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(Stammering; Disfluent Speech)

En Español (Spanish Version)


Stuttering is a speech disorder in which the flow of speech is interrupted by:

  • Repetition or prolongation of sounds, words, or syllables
  • An inability to begin a word

The person who is stuttering may frequently blink the eyes and/or have abnormal facial or upper body movements in an attempt to speak.


The cause of stuttering is still incompletely understood. Some experts have suggested that stuttering may occur when:

  • A child's ability to speak does not match his or her verbal demands
  • There are psychological factors in a child’s life, such as mental illness or extreme stress
  • Problems occur in the connections between muscles, nerves, and areas of the brain that control speech
Considerable current evidence suggests that stuttering is caused by problems in the part of the brain which controls the timing of speech muscle activation. The reasons for such problems of speech timing remain unclear.

Muscles and Nerves Involved in Speech

Tongue Innervation

© 2008 Nucleus Medical Art, Inc.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

  • Family history of stuttering
  • Sex: male
  • Age: between 2 to 6 years of age


Symptoms may include:

  • Repetition of sounds, syllables, words, or phrases
  • Prolongation of sounds within words
  • Between-word pauses and lack of sound
  • "Spurting" speech
  • Accompanying behaviors, such as:
    • Blinking
    • Facial ticks
    • Lip tremors
    • Tense muscles of the mouth, jaw, or neck
  • Worsening symptoms when speaking in public
  • Improvement in symptoms when speaking in private


The doctor will ask about your symptoms and medical history, and perform a physical exam. Diagnosis may be based on:

  • Stuttering history
  • Circumstances under which stuttering occurs
  • Speech and language capabilities
  • Evaluation of hearing and motor skills, including a general pediatric and neurological examination.

You or your child will likely be referred to a speech language pathologist for further evaluation or treatment.


There is no cure for stuttering. However, treatment may dramatically improve stuttering. The main goal of treatment is to establish and maintain a feeling of control over speech fluency. Recovery rate is approximately 80%, more in girls than in boys.

The doctor or speech therapist can evaluate the stuttering pattern and assess what strategies may work best. Possibilities may include:

Drug Therapy

As yet little evidence supports the use of drugs to improve speech fluency.

Behavioral Therapy

This treatment often focuses on behavioral modifications that can be made to improve fluency.

Speech Therapy

A primary goal of this type of therapy is to slow the rate of speech.

There is currently not enough evidence to establish which form of treatment for stuttering is most effective.


There are no guidelines for the prevention of stuttering. However, early recognition and treatment may minimize or prevent a life-long problem.


The National Stuttering Association

The Stuttering Foundation of America


Canadian Stuttering Association

Institute for Stuttering Treatment and Research (ISTAR)


American Speech-Language-Hearing Association website. Available at: .

Anomalous anatomy of speech-language areas in adults with persistent developmental stuttering. Neurology . 2001 Jun 4.

Bothe AK, Davidow JH, Bramlett RE, et al. Stuttering treatment research 1970-2005:I. Systematic review incorporating trial quality assessment of behavioral, cognitive, and related approaches. Am J Speech Lang Pathol . 2006;15:321-41.

Bothe AK, Davidow JH, Bramlett RE, et al. Stuttering treatment research 1970-2005:II. Systematic review incorporating trial quality assessment of pharmacological approaches. Am J Speech Lang Pathol . 2006;15:342-52.

Gordon N. Stuttering: incidence and causes. Dev Med Child Neurol. 2002;44:278-281.

National Institute on Deafness and Other Communication Disorders website. Available at: .

The National Stuttering Association website. Available at: .

Sommer M, Koch MA, Paulus W, et al. Disconnection of speech-relevant brain areas in persistent developmental stuttering. Lancet. 2002;360(9330):380-383.

Yairi E, Ambrose NG: Early childhood stuttering: persistency and recovery rates. J Speech Lang Hear Res. 1999;42: 1097-112.

Last reviewed November 2007 by Rimas Lukas, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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