Electropalatography

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The electropalatography or -graphy (from Latin. Palatum : dt "taste buds", gr.. Graphein . Dt "write") is a method for continuous measurement of the tongue and palate contacts in speech production. Electropalatography (also called EPG ) is a measurement method for articulation points in the oral cavity. The patient has a thin artificial palate in the mouth that is covered with electrodes . When the tongue makes contact with the roof of the mouth, the electrodes transmit electrical signals to the electropalatograph. This shows the electrical impulses on a screen in the form of a palatogram.

application

The electropalatograph is mainly used as a therapeutic aid for speech disorders , as well as in experimental phonetics . The patient sees a direct comparison between his incorrect and correct articulation on a screen . With this constant feedback , the patient can independently correct his speech production and adapt it to the norm.

For every single person an artificial palate made of acrylic has to be made, which is equipped with approx. 60-100 electrodes. To ensure that it fits exactly, a dentist makes an impression of the palate to produce a plaster model. The artificial palate is only about 0.5 mm thick so that it disturbs as little as possible when speaking. The electrodes are connected with thin wires that are bundled behind the molars and then led out of the side of the mouth.

During the application, a weak alternating voltage of around 100 Hz is applied to the artificial palate. Weak currents can flow where the tongue touches the electrodes. If this is the case, the corresponding lamp in the palatogram lights up.

The electropalatograph is also the only device with which tongue-palate contact can be made visible both spatially and temporally. In the dental and alveolar area directly behind the upper row of teeth, the density of the electrodes is greater, because the small differences between the articulation points are more important there.

application areas

Electropalatography is mainly used for research purposes. The therapeutic application focuses on:

disadvantage

A disadvantage of this procedure is that the artificial palate can interfere with normal speech, but this is hardly of any consequence. Furthermore, there is of course no information on open vowels or on sounds that are formed too far back ( velar , eg: [gkr]) or on the lips ( labial , eg: [mbp]). Sounds like [dtlns ʃ ] are best represented.

In addition, the procedure is very expensive, since each test subject has to have his own artificial palate.

See also

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