Fluency Mid-Term Test - Part One: Basics of Stuttering

What is stuttering

Stuttering is a speech disorder that typically emerges in early childhood, it is characterised by frequent repetitions of sounds and monosyllabic words, sound prolongation and interruptions in the forward flow of speech which are blocks. Stuttering is often accompanied by physical muscle tension and struggle.

What impacts does stuttering have?

Stuttering can impact a child’s academic, emotional and social abilities and their later vocational potential and achievements. People who stutter are often paid less than people who do not stutter

Components of stuttering

• Core behaviours = basic speech behaviours 

• Secondary behaviours = physical concomitants 

• Feelings & attitudes = emotional characteristics

Types of speech disfluency

1. part-word repetitions (sound or syllables) 

2. single-syllable whole-word repetitions 

3. multi-syllable word repetitions 

4. phrase repetitions 

5. prolonged sounds 

6. blocks & broken words - pauses

7. tense pause - when a block occurs in between words

8. interjections - can be used as a secondary behaviour - to delay saying the word

9. revisions & incomplete utterances

Stuttering-like / stuttered disfluencies

• part-word repetition 

• single-syllable word repetition 

dysrhythmic phonation 

• sound prolongations 

• blocks 

• broken words

Speech behaviours - Other disfluencies

• phrase repetition 

• revision 

• Interjection

Speech behaviours of stuttering - Lidcombe Behavioural Data Language

Frequency of disfluencies

• number of disfluencies per 100 words or syllables 

• most of speech in PWS is fluent 

• ~ 10% (on average) is stuttered 

• large fluctuations depending on day or situation 

• The one constant about stuttering is that it changes!

• People who stutter find that they often don’t stutter when whispering, when talking to a baby or when talking to a pet as they don’t see this as a pressurised environment, pressure makes stuttering worse

 Duration of disfluencies

• from beginning to end of disfluent event 

• repetitions: number of extra iterations of speech segment - /k/ /k/ /k/ cat - only three /k/ sounds are counted because these are the sounds that were additional to the word

• longer than 0.5 sec more likely to be judged as stuttered 

• overall mean of 1 sec, but can be much longer

Secondary behaviours = physical concomitants

Tense body movements 

• most frequently in head & neck 

• other body parts possible - sometimes people clench their fist or tap their foot or clench their toes in their shoe

• may be covert 

Assumption that behaviours develop as techniques to get out of stuttering

• however, also been observed in children

Secondary behaviours

• head jerks 

• squinting 

• eye closing 

• facial grimaces 

• tongue protrusion 

• pressured lips 

• jaw wide open 

• jaw closed tightly 

• clenching hands 

• arm movements 

• raising shoulders 

• irregular inhalation

Feelings & attitudes = emotional characteristics

Complex emotions develop 

• fear, anxiety, panic, frustration, shame, humiliation, anger, … 

• can occur prior, during & after stuttering 

can lead to avoidance behaviours 

• saying own name 

• certain speech sounds 

• speech situations

Different Behaviours of Stuttering

Factors that influence stuttering

Repeated readings of a passage 

Adaptation effect 

• reading passage 5 times – stuttering frequency on average decreases by half, stuttering will reduce each time that they read it - can anticipate what sounds will be tricky, motor planning rehearsal

Consistency effect 

• stuttering tends to occur on same words during repeated readings 

Adjacency effect 

• when stuttered words are removed from a passage, stuttering tends to occur near removed ones during repeated reading

Auditory feedback and how it influences stuttering

Auditory feedback

 Delayed Auditory Feedback – DAF 

• creates slow & unusual speech 

• can reduce or eliminate stuttering 

• can induce disfluencies in NFS 

Altered Auditory Feedback – AAF 

• change pitch up- or downwards 

Masking 

• noise presented though earphones eliminates feedback 

• reduces or eliminates stuttering

fluency-inducing conditions

• change in customary speech / acting 

• singing 

• whispering 

• rhythmic speech 

• reduced speech rate / slow / prolonged speech 

• chorus reading 

• Shadowing

Loci of stuttering - Language factors

• first word of utterance 

• >90% initial word consonants 

• consonants > vowels 

• content words > function words

• can be function words > content words in children

• stressed > unstressed syllables 

• increased utterance length 

• difficult sounds? – individual factor

Age at onset of stuttering

• range 1.5 - 5 years 

• mean of 33 months 

• possible but much less probably for stuttering to begin in older children, teens & adults

• 24-36 months: 56% of onsets 

• 18-42 months: 84% of onsets

Gender (biological sex) of stuttering

Overall 

• 3 males to 1 female 

Childhood (near onset) 

• 2 males to 1 female 

Adulthood 

• 4 males to 1 female

Incidence & prevalence of stuttering

Prevalence 

• number of all cases currently identified 

• even if they did not begin recently 

Lifetime incidence 

• number of all cases ever exhibited a disorder 

• currently or in the past 

• even if they recovered

Prevalence of stuttering in school

• Subgroup mean of preschool kids who stutter = 3.46%

• Subgroup mean of school kids who stutter = 0.83%

• Lifetime percent of people who stutter = 0.72%

incidence of stuttering studies

• varies from 3.2% - 17.7% 

• => 5% lifetime incidence

Incidence & prevalence of stuttering in New Zealand

speech recordings at 2;0 years of age 

• 2/42 children stuttered 

• 5% prevalence 

speech recordings at 3;6 years of age 

• 1/42 children stuttered 

• 2.4% prevalence

Incidence & prevalence of stuttering Estimates for New Zealand

overall population 

• 5,200,000 

NZ stuttering incidence (5%) 

• 260,000 

NZ stuttering prevalence (0.7%) 

• 36,400