Atypical Cerebral Asymmetries and Stuttering

Atypical Cerebral Asymmetries in AWS

• Foundas et al (2001; 2003) researched atypical cerebral asymmetries in AWS
• The text does not state if atypical cerebral asymmetries is a cause or a result of stuttering

Temporal Processing

• Kent (1984) proposed inability to perform precise timing functions due to left hemisphere underdevelopment
• Could lead to issues with processing speech output due to fine motor control
• Kent also suggests emotion may play a role in timing disruption
• Peters and Guitar (1991) found that when individuals who stutter are stressed, there is cross-hemispheric interference

Linguistic Processing

• De Nil (2004) found the basic deficit in stuttering to be in the sensori-motor control of speech.
• High linguistic demands cause speech systems to breakdown more frequently in people who stammer (Kleinow and Smith, 2000)
• Stutterers have limited extra neuronal resources due to their s/m defect (De Nil & Bosshardt, 2001)
• This means stutterers are more likely to require more brain activity to compensate for their stuttering
• Stuttering is more likely when linguistic complexity is increased (Starkweather, 1981)
• Johnson and Rosen (1937) found individuals who stutter exhibit increased speech rate
• Reducing linguistic complexity may decrease stuttering in children.

The Neurotic/Psycho-analytic Explanation of Stuttering

• Stuttering was originally seen as a neurosis, a result of repressed need and symptom of conflict
• The source of conflict was posited to be psycho-sexual (Glauber, 1982)
• The psycho-sexual hypothesis also suggests inadequate interpersonal relationships could lead to stuttering (Barbara, 1965, 1982; Wyatt 1969)
• Proposed reasons for stuttering include gaining attention, sympathy and avoiding responsibilities
• Freud himself did not believe in the effectiveness of a psycho-analytical approach with stuttering

The Diagnosogenic Theory

• Also known as the "stuttering begins with its diagnosis" theory
• This theory proposes that negative reactions from those around children experiencing disfluency can cause the disfluency to become stuttering
• Van Riper (1982), Yairi (1997), and Yairi and Ambrose (1999) found that both stutter-like and normal disfluencies occur at stuttering onset, making this theory invalid

Learning

• Classical conditioning can evoke negative emotional responses (Pavlov's dog)
• This can occur through repeated associations: a neutral stimulus (phone) and another stimulus (dysfluency) that consistently evokes a response (emotional arousal)
• The repeated associations result in the neutral stimulus (phone) evoking the emotional response associated with stuttering, even if stuttering hasn't yet happened.
• The emotional response can actually trigger stuttering.
• This theory has clinical implications: a child may learn that certain speaking situations are challenging
• Unlearning these associations has potential for change in therapy e.g. avoidance reduction therapy, family communication skills

Learning: Operant conditioning

• Skinner (1953) proposed the association between a behaviour and a consequence
• Positive reinforcement increases behaviour, negative reinforcement decreases behaviour
• Operant conditioning suggests disfluency is shaped by the response it elicits, and listeners’ responses to a child’s disfluencies reinforce their occurrences
• In this theory, disfluencies are shaped into greater abnormality with associated struggle and secondary characteristics (avoidance and escape behaviours)
• Operant conditioning is better at explaining how stuttering evolves, not explaining the onset of stuttering.

Multifactorial Dynamic Pathways Theory of Stuttering

• This theory was proposed by Smith and Weber (2017)

Social versus Medical Models of Disability

• Constantino (2018) suggests a social model of disability where impairment is a medical or physical condition and disability is a social condition.
• Within the social model, disability is imposed on top of impairment through discrimination, stigma and prejudice.
• Individuals who stutter are disabled by societal expectations of fluency, discrimination against nonstandard speech, and speaking time constraints.
• The medical model suggests individual who stutters has a deficit in functioning that can be researched, identified, modified, and cured.
• The main difference between the two theories is that the medical model positions the deficit within the individual, while the social model positions the disadvantage within society.

Neurodiversity

• Constantino (2018) proposes that neurodiversity emphasizes natural variation and the unique skills, experiences, and traits of neurodivergent individuals.
• Neurodiversity rejects the medical model’s claim that stuttering is a pathology and the social model’s claim that it is an impairment.
• Rather, there is a mismatch between stuttering and an environment not designed for the individual.

Resources

• StutterTalk Podcast
• Film: When I Stutter
• Play: Unspoken
• Spotify: Vivian Sisskin

Additional Resources

• Campbell, P., Constantino, C.& Simpson, S.(2019).Stammering pride and prejudice: Difference not defect.J&R Press.Constantino, C.(2018).What can stutterers learn from the neurodiversity movement?Seminars in Speech and Language, 39(4).Dr Soo-Eun Chang interview on StutterTalk: https://stuttertalk.com/what-causes-stuttering-with-dr-soo-eun-ch ang-568/ (5.30-8.10) Cluttering: https://www.youtube.com/watch?v=LfXgh3dQH1M Singer, C.et al.(2020).Clinical Characteristics Associated With Stuttering Persistence: A Meta-Analysis.Journal of Speech, Language, and Hearing Research, (63) 2995–3018.