Dr. Gerald Maguire's interest in stuttering dates back to the time he was a toddler, when he first tried to string sentences together.
Through the years, as listeners pleaded with him to "just relax," he struggled to speak with the same fluency as those around him, always believing that it was a matter of psychic strength, of trying harder to force out the words trapped inside.
His research is proving him wrong.
The UC Irvine psychiatrist and his colleagues have traced the often-embarrassing, much-maligned disorder to a spot deep within the brain where a central switchboard activates speech circuits. According to their preliminary findings in four patients, the spot, known as the left caudate, is not nearly as active in stutterers as among those who speak fluently, which may disrupt the brain's speech signals.
The research, published last month in the British journal Neuroreport, is not the first to suggest a neurological basis for stuttering, but it is the first to precisely pinpoint an anatomical culprit.
And while Maguire, 29, stresses that more people need to be studied, many stutterers are hailing the findings as the surest proof yet that their oral stumbling is not the outward sign of a tortured inner existence.
"It's the best proof we have that stuttering is a medical problem, that people who stutter are not different in any way emotionally or psychologically," said John Ahlbach, executive director of the National Stuttering Project, a San Francisco-based organization with 4,000 members.
"Some people will fight to their dying day, they'll go from Gestalt to Rolfing to EST to anything that will provide the solution that they think is there . . . but from everything we know about the problem, it is wrapped up in how (the) body works, in how (the) brain handles speech," Ahlbach said.
The researchers and some who have followed their work caution against all-or-nothing explanations, however.
Stuttering, which afflicts 2 million to 3 million Americans, may have a basis in biology, but "it doesn't account for everything," said Matt Ronayne, a speech pathologist who is president of the Stuttering Project's Orange County chapter. "A lot of people who stutter . . . are struggling so hard to be fluent that they are actually creating what they are struggling against. . . . It's kind of a paradoxical effect."
Ronayne, a 33-year-old Huntington Beach resident, said many of the behaviors that accompany stuttering--shutting one's eyes, for example, or clenching one's fists in an effort to force out a word--are learned. The speech and the associated behaviors are worsened by anxiety and shame, he said.
Maguire and his fellow researchers, including UCI psychiatrist Joseph Wu and Cal State Fullerton speech pathologist Glyndon Riley, do not dismiss the role of psychology.
"If you're more anxious and tense, you're likely to stutter more," Maguire said.
But their key finding, which they stress requires further testing, is that an underactive caudate is the primary reason for stuttering, with other factors--including anxiety--of secondary importance.
"We don't want to say we have the answer," said Wu, acting director of UCI's Brain Imaging Center. But "we think this is a very important crack in the mystery of what causes stuttering."
Riley, who has worked with stutterers for more than three decades, suspects that the caudate will not, however, turn out to be implicated in the case of every stutterer.
The team made its discoveries using a PET scan machine, an instrument that has explored the brain's role in everything from schizophrenia to Parkinson's disease.
The machine allows researchers to create color-coded images of brain activity. Subjects are injected with a sugar molecule attached to radioactive tracers, which then is taken up by the brain. Later, X-rays emitted by the tracers are detected by the machine and reproduced in a computer image, showing which areas of the brain have the most metabolic activity.
"This (technology) gives us an unprecedented telescope into the living brain," Wu said.
In the Neuroreport research, the pictures of the four stuttering subjects' brains were compared to those of four patients who do not stutter. In addition, pictures were obtained when the stuttering patients experienced speech problems and when they did not.
The images showed that among stutterers, brain activity is drastically reduced in the left caudate, an area the size of an almond at the brain's core. This holds true whether the stutterer is in a period of fluency, suggesting the lower activity of the caudate is a permanent trait.
