center frequency   500 Hz    ( Filtered cow voice )      
medium tones  -  center frequency 1500 Hz    ( Filtered rooster voice )      
high tones        -  center frequency 4000 Hz    ( Filtered birds voices )      

These bands cover the most important frequency range of sounds needed for the baby’s  speech development.
The animal voices according to their pitch have been matched with these bands and additionally filtered to narrow their frequency

Before you start the test it is necessary to calibrate the mobile phone for the hearing test. This procedure is described in
CALIBRATION section and you can do that for the older child.

If the baby has not yet developed  more interest in listening to noises this can be improved by presenting from time to time the louder
noises from the toys on each side of the baby’s head. This conditioning can also be done by using the parents own voices or
activating sound from the mobile phone close to the baby’s ear.  After the baby shows interest in sounds, you can start using the
mobile phone at the distance of about 30 cm.

( you may consider further conditioning if necessary by simultaneous presenting sound and touching the baby’s auricle
and after that, when the baby starts turning the head and/or eyes, presenting sound only and watching whether the
baby will turn the head following the sound presentation without touching the ear ).

When performing the test the parent holds the mobile phone at the ear level at a predetermined distance from the baby’s ear, turns
the sound "on" and observes the baby’s reaction.
This procedure should be repeated for all three sounds and for both ears. It is not relevant which sound or ear you will use first and
in which order you will conduct the test as long as you will be able to complete testing for each ear and for all 3 sounds.

The testing may be repeated many times at home on different days when the baby is alert but not expecting the sound, to convince
the parents on the test results repeatability.  
With this test, parents can monitor their baby's hearing over many months, taking care themselves of their baby's normal
If they found that their baby is not responding in a repetitive manner to even one sound, then they should approach the specialized
audiological center for help.


There is a number of clinical and practical issues you should know before commencing the testing of your baby.

1.  Babies as young as 3 months old turn eyes towards the source of sound - or  just move head from side to side
searching for sound. At this age they already may show interest in sounds coming from the surrounding area and begin some
localization effort  by moving eyes or head towards the source of sound.

At age of 4 months they turn head directly towards the side of the sound, but cannot find it above or below the ear.

There are however some developmental differences among such young babies when they start to clearly localize the source of sound.
Initially, localization is crude and limited by the baby’s ability to control the eye and head movement, but by the age of 6 months the
baby should make reasonably clear movements towards the source of sound.

2.  The best time to do the test is when the baby is alert, but not fatigued, hungry, upset and crying, in need to change nappies or
sick. These precious moments have to be clearly identified and used for the test.
There may be not many of them during one day, but contrary to the limited time given for the test at the specialized centers, the home
test is not limited by time factor and may be carried on over many days to be completed in the child’s familiar environment ( family
home ) and friendly people ( parents ).

3. Typically the baby will respond to sound by eye and/or head movement. In some cases presentation of sound will only stop the
baby’s motor activity like moving hands and legs. This is also a response and it is called a "listening" response. Careful observation
of all type of responses is required and their repetitive occurrence in presence of the sound should be confirmed and not misjudged
with the baby’s spontaneous activity.

4. Some children respond better to the sound stimuli when a so called "distraction" technique is used during the test.
In this method one person positioned in front of the baby captures it's attention i.e. by playing with toy, while the other person
standing on side and not being seen by the baby waits ready to present the sound.
When the baby shows growing interest in this play, the toy is suddenly hidden. This significantly increases the baby’s attention and at
this point the sound should be presented by the second person using the mobile phone.


. Before the test make sure that all noisemakers like TV set, radio, stereo unit, computer etc. are turned "off", there is no noise
coming through the open doors or open windows and other family members will not interfere with your test.

2. You will need to approach the baby from behind in a very quiet way so they will not be aware of your presence.
Make sure that there is enough room to move from one side to the other side behind the baby’s head, that your clothing, jewellery,
shoes and floor will not make noises when you are moving.
Such noises can evoke the baby’s reaction instead of sound produced by the mobile phone.

3. Take care that your body movement will not cut the light seen by the baby, or create noticeable air movement to
the baby, otherwise it may react to these changes instead to the sound. Do not use perfume during the test.

4. Position the mobile phone at the ear level about 30 cm from the baby when you present the testing sound.

5. Carefully observe the baby’s reaction like turning eyes and/or head towards the sound source, stopping spontaneous hands
and/or legs movement, changing the rate of sucking etc.
Repeat this procedure a few times for each sound and for each ear to make sure that the responses are repeatable. If after initial
positive reaction the baby looses interest in sounds, repeat this procedure a few hours later or on another day.

6. Carefully note the baby’s positive or negative responses shortly after each sound presentation.

Do not rely on your ability to remember the baby’s reactions, which ear was tested and what sound was used, to make
such notation later. It is very easy to forget individual results. Please use the RECORD FORM.

If  there is no repeatable response even to one sound,  you should contact the Audiological Center,