J. Scott Yaruss, associate professor in communication science and disorders at the University of Pittsburgh School of Health and Rehabilitation Sciences and co-director of the Stuttering Center of Western Pennsylvania, explains.

Stuttering is a communication disorder generally characterized by involuntary disruptions in the flow of speech. These disfluencies can take many forms, such as repetitions of parts of words (li-li-like this) and moments when a sound or a period of silence is prolonged (lllllike this or l-----ike this). Individuals who stutter often experience negative emotional, cognitive or behavioral reactions that can further affect their ability to communicate. Ultimately, stuttering can have a significant adverse impact on an individuals quality of life and ability to participate in daily activities.

The stuttering classification encompasses a number of communication disorders: neurogenic stuttering and psychogenic stuttering are associated with sudden onset and, as their names imply, with a specific known cause--either a flaw in the makeup of the brain or a profound psychological challenge. These disorders are relatively rare and differ in terms of etiology, symptoms and treatment from developmental stuttering, the most common disorder. Developmental stuttering typically starts in early childhood, between the ages of two and a half and four. The onset of the disorder, which can be gradual or relatively sudden, generally occurs during the period of rapid development in a childs language skills, motor skills, temperament, and social interaction. Later onset of developmental stuttering has also been reported, though less is known about this variant.

The causes of developmental stuttering are not well understood and various theories have been offered throughout the history of speech-language pathology. The roots of stuttering have been attributed to a number of causes: emotional problems, neurological problems, inappropriate reactions by caregivers and family members, language planning, and speech motor difficulties, among others. Many of these theories have shown promise in explaining some characteristics of stuttering but no single theory has comprehensively described the internal and external experiences of people who stutter.

The growing consensus is that many factors influence stuttering. Current theories suggest that it arises due to a combination of several genetic and environmental influences. Some elements currently being examined include motor skills, language skills, and temperament. It is presumed that a child experiences disruptions in speech production due to an interaction among these (and presumably other) factors.

There is no known cure for stuttering, though many treatment approaches have proven successful for helping speakers reduce the number of disfluencies in their speech. Young children who have stuttered for only a short time have a high rate of natural recovery, though it is impossible to determine which children are most likely to recover and which are likely to continue stuttering.

Most experts recommend early evaluation and treatment aimed at preventing the development of a chronic communication disorder. As children approach the school-age years and adolescence, treatment often shifts toward addressing additional factors, such as reducing negative reactions to stuttering and minimizing the adverse impact of stuttering on communication ability and quality of life.

Speech-language pathologists disagree about which approach is best for older children and adults. Treatment options include training to change speech patterns, counseling to minimize negative reactions, pharmaceutical interventions, and electronic devices that enhance fluency. Self-help and support groups also play a prominent role in recovery for many people who stutter.

The ultimate outcome of therapy is to ensure that communication difficulties do not encumber the speaker even if some stuttering remains in the persons speech. Many people who stutter are able to make positive changes in their speech skills, communication abilities, and cognitive reactions so they can communicate effectively.