By Anne Smith, Ph.D., Purdue University
In July of this year, I was honored to be a keynote speaker at the meeting of International Fluency Association in the wonderful city of Dublin, Ireland. In my talk, "Physiological Indices of Speech and Language Processes: New Windows on the Onset of Stuttering in Young Children," I reviewed some of the accomplishments of the Purdue Stuttering Project and outlined our ongoing research studies. Here are some of the highlights from that talk:
First, to let you know our point of view about stuttering ' Despite the diversity of the disorder in different people who stutter, all individuals who stutter exhibit breakdowns in the motor processes necessary for speaking. The factors that influence these breakdowns in speech are complex. We have proposed that a complete model of stuttering must incorporate motor, linguistic, cognitive, psychosocial, and genetic factors, and that the model must explain how these factors interact during childhood to produce the disruptions in speech that makes one a person who stutters.
What we know from studies of adults who stutter ' Much of our earlier work on the Purdue Stuttering Project was focused on adults who stutter. These studies were essential to establish what the physiological bases of the disorder are in individuals with chronic stuttering. Our findings, in addition to those from many other research groups, mapped the differences in speech movement and muscle activity that occur during disfluent speech in the face, voice, and breathing areas. We also looked at language processing in adults who stutter when they are not speaking. One surprising finding was that when adults who stutter are reading, their brains are processing some aspects of language very differently compared to control participants who do not stutter.
What we are doing now "We all know that stuttering starts in very young children. Over the past five years, we have been developing ways to gather the same physiological measures from young children. By adapting our methods and making them kid friendly, we have been able to test children as young as four. In the current phase of the Purdue Stuttering Project, we are bringing in a group of 50 children who stutter ages 4-5 years. We plan to test these children and a matched group of non-stuttering children over a five-year period (please note that the NIH, because of budget restraints, only gave us 3 years of funding , and we hope to get them to support the later years!)."
We know from earlier research that approximately half of the children who are stuttering at 4-5 years, will persist and have a chronic stuttering problem, while approximately half of these children will recover. By using new experimental windows on how young brains are developing speech, we hope to develop methods by which we can predict which children are likely to have a chronic stuttering problem. In addition we will attempt to determine the factors that play a critical role in the development of chronic stuttering so that better therapies for young children will be available.
Thanks to the National Institute on Deafness and Other Communicative Disorders and to the Malcolm Fraser Foundation for their support of the Purdue Stuttering Project, which is co-directed by Anne Smith, Ph.D., and Christine Weber-Fox, Ph.D. It has been exploring new frontiers in the physiology of stuttering since 1989.