Stuttering: Core and Secondary Behaviors

• Stuttering is a fluency disorder characterized by interruptions in speech, including pauses, repetitions, and hesitations
• The term "stutterers" is avoided, favoring person-centered language
• Stuttering affects individuals across all ages, sexes, cultures, races, occupations, and income levels

Causes and Development

• The exact cause of stuttering is unknown, but genetics plays a strong role
• Onset typically occurs between ages 2-5
• Natural childhood stressors like vocabulary growth or new siblings may trigger onset
• Some children recover naturally, while others need intervention; severe cases past puberty may only show partial recovery

Fluency vs. Stuttering

• Fluency is defined as the effortless flow of speech
• Stuttering involves increased frequency and duration of speech stoppages
• Normal disfluencies are common in children and adults, often related to language development or uncertainty
• Stuttering can be developmental (childhood-onset) or acquired from brain damage, disease, or trauma

Core Behaviors of Stuttering

• Repetitions are the most common behavior in children, occurring at the sound, syllable, or single-word level
• Prolongations can range from fractions of a second to minutes
• Blocks are the most advanced behavior; airflow, voicing, or articulatory movement stops

Severity and Frequency

• Mild stuttering involves disfluencies in about 5% of spoken words
• Severe stuttering can affect up to 50% of words spoken
• The average duration of core behaviors is about one second but may extend to five seconds

Secondary Behaviors

• Escape behaviors terminate a stuttering moment (e.g., eye blinking, head nodding)
• Avoidance behaviors prevent anticipated stuttering, often based on past experiences

Emotional and Psychological Impact

• Negative emotions like frustration and fear can reinforce stuttering
• Avoidance and social impact can lead to reduced social interactions and professional limitations

Predictors of Persistent Stuttering

• Family history increases the risk if relatives also stutter
• Males are more likely to persist in stuttering than females
• Later onset (beyond age 3;6) links to a greater risk of persistence
• Increased severity, longer durations, and prolongations/blocks indicate higher persistence risk
• Weaker phonological abilities may correlate with continued stuttering

Additional Factors Predicting Stuttering

• Stuttering is more likely to continue if it persists beyond one year, especially in boys
• A higher risk can be signaled by Stuttering moments of more than three repetition units
• Likelihood of continuation increases if sound prolongations and blocks persist without improvement
• Deficits in phonology correlate with persistent stuttering
• Males stutter at a 3:1 ratio compared to females; females recover faster and more frequently
• Stuttering is somewhat consistent in patterns
• Some individuals can predict when they will stutter
• People tend to stutter on the same words when rereading passages
• Repeated readings reduce stuttering frequency (adaptation effect)

Grammatical and Fluency-Related Factors

• Adults stutter more on: consonants, initial word positions, contextual speech (vs. isolated words), nouns/verbs/adjectives/adverbs, longer words, stressed syllables

Fluency-Inducing Conditions

• Includes speaking alone, relaxed, or with infants/animals, speaking in unison or in a prolonged manner, using rhythmic pacing or delayed auditory feedback, swearing or speaking in another dialect

Genetics and Neurological Differences

• Stuttering often runs in families Identical twins show a higher concordance rate for stuttering than fraternal twins
• Both genetic and environmental influences play a role
• Left hemisphere anomalies and greater right hemisphere activation are present in stutterers
• There is poor auditory processing, slower reaction times, and altered tactile/visual processing
• Some individuals who stutter experience higher autonomic arousal

Childhood Factors

• Children with sensitive temperaments may react to stress with increased physical tension and stuttering

Factors Affecting Stuttering

• Stuttering is influenced by a mix of sensory-motor, language, and emotional factors
• Onset is typically gradual and not linked to extreme stress
• Speech fluency may suffer with high developmental demands
• Delayed motor development could be a contributing factor

Cognitive and Emotional Factors

• Rapid cognitive growth (ages 2-6) can temporarily disrupt fluency
• By ages 3-4, children become aware of speech differences, leading to shame and increased tension
• Stress and rapid breathing can contribute to disfluencies
• Temperament and anxiety may lead to increased stuttering in stressful situations

Speech & Language Environment

• Parental factors such as fast speech rates, interruptions, and complex language use may exacerbate stuttering
• Life events (e.g., moving, new siblings, divorce, family hospitalization) can trigger or worsen disfluencies

Physical & Motor Development:

• Growth in vocal tract structures (ages 2-5) demands increased neural coordination
• Children who stutter may also have higher rates of articulation disorders

Variability in Stuttering Development

• Stuttering progression may fluctuate between normal disfluency and more severe stuttering
• Some children have a gradual onset (reps → prolongations → blocks), while others have a sudden onset with high tension
• A small group of individuals experiences psychogenic stuttering, influenced by psychological factors

Developmental Levels of Stuttering

• Normal Disfluency (Typical in Young Children): Occasional repetitions, interjections, and revisions are common No awareness or reaction to disfluencies Usually fewer than 10 disfluencies per 100 words Disfluencies decline after age 3
• Borderline Stuttering (Ages 2-3.5): More frequent disfluencies than typically developing peers More than 10 disfluencies per 100 words with multiple-unit repetitions Loose, relaxed disfluencies Little to no awareness
• Beginning Stuttering (Ages 3.5-6): Increased muscle tension and faster, irregular repetitions Prolongations and first signs of blocks appear Escape behaviors develop

Intermediate Stuttering (Ages 6-13)

• Blocks become the dominant feature, which involves tension and struggle
• Increased anticipation of stuttering leads to avoidance behaviors
• Situational fears emerge
• Emotional responses shift with fear before stuttering, embarrassment during, and shame after
• Therapy focuses on reducing avoidance behaviors and building confidence

Advanced Stuttering (Teens & Adults)

• There are long, tense blocks with physical struggle and tremors
• Highly ingrained avoidance behaviors are present
• There is a strong emotional impact
• Therapy emphasizes desensitization and deconditioning avoidance behaviors

Key Takeaways for Treatment

• Early intervention can prevent progression from borderline to advanced stuttering
• Avoidance behaviors become harder to unlearn over time
• Therapy for older individuals modifies reactions, and changes negative self-perceptions

Case Studies

• VK (2;6 years old): Started stuttering at 2;3 years, is bilingual (English & Hindi), mild to moderate developmental stuttering with 20% disfluencies, and no secondary behaviors or frustration are observed
• MJS (18 years old): Stuttering since childhood with minimal response to therapy, reports neck tension and avoidance strategies, doesn't stutter while reading aloud, stutters more under school pressure and is confused, and less with friends and family
• JE (32 years old, ASD): Severe mixed receptive/expressive language disorder with anticipatory blocks (5-7 seconds), limited verbal output and struggles with motor speech control and sustained phonation
• NK (2;3 - 3;2 years old): Initially had an expressive vocabulary of fewer than 50 words, language skills improved, but repetitions and prolongations persisted