Electropalatography

The Elektropalatografie or chromatography (from Latin palatum: ger " palate ", large graphein: ger " write") is a method for the continuous measurement of tongue - palate contacts in language production. The Electropalatography (also called EPG) thus provides a method of measuring points of articulation in the mouth dar. The patient has a thin artificial palate in the mouth, which is studded with electrodes. The contact of the tongue with the palate, the electrodes transmit electrical signals to the Elektropalatograf. This represents the electrical impulses on a screen in the form of a Palatogramms

Application

The Elektropalatograf is mainly used as a therapeutic tool in speech disorders, as well as in experimental phonetics. The patient looks at a screen for direct comparison between his erroneous and the correct pronunciation. Through this constant feedback from the patient can self- correct his speech production and to adapt the norm.

An artificial palate made ​​of acrylic must be established for each individual person, which represent approximately 60 - is busy 100 electrodes. To ensure that this fits exactly does a dentist a plaster cast of the palate. The artificial palate is only about 0.5 mm thick, so that it interferes as little as possible when speaking. The electrodes are connected with thin wires which are bundled behind the molars and then taken out from the mouth side.

In use, a low AC voltage of about 100 Hz is applied to the artificial palate. There, where the tongue touches the electrodes, weak current can flow. If this is the case, the corresponding lamp lights up on the Palatogramm.

The Elektropalatograf is also the only device by which the tongue - palate contact in time and space can be visualized at the same time. In the dental and alveolar area directly behind the upper teeth, the density of the electrodes is greater, because there it is more important to the small differences in the points of articulation.

Areas of application

The Elektropalatografie is used primarily for research purposes. The focus of the therapeutic application are:

• Phonological disorders
• Cleft lip and cleft palate in children
• Entwicklungsdyspraxien
• Dysarthria in adults.

Disadvantages

A disadvantage of this method is that the artificial palate can interfere with normal speech transition, but this is hardly noticeable. Furthermore, there is of course no information to open vowels or to such sounds that are too far back ( velar, eg, [ gkr ] ) or on the lips (labial, eg, [ mbp ] ) are formed. The best sounds like [ dtlns ʃ ] are displayed.

Moreover, the process is very expensive, since each subject has to have its own artificial palate.