Understanding Stuttering: Causes and Influences

The Words We Use

• “People who stutter” is preferred over “stutterer” or "PWS"
• "Disfluency" can be normal or abnormal
• "Disfluency" is the preferred term over "dysfluency"

Do All Cultures Have Stuttering?

• Stuttering is recognized as ancient and universal across cultures

What Causes People to Stutter?

• The exact causes remain unclear, but significant factors include genetic, congenital, developmental, and environmental influences
• Negative emotional experiences can lead to negative feelings and attitudes about stuttering

Factors Contributing to Stuttering

• Bullying is a factor that contributes to stuttering
• High demands may influence stuttering
• Environmental factors can exacerbate stuttering
• Development influences
• Genetic and congenital components play a role

Definitions

• Fluency versus disfluent speech varies on:
  • Extra sounds like repetitions
  • Location and frequency of pauses
  • Rhythmic patterning
  • Intonation and stress
  • Overall rate of speech
• Starkweather (1980, 1987) suggested that rate and effort are critical to fluency
• A fluent speaker produces speech effortlessly at a comfortable rate for listeners

Stuttering: General Description

• Stuttering involves an abnormally high frequency and/or duration of speech stoppages
• This includes speakers’ reactions to these stoppages, with reactions being behavioral, emotional, and/or cognitive
• It's important to distinguish stuttering from typical disfluencies as well as neurogenic and psychogenic stuttering

Core Behaviors of Stuttering

• Repetitions include single-syllable word or part-word, such as repeating a word or syllable more than two times
• Prolongations involve sound or airflow continuing but with the movement of articulators stopped
• Prolongations as short as one-half second may be perceived as abnormal
• Blocks are defined as an inappropriate stoppage of airflow or voicing, where movement of articulators may be stopped
• Blocks can occur at respiratory, laryngeal, and articulatory levels and may be accompanied by tremors of the lips, tongue, jaw, or laryngeal muscles
• On average, individuals who stutter exhibit stuttering in about 10% of words when reading
• Individual stutters typically last around 1 second on average

Secondary Behaviors

• Secondary behaviors are learned and triggered by the experience or anticipation of stuttering
• Escape behaviors occur when the speaker is stuttering and attempts to end the stutter and finish the word
• Avoidance behaviors happen when the speaker anticipates a stutter and tries to avoid it

Feelings and Attitudes

• Stuttering often leads to feelings of embarrassment and frustration
• Feelings can intensify as stuttering experiences increase
• Fear and shame may develop and affect the frequency and severity of stuttering
• Attitudes are feelings that become permanent and influence a person's beliefs, which can be about oneself or listeners

Functioning, Disability, and Health

• The limitation stuttering imposes on an individual's ability to communicate is viewed as a disability
• This limitation is affected by the severity of stuttering along with feelings and attitudes
• Handicap refers to the limitation stuttering places on individuals’ lives, impacting social life, school, work, and community

The Human Face of Stuttering

• Examples of individuals at various developmental levels are available for review, including:
  • Borderline stuttering (young preschool age)
  • Beginning stuttering (older preschool age)
  • Intermediate stuttering (school age)
  • Advanced stuttering (teens and adults)

Basic Facts and Their Implications

• Onset may be gradual or sudden, with sporadic occurrences at the beginning
• Onset is often between 2 and 3.5 years (average 2.8 years)
• Prevalence measures how many people stutter at any given time
• Kindergarten prevalence: 2.4%; school-age: about 1%; adults: slightly less than 1%
• Incidence measures how many people have stuttered at some point in their lives, which is about 5%
• 70-80% of children recover from stuttering without treatment

Basic Facts and Their Implications (cont.)

• Factors associated with lower likelihood of spontaneous recovery include:
  • Relatives who were persistent stutterers
  • Being male
  • Onset after 3.5 years
  • Stuttering not decreasing during first year after onset or persisting beyond 1 year
  • Multiple unit repetitions
  • Prolongations and blocks
  • Below normal phonological skills
• Factors associated with recovery:
  • Being right-handed
  • Growing up with a nondirective mother
  • Slower speech rate and/or more mature speech motor system
  • Mothers of children who recovered used simpler language when talking to their children
  • White matter are more mature
  • Tend to breastfeed for longer

Sex Ratio

• The sex ratio is almost even (1:1) at the onset of stuttering
• Girls typically start stuttering and recover earlier than boys
• With stutterers of school age and older the ratio becomes 3:1 (boys to girls)

Variability and Predictability of Stuttering

• The 1930s saw interest in stuttering shift towards social, psychological, and linguistic aspects
• Anticipation: People who stutter can predict which words they will stutter on in a reading passage
• Consistency: Stutterers tend to stutter on the same words each time they read a passage
• Adaptation: Stuttering decreases with up to about six readings of a passage

Language Factors

• Adults who stutter do so more frequently on:
  • Consonants
  • Sounds in word-initial position
  • Sounds in contextual speech
  • Nouns, verbs, adjectives, and adverbs
  • Longer words
  • Words at the beginning of sentences
  • Stressed syllables
• In preschool children, locations and frequency of stuttering are different than in older individuals
• Stuttering in preschool children occurs most frequently on pronouns and conjunctions
• In preschool children, stuttering appears most frequently as repetitions of parts of words and single-syllable words in sentence-initial position
• Linguistic planning and preparation seem to be the trigger

Fluency-Inducing Conditions

• Fluency inducing conditions include:
  • When speaking alone or when relaxed
  • When in unison with another speaker
  • To an animal or to an infant
  • In time or with rhythmic stimulus or when singing, in a different dialect
  • While simultaneously writing, while swearing
  • In a slow, prolonged manner
  • Under loud masking noise, when listening to delayed auditory feedback
  • When shadowing another speaker, when reinforced for fluent speech
• Fluency-inducing conditions may be due to reduced demands on speech motor control and language formation (Andrews et al., 1982)
• Cortical and subcortical networks are impaired in people who stutter
• Fluency-inducing conditions help compensate for deficits in neural systems by providing:
• Timing cues
• Slowing speech production
• Allowing focus on fluent speech

A Model of Stuttering

• Stuttering is a neurodevelopmental disorder appearing in preschool years, triggered by:
  • Stress from language development
  • Environmental stress leading to discoordination of speech production
  • This results in an excess of disfluencies
• Children may regain fluency when stresses are reduced or they learn to compensate, leading to complete recovery for some
• If neural pathways remain inadequate for fluency and/or negative reactions to stuttering occur, children may persist in stuttering
• Children who persist usually develop learned behaviors, which makes their stuttering more conspicuous

Explore the multifaceted nature of stuttering, encompassing its universal presence across cultures and the ongoing quest to understand its causes. Significant contributing factors include genetic predispositions, congenital conditions, developmental stages, and environmental influences. Negative emotional experiences, such as bullying, and high-pressure situations can also impact stuttering.