July 27, 2004 -- Stuttering has traditionally been thought of as a problem with speech, but new research shows that when people who stutter aren't speaking, their brain processes language differently -- even when just thinking about language.
In what's billed as the first study of its kind, Purdue researchers measured the brain's electrical activity and the time it takes to respond to questions in people who stutter.
"There was a significant delay in response time when subjects were given a complex language task," says researcher Christine Weber-Fox, PhD, assistant professor of speech sciences and a cognitive neuroscientist.
"We also found that in people who stutter, certain areas of the brain are more active when processing some language tasks."
During the study 22 adult participants responded by pressing a button to questions regarding sentence meaning, grammar or sentence structure, and rhyming while wearing a "bathing cap" which measured brain activity.
The study shows that a stutterer's delay in articulating words may actually begin before the first syllable is uttered, as they "prepare" what they will say.
Testing Language ... Without Speaking
In her study, to be published in the Journal of Speech, Language, and Hearing Research, she and colleague Anne Smith, PhD, flashed a series of two words on a computer screen. The participants -- half of whom stutter -- were asked which pairs rhymed, without saying the words out loud. Some word groups were spelled alike but did not rhyme, such as "gown" and "own"; others rhymed but weren't spelled similarly, such as "cone" and "own"; while others were completely different, such as "cake" and "own."
The results: Most stutterers were able to quickly identify words that both looked alike and rhymed, such as "thrown" and "own." But their response time was delayed for the other more complex languages tasks.
How can these findings help?
"This research points us more into the direction of adequate assessment and intervention," says stuttering researcher Edward G. Conture, PhD, of Vanderbilt University, who was not involved in the study.
"Therapeutically, it doesn't offer a lot at this point, but it provides the basis for better understanding," he tells WebMD. "It shows that speech and language pathologists need to pay attention to speech and language planning in people who stutter, as well as production skills."
Toddlers Also Have Planning Delays
Just last month, Conture published his own research on children in the same journal that bears similarities to the Purdue study on adults, expected to be published in December. "In both situations," he says, "we find that the planning stage of speech is either slower, not as efficient, or somehow different in people who stutter than it is for fluent people."
His study shows that preschoolers who stutter are slower than fluent children in "planning" sentence structure. He finds these youngsters often improve their speaking when they are "primed" in this speech-planning phase with an example of similar sentence structure, and then asked to describe a picture.
"For example, they heard the sentence 'the man is throwing a stick' just before they are shown a picture in which a girl is petting the cat. The words are different, but in both sentences, there is a noun, verb, and direct object," he says.
While both studies explore a new area of research -- what occurs in planning speech that could affect how it's delivered -- their findings may offer some immediate benefit to many of the one in 20 Americans who stutters, says Jane Fraser of the Stuttering Foundation of America.
"We've long known that people who stutter can 'cure' themselves by finding a rate of speech that's right for them," she tells WebMD. "If you slow it all down, and use more pauses, there's a little more time inserted for the planning stage of speech."