The effortless flow of speech. Effort determines the differences between stuttering and normal disfluencies.
Abnormally high frequency and/or duration of stoppages in the forward flow of speech.
Core behaviors of stuttering
Repetitions, Prolongations, and Blocks
sound, syllable, whole word, or phrase.
typically on voiced sounds
absence of airflow or sound
Escape happens during disfluency and Avoidance happens before. Verbal-um, like, talking around, you know. Non-verbal-eye-blinking, head nodding, rocking, tapping.
Stuttering is like an iceberg, we only see the tip. Negative self image, bullying, listeners' attitudes.
Stuttering in History
Demonsthenes, Moses. Most all cultures have stuttering but in primarily written cultures talking was not as important so there wasn't a prevalence.
What causes stuttering
genetic basis, neural connections or pathways(PWS' brains are different), age of onset, factors that precipitate onset in a child with a predisposition for stuttering.
Is there a cure
YES! About 80% of kids who begin to stutter spontaneously recover (without treatment)! Children who are borderline stutterers have a 100% chance of being brought back!
2-5 years of age. Not just related to making sounds-spoken language!
Currently: About 1% for school-aged kids, perhaps less than 1% for adults.(Bloodstein, 1995)
At some time: About 5%
Recovery without treatment
Range from 20-80% due to type of study retrospective/longitudinal
Characteristics of kids who recover
o relatives who stutter, or all recovered, earlier age of onset, stronger phonological & language skills, higher nonverbal intelligence, more likely to be girls, right-handed, mothers use slow, age-appropriate language.
3:1 male to female, 3:1 first grade and 5:1 fifth grade-may increase as children get older (Bloodstein.) Girls begin to stutter earlier and recover earlier and more frequently (Yairi)
Variability and Predictability
Anticipation- "can sense when it's coming", Consistency- stuttering on many of the same words when reading the same passage, Adaptation- stuttering occurs less frequently with repeated readings (6) Concluded that stuttering had characteristics of a "learned" behavior.
Spencer Brown Iowa ('35-'45) Adults who stutter mostly do so on longer more complex words whereas children stutter on smaller words since that is what they use more often. PWS have trouble planning and beginning an utterance but it becomes easier towards the end.
Bloodstein (1948, 1950)
Studied 115 conditions under which stuttering is reduced or absent:alone, relaxed, choral speaking, to an animal or infant, rhythmic stimulus, singing, different dialect, while writing, swearing.
Andrews et al (1982)
masking, slow, prolonged speech, DAF, shadowed speech
Explanations of why some fluency-enhancing conditions work
Bloodstein-communicative pressure, Wingate-Modified Vocal Hypothesis, reduced neurophysiological demands of S/M control and language.
stuttering is inherited or congenital, appears when child is learning complex and rapid coordinations of S/L production. At some point a child who doesn't recover learns maladaptive responses to disfluencies. Learning is affected by temperament and awareness.
about 7 disfluencies per 100 words, interjections(um, like, you know), revisions, whole-word and phrase repetitions, 1-2 units per repetition or interjection, children generally unaware only attracts some adult attention, no secondary behaviors. Young children are learning language, S/M control, family stress/events, communicative pressure/excitement.
More than 7 disfluencies per 100 words, more than 50% are "stutter-like", more than 1-2 units, sound and syllable repetitions, prolongations sometimes, loose and relaxed disfluencies. Little if any awareness, rarely express frustration, same underlying factors as normal disfluency except maybe a more hurried lifestyle.
confirmed stutterer, more than 10 disfluencies per 100 words, muscle tension, signs of hurrying, rapid and irregular repetitions, prolongations, pitch rises, first sign of blocks, fixed articulatory postures(tense face, leaning), escape behaviors emerge, aware of disfluency, may express frustration, no strong negative feelings about self as speaker, sensitivity to stress and change, emotion of frustration, tension responses.
blocks w/ sound or voice shut off, repetitions & prolongations, escape behaviors, avoidance(word, situation), fear, embarrassment, shame, conditioned tension responses, more intense fear reaction, avoidance conditioning(negative reinforcement)
longer, tense blocks(often w/ tremor), repetitions & prolongations, complex escape & avoidance behaviors(rapid, habituated), fear, embarrassment, shame, pervasive, negative self-concept, strong conditioned habits, automatic avoidance behaviors, negative perceptions of self & others.
more frequent "normal disfluencies, closer to "stuttered" disfluencies, variety of etiologies: CVA(stroke), TBI, Tumors, Diseases(PD), toxicity.
40% of clutterers also stutter, speech characteristics: excess normal disfluencies, reduced intelligibility, rapid bursts of speech, slurred syllables, omitted syllables, clients are frequently unaware, except when listeners can't understand them, often appears when stuttering improves, stuttering may worsen when reducing rate. Other issues: language, attention, auditory processing, writing and reading deficits, learning disabilities. Etiology: probably neurological, possibly related to the basal ganglia, dopaminergic system(low), onset may be as early as PS years, but not usually diagnosed until interference w/ school performance.
Stuttering often runs in families
Newcastle studies & Yale studies compared family history of CWS & NSC, CWS had far more stuttering relatives, males at higher risk than females, female CWS more likely to have stuttering relatives, but most had been stuttering for several years(didn't get kids at onset)
Ambrose(1993) took family history of CWS recently diagnosed, 2/3 of 69 kids had relatives who stuttered, M&F CWS had similar chances of having stuttering relatives, very young F CWS often recovered; may have had lower "genetic loading"
Ambrose(1997) looked at CWS who recover & those who persist, analyzed family trees of 66 CWS soon after onset, followed for several years, grouped into persistent & recovered, M/F ratio of 7:1 (persistent), 2:1 (recovered), persistence also ran in families, both types transmitted by genes, but persistent stutterers have additional genetic factors that hamper recovery.
Yairi(1996) factors that predict recovery: good scores on tests of phonology, language, and nonverbal skills, family member who recovered, early age of onset.
Identical/Fraternal: all identical genes/25% shared genes, higher "concordance" in identical twins.
Howie(1981) 6/16 pairs were discordant so genes alone did not explain stuttering
Andrews(1990) 3810 unselected twin pairs, 71% of variance was accounted for by genetic factors, 29% by environmental factors, including factors affecting the fetus.
Felsenfeld(2000) found 70% & 30% but no data on chronicity-if kids were chronic stutterers.
Bloodstein(1995) interviewed 13 adopted PWS about stuttering in adoptive families, 4 of 13 reported relatives who stuttered.
Felsenfeld(1997) small sample of adopted CWS, got info about adoptive & biological families, history of suttering in biological families was slightly more predictive of stuttering.
Drayna (NIH) Cameroon Studies found Chromosome 18. Blood samples from family in Cameroon.
Cox & Yairi(2000) Chromosomes 1, 13 & 16
Probably several genetic pathways that lead to stuttering: S/M control, language & learning ability, sensory processing, vulnerable temperament, all in combination w/ environmental factors.
Congenital & Early Childhood Factors
30-60% of PWS have a family hx 40-70% do not
West(1939) 204 PWS, 100 w/o family hx; 85% reported "congenital" factors. Infectious diseases, NS diseases, and injuries just prior to onset of stuttering.
Boehme(1968) 313 w/ brain damage at birth; 245 developed stuttering
Poulos & Webster(1991) 57 of 169 PWS reported no family hx, 37% reported congenital factors, 2.4% of PWS with family hx reported such factors (anoxia at birth, premature birth, childhood surgery, head injury, Mild CP, Mild MR, experiencing intense fear) Rules of 10: 10 weeks old, at least 10 lbs, and 10 grams of hemoglobin)
Developmental Factors: Physical
spurts of motor development, learn to walk OR talk, changes in vocal tract, pharynx: 4cm long in newborns, about 12cm in adults, longer in males, 80% increase in volume from infancy to adulthood, more vertical than horizontal.
Developmental Factors: Cognitive
cognitive deficits>high incidence of stuttering(Van Riper 1982) perception, attention, working memory, "executive functions" Developmentally Disabled people have slower S/L acquisition.
Yairi(1996) 32 CWS, 12 stuttered for 36 months or more, persistent CWS scored lower than NS, but not lower than norm for the test, CWS who recovered did NOT score lower than NS.
Developmental Factors: Social & Emotional
emotional arousal, hurry & excitement, temperament(evidence of a certain temperament in stuttering). emotion- may be etiological in some PWS, may change stuttering in some PWS, stuttering generates negative emotions(anxiety and autonomic arousal, temperament)
Hill(1954) NS showed stuttering when a light associated w/ electric shock flashed(expectation created momentary anxiety)
Autonomic arousal studies both PWS & NS show increase during speaking, but higher arousal w/ more stuttering in PWS, only PWS' speech is vulnerable to breakdown(unless arousal is unusually high)
Temperament sensitive or inhibited temperament, react to novel people & situations w/ increased muscle tension and physiological signs of stress, in CWS, tension may be triggered when child is normally disfluent.
Guitar(2003) greater acoustic startle responses in adult PWS w/ a correlation w/ Nervous subscale
Temperament Survey Studies more sensitive, difficult, restless, impulsive, high frustration reactions, lack of persistence.
Developmental Factors: Speech & Language
onset of stuttering: more complex utterances>stuttering, utt. length may have a greater effect, normal disfluencies emerge when child begins to master a new lang. construction, not yet automatized>fewer resources. From ages 2-3 children's lexicon increases from 50 to >500 words, about 5-7 new words per day, single word utterances, successive single word pairs with sentence-like intonation and durations, multiword sentences, "syllable-timed" prosody> complex prosodic patterns
Delayed & Deviant S/L Development
If PWS have constitutional differences, are other S/L processes affected?
Are delays in S/L development related to appearance of stuttering or disfluency? Depends on age of first word & first sentence, size of receptive vocab, MLU, and expressive and receptive syntax.
Studies w/ PWS & NS show mixed results-some show that CWS have 2 1/2 times incidence of articulation disorders but some show NO differences.
Nippold(1990) no support for hypothesis that CWS are also likely to have lang. or artic. difficulties, but subgroups of CWS who do
Bernstein Ratner(1997) differences b/t CWS and NS are very subtle, more sophisticated tests are needed to look for subgroups of CWS and AWS
Interpretations of findings
kids w/ artic. or lang. deficits start to believe that talking is hard, anticipation of difficulty, hesitation and struggle, then stuttering. Artic., lang., & stuttering>common deficit, passed on genetically, delayed dev. or damage to S/L areas of brain, small differences in how brain processes such functions could tip the balance toward any of these disorders. L.I. kids found to have high frequencies of "stuttered" disfluencies (but were NS), difficulties formulating & executing utterances beyond their language abilities. Other factors that may turn L.I. kids into CWS-vulnerable temperament, environmental pressures, traumatic life event. Artic. & lang. disorders may be related to recovery, CWS w/ phon. or lang. differences> more likely to persist or take longer to treat, seems to be phonological status, rather than exp. lang. status, near onset of stuttering that may predict recovery.
Environmental Factors: Parents
Wendell Johnson(University of Iowa) "Diagnosogenic Theory"-Caused by parents "diagnosing" the child's speech as stuttering.
Mary Tudor "Monster Study"- she could create stuttering "someone is watching you speak" scaring people into stuttering.
Johnson(1959) The Onset of Stuttering, parents of 150 CWS & 150 NS, parents of CWS more "perfectionistic"and had "higher standards of behaviors"-had parents who diagnosed them, "same types of disfluencies" were judged differently by the two groups of parents-Good data but misinterpreted.
McDearmon(1968) re-analyzed Johnson's data and found there were differences in the disfluencies.
Environmental Factors: Speech & Language
Stressful adult speech models-rapid speech rate, complex vocab., complex syntax, bilingual home. Stressful speaking situations for child-competition for speaking, frequent interruptions, demand for display speech, loss of listener attention, hurried when speaking, frequent questions, excited when speaking, many things to say.
Environmental Factors: Life Events
child's family moves, parents separate or divorce, family member dies, family member is hospitalized, parents loses job, baby is born or child is adopted, additional person in house, parent goes away frequently, holidays or visits, change in routine, excitement, anxiety.