Neurogenic Stuttering
Author: Roselyn Mathew, Reg. CASLPO, Speech-Language Pathologist
Date: Wednesday, September 10, 2025
Table of Contents
Stroke
Traumatic Brain Injury (TBI)
Neurodegenerative diseases
Brain tumours
Other neurological conditions
Neurogenic stuttering vs Developmental stuttering
Onset
Cause
Distribution of dysfluencies
Adaptation effect
Secondary behaviours
Emotional reaction
Neurogenic Stuttering vs Cluttering
Rate of speech
Clarity
Awareness
Consistency
Underlying causes
Types of dysfluencies
Speech therapy
Addressing the cause
Medication
Psychological support
Multidisciplinary care
Introduction
Fluency in speech refers to the ability to speak smoothly without unnecessary interruptions. A fluent speaker moves naturally from one word to the next, maintaining rhythm, pace, and ease of communication. When fluency is disrupted, speech may sound broken, hesitant, or uneven, which can make it harder for others to follow.
Stuttering is the most known disorder of fluency. While many people associate stuttering with childhood, all types of stuttering do not begin early in life. Some appear later as a direct result of neurological injury or disease. This is called neurogenic stuttering.
Neurogenic stuttering is an acquired fluency disorder that emerges after damage to the brain. It is linked to neurological events such as strokes, head injuries, or progressive diseases that interfere with the normal control of speech. Unlike developmental stuttering, where there is no confirmed cause, neurogenic stuttering is tied to specific structural or functional changes in the nervous system.
Causes
Speech production is a complex process that depends on several brain regions working together. Areas responsible for movement, timing, planning, and language must coordinate seamlessly. When these systems are disrupted, fluency can break down. Neurogenic stuttering appears when this coordination is disrupted by injury or any neurological conditions.
The most common causes of neurogenic stuttering include:
Stroke
When blood supply to part of the brain is interrupted, nerve cells in that region may become permanently damaged. If the affected areas are responsible for motor planning or speech control, stuttering can develop as a direct result.
Traumatic Brain Injury
Head injuries can cause impairments in the neural pathways needed for fluent speech. In some cases, stuttering starts immediately after trauma, while in others it appears gradually during recovery.
Degenerative Diseases
Conditions such as Parkinson’s disease, multiple sclerosis, or amyotrophic lateral sclerosis gradually damage the nervous system. As these conditions advance, stuttering may emerge alongside other motor or communication problems.
Brain tumours
A tumour pressing on regions responsible for language and motor planning may disturb fluency. In such cases, stuttering can be one of several neurological symptoms.
Other Neurological conditions
Infections or seizures that affect the brain may also trigger disfluency in speech.
Symptoms
Neurogenic stuttering presents with distinct speech disruptions caused by neurological dysfunction. Key symptoms include:
Repetitions of sounds, syllables, or words – Involuntary recurrence of speech sounds either as syllables or whole words (e.g., "m-m-m-make" or "to-to-to").
Prolonged speech sounds – Stretching of phonemes (e.g., "mmmmine" instead of "mine").
Speech blocks – Sudden pauses or inability to produce sounds, often with visible effort.
Irregular disfluency patterns – Disruptions may occur unpredictably, even on typically easy words or mid-sentence.
Co-occurring neurological deficits – May accompany other impairments like slowed speech, word-finding difficulties, or motor control issues
Differential Diagnosis
Fluency disorders can appear similar on the surface, but careful observation highlights important differences. Distinguishing between neurogenic stuttering, developmental stuttering, and cluttering is essential for treatment.
Neurogenic Stuttering vs Developmental Stuttering
Although both may appear similar, the differences are clear when examined closely.
Onset
Developmental stuttering almost always begins in early childhood, typically between ages two and six, when language skills are rapidly developing. For example, a child may begin to repeat sounds like “b-b-bell” or block on words while learning new vocabulary.
Neurogenic stuttering appears later in life, often after a stroke or brain injury. An adult who has had a car accident and sustained a head injury might suddenly or gradually develop frequent repetitions and blocks due to neurogenic stuttering.
Cause
Developmental stuttering does not have a single known cause but is linked to a combination of genetics, speech-motor development, and environmental influences.
Neurogenic stuttering, by contrast, always follows a neurological impairment. For instance, someone recovering from a stroke that affected the left hemisphere of the brain may develop stuttering which they never had before.
Distribution of dysfluencies
In developmental stuttering, disruptions are more likely to occur at the start of sentences or on specific sounds. For example, a person may struggle especially with words beginning with “s” or “p.”
Neurogenic stuttering occurs more evenly across all parts of speech. A person may show repetitions or blocks in the middle of words just as often as at the beginning.
Adaptation effect
People with developmental stuttering often show improvement when they read a passage several times, the frequency of stuttering decreases.
People with neurogenic stuttering usually do not benefit from this repetition. Reading the same sentence again produces the same level of disfluency.
Secondary behaviors
People with developmental stuttering often have coping mechanisms, such as avoiding difficult words, blinking rapidly, or tapping a foot before speaking. Over time, these become part of stuttering.
People with neurogenic stuttering rarely shows such habits because it begins suddenly in adulthood. The person may feel frustrated but does not usually develop secondary behaviours.
Emotional reaction
Developmental stuttering often causes deep emotional distress. Many children grow anxious about speaking in class or around peers, and adults may avoid phone calls or public speaking.
Neurogenic stuttering can be frustrating, but the emotional reaction is usually less intense when compared to developmental stuttering. Since neurogenic stuttering appears after an injury or illness, many individuals accept it as part of their medical condition rather than as a reflection of themselves.
Neurogenic Stuttering vs. Cluttering
Cluttering, though also a fluency disorder, looks very different in speech.
Rate of speech
Cluttering is marked by an excessively fast, irregular pace. For example, a person may rush through a sentence like “Iwenttothestoreandboughtsome fruits” without pauses, making it hard to understand.
Neurogenic stuttering does not involve fast speech. Instead, it presents as interruptions like “I… I… I went to the store” or long blocks before a word.
Clarity
In cluttering, speech often sounds disorganized because syllables may be dropped or blended together. Words like “probably” might come out as “prolly.”
In neurogenic stuttering, words themselves are pronounced clearly once spoken, but the problem lies in starting or continuing smoothly.
Awareness
People with cluttering are often unaware of the speech issues. They may believe they are speaking normally and might get surprised when they are told that their speech is hard to follow.
Most of the individuals with neurogenic stuttering are aware of the breaks and interruptions. They may pause and apologize mid-sentence or might get frustrated.
Consistency
Cluttering may vary depending on focus. When asked to slow down and pay attention, usually people with cluttering can produce clearer speech. For example, their speech might improve when reading slowly from a book.
Neurogenic stuttering does not change much with effort. Whether relaxed or concentrating, the disfluencies remain similar.
Underlying cause
Cluttering usually begins in childhood and is linked to speech-motor planning and organization issues.
Neurogenic stuttering is always acquired and connected to a specific brain event such as stroke, injury, or illness.
Types of dysfluencies
Cluttering rarely includes the long blocks or tense prolongations, which is typical in stuttering. Instead, it produces a disorganized “rushed” pattern.
Neurogenic stuttering involves classic behaviors such as repeating syllables or getting a block while speaking.
Treatment
Managing neurogenic stuttering requires a combination of direct therapy and support for the underlying neurological condition.
Speech-language pathologists use strategies to reduce the frequency and severity of stuttering. Techniques are personalized based on the severity and nature of symptoms.
Addressing the cause
Treatment of the underlying condition, such as rehabilitation after a stroke, may reduce symptoms.
Medication
There is no specific drug to treat neurogenic stuttering, but medications that target the underlying condition may provide indirect improvement.
Psychological support
Counselling and support groups can help reduce stress, improve coping, and enhance quality of life.
Multidisciplinary care
Neurologists, therapists, and psychologists often work together to provide comprehensive care.
Conclusion
Fluency, which is the ability to speak with smoothness and ease, is essential for human connection. Neurogenic stuttering is an impairment of fluency due to damage to the brain. It is distinguished from developmental stuttering by its identifiable cause, similar distribution of disfluencies, absence of adaptation effect, and lack of secondary behaviours. Unlike cluttering, it does not involve rapid or disorganized speech, but instead clear disruptions such as repetitions, prolongations, and blocks are observed. Although a complete cure is not always possible, therapy can reduce symptoms and restore confidence in communication. These interventions provide a foundation for progress and in helping individuals to benefit from continued support and understanding. Continued awareness and thoughtful care ensure that individuals facing this challenge are met with respect, patience, and understanding.
To speak with a psychotherapist or one of the speech-language pathologists at Well Said: Toronto Speech Therapy, schedule an initial consultation by clicking the link below or calling (647) 795-5277.
