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Researchers Explore Taste, Speech

Published: February 2, 2015

According to new research at CSULB, we may not need our tongues to taste or speak. This information could prove invaluable when it comes to helping rehabilitate those who have lost or damaged their tongues as a result of cancer or other means.

Betty McMicken, an associate professor in CSULB’s Department of Speech-Language Pathology and her colleague, Long Wang, an assistant professor in Family and Consumer Sciences, have been investigating Isolated Congenital Aglossia (ICA), a rare condition in which a person is born without a tongue.

The researchers conducted a series of tests on a volunteer with ICA, which included the detection of basic tastes and the involvement of different parts of the mouth and throat during the pronunciation of different speech sounds. They hypothesized that the subject would not taste anything or be able to speak and be understood. However, in the laboratory, the ICA volunteer detected all the basic tastes—sour, sweet, bitter, salty and umami. It was also the first study to report that umami was sensed by an ICA subject. In addition, in perceptual studies, the subject demonstrated 78 percent intelligible vowels and consonants and completely intelligible contextual speech.

“The research findings are significant because they demonstrate that the tongue is not essential for humans to detect taste or to produce intelligible speech,” said Wang. “There are currently unknown receptors and other structures of signal delivery in this subject that serve as an alternative mechanism for taste recognition and the production of speech.”

Currently, less than 10 people in the world are known to live with ICA. Additionally, the Centers for Disease Control and Prevention reports that more than 40,000 people have been diagnosed with oral or pharyngeal cancer and many of those identified have their tongues surgically removed.

“With these findings, additional research on the subject can be conducted to develop rehabilitation regimens that could potentially allow those without a tongue to regain their ability to taste and to speak in a more understandable manner,” said McMicken. “The results of these investigations may be promising in maintaining and improving quality of life.”