Transcript Etiology
Etiology • Theories – 1. Organic, Constitutional, or Medical – 2. Neurotic – 3. Behavioral or Learned . Organic, Constitutional, or Medical • Theories – – – – – – 1. Cerebral Dominance 2. Biochemical 2. Laryngeal Dynamics 3. Heredity 4. Middle Ear Dysfunction 5. Neurological Functioning 1. Theory of Cerebral Dominance • Theories: Orton and Travis • Fact: more stutterers are left handed • Supporting Research – Moscovitch (1973) asserts that the right hemisphere in righthanded people maintains some limited underlying ‘verbal competence’ – Geschwind limit of this verbal competence ‘depends on the degree to which the dominant hemisphere can control the verbal behavior of the minor hemisphere via midline commissures and other pathways” • Tenant: – defective ‘motor lead control’ or incomplete cerebral dominance 2. Laryngeal Dynamics’ Theory • Theorist: Adams • Stutterers have longer VOT, SIT (speech initiation times) VIT (voice initiation times) • describes characteristics – does not identify causal components of disorder, 3. Biochemical • • • • • • Theorist: West Compared to a mild form of epilepsy term: dsyphemia Current Research: Dopamine Questions? Cause or effect 6. Middle Ear Dysfunction • Theorist: Webster • Non-synchronized middle ear muscle firing which means there are non-synchronized messages to the brain 4. Heredity Model Theory • Theorists: Kidd, Goldberg, Wepman • Facts: stuttering runs in families, 8-15% – 65-70% had stuttering relatives – twinning studies • more stuttering in monozygotic twins, risk 77% • Stuttering is determined by many factors, the factors are both hereditary and environmental and it affects the sexes differently – related to a THRESHOLD MODEL 5. Neurological Functioning • Theorist: Perkins • use of Positron Emission Tomography (PET) scans • there is a neurophysical difference at the moment of stuttering • Current research: role of Prefrontal Cortex • Function: • Question: cause or effect? III. Learning Theories • • • • • 1. Diagnosogenic 2. Two-Factor 3. Approach-Avoidance 4 Capacities/Demands 5. Anticipatory/Struggle 1. Diagnosogenic Theory • Wendell Johnson, 1940’s • Tenants: – a diagnosogenic disorder is one that is caused by its diagnosis • person’s behavior is labeled as ______ and _____ – dysfluency in the ‘ear of the beholder’ – listener (PARENT) reinforced s=through negative reinforcement which parent believes in punishment Diagnosogenic Theory continued • 3 Behaviors that must occur – 1. Child repeats or hesitates while speaking • frequency is not a critical variable – 2.listener ‘diagnoses’ repetitions as abnormal and react accordingly • • • • • “stop and start over thinking for what you are saying before you say it take a deep breath before you start talk more slowly non-verbal response such as looking away – 3. Child becomes concerned and tries not to be dysfluent • attends more to the dysfluencies than previosly and becomes upset when they occur 2. Two Factor Theory • Theorist: Brutten and Shoemaker • Stuttering results from the interaction of genetic and environmental factors • Factor I behaviors result from emotional learning – classically conditioned – modified either though reconditioning or counterconditioning – reconditioning involved returning a conditioned stimulus to its previous neutral status • repeated presentations of the conditioned stimulus without negative consequences • ex: salesperson Factor I Classical Conditioning Cont. – counterconditioning-learning new responses to a conditioned stimulus • repeated presentation of the conditioned stimulus in various negative emotion producing situations in a hierarchy Two Factor Theory: Factor II • Factor II behaviors learned through operant conditioning – instrumental responses operantly conditioned over the years – developed in an attempt to prevent or reduce the severity of stuttering – secondary behaviors – reduced through reinforcement, nonreinforcement or punishment • reinforcement of fluency enhancing behaviors results in elimination 3. Approach-Avoidance Theory • Sheehan • Tenant – conflict arises in which the motivational drives subserving both approach and avoidance are simultaneously aroused – when the APPROACH drive is dominant, fluent speech – when there is Avoidance BUT the speaker speaks, then….. – Origins in learned speech anxieties and/or unconscious personally factors 4. Capacities/Demands Theory • Starkweather • Tenants – capacities for fluent speech-motoric,cognitive, linguistic skills that make speech easy for most children-interact with demands for fluency placed on child by the external communicative environment and by child himself • as capacity for fluency grows, expectations of parent and child also increase • capacities and demands are increasing as a function of age 5. Anticipatory Struggle Hypothesis • Bloodstein • Tenants: • disorder maintained by anticipating stuttering and then struggling to avoid it III Neurotic Theory • 1. Glauber • 2. Bloom • 3. Frustration Theory Neurotic Theory Concepts • Stuttering as a type of neurosis • stutter because they attempt to cope with some type of repressed (unconscious) neurotic need in a way that allows them to be dysfluent • hypotheses look upon stuttering as being both a symptom of an unsatisfied repressed emotional need AND purposeful behavior 1. Neurotic Theory: Glauber • Stuttering behaviors -symbolic of the repressed need • Repressed need for: – infantile need for oral erotic gratification – infantile need for anal erotic gratification • stuttering represents anal movements “displaced upwards” 2. Neurotic Theory: Bloom • Aggressive expression of hostile feelings person is afraid to express openly – stutterer makes those with whom he/she speaks uncomfortable • assumes stuttering is ‘painful’ for the listener Neurotic Theory Thoughts • For many stutterers, stuttering is nonsymptomatic – does not cluster with other problems • Neither stutterers or their parents show no greater evidence of neurotic symptoms than the population Etiology Questions • What is Peters and Guitars’ theory of causality • What is yours? • Which one/s have you discounted • What is “the point” of so many causation theories? End of Lecture Notes The door is open to …..