Stuttering

Overview

Stuttering is a speech disorder characterized by repetition of sounds, syllables, or words; prolongation of sounds; and interruptions in speech known as blocks. A person who stutters knows exactly what they want to say but has trouble producing a normal flow of speech. These speech disruptions may be accompanied by struggle behaviors, such as rapid eye blinks or tremors of the lips.

Stuttering affects people of all ages. It occurs most often in children between the ages of 2 and 6 as they are developing their language skills. Most children outgrow stuttering. Some will continue to stutter, and stuttering can persist as a lifelong communication disorder.

Related Terms: 

• Stammering
• Disfluent speech
• Fluency disorders

Signs and Symptoms

Stuttering involves several distinct speech disruptions:

• Repetition of sounds, syllables, or words
• Prolongation of sounds
• Interruptions in speech known as blocks
• Struggle behaviors, such as rapid eye blinks or tremors of the lips

Symptoms of stuttering can vary significantly throughout a person’s day:

• Speaking before a group or talking on the telephone may make stuttering more severe
• Singing, reading, or speaking in unison may temporarily reduce stuttering

Related Health Effects

Stuttering can make it difficult to communicate with other people, which often affects a person’s quality of life and interpersonal relationships. Stuttering can also negatively influence job performance and opportunities, and treatment can come at a high financial cost.

Causes and Risk Factors

The precise mechanisms that cause stuttering are not understood. Stuttering is commonly grouped into two types: developmental and neurogenic. At one time, all stuttering was believed to be psychogenic — caused by emotional trauma. Today, psychogenic stuttering is known to be rare.

Developmental Stuttering

Developmental stuttering occurs in young children while they are still learning speech and language skills. It is the most common form of stuttering. Some scientists and clinicians believe that developmental stuttering occurs when children’s speech and language abilities are unable to meet the child’s verbal demands. Most scientists and clinicians believe that developmental stuttering stems from complex interactions of multiple factors.

Recent brain imaging studies have shown consistent differences in people who stutter compared to those who do not stutter. Developmental stuttering may also run in families, and research has shown that genetic factors contribute to this type of stuttering.

Neurogenic Stuttering

Neurogenic stuttering may occur after a stroke, head trauma, or other types of brain injury. With neurogenic stuttering, the brain has difficulty coordinating the different brain regions involved in speaking, resulting in problems producing clear, fluent speech.

Risk Factors for Persistent Developmental Stuttering

Boys are more likely to stutter than girls.

Diagnosis

Health professionals generally recommend that a child be evaluated if they have stuttered for three to six months, exhibit struggle behaviors associated with stuttering, or have a family history of stuttering or related communication disorders. Some researchers recommend that a child be evaluated every three months to determine if the stuttering is increasing or decreasing.

For very young children, early treatment may prevent developmental stuttering from becoming a lifelong problem.

Stuttering is usually diagnosed by a speech-language pathologist — a health professional trained to test and treat individuals with voice, speech, and language disorders. The speech-language pathologist considers a variety of factors, including:

• The child’s case history, such as when the stuttering was first noticed and under what circumstances
• An analysis of the child’s stuttering behaviors
• An evaluation of the child’s speech and language abilities
• The impact of stuttering on the child’s life

When evaluating a young child for stuttering, a speech-language pathologist tries to determine if the child is likely to continue stuttering or outgrow it. To make this determination, the speech-language pathologist considers factors such as:

• The family’s history of stuttering
• Whether the child’s stuttering has lasted six months or longer
• Whether the child exhibits other speech or language problems

Treatment and Management

Although there is currently no cure for stuttering, a variety of treatments are available. The nature of treatment differs based on a person’s age, communication goals, and other factors. Working with a speech-language pathologist is important to determine the best treatment options.

Therapy for Children

Treatment for young children often involves teaching parents ways to support their child’s production of fluent speech. Parents may be encouraged to:

• Provide a relaxed home environment that allows many opportunities for the child to speak, including setting aside time to talk, especially when the child is excited and has a lot to say
• Listen attentively when the child speaks and focus on the content of the message, rather than responding to how it is said or interrupting the child
• Speak in a slightly slowed and relaxed manner to help reduce time pressures the child may experience
• Wait for the child to say the intended word and avoid completing the child’s sentences
• Talk openly and honestly with the child about stuttering if they bring up the subject, and let the child know that some disruptions are okay

Stuttering Therapy for Teens and Adults

Current therapies for teens and adults should include the individual who stutters in determining the goals for therapy. 

Traditional treatment approaches focused on increasing fluency. These approaches may include speaking more slowly, regulating breathing, or gradually progressing from single-syllable responses to longer words and more complex sentences. Most of these therapies also help address the anxiety a person who stutters may feel in certain speaking situations. 

Newer treatment approaches, referred to as stutter-affirming treatment, focus on reframing the individual's attitude toward their own speech in a positive light. To achieve acceptance, treatment focuses on three priorities: rejection of the need for fluent speech, learning to appreciate one's own stuttering, and self-advocacy. The goal of stutter-affirming treatment is to reduce negative emotions and secondary behaviors through acceptance of one's own identity as a person who stutters.

Drug Therapy

The U.S. Food and Drug Administration has not approved any drug for the treatment of stuttering. However, some drugs approved to treat other health problems — such as epilepsy, anxiety, or depression — have been used to treat stuttering. These drugs often have side effects that make them difficult to use over a long period of time.

Electronic Devices

Some people who stutter use electronic devices to help control fluency. For example, one type of device fits into the ear canal, much like a hearing aid, and digitally replays a slightly altered version of the wearer’s voice so that it sounds as if they are speaking in unison with another person. In some people, electronic devices may help improve fluency in a relatively short period of time. Additional research is needed to determine how long such effects may last and whether people can easily use and benefit from these devices in real-world situations.

Self-Help Groups

Many people find their greatest success through a combination of self-study and therapy. Self-help groups provide a way for people who stutter to find resources and support as they face the challenges of stuttering.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on stuttering.

Community Support

• American Speech-Language-Hearing Association
• National Stuttering Association
• Stuttering Foundation is a nonprofit organization helping those who stutter.

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH. 

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.

Researchers around the world are exploring ways to improve the early identification and treatment of stuttering and to identify its causes.

Genetics

Scientists have been working to identify the possible genes responsible for stuttering that tend to run in families. National Institutes of Health (NIH) scientists have identified variants in four genes that account for some cases of stuttering in many populations around the world, including the United States and Europe. All of these genes encode proteins that direct traffic within cells, ensuring that various cell components get to their proper location. Such deficits in cellular trafficking are a newly recognized cause of many neurological disorders. Researchers are now studying how this defect in cellular trafficking leads to specific deficits in speech fluency.

Predicting Recovery

Researchers are also working to help speech-language pathologists determine which children are most likely to outgrow their stuttering and which children are at risk for continuing to stutter into adulthood. Researchers are examining ways to identify groups of individuals who exhibit similar stuttering patterns and behaviors that may be associated with a common cause.

Brain Imaging

Scientists are using brain imaging tools such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) scans to investigate brain activity in people who stutter. NIH-funded researchers are also using brain imaging to examine brain structure and functional changes that occur during childhood — changes that differentiate children who continue to stutter from those who recover. Brain imaging may be used in the future to help treat people who stutter.

Speech Pattern Recognition

Researchers are studying whether people who stutter can learn to recognize, with the help of a computer program, specific speech patterns linked to stuttering and to avoid using those patterns when speaking.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.