Are the Brains of People Who Stutter Different?

By Anne L. Foundas, MD, Summer 2001
Tulane University

For the past four years, our research group has been interested in learning more about the biological basis of stuttering. In earlier studies, our group and others have found that specific brain regions that mediate speech, language and motor functions are asymmetric or larger in one hemisphere than the other, and the larger region is often functionally dominant.

So, the left side of the brain is usually dominant for language functions, and the plenum temporale, a portion of language cortex, is larger in the left hemisphere in most right-handed adults. Frontal cortical language areas, like the pars triangularis and pars opercularis, have also been found to be larger in the left hemisphere in most adults.

There is some evidence that these brain regions are atypical in individuals with developmental language disorders, like dyslexia and specific language impairment; but these regions have not been studied in individuals who stutter. Atypical anatomy can be defined as atypical asymmetry, or atypical size. In addition, atypical bumps or gyri have been found. Our goal was to determine whether adults with perisitent developmental stuttering (PDS) have atypical anatomical features within cortical areas that mediate speech and language functions.

We studied sixteen adults with persistent developmental stuttering and sixteen fluent adults matched for age, gender, handedness, and education. Volumetric MRI scans were acquired, and anatomical brain regions that mediate speech and language functions were measured and the groups were compared.

We found that the right and left planum temporale was significantly larger with reduced interhemispheric size or more symmetry in the adults who stutter. Gyrification patterns also differed between the groups with some anatomical configurations unique to the adults who stutter. These included variants in the anatomy of the diagonal sulcus, and extra-gyri along the superior bank of the sylvian fossa.

Overall, the adults with PDS had significantly more atypical anatomical features (average of 4 per individual) than controls (average one per individual). Some distinct features were seen in men versus women and right versus left handers. All of the right-handed women who stutter had extra-gyri, but none had atypical planar asymmetry.

In contrast, the majority of right-handed men who stutter (6 of 9) had extra-gyri and atypical planar asymmetries (5 of 9). Left handed men who stutter had atypical planar asymmetries, but rarely had extra-gyri. Furthermore, 5 of 9 right handed men with PDS had a double diagonal sulcus. This unique anomaly only occurred in one left-handed and one right-handed female with PDS, and was never seen in a control.

These results provide strong evidence that adults with PDS have anomalous anatomy in perisylvian brain regions. No one anatomical feature distinguished the groups, but multiple loci within a widely distributed neural network differed between groups.

These results provide the first evidence that anatomic anomalies may put an individual at risk for the development of stuttering, and suggest that distinct features may be more common in men versus women, and right versus left handers who stutter.

Our research efforts are currently expanding to include functional MRI and treatment studies in adults who stutter. These proposed studies will provide a biological framework to learn more about the anatomy and functional activation of cortical regions in individuals who do and do not stutter, should provide information to develop targeted behavioral and pharmacological interventions, and may lead to earlier detection of individuals at risk for developmental stuttering.

Acknowledgments: This study was supported by NIH grant DC00135, PHS CRR Grant RR05096 Tulane-LSU General Clinical Research Center, and the Department of Veterans Affairs South Central MIRECC. These results will be presented at the 53rd Annual Meeting of the American Academy of Neurology, Philadelphia, PA, May 8, 2001, and are in press, Neurology. A Dana Foundation Grant has been awarded for the treatment study.

CELEBRITY FOCUS

Bill Walton

From BillWalton.com

Thank you for your interest in my life long problem with my speech and communication skills. I was a very shy and reserved young man who could not speak at all without severely stuttering until I was 28 years old. Always a success in the classroom and on the basketball court, I took refuge in the things that I did well as a youngster. A straight A student, my athletic abilities covered the deficiencies that limited my overall growth and development. The game of basketball was my religion, the gym my church. It was a convenient way of avoiding my responsibilities of developing my human relation skills.

When I was 28, a chance encounter at a social event with Hall of Fame broadcaster Marty Glickman completely changed my life in so many ways that things have never been the same since, nor have they ever been better. That day, in a very brief, private conversation (one way, mind you, since I literally could not speak at the time) Marty explained, patiently and concisely, that talking, communicating was a skill not a gift or a birthright and that like any skill, whether it be sports, music, business or whatever, needed to be developed over a lifetime of hard work, discipline, organization and practice. Marty gave me some simple tips that day and then encouraged me to take those keys and apply them to methods of learning that I had received from the special teachers that I had come across in my life, particularly the 6 Hall of Fame basketball coaches that I had played for throughout my career. The beginning of my whole new life was as simple as that. No gimmicks, tricks or shortcuts. Just the realization that with some help, guidance and a lot of hard work that I too could do what seemed so easy, simple and natural to everyone else, yet seemed impossibly out of my reach and comprehension.

Bruce Willis

While the world knows Bruce Willis as an A-list actor, few know that he struggled with stuttering throughout his first 20 years.

Walter Bruce Willis was born in 1955 in West Germany to his German mother, Marlene, and his American GI father, David Willis. The family settled in David’s hometown of Penns Grove, New Jersey in 1957, and the couple has three other children.

Marilyn Monroe

From Edward S. Herrington's letter to Southcoasttoday.com

I am writing in response to "The importance of voice" (May 29), which mentioned that famous actor James Earl Jones struggled with stuttering. Another famous voice that you cited was the trademark breathy voice of Marilyn Monroe; however, you did not make mention of the fact that Marilyn Monroe also struggled with stuttering at various points in her life, sometimes very painfully.

Mel Tillis

Mel Tillis, born Lonnie Melvin Tillis, was an influential figure in country music, both as a songwriter and a performer. His journey to fame was marked by overcoming personal challenges, including a stutter that he turned into a defining part of his public persona.

Byron Pitts

Byron Pitts has brought much attention to stuttering with his memoir, Step Out on Nothing: How Faith and Family Helped Me Conquer Life’s Challenges, released in September, 2009. The book not only details his speech difficulties, but also his illiteracy until age 12 and his unstable family life. Pitts overcame the odds to become the chief national correspondent with ABC News.