Stuttering also called stammering or childhood-onset fluency disorder is a speech disorder characterized by repetition of sounds, syllables, or words; prolongation of sounds; and interruptions in speech known as blocks. An individual who stutters exactly knows what he or she would like 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 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.
Stuttering is a common speech disorder in persons of all ages that can cause disturbances in the normal fluency and time patterning of speech.[rx] Developmental stuttering (DS)—stuttering that is inappropriate for the level of language development—is the most common form.[rx] Current evidence suggests the disorder stems from inherited central nervous system abnormalities that disrupt the fluent speech.[rx]
Symptoms of stuttering can vary significantly throughout a person’s day. In general, speaking before a group or talking on the telephone may make a person’s stuttering more severe, while singing, reading, or speaking in unison may temporarily reduce stuttering.
Stuttering is sometimes referred to as stammering and by a broader term, dysfluent speech.
Who stutters?
Roughly 3 million Americans stutter. 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. Approximately 5 to 10 percent of all children will stutter for some period in their life, lasting from a few weeks to several years. Boys are 2 to 3 times as likely to stutter as girls and as they get older this gender difference increases; the number of boys who continue to stutter is three to four times larger than the number of girls. Most children outgrow stuttering. Approximately 75 percent of children recover from stuttering. For the remaining 25 percent who continue to stutter, stuttering can persist as a lifelong communication disorder
What are the causes and types of stuttering?
The precise mechanisms that cause stuttering are not understood. Stuttering is commonly grouped into two types termed developmental and neurogenic.
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 those who stutter compared to nonstuttering peers. Developmental stuttering may also run in families and research has shown that genetic factors contribute to this type of stuttering. Starting in 2010, researchers at the National Institute on Deafness and Other Communication Disorders (NIDCD) have identified four different genes in which mutations are associated with stuttering. More information on the genetics of stuttering can be found in the research section of this fact sheet.
Neurogenic stuttering
Neurogenic stuttering may occur after a stroke, head trauma, or another type of brain injury. With neurogenic stuttering, the brain has difficulty coordinating the different brain regions involved in speaking, resulting in problems in the production of clear, fluent speech.
At one time, all stuttering was believed to be psychogenic, caused by emotional trauma, but today we know that psychogenic stuttering is rare.
Researchers continue to study the underlying causes of developmental stuttering. A combination of factors may be involved. Possible causes of developmental stuttering include:
- Abnormalities in speech motor control. Some evidence indicates that abnormalities in speech motor control, such as timing, and sensory and motor coordination, may be involved.
- Genetics. Stuttering tends to run in families. It appears that stuttering can result from inherited (genetic) abnormalities.
Stuttering resulting from other causes
Speech fluency can be disrupted by causes other than developmental stuttering. A stroke, traumatic brain injury, or other brain disorders can cause speech that is slow or has pauses or repeated sounds (neurogenic stuttering).
Speech fluency can also be disrupted in the context of emotional distress. Speakers who do not stutter may experience dysfluency when they are nervous or feel pressured. These situations may also cause speakers who stutter to be less fluent.
Speech difficulties that appear after an emotional trauma (psychogenic stuttering) are uncommon and not the same as developmental stuttering.
Males are much more likely to stutter than females. Factors that increase the risk of stuttering include:
- Delayed childhood development. Children who have developmental delays or other speech problems may be more likely to stutter.
- Having relatives who stutter. Stuttering tends to run in families.
- Stress. Stress in the family, high parental expectations, or other types of pressure can worsen existing stuttering.
Symptoms
Stuttering signs and symptoms may include:
- Difficulty starting a word, phrase, or sentence
- Prolonging a word or sounds within a word
- Repetition of a sound, syllable, or word
- Brief silence for certain syllables or words, or pauses within a word (broken word)
- Addition of extra words such as “um” if difficulty moving to the next word is anticipated
- Excess tension, tightness, or movement of the face or upper body to produce a word
- Anxiety about talking
- Limited ability to effectively communicate
The speech difficulties of stuttering may be accompanied by:
- Rapid eye blinks
- Tremors of the lips or jaw
- Facial tics
- Head jerks
- Clenching fists
Stuttering may be worse when the person is excited, tired, or under stress, or when feeling self-conscious, hurried, or pressured. Situations such as speaking in front of a group or talking on the phone can be particularly difficult for people who stutter.
However, most people who stutter can speak without stuttering when they talk to themselves and when they sing or speak in unison with someone else.
How is stuttering diagnosed?
Stuttering is usually diagnosed by a speech-language pathologist, a health professional who is trained to test and treat individuals with voice, speech, and language disorders. The speech-language pathologist will consider 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, and an evaluation of the child’s speech and language abilities and the impact of stuttering on his or her life.
When evaluating a young child for stuttering, a speech-language pathologist will try to determine if the child is likely to continue his or her stuttering behavior or outgrow it. To determine this difference, the speech-language pathologist will consider such factors as the family’s history of stuttering, whether the child’s stuttering has lasted 6 months or longer, and whether the child exhibits other speech or language problems.
If you’re the parent
If you’re the parent of a child who stutters, the doctor or speech-language pathologist may:
- Ask questions about your child’s health history, including when he or she began stuttering and when stuttering is most frequent
- Ask questions about how stuttering affects your child’s life, such as relationships with others and school performance
- Talk to your child, and may ask him or her to read aloud to watch for subtle differences in speech
- Differentiate between the repetition of syllables and mispronunciation of words that are normal in young children, and stuttering that’s likely to be a long-term condition
- Rule out an underlying condition that can cause irregular speech, such as Tourette’s syndrome
If you’re an adult who stutters
If you’re an adult who stutters, the doctor or speech-language pathologist may:
- Ask questions about your health history, including when you began stuttering and when stuttering is most frequent
- Rule out an underlying health condition that could cause stuttering
- Want to know what treatments you’ve tried in the past, which can help determine what type of treatment approach may be best
- Ask questions to better understand how stuttering affects you
- Want to know how stuttering has impacted your relationships, school performance, career, and other areas of your life, and how much stress it causes
How is stuttering treated?
Although there is currently no cure for stuttering, there are a variety of treatments available. The nature of the treatment will differ, based on a person’s age, communication goals, and other factors. If you or your child stutters, it is important to work with a speech-language pathologist to determine the best treatment options.
Therapy for children
For very young children, early treatment may prevent developmental stuttering from becoming a lifelong problem. Certain strategies can help children learn to improve their speech fluency while developing positive attitudes toward communication. Health professionals generally recommend that a child be evaluated if he or she has stuttered for 3 to 6 months, exhibits struggle behaviors associated with stuttering or has a family history of stuttering or related communication disorders. Some researchers recommend that a child be evaluated every 3 months to determine if the stuttering is increasing or decreasing. Treatment often involves teaching parents about 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. This includes setting aside time to talk to one another, 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. This can help reduce the time pressures the child may be experiencing.
- Listen attentively when the child speaks and wait for him or her to say the intended word. Don’t try to complete the child’s sentences. Also, help the child learn that a person can communicate successfully even when stuttering occurs.
- Talk openly and honestly to the child about stuttering if he or she brings up the subject. Let the child know that it is okay for some disruptions to occur.
Stuttering therapy
Many of the current therapies for teens and adults who stutter focus on helping them learn ways to minimize stuttering when they speak, such as by speaking more slowly, regulating their 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.
Drug therapy
The U.S. Food and Drug Administration has not approved any drug for the treatment of stuttering. However, some drugs that are 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.
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 into the ear so that it sounds as if he or she is speaking in unison with another person. In some people, electronic devices may help improve fluency in a relatively short period. 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. For these reasons, researchers are continuing to study the long-term effectiveness of these devices.
After a comprehensive evaluation by a speech-language pathologist, a decision about the best treatment approach can be made. Several different approaches are available to treat children and adults who stutter. Because of varying individual issues and needs, a method — or combination of methods — that’s helpful for one person may not be as effective for another.
Treatment may not eliminate all stuttering, but it can teach skills that help to:
- Improve speech fluency
- Develop effective communication
- Participate fully in school, work, and social activities
A few examples of treatment approaches — in no particular order of effectiveness — include:
- Speech therapy. Speech therapy can teach you to slow down your speech and learn to notice when you stutter. You may speak very slowly and deliberately when beginning speech therapy, but over time, you can work up to a more natural speech pattern.
- Cognitive behavioral therapy. This type of psychotherapy can help you learn to identify and change ways of thinking that might make stuttering worse. It can also help you resolve stress, anxiety, or self-esteem problems related to stuttering.
- Parent-child interaction. Parental involvement in practicing techniques at home is a key part of helping a child cope with stuttering, especially with some methods. Follow the guidance of the speech-language pathologist to determine the best approach for your child.
Self-help groups
Many people find that they achieve 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.
Coping and support
If you’re the parent of a child who stutters, these tips may help:
- Listen attentively to your child. Maintain natural eye contact when he or she speaks.
- Wait for your child to say the word he or she is trying to say. Don’t jump in to complete the sentence or thought.
- Set aside time when you can talk to your child without distractions. Mealtimes can provide a good opportunity for conversation.
- Speak slowly, in an unhurried way. If you speak in this way, your child will often do the same, which may help decrease stuttering.
- Take turns talking. Encourage everyone in your family to be a good listener and to take turns talking.
- Strive for calm. Do your best to create a relaxed, calm atmosphere at home in which your child feels comfortable speaking freely.
- Don’t focus on your child’s stuttering. Try not to draw attention to the stuttering during daily interactions. Don’t expose your child to situations that create a sense of urgency, pressure, or a need to rush or that require your child to speak in front of others.
- Offer praise rather than criticism. It’s better to praise your child for speaking clearly than to draw attention to stuttering. If you do correct your child’s speech, do so in a gentle, positive way.
- Accept your child just as he or she is. Don’t react negatively or criticize or punish your child for stuttering. This can add to feelings of insecurity and self-consciousness. Support and encouragement can make a big difference.
What research is being conducted on stuttering?
Researchers around the world are exploring ways to improve the early identification and treatment of stuttering and to identify its causes. For example, scientists have been working to identify the possible genes responsible for stuttering that tend to run in families. NIDCD scientists have now identified variants in four such 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 within the cell. 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.
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. In addition, researchers are examining ways to identify groups of individuals who exhibit similar stuttering patterns and behaviors that may be associated with a common cause.
Scientists are using brain imaging tools such as PET (positron emission tomography) and functional MRI (magnetic resonance imaging) scans to investigate brain activity in people who stutter. NIDCD-funded researchers are also using brain imaging to examine brain structure and functional changes that occur during childhood that differentiate children who continue to stutter from those who recover from stuttering. Brain imaging may be used in the future as a way to help treat people who stutter. Researchers are studying whether volunteer patients who stutter can learn to recognize, with the help of a computer program, specific speech patterns that are linked to stuttering and avoid using those patterns when speaking.
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