Study Holds Promise for Patients Silenced by Stroke
Callier Center Researcher Using Rare Machine to Track Speech Movements
To say the word “slant,” the tongue must touch a bit behind the teeth. For the word “boot,” the mouth must be pursed.
Although automatic to most people, speech is a complex process of tongue, mouth and jaw, a combination of body parts known as the articulatory organs, which, because they are inside the mouth, are difficult to observe in action.
“In the past scientists used candle soot to mark the placement of these organs in making words,” said Dr. William F. Katz, a professor of communications disorders at the UT Dallas Callier Center, in the School of Behavioral and Brain Sciences.
Today Katz is using an Electromagnetic Articulograph (EMA) to see inside patients’ mouths to track their speech movements. The EMA is a machine so rare that there are only about 40 in the world, but it holds out promise as a therapy tool for people who have lost the ability to speak. The Callier Center has two of these advanced machines. With a three-year grant from the Department of Veterans Affairs, Katz is using the machine to treat stroke victims.
Wearing a halo apparatus over their heads, the patients sit in front of computer screens. Small sensors attached to thin wires are placed inside their mouths. As they struggle to form words, magnified images of their mouth movements appear on the screen before them. The EMA machine helps patients with motor learning by showing them how to position their tongues to create speech sounds – a process that Katz calls “physical therapy for speech.”
Most of the people Katz sees at the Callier Center suffer from Apraxia of Speech (AOS). This disorder is marked by an inability to perform voluntary movements of the articulatory organs, which are necessary to produce spoken language. So even though they understand language, some stroke survivors may not be able to produce any words at all or may say the wrong words instead.
However, the EMA is not a magic bullet and is very expensive, costing $50,000 to $80,000.
“It takes a lot of time to fix broken speech, but this machine is giving us an important new tool,” said Katz. “The VA has a long history of funding cutting-edge research, and we could not do the work we are doing without its support.”
The research and therapy is taking place in Dallas and Pittsburgh.