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Theories of Etiology
Theories: "Moment of Stuttering"
Hereditary Studies
Brain
Language
100
Cerebral Dominance
  • idea that a person with stuttering lacks a dominant hemisphere for speech and language.
  • Lack of cerebral dominance leads to disruption in control of speech structures, which leads to motor disorganization and stuttering.
100

Breakdown Hypothesis

  • Idea that stuttering occurs when there is a momentary breakdown in complicated coordination of multiple systems involved in speech production (a physical breakdown way of thinking about stuttering)
100

Twin Studies

Examine concordance of stuttering among twins

Greater concordance (sharing stuttering) among identical twins than fraternal twins.

100

Motor Speech

reduced gray matter in Brocas area

100

Delay

  • Children who stutter are 2-3 times more likely to display dissociations in speech and language development compared to their typically fluent peers. (Language really good and speech is not, or vice versa)
200

Diagnosogenic Theory

  • Idea that the amount and type of disfluencies in young children is indistinguishable in CWS compared to CWNS, until they are “diagnosis.”
200
Repressed Need Hypothesis

Stuttering is a neurotic symptom of unconscious needs

200

Family Studies

examine family trees to investigate the frequency and pattern of the occurrence of stuttering between relatives.

200

Auditory Perception

reduced bilateral temporal lobe areas

200

Development

  • Stuttering onset typically occurs during bursts of language development
  • Because children with predispositions to stutter have reduced sensorimotor control, bursts of language development can stress an already vulnerable system and contribute to the emergence of stuttering.
300

Communicative Failure/Anticipatory Struggle

  • Idea that stuttering develops from a child’s continued frustration and failure when trying to speak. This failure due to: delays/disorders in speech/lang; emotionally traumatic events when trying to speak; normal disfluencies are criticized by listeners.
  • Communicative failure cannot cause stuttering but may influence the frequency of stuttering.
300

Anticipatory Struggle Hypothesis

Idea that stuttering occurs when PWS interfere with the way they are talking because of their belief that speaking is difficult. (anticipation of stuttering leads to stuttering)

300

Adoption Studies

examine occurrence and development of stuttering in siblings who were adopted soon after birth and placed in different families.

300

White Matter Tracts

less dense in L hemisphere and more dense in R hemisphere

300

Complexity

  • Stuttering varies with language complexity
  • PWS are more likely to stutter…
  • On long and linguistically complex words and utterances
  • On grammatical words in childhood, but content words in adulthood
  • On words at the beginning of an utterance
400

Demands and Capacities Model

  • Idea that typical disfluencies and stuttering emerge when the child’s capacities for producing fluent speech are not equal to the demands on the child for fluent speech.
400

Role-Conflict Theory

  • Idea that when people who stutter use false-role behaviors, they are more likely to experience role-conflict and, in turn, stutter more.
  • people who stutter occupy separate and incompatible roles of being both a person who stutters and a person who can speak fluently.
400

Genetic Study 1

  • Genome Wide Association Study
  • Compares chromosomes among unrelated groups of people
400

Brain Laterality

Overactivation in the right hemisphere may be a cause of stuttering (present before the onset of stuttering) or a compensation for low activation in the left hemisphere (develops after the onset of stuttering).

500

Multifactorial Model

  • Stuttering results from the complex interaction of a # of risk factors; not likely to be triggered by one stimulus, but by several.
500

Genetic Study 2

  • Genetic Linkage Studies
  • Compares chromosomes between family members with and without specific traits.
  • ***Stuttering is polygenetic (MANY GENES)
500

Myelination

  • Speculated to result in reduced speech-motor coordination.
  • Could make speech motor coordination vulnerable to “cross talk” or interference from other domains of the brain. (eg, emotion/language)