Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at July 2, 2016

Stuttering is a disorder of speech that involves an individual making repetitive sounds, elongating certain sounds, and being unable to make any sounds for periods of time. Stuttering can greatly inhibit social functioning, occupational functioning, and cause psychological distress to a person. It is sometimes referred to as disfluent speech or stammering.


Definition & Facts

Stuttering affects roughly 3 million Americans and is most prevalent among children – a condition called developmental stuttering. Up to 10% of children stutter at some point while they're acquiring their language skills between the ages of two and six, though 75% of them will recover without any speech problems. Males stutter at a rate of incidence that is three or four times higher than that of females.

Stuttering is a disfluency of speech. Most people experience disfluencies under certain conditions. Speaking in a competitive environment or in a setting in which the individual feels stressed or emotional may all trigger disfluency. Children first learning how to speak experience disfluency, while people trying to learn a foreign language will occasionally also have disfluent speech.

However, people with this speech disorder develop a chronic disorder. According to the Stuttering Foundation, stutterers do not not stutter because they are emotional or nervous. They also do not stutter because they are shy, and stuttering is not a reflection of intelligence or cognitive abilities. Stuttering is also not contagious.

Stuttering often causes participation restrictions. These are disabilities that the World Health Organization defines as preventing a person from partaking in certain life activities. The effects of stuttering on social interaction, job prospects, and the ability to successfully achieve educational goals involve such participation restrictions.

Symptoms & Complaints

People who stutter find communicating extremely difficult. Whereas fluent speech is expressive, organized, and smooth, stuttering involves repetition of certain sounds, prolongation of certain sounds, and periods of disruption or interruption in speech.

There may be long pauses between words or between syllables of one word. The stutterer may get stuck on the same sound in one word. Words are repeated and rephrased abnormally, and interjections like 'uh' and 'um' are used with frequency.

A stutterer will appear under a degree of physical stress while trying to communicate. They will be 'struggling to get their words out.' They may tap their feet, jerk their head, furrow their brow (their forehead may appear with wrinkles), and show other physical signs of tension indicative of struggle. Tremors and eye movements may also indicate tension as the speaker attempts to produce fluent speech.

Stutterers have techniques to try and reduce the appearance of their stuttering; this is referred to as covert stuttering. Stutterers may use circumlocution (rearranging words in sentence), avoiding certain words altogether, and pretending to forget what they had to say as a reason to not use words they know cause stuttering. Stutterers may also avoid social and professional situations which tend to bring out their stuttering. Overt stutterers, by contrast, do not attempt to conceal their stuttering from others.


The exact mechanisms that cause stuttering are not fully understood but may involve family history and genetic factors. The process of the child's acquisition of grammatical skills between the ages of two and six may be involved, though onset can begin when a child is only a year and a half or it can begin as late as thirteen years old in some cases.

A child's temperament and his or her propensity to feel frustrated at setbacks may exacerbate the process of developing stuttering. Teasing or negative social input that a child experiences in reaction to displaying the initial signs of a stutter likewise may induce feelings of guilt and self-pity that worsen the condition. However, it is unknown what the exact interaction is between the stutter intrinsically worsening and/or an individual's reaction to said worsening as these dynamics play out in the development of a stutter.

Neurogenic stuttering is caused by injury to the central nervous system including the brain and spinal cord due to trauma or disease. Such causal factors include tumors and cysts (e.g. brain tumors), stroke, and head trauma. Meningitis, which is typically caused by bacterial infections like Meningococcus bacteria and viral infections such as the Epstein-Barr virus, measles, and mumps may also cause neurogenic stuttering.

Neurodegenerative diseases like multiple sclerosis and Parkinson's disease are also possible causal conditions of stuttering. HIV and Guillain-Barré syndrome may also cause neurogenic stuttering. Finally, neurogenic stuttering may be a side effect of some medications.

Diagnosis & Tests

A speech-language pathologist will diagnose stuttering. They will ask about the person's medical history and his or her family history. The speech pathologist will try to determine when exactly the stuttering began. Diagnosis will analyze the child's presentation of symptoms. He or she will note both the frequency and variety of disfluencies exhibited by the child's' speech.

The speech pathologist will also determine how the stuttering is affecting the individual. Psychological and social effects will be inquired about. This will enable the diagnosing clinician to ascertain the level of severity of the disorder that the patient is dealing with, which is essential for establishing a treatment plan.

Treatment & Therapy

Treatment will typically involve speech therapy with a speech-language pathologist. Techniques will be practiced to improve the fluency of speech. Such techniques involve using shorter words and shorter sentences until longer words and longer sentences can be smoothy communicated. Proper breathing will also be practiced in order to reduce tension.

There are currently no medications that are approved to treat stuttering. Group therapy and cognitive behavioral therapy (a type of psychotherapy) may be helpful to individuals in order to reduce anxiety and psychological stress surrounding this condition.

Prevention & Prophylaxis

Because the causes and mechanisms of stuttering are still mysterious and may also involve genetics and hereditable factors, it is a disorder that cannot be definitively prevented yet. That being said, stuttering may be prevented from worsening by providing a child who is developing a stutter with a nonjudgmental environment.

Likewise, loved ones, friends, and caretakers of people with stutters are advised not to 'coach' stutterers during ordinary conversation. Finishing sentences or offering motivational encouragement to a person in the midst of stuttering will only make the stutterer feel more self-conscious and frustrated and less able to produce fluent speech.

Speaking with stutterers in frank and compassionate terms can help facilitate better communication. Simply asking the person with the stutter how best to respond to certain disruptions in conversation can help facilitate open but empathetic communication.

To the extent that certain types of stuttering are caused by damage to the central nervous system, prevention could incorporate vaccines against certain underlying viruses that cause meningitis (meningococcal vaccine) and use of proper safety headgear while engaging in activities with a risk of head trauma like contact sports and cycling.