Stuttering Center Research

Although stuttering has been the subject of intense research for many years, there is still much that is unknown or poorly understood about the disorder. Examples of some of the more intriguing questions that are still being investigated include:

  • What causes people to stutter?
  • Why do some children recover without treatment?
  • How can a clinician determine whether a child will develop chronic stuttering?
  • What makes a person stutter on a particular word or utterance?
  • Which measures are most important when evaluating stuttering, and what is the most reliable way to obtain these measures?
  • How do we document improvements in treatment when many of the changes are "under the surface" (e.g., changes in feelings or attitudes toward speaking)?
  • How well does treatment work, and how does a clinician determine what type of treatment is best for a specific individual who stutters?

Pursuing answers to these and other questions is the primary goal of the broad-based research program at the University of Pittsburgh Speech Fluency Laboratory and the Stuttering Center of Western Pennsylvania. Following is a summary of some of our current projects:

Evaluating the Impact of Stuttering

Many current treatments for stuttering in school-age children, adolescents, and adults are based on finding a balance between helping speakers improve their fluency through changes to speech production ("speech modification" techniques) and helping speakers improve their attitudes and feelings about stuttering to reduce the severity of stuttering ("stuttering modification" techniques). Ultimately, the goal of treatment is to reduce the overall impact of stuttering on the person's life.

Unfortunately, many of the changes that occur in treatment are difficult to quantify. For example, one goal might be increased participation in social activities that the speaker previously avoided. Although it is relatively easy to document changes in fluency in different situations, clinicians have not always had a reliable way of measuring increased participation or reductions in the overall impact of stuttering.

To address the need for improved measurement tools, researchers at the Stuttering Center have developed a new broad-based instrument designed to assess the full impact of the stuttering disorder. The instrument, called the Overall Assessment of the Speaker's Experience of Stuttering (OASES), examines the entirety of the stuttering disorder from the perspective of the person who stutters.

The OASES contains four sections: (a) general information about the speaker's perception of stuttering, (b) the speaker's affective, behavioral, and cognitive reactions to stuttering, (c) the impact of stuttering on the speaker's functional communication abilities in key situations, and (d) the impact of stuttering on the speaker's overall quality of life

The OASES-A (for adults ages 18 and over) was published in English and Spanish by Pearson Assessments. The OASES-S (for school-age children, ages 7-12) and OASES-T (for teenagers, ages 13-17) have also been published! For more information about the OASES, contact J. Scott Yaruss, PhD, Co-Director of the Stuttering Center, at

We hope that by developing these instruments, we will be able to improve the documentation of the changes that occur during stuttering treatment and thereby improve treatment outcomes research for individuals who stutter.

(Para)Linguistic Factors Influencing Childhood Stuttering

Many treatments for childhood stuttering involve changing certain characteristics of children’s speech. For example, common strategies involve slowing children's rate of speech or increasing the number and length of pauses they use in conversation. Similar changes are encouraged for parents or other conversational partners to provide a communication model and environment that facilitates fluency.

As part of a broader attempt to evaluate the efficacy of stuttering treatment, researchers at the Stuttering Center have conducted a series of studies designed to assess the degree to which manipulation of these and other factors influences the likelihood that stuttering will occur on a particular utterance. In addition to providing data about the factors that affect stuttering, this research provides information about the value of common treatment techniques. This research previously received funding through a 5-year grant from the National Institutes of Health.

A Note about Student Involvement

Undergraduate and graduate students at the University of Pittsburgh have been involved in all aspects of these studies, including developing new research ideas, collecting and analyzing data, learning to use equipment, writing and editing portions of manuscripts, and appearing as co-authors on publications resulting from research in which they have had substantial participation. Students are encouraged to contact J. Scott Yaruss, PhD (412-383-6538) to discuss any of the projects listed above or to propose new projects that relate to theory and clinical practice in the field of stuttering.