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7/30/2019 Electro Pal at Ography
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Electropalatography
By: Alex Martinez
7/30/2019 Electro Pal at Ography
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Definition
Electropalatography (EPG) is an instrumental technique
for determining tongue/palate contact during speech. It
uses an artificial palate with 62 electrodes embedded in its
tongue facing surface. The electrodes on the palate areconnected to an electronics unit, which collect data from
the palate and passes it on to a computer.
Each palate is made to fit the subject and requires a dental
impression with subsequent fitting. There are two commercially available versions of the EPG
that have been most widely used to investigate children
with persistent sound system disorders. (EPG3 &
American Palatometer.
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Population: Consideration for Candidacy
EPG has been used successfully to treat disorders ranging
from Dysarthria, Apraxia, Cleft palate, Dysfluency, and
Articulation/Phonological disorders.
Children and adults can benefit from this device inimproving their overall production of speech.
Child must be mature enough in tolerating having a dental
impression as well as cognitively developed. They need to
comprehend what the device is for and what it is trying toteach them in therapy.
For adults the EPG could be used primarily to address
dysarthric or apraxic speech.
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Advantages
EPG has the facility to provide visual feedback of tongue-
palate contacts. The tongue position is placed on the
computer screen and flashing lights indicate the electrode
the tongue touched. It records alveolar,post-alveolar, palatal, velar placement,
and registers specific characteristics for consonants.
The EPG allows objective assessment and provides a
dynamic visual presentation of articulatory goals that arenormally not seen.
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EPG can contribute to the diagnosis of speech disorders by
revealing information relevant to underlying deficits,
information not available from transcription-based
analyses.
The strategy of the system is to compare the patterns of
tongue contact for a pathological speaker with a normal
speaker and interpret the differences.
The ultimate goal of the therapy is to have the user produce
the sounds in all contexts without the pseudopalate and
without visual feedback.
If these goals are accomplished the subject is well on their
way to overcoming their speech difficulties.
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Disadvantages
Financial constraints, these palates are very expensive and
must be manufactured for each child. Their period of use
is also limited because children grow and it will make
them useless. Additional hardware is required including a personal
computer and software for proper treatment of these
disorders.
Access to these techniques are limited and can only befound in a few centers.
Proper training is essential in using these methods
effectively, while assisting in EPG data interpretation.
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Types of Cases
Cochlear Implant User - A Case Study
A 8.9 year-old girl was referred for remediation of her
velar stop consonant production.
Child had a profound bilateral sensory-neural hearing loss
present from birth. Child was given a cochlear implant
three years ago.
Child was treated 2 times a week for 45 minute sessions.
The aim was to use the EPG to help her achieve the correct
articulation by visual feedback initially and eventually by
tactile and proprioceptive feedback.
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Types of Cases (cont..)
The sessions were divided into two main parts: The
establishment of correct tongue positions using the EPG
and to ensure that the positions could be maintained
without the artificial palate or visual feedback. The results indicated a significant improvement in the
production of voiced/voiceless velar plosives.
Improvement was also observed in the production of
voiced/voiceless velars. This was maintained 5 weeksafter therapy indicating a generalization of skills.
Childs responses indicated good intelligibility for all
words post EPG therapy, in comparison with
speech/language therapy.
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Types of Cases (cont..)
Articulation disorders - Gibbon and Hardcastle (1987)
described the effects of using EPG to remediate a lateral
lisp in a 12 year-old boy.
Therapy involved four 1 hr. weekly sessions, with eachtime the training progressing. It progressed from
producing static lingual palatal contact, to producing
contact with an air stream, and through progressively more
complex utterances. By the 4th session, the child could produce appropriate /s/
and self-correct when errors occurred. Contact patterns
were recorded 6 months after therapy and approached the
normal pattern.
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Types of Cases (cont..)
Phonological disorders.
With these types of problems, children typically can
produce all sounds in their language.
Therapy is done to improve phonological processes inteaching the rules for application in an attempt to
remediate place and manner of production errors.
Gibbon (1993) investigated the possibility that differences
between sounds that were heard as being neutralized couldbe found using the EPG.
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A 9 year-old girl was evaluated in which her productions
included alveolar backing for stop consonants. She had
received traditional therapy, but results indicated no
success for this problem.
After twelve weeks of therapy, the child produced distinct
alveolar stops. Her improved articulatory ability
corresponded with accurate listener identifications.
Finally, her duration of the alveolar stops, pre-post
therapy, were quicker and can be as a result of the
simplification and a better definition of the demands for
her articulatory movements
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Conclusion
The electropalatography technique is proving itself to be
useful at providing new insights into the bases for various
speech problems and for providing an alternative method
of speech remediation. EPG allows for objective assessment, enabling appropriate
targeting of therapy. It also provides visual feedback,
which assists in therapy and can be motivating for the
therapist and client. Therefore, the therapist can target theclients speech problems and they can correct themselves
with the aid of the computer screen.
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Conclusion (cont)
The accumulated EPG research suggests that EPG can
make a valuable contribution to the assessment, diagnosis,
and treatment of children with persistent sound system
disorders. The purpose of setting up the EPG network is to facilitate a
more widespread use of this relatively specialist
instrumental technique for speech language pathologists
working in clinical contexts than has been feasible in thepast.
It has been used successfully to treat articulation (cleft
palate) and phonological disorders.
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Further Research
In terms of EPG treatment, further systematic research is
needed involving groups of children with persistent sound
system disorder, so the effects of treatment can be
quantified and identify the children that benefit from visualfeedback treatment.
More longitudinal studies are needing involving a wider
number of subjects.
Research must be expanded within the field in providingmore training opportunities and data on the results of uses
of the EPG in therapy.