Scientists have come up with a device that may revolutionize speech research: high-tech dentures that capture minute details of tongue movement in unprecedented detail.
Recording the movement of the human tongue during speech has been a 50-year-long uphill battle for researchers trying to better understand speech impediments. Devices put in the mouth to record tongue placement would often disrupt the speech itself, rethulting in flawed ecthperimenth.
“The tongue, like other human tissues, is a flabby body,” says Christophe Jeannin of the Institut de la Communication Parlée. Because it acts like a liquid and a solid—honey and rubber—at the same time, accurately capturing the physics of its motions is difficult. But by incorporating sensors into dentures at their laboratory near Grenoble, France, Jeannin and his colleagues have made it a snap to measure the tongue’s positions. The catch? It requires subjects who are toothless.
Jeannin installed dentures in 20 such volunteers and asked them to repeat French tongue twisters over the course of six weeks. Pressure sensors placed in different positions in the palate of the dentures sent signals to a computer connected by wire every time they were touched by the tongue. To determine the best positions for the sensors, subjects first wore a preliminary set of dentures with a powdered coating that revealed where the tongue made the most contact. After continually recalibrating the dentures, the researchers came up with a final tool that is able to gather extremely accurate data about tongue movement.
The technology’s applications include research on orthodontic devices, such as braces and retainers, that are less of a hindrance in conversation as well as better predictions of the consequences that oral surgery might have on speech. Jeannin’s dentures could even help develop more lifelike robotic speech—that is, if researchers can find enough willing toothless subjects for their studies.