Electropalatography: EPG
What is EPG?
Electropalatography is a technique for recording the
timing and location of tongue contact with the roof of the mouth (hard palate)
during speech. EPG requires the speaker to wear an artificial palate
which is similar to an orthodontic brace and fits against the hard palate.
The EPG palate has 62 silver electrodes embedded in it. When the tongue touches
these electrodes the pattern is recorded by a computer. By using specially
designed software (Articulate
Assistant) these patterns can either be viewed straight away or analysed
later.
EPG Applications.
EPG has both research and clinical applications. In research we can use the
technique to find out about the tongue-contact patterns both typical speakers
and speakers with speech disorders make.
EPG has been used with a wide variety of speech disorders, most notably cleft
palate but also functional articulation disorders, hearing impairement and
in adults with aquired speech disorders (for example, difficulty with speech
following a stroke). EPG can be used to help diagnose speech disorders which
in turn can lead to better, more efficient treatment. It is also a useful
tool for tracking progress, giving a clear representation of speech before
and after therapy.
Click here for more information about EPG and interpreting EPG patterns
EPG Therapy.
Usually in speech and language therapy the patient relies on auditory feedback
(listening to the sounds and words he or she is producing) to modify his speech.
With EPG therapy the patient also has the advantage of visual feedback. Patterns
of tongue-palate contact (EPG patterns) can
be displayed live on a computer screen (see here).
The speech and language therapist can then help the patient to modify his
speech so that it sounds more like that of his peers.
This picture shows the EPG software. On the left we can see the EPG pattern the patient is making with his tongue and the right-hand picture shows the pattern he is aiming for. By using this real-time visual feedback the patient can modify his tongue shape to more closely match the target pattern. The speech and language therapist also wears an EPG palate to allow her to demonstrate sounds to the patient.
EPG and Down's Syndrome
People with Down's syndrome often prefer visual methods of learning to auditory
methods. For example, many children with Down's syndrome find it easier to learn
words via the written word rather than relying on only auditory information.
In the same way we can predict that people with Down's syndrome would find it
easier to modify their speech when given a visual model rather than only an
auditory one. This makes EPG a suitable method for using with children with
Down's syndrome.
Only two electropalatographic research studies investigating speech in Down's syndrome have been published. The first study by Hamilton
investigated the speech patterns of three young adults with Down's syndrome
but did not evaluate therapy using EPG. The second study by Gibbon
evaluated EPG therapy for a ten year old girl with Down's syndrome. EPG proved
to be a very useful technique for improving this child's speech but more work
is needed to determine which children with Down's syndrome EPG will be most
useful for.
Our Speech in Down's syndrome Project will investigate
the speech skills of children and young people with Down's syndrome using EPG
and will compare progress made with EPG therapy to progress made with more
traditional speech therapy.
Useful links for more information on EPG
Bibliography of
EPG research papers compiled by Prof Fiona Gibbon
Articulate
Instruments EPG software and hardware
Review
of EPG by the National Institute of Clinical Excellence
Links to other research projects using EPG
Cleftnet UK: EPG and cleft palate
[home] [Speech in DS] [Voice] [EPG] [Research team] [publications] [contact]
