Electro Pal at Ography

7/30/2019 Electro Pal at Ography

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Electropalatography

By: Alex Martinez


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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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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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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.

Documents

Electro Pal at Ography