Exam 2 Flashcards
Genetics and Stuttering
Genotype
Specific genetic constitution in one or several sites.
Genetics and Stuttering
Phenotype
Realization of observable characteristics
Genetics and Stuttering
Penetrance
The likelihood that a person with a specific gene will show that gene’s effects. i. Development of phenotypes is not an all or nothing phenomena.
Genetics and Stuttering
Pleiotropy
Multiple effects of a gene
Genetics and Stuttering
Variable expressivity
Extent or manner of expression (mild to severe across people or time or as different traits across time)
Genetics and Stuttering
Reaction range
Qualitatively and quantitatively different phenotypes that can develop from the same genotype under varying environmental conditions.
- Each genotype has a specific range of phenotypes that can develop
- A phenotype within that range develops because of environmental interactions that occur throughout development
Genetics and Stuttering
Possible relationships of genotypes and phenotypes (3)
- Different genotypes can produce different phenotypes
- Different genotypes can produce phenotypes that are indistinguishable (genetic heterogeneity)
- Same genotypes can produce more than one phenotype, sometimes depending on environmental conditions (pleiotropy and variable expressivity)
Genetics and Stuttering
Realization of a function specified in segments of DNA is dependent on what?
- On metabolic system of cell
- Which is dependent on the whole organism
- Which is dependent on the physical and social environment needed for the organism’s development
- Thus, we cannot say if genetic constitution or environment is more important.
Genetics and Stuttering
Genetic Models in stuttering (3)
- Monogenetic
- Polygenetic
- Mixed
Genetics and Stuttering
Genetic Model: Monogenetic
Single gene is implicated in the transmission of stuttering.
Genetics and Stuttering
Genetic Model: Polygenetic
Cumulative effects of multiple, unrelated genes. Would result in a normal distribution of fluency skills.
Genetics and Stuttering
Genetic Model: Mixed
Both a single gene and the effects of other genes are implicated in transmission.
Genetics and Stuttering
What are the simple genetic transmission patterns? (3)
- Dominant
- Recessive
- Sex-linked recessive
Genetics and Stuttering
Simple genetic transmission patterns: dominant
Presence of one gene in the gene pair causes expression of the trait.
- High incidence form parent to child
- Too low of an incidence among relatives to fit this.
- Example: Huntington’s Chorea
Genetics and Stuttering
Simple genetic transmission patterns: recessive
Effects of one gene are subordinate to the other in the pair. Need both to cause the effects.
- Example: Brown eyes = dominant, blue eyes = recessive
- Trait less often in parents than in affected child’s siblings
- This is not the case with stutterers.
- Near equal incidence for siblings and offspring
Genetics and Stuttering
Simple genetic transmission patterns: sex-linked recessive
Recessive transmission linked to the chromosomes determining gender.
- Rarely transmitted from father to son (e.g., hemophilia)
- High frequency of rather to son transmission in stuttering
Genetics and Stutterin
Do transmission patterns in stuttering fit simple transmission patterns
Patterns of incidence in families of stutterers do not fit these patterns of genetic transmission.
Operant Methodology
Operant
Future occurrences of behavior are a function of its consequences
Operant Methodology
Reinforcement
Reinforcement increases the behavior
- Positive reinforcement - presentation
- Presented after behavior
- Negative reinforcement - withdrawal
- Withheld/removed after behavior
Operant Methodology
Punishment
Punishment after behavior decreases the behavior
- Type 1 - presentation
- Example: person stutters, electric shock is given, stutter decreases
- Type 2 - withdrawal
- Example: person stutters, clinician uses time-out (withdraws the person-to-person interaction), stutter decreases
Operant Methodology
Discriminative stimulus
When its presented, it consistently evokes the behavior
- Police car on freeway makes you start breaking
Operant Methodology
Stimulus control
Presence of stimuli makes occurrence of behavior more likely.
Operant Methodology
Punishment by contingent presentation - ways this was done
Type 1 Punishment
- Electro-shock therapy
- Noise
Operant Methodology
Punishment by contingent presentation - Summarize the results
Presentation of various stimuli can reduce stuttering.
Operant Methodology
Punishment by contingent presentation - Goldiamond, Flanagan, and Azrin (1958)
- Stutterers received loud blasts of white noise contingent on stuttering during oral reading.
- Quickly eliminated stuttering.
- When headphones were removed, stuttering returned.
- Showed that stuttering could be changed by contingent environmental events – therefore considered an operant behavior
- Penalties were supposed to make it worse
Operant Methodology
Punishment by contingent presentation - Cooper, Cady, and Robbins (1970)
- 2 groups of 14 stutterers
- “right, wrong, tree”
- All reduced stuttering
- Replicated in 1978 with 2 groups of 18 children
Operant Methodology
Punishment by contingent withdrawal - ways this is done
Type 2 Punishment
1. Time Out
Response Cost
Operant Methodology
Punishment by contingent withdrawal - Time Out
- Procedure: signaled to stop speaking for 10, 20, or 30 seconds
- Presumed that speaking was reinforcing
- Or was not speaking an aversive stimulus?
- One study asked stutterers about T.O. 6 out of 8 said they saw it as a time to relax. 1 said it was aversive/failure and disapproval. - T.O. has 2 components:
- Interruption of speaking = removal of positive reinforcement
- Imposed silence = presented aversive stimulus
Operant Methodology
Punishment by contingent withdrawal - Response Cost
Subjects were given an amt of points. They lost one for each moment of stuttering
Operant Methodology
Punishment by contingent withdrawal - Summarize the results
- Punishment by withdrawal is reliably affective.
- T.O. is particularly effective.
Operant Methodology
Punishment by contingent withdrawal - Haroldson, Martin, and Starr (1968)
- Using T.O.
- Used red light for 20 seconds every time the person stuttered
- Reduced stuttering by 88%
Operant Methodology
Punishment by contingent withdrawal - Martin, Kuhl, and Haroldson (1972). Note why this study was “controversial.”
- Using T.O.
- 2 children aged 3 and 4 years old
- They got to talk to a beautiful puppet named Suzybelle illuminated in a glass case
- When they stuttered, the light went out and Suzybelle stopped talking for 10 seconds
- Significantly reduced stuttering. Maintained a year later.
- It was thought that “punishment” of stuttering with children would make it worse.
Operant Methodology
Punishment by contingent withdrawal - Halvorson (1971)
Subjects were given an amt of points. They lost one for each moment of stuttering.
Operant Methodology
Reinforcement by contingent presentation - ways this is done
- Reinforcing stuttered speech
2. Reinforcing non-stuttered speech
Operant Methodology
Reinforcement by contingent presentation - reinforcing stuttered speech
- Two studies of children 9-10 and 6-9 showed that reinforcement of stuttering did increase stuttering
- Summary: contradictory evidence, but were the “reinforcers” reinforcing?
Operant Methodology
Reinforcement by contingent presentation - reinforcing non- stuttered speech
- One study of 3 children (from 9-11) showed that reinforcement of 5 seconds, then 10 seconds of non-stuttered speech reduced stuttering in a few sessions.
- It generalized to other settings.
- No previous tx helped
Operant Methodology
Reinforcement by contingent withdrawal - ways this is done
- Loud tone – See Flanagan et al. (1958)
- Continuous shock – See Martin et al. (1975)
- DAF – Goldiamond
Operant Methodology
Reinforcement by contingent withdrawal - summarize the results
Though operant effects shown to increase stuttering, the studies have shown limitations.
Operant Methodology
Reinforcement by contingent withdrawal - Flanagan et al. (1958)
- Provided a 6000Hz 105dB tone ended for 5 sec. after each stuttering
- Increased stuttering by 30% in all subjects
- Reversed when treatment ended
Operant Methodology
Reinforcement by contingent withdrawal - Goldiamond in two studies (1962; 1965)
- Shut off DAF for 10 sec. after stuttering
- Increased stuttering by 37% for one and a small increase for the second
- This study showed extended DAF produced slow prolonged speech
Operant Methodology
Reinforcement by contingent withdrawal - what is stimulus control?
Presence of stimuli makes occurrence of behavior more likely.
Operant Methodology
Reinforcement by contingent withdrawal - what was learned in Martin and Siegel (1966)?
Showed nylon strap or blue light associated with punishment reduced stuttering alone.
Operant Methodology
Reinforcement by contingent withdrawal - summarize research as a whole
- These studies do not deal with operant conditioning as a factor in the onset of stuttering.
- These studies deal with the nature of stuttering instead of its cause. - If stuttering itself has operant properties, it doesn’t mean its origin is operant.
- Most of the time, stuttering acts like operant behavior.
- When it doesn’t, there were often problems with the research design.
- We don’t know the maintaining environmental variables for stuttering.
Neurological Perspectives
Summarize study by R.K. Jones (1966)
- Wada Test used to determine dominance before surgery to treat epilepsy.
- Injection of sodium amytal into carotid arteries. - When it reaches cerebral hemispheres it blocks activity.
- Patient talks. If pt stops talking, the language dominant hemisphere is found.
Neurological Perspectives
What is the Dichotic Word Test?
Dichotic Word Test: audiology test
- Shows if right ear dominant, then person is language dominant in the left hemisphere
Neurological Perspectives
Dichotic Word Test - how it’s used in stuttering research
- Curry and Gregory studies
- Other studies showed right or weak dominance, others showed no difference
- Visual field tests (corresponding to dichotic listening)
Neurological Perspectives
Is there a consistent trend for PWS not to be left hemisphere dominant for language?
Evidence of hemispheric asymmetry for language is inconsistent.
Neurological Perspectives
Is the anatomical structure of the brain in PWS different than nonPWS
NO. Research does not support it.
Neurological Perspectives
Do PWS have brain lesions?
No.
Neurological Perspectives
Is the physiology or functioning of the brain consistently different between PWS and nonPWS?
Yes. There are differences in the motor speech control areas for PWS and nonPWS.
Neurological Perspectives
For studies that did show differences between physiology and functioning, what were the major areas of the brain in which differences were seen?
There were abnormalities in the motor speech control areas, specifically abnormal blood flow patterns to the motor speech areas, as well as hypo-activity in the Broca’s and Wernicke’s area that went away during choral reading, as opposed to solo reading.
Neurological Perspectives
Would differences in brain functioning (versus anatomical structures) prove a neurological cause of stuttering? Why or why not?
- No. It is inconsistent.
- Several studies show some anomalies of brain function (physiology) – though not consistently and not in the best study to date.
- In studies that do show anomalies these are in language and speech processing areas of the brain.
