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Symposium: From Freud to fMRI: Untangling the Mystery of Stuttering

10:00 AM - 11:30 AM EST on Sunday, February 20th

Brain Anatomy and Function in People Who Stutter *

De Nil, Luc
Professor and Chair
Department of Speech-Language Pathology, University of Toronto, Canada

Using functional and structural brain imaging, researchers have been able to show that adults and children who stutter differ in how their brain processes and plans speech. Persons who stutter typically show a significant overactivation in areas of the brain that are involved in speech production. Such overactivation may be the result of increased effort needed to produce speech, or may point to a deficient ability to acquire and control the very fast and well coordinated motor movements that are necessary for the production of fluent speech. Most likely, the observed functional differences reflect both such deficient processing ability and the increased effort that is a result during speech. In addition to the observed brain activation differences during speech in persons who stutter, recent brain imaging has also demonstrated structural-anatomical differences in brain areas involved in speech production. While these anatomical differences to some extent may develop as a result of stuttering, it is intriguing that in our research we have found anatomical lesions in these same areas that appear to be associated with acquired stuttering symptoms in stroke patients. This latter observation may suggest that at least some of the anatomical differences may be causally related to developmental stuttering. In my presentation, I will review current brain imaging findings in both developmental and acquired stuttering and link these findings to some clinical observations and treatment approaches in stuttering.

How Stuttering Emerges from the Interfaces Between Linguistic and Motor Processing *

Smith, Anne
Purdue University, USA

Stuttering is a neurodevelopmental disorder that typically starts when the child is 2-5 years old. Most children who stutter recover with or without therapy, but approximately 25 percent of them develop a chronic problem that is difficult to treat. Our NIH supported project seeks to find physiological markers for chronic stuttering, so that the probabilty of persistence or recovery can be determined early. Adults who stutter show many subtle differences in speech motor and language processes even when they are not overtly stuttering. We have initiated a longitudinal investigation to determine if these atypical neural processes are present at or near the onset of stuttering in young children.

Identifying the Genetic Contributions to Stuttering *

Drayna, Dennis
National Institutes on Deafness and Other Communication Disorders, USA

The fundamental deficits that underlie stuttering at the molecular and cellular level have remained a mystery. The observation that stuttering often runs in families opened the possibility of using modern methods of human genetics and genomics to gain insights into causative genetic variants in this disorder. Initial family studies identified a location on chromosome 12 that harbored such variants, and subsequent analyses have now identified variants within the GNPTAB, GNPTG, and NAGPA genes that occur in individuals who stutter but are not found in normal control individuals. These genes encode a pathway that targets a diverse group of enzymes to a place in the cell called the lysosome, which serves as the cell's "recycling bin." Such mutations have been identified in 5-10 percent of individuals with familial stuttering, and they suggest a previously unsuspected role for an inherited deficit of cell metabolism in stuttering.

Organizer - From Freud to fMRI: Untangling the Mystery of Stuttering *

Ratner, Nan
Professor and Chairman
University of Maryland, USA

What causes stuttering? From antiquity to the present time, many have offered observations and opinions. Because stuttering has a unique onset profile in childhood that disrupts previously fluent speech and language use, psychoanalysts felt that it was a neurotic symptom of unresolved conflicts, trauma or fixation. Behavioralists felt quite certain that it was a learned behavior, a bad habit, that emerged somehow from feedback to children