Stuttering in Adulthood

Description of Adult Stuttering

Approximately 1% of adults stutter. Adults who stutter may have persistent developmental stuttering – their stuttering started in childhood and it did not naturally resolve or improve completely with treatment. The cause of stuttering is biological; it is not "psychological" (see below under "Frequently Asked Questions" for a discussion of this). Whether it starts and whether it resolves is largely genetic - over 2/3 of people who stutter have someone else in their family who also stutters. Moreover, studies have shown differences in patterns of activity in the brains of many people who stutter compared to that of people who don't stutter. The environment also plays a role, interacting with the genetic factors and influencing early recovery in young children. When developmental stuttering persists into adulthood, it is often termed advanced stuttering.


Others experience the onset of stuttering in adulthood. This acquired stuttering may be a result of a neurogenic condition such as Parkinson’s disease, traumatic brain injury, or a stroke. This is termed neurogenic stuttering or stuttering associated with acquired neurogenic disorder (SAAND)Others may acquire psychogenic stuttering following a traumatic event or severe stress.


Adults who stutter can improve with treatment with a speech-language pathologist (S-LP). Although it is rare for persistent developmental stuttering to naturally resolve in adulthood, intervention can result in significant improvement. Neurogenic and psychogenic stuttering can also be improved with intervention. 

The Neurophysiology of Stuttering

First, interpretation of research findings to date must be made with caution due to the limitations of imaging techniques used by researchers for studying speech (e.g., noisy machinery that influences speaking patterns and activates the auditory cortex and movement artifacts). Also, the statistical differences have revealed tendencies at the group level; they were not major differences, and not all persons who stutter exhibit differences in brain imaging from normally fluent persons. Finally, across studies revealing abnormal activation patterns there has been a lack of consistent findings in terms of the location of the abnormal activation.

Generally, studies comparing the neural activity of people who stutter with fluent speakers has found: (1) overactivation in motor areas, especially in the right hemisphere, although the specific areas identified differ across studies, (2) reduced activity in the auditory cortex of the left hemisphere during both overt and imagined stuttering, (3) transcranial magnetic stimulation studies suggest abnormal inhibition and facilitation patterns of input to the motor cortex (e.g., from the basal ganglia), (4) that there is no evidence for bilateral representation of speech as was proposed in the 1930s, and (4) after therapy, there is increased activity in speech areas of the left cortex.

At the group level, anatomical studies have revealed in those with persistent stuttering: (1) reduced grey matter in the speech areas of the left hemisphere without homologous increase in the right hemisphere, maintaining hemispheric asymmetry, (2) reduced white matter density of association tracts in the left hemisphere and greater density of the corpus callosum, and (3) normalized densities in those with natural recovery.

Most evidence supports further exploration of abnormal input to the motor cortex from structures that modulate motor activity such as the basal ganglia.

Based on these findings, it has been proposed that for persons with persistent stuttering, the left hemisphere speech system is vulnerable to interference from input from supplementary motor areas. With decreased activation in the left hemisphere, the right hemisphere becomes overactivated and interferes with activity in the left hemisphere.

The findings to date also support the clinical rationale of current approaches to treatment. Namely, that by directly targeting use of motor speech strategies, connections in the motor areas of the left hemisphere may be activated and strengthened. Also, if negative avoidance-oriented thoughts and emotions (affective and cognitive sequelae of stuttering) are based in the right hemisphere are actively decreased, this may reduce activation in this hemisphere, reducing interference with temporal processing of speech operations and positive approach-oriented thoughts and feelings in the left hemisphere.


An assessment is completed before starting treatment. The purpose of assessment is to characterize the nature of the stuttering symptoms, secondary behaviours (e.g., muscle tension, blinking), emotional and cognitive reactions, and measure the severity of the stutter. This information informs the development of the treatment program and provides a baseline to measure progress. An additional purpose for those with acquired stuttering is differential diagnosis – to determine whether an individual is presenting with neurogenic or psychogenic stuttering, as the cause determines the treatment approach.


During assessment, the S-LP will ask the individual to complete specific tasks to measure stuttering symptoms. These tasks may include conversation, reading a passage, describing a picture, and speaking on a topic. A detailed case history will also be collected through interview. The S-LP will also ask the person to complete various questionnaires and scales related to their experience of stuttering.​ This data will be analyzed by the S-LP and summarized in a written assessment report. The S-LP will explain the results of the assessment either during a debriefing appointment (in person or by phone) or at the beginning of the first treatment session, depending on the needs of the individual client.


Treatment is carried out with an S-LP. At Shoreline, these appointments are carried out in the office or by videoconference in some cases. Depending on the person, treatment may involve the following:

  • Reducing/eliminating secondary behaviours - learned behaviours that an individual has developed over time to help them cope with their stuttering, albeit ineffectually (e.g., blinking, pinching oneself);

  • Dealing with emotional responses to stuttering (e.g., anxiety associated with specific speaking situations such as using the phone);

  • Working through cognitive responses to stuttering (e.g., negative thoughts about one's speaking skills, worth, or ability to exert control over their speech);

  • When appropriate, a referral to a psychologist to help address these emotional and cognitive responses;

  • Motor skills training: Learning fluency shaping techniques to reduce the likelihood of stuttering episodes occurring; learning stuttering modification techniques to regain control during stuttering episodes.

In addition to sessions in the clinic, clients will need to commit to daily home practice (about 10 minutes a day) and complete weekly carryover assignments - intentionally applying fluency shaping and stuttering modification techniques in daily activities such as a specific phone call or when checking out at the grocery store. Home practice and carryover assignments are critical to making progress and clients must be ready to commit to these components before initiating treatment.


The length and frequency of appointments can vary depending on a person’s needs and constraints. Clients can expect to commit to one 45- or 60-minute session in the clinic per week or every other week. Client also have the option of longer sessions (90-minutes) and more frequent appointments (e.g., two per week). These options will be discussed during the debrief after assessment. For those who live outside of the HRM, have the necessary computer equipment and competency, and have a reliable internet connection, treatment sessions can also be conducted via videoconference (WebEx).

Motor Skills Training


Treatment for stuttering in adulthood frequently includes motor skills training. There are two complementary categories of techniques in motor skills training - fluency enhancement (FE) and stuttering modification (SM). The goal of FE is to modify speech to produce smooth, forward-flowing speech free of tension which reduces the likelihood of stuttering. The goal of SM is to increase control over stuttering episodes that occur to change the form of the stutter to minimize the degree of abnormality and regain control of speech effectively.

These two approaches have similarities:

  • gives the person who stutters more control over their speech 

  • increases fluency

  • slows speech down (within a natural range) to exert more control or reset the speech system

  • focus on the forward flow of speech 

  • uses vowels to move speech forward

  • use easy onsets (a technique which sets up the speech system for optimal tension levels)

These two approaches also have differences:

  • FE focuses on maximizing fluency broadly across all speech productions, whereas SM focuses more narrowly on modifying stuttering episodes

  • FE seeks to enhance fluency by increasing motoric control overall (e.g., slower speech means can get to articulatory targets), while SM focuses specifically on changing the pattern of the stutter from a block (stoppage of airflow with tension) to an easy open repetition of sounds where the air is still moving and tension is released

  • FE involves a hierarchy of steps that begins in the treatment room and is eventually transferred to real life situations (i.e., not until a near-normal rate is achieved), while SM, however, is applied in situations of daily living as soon as the techniques are learned

These techniques are learned with the guidance of an S-LP through repeated practice and in contexts with increasing difficulty (e.g., single words >> sentences >> conversation). When a person is first introduced to these techniques, they may feel awkward, effortful, and unnatural. With practice and eventual mastery, however, they become more natural and automatic and less effortful.

These two approaches are complementary, depending on how the person who stutters presents. Both provide useful tools to the individual to gain greater control over their speech. FE makes it less likely that they will stutter in the first place, and SM gives them a strategy to adaptively modify their stutter so that it will be less disruptive.


Over time, many people who stutter develop feelings of discomfort or fear associated with stuttering, speaking, and/or reading and may avoid specific speech sounds, words, or situations (e.g., speaking on the phone, applying for certain jobs, going to parties, reading aloud). These thoughts and feelings can frequently cause significant distress and limit engagement in desired life activities (e.g., going for coffee with a new acquaintance, pursuing a career in education). To address this, desensitization is often a critical part of a person's treatment program. The goal of desensitization is to eliminate or reduce these fears or feelings of discomfort so that stuttering is no longer a source of fear nor a reason to avoid activities that involve speaking.


This process requires both time, patience, self-compassion, and courage. It often starts with exploring what is termed a "fear hierarchy" - a hierarchy of specific speaking situations that cause anxiety or fear ordered from least difficult to most difficult. This hierarchy is very personal and specific. For example, speaking on the phone with one's spouse may be less fearful than speaking on the phone with a stranger. Desensitization also means gaining greater acceptance and comfort with episodes of stuttering, so that stuttering in and of itself is no longer a source of fear.


One of the goals of desensitization is to support an individual to gain more control over their own reactions to stuttering so that this response does not restrict them in pursuing their life goals.

Frequently Asked Questions About Stuttering

Is stuttering a "mental illness"? Is it a psychological condition?

Stuttering is actually biological, not psychological. Whether it starts and whether it resolves is largely genetic. Moreover, studies have shown differences in patterns of activity in the brains of some people who stutter compared to that of people who don't stutter. The environment also plays a role, interacting with the genetic factors and influencing early recovery in young children.

Children who are shy are not more likely to start stuttering. People who continue to stutter are not more sensitive or neurotic. It might be that children who recover from stuttering or have less severe stuttering are better at controlling their own reactions– but we need to understand this better. Social anxiety in certain situations is more common, but it is different than typical social anxiety disorder (see below).

Although the cause of stuttering is not psychological, people who stutter can certainly have psychological reactions to stuttering. Losing control of your speech can be extremely frustrating, so there are some common reactions. This may include experiencing emotions such as anxiety or fear, developing behaviours like eye clenching to try and force words out, the appearance of not remembering names or words because the person is avoiding words they expect to stutter on, or avoidance of situations where they expect to stutter more. People who stutter may have negative thoughts about their ability to talk and what others think about them. Stuttering does not affect intelligence.

What is the relationship between stuttering and social anxiety? Will Cognitive Behaviour Therapy (CBT) reduce stuttering?

Although Cognitive Behaviour Therapy (CBT) certainly has utility for people who stutter, it has limitations. Although there is a higher prevalence of social anxiety among PWS compared to the general population, stuttering itself is not caused by social anxiety. Furthermore, PWS may be better characterized as having features of social anxiety (i.e., cognitive components more than emotional or physiological components) rather than a “pure” diagnosis of social anxiety. PWS who also experience social anxiety may benefit from CBT because it decreases the symptoms of social anxiety, but a decrease in stuttering should not be expected.

That being said, S-LPs often find principles of CBT helpful in supporting PWS in a number of ways. PWS are more likely to experience state anxiety in specific speaking situations (versus those with anxiety disorders who experience both trait and state anxiety). CBT guides a person to identify irrational thoughts and responses to situations and to replace these irrational thoughts with rational and productive ones. This is relevant for PWS who exhibit negative thoughts about themselves (e.g., “I am ashamed of myself because I stutter.”) and beliefs about others’ perceptions (e.g., “No one will want to date me because I stutter.”). The PWS can be helped to evaluate these beliefs and thoughts and to replace them with more accurate ones (e.g., “If someone I want to date likes who I am, and if I accept my stuttering, then they will too.”).

What is a "delayed auditory feedback" (DAF) system?


Delayed auditory feedback (DAF) systems alter the sound of your voice with the goal of decreasing stuttering. The unit looks like a hearing aid and is worn in one ear. There are also DAF applications for smart phones. It alters the sound of your voice (and others’) and is intended to reduce the number of stuttering episodes. 

Over the past 12 years researchers have helped us learn more about these types of devices. First, how well it works depends on a few things. It depends on the task – it works best when reading aloud, then conversation, then monologue. In these situations it may reduce stuttering by 2-79% - a big range. It also depends on the situation. Stuttering is reduced more in the clinic or lab than in daily life. Over the long term, some people continue to benefit, whereas for others, the initial effect wears off over a few hours or weeks. There are various levels of satisfaction – when asked, some would purchase the device again, whereas others would not.

For those who do experience a benefit, their speech may sound more natural, with fewer stutters, although with a slower speech rate. They may avoid fewer situations, and have greater confidence. Users have also described disadvantages. As the altered signal is coming through only one ear, you have to process two signals at once. Many report background noise and acoustic interference is bothersome. There is also a significant cost. In Canada, the device costs around $5000 (often with a trial period and partial refund if it's not a good fit).

Overall, some benefit from using a DAF system, and some don’t. For those who do benefit, it varies on how much stuttering is reduced, in what situations and activities, and if the benefit is maintained over time. Some people use the device every day, others intermittently (e.g., when doing public speaking). It’s important to go in with the right expectations. DAF systems do not eliminate stuttering – but may reduce it. Really, a person won’t know if it will help until they try it.

DAF systems are not available at Shoreline.

"Stuttering Phenomenon #3: Delayed Auditory Feedback"

Tiffani Kittilstved

Ms. Kittilstved is an S-LP and a person who stutters. In this video, she briefly demonstrates and explains DAF.

Resources and Links

"When I Stutter" Documentary


Canadian Stuttering Association

"Top 3 Things When Meeting Someone who Stutters"

"5 Common Myths About Stuttering Debunked (It's Not Psychological!)"

Char Adams ("The Stuttering Journalist")

"Life with a Stammer"

Walter Scott at TEDxGuildford 2018

In this video, Mr. Scott advocates for changing attitudes about stuttering in society. He also briefly describes stuttering in a historical context and current understanding of the cause of stuttering.

Personal Experiences

In these videos, adults share their experiences with stuttering. In some videos, they use the term "stammering"; this is the word used for "stuttering" in the United Kingdom.

*** = favourites

***"How I Overcame My Fear of Stuttering"

LeRon Barton at TEDxWilson Park 2018

In this Ted Talk, Mr. Barton speaks eloquently about how he overcame his fear of speaking due to stuttering and how he developed confidence as a highly skills speaker.

***"Speech Therapy! My First Session in YEARS!"

Matice Ahnjamine

In this video, Ms. Ahnjamine shares a filmed portion of a therapy session with her S-LP.

"What is Stuttering?"

Matice Ahnjamine

In this video, Ms. Ahnjamine briefly describes some of the features and causes of stuttering.

"The Thing Is, I Stutter"

Megan Washington at TEDxSydney 2014

Ms. Washington, a musical artist in Australia, speaks about her experience with stuttering. She speaks candidly about some of her struggles with speaking and contrasts that with the fluency she experiences when singing. In the video, Ms. Washington demonstrates a fluency technique that she learned in treatment. It should be noted that she produced an exaggerated form when demonstrating it for the sake of the audience, and she went on to make excellent and valid points about the usefulness of the technique for her (both its benefits and drawbacks for her). Subsequently, the demonstration resulted in a speaking style that sounded quite unnatural. Mastery of this particular blend of strategies typically results in a more natural speaking style than what was presented.

"Discussing the Impact of Stuttering in Social Situations"

J. Scott Yaruss for MedBridge

In this short video, Dr. Yaruss, S-LP, interviews Sebastian, a young man who stutters. Sebastian shares a little about the impact of stuttering on social situations.

***"Let Me Finish: A Stuttering Documentary"

"Stammering - Wil's Story" 

County Durham & Darlington NHS Foundation Trust

In this short video, a young man describes his experience with stuttering before starting treatment.

***U.S. Vice President Joe Biden's speech at the American Institute for Stuttering Gala (2016)

In this exceptional speech, Mr. Biden speaks with great passion, insight, and frankness about stuttering. 

Bruce Willis at the American Institute for Stuttering Gala (2016)

Wayne Brady at the American Institute for Stuttering Gala (2017)


Halifax Support Group for People Who Stutter

Alison Thompson