copyright 2010 delmar, a part of cengage learning. all rights reserved. 1 an historical perspective...

1Copyright 2010 Delmar, a part of Cengage Learning. ALL RIGHTS RESERVED.

An Historical Perspective of An Historical Perspective of EtiologiesEtiologies

CHAPTERCHAPTER 33


• Scientists often strive for special status by Scientists often strive for special status by claiming a unique form of “objectivity” inherent in claiming a unique form of “objectivity” inherent in a supposedly universal procedure called a supposedly universal procedure called thethe scientific method. . . . This image may be scientific method. . . . This image may be beguiling, but the claim is chimerical, and beguiling, but the claim is chimerical, and ultimately haughty and divisive. For the myth of ultimately haughty and divisive. For the myth of pure perception raises scientists to a pinnacle pure perception raises scientists to a pinnacle above all other struggling intellectuals, who must above all other struggling intellectuals, who must remain mired in constraints of culture and psyche. remain mired in constraints of culture and psyche. (p. 148) (p. 148)

Stephen Jay Gould (1995)Stephen Jay Gould (1995)


• Slavish adherence to a theoretical protocol and maniacal Slavish adherence to a theoretical protocol and maniacal promotion of a single theoretical approach are utterly in promotion of a single theoretical approach are utterly in opposition to science. (p. 217) opposition to science. (p. 217)

Bruce Wampold (2001)Bruce Wampold (2001)

• . . . no model or theory will get it right all the time, and in . . . no model or theory will get it right all the time, and in practice, often a single theory (approach) explains only a practice, often a single theory (approach) explains only a small amount of the variance in targeted behaviors.” small amount of the variance in targeted behaviors.” (p.66) (p.66)

Jill Cockburn (2004)Jill Cockburn (2004)


An historical perspective of An historical perspective of etiologies . . . and theetiologies . . . and the ZEITGEISTZEITGEIST

• ““Learning theory seems to suggest that man is Learning theory seems to suggest that man is basically a ping-pong ball with a memory.”basically a ping-pong ball with a memory.”

• Models of information theory (breakdown Models of information theory (breakdown theories) suggest that humans are “basically a theories) suggest that humans are “basically a digital computer constructed by someone who digital computer constructed by someone who had run out of insulating tape.” (1966, p. 22)had run out of insulating tape.” (1966, p. 22)


An historical perspective of An historical perspective of etiologies . . . and theetiologies . . . and the ZEITGEIST ZEITGEIST

(continued)(continued)

• ““Psychoanalytic theories seem to suggest that Psychoanalytic theories seem to suggest that man is basically a battlefield. He is in a dark man is basically a battlefield. He is in a dark cellar in which a well-bred spinster lady and a cellar in which a well-bred spinster lady and a sex-crazed monkey are forever engaged in sex-crazed monkey are forever engaged in mortal combat, the struggle being refereed by a mortal combat, the struggle being refereed by a rather nervous bank clerk.” (1966, p. 21)rather nervous bank clerk.” (1966, p. 21)

Don Don BannisterBannister


So why bother with old (or new) So why bother with old (or new) theories?theories?

• Will need an answer (nature v. nurture)Will need an answer (nature v. nurture)• Beware of authoritative answers Beware of authoritative answers

• (Ed Conture’s comments, 1990, 2001)(Ed Conture’s comments, 1990, 2001)

• Stuttering across time and culturesStuttering across time and cultures• Your perspective will make a difference to your Your perspective will make a difference to your

clientclient• Stereotypes usually negativeStereotypes usually negative

• Anchoring in experience of the fluent speakerAnchoring in experience of the fluent speaker• Acknowledgement may assist the listenerAcknowledgement may assist the listener


Table 3-1Table 3-1 Types of theories explaining the onset and Types of theories explaining the onset and development of stuttering described in the following development of stuttering described in the following

sections.sections.

PhysiologicalPhysiological Cerebral AsymmetryCerebral Asymmetry

Temporal ProcessingTemporal Processing

Linguistic ProcessingLinguistic Processing

Cybernetic DysfunctionCybernetic Dysfunction

Genetic FactorsGenetic Factors

Modified VocalizationModified Vocalization

PsychologicalPsychological PsychosexualPsychosexual

Repressed NeedRepressed Need


Table 3-1Table 3-1 Types of theories explaining the onset and Types of theories explaining the onset and development of stuttering described in the following development of stuttering described in the following

sections. (continued)sections. (continued)

LearningLearning DiagnosogenicDiagnosogenic

Anticipatory StruggleAnticipatory Struggle

Classical and Operant ConditioningClassical and Operant Conditioning

MultifactorialMultifactorial Multifactorial-Dynamic ModelMultifactorial-Dynamic Model

Demands and Capacities ModelDemands and Capacities Model


Emotional/psychological viewsEmotional/psychological views

Freudian, neo-FreudianFreudian, neo-Freudian• Repressed-need hypothesis—stuttering as a Repressed-need hypothesis—stuttering as a

symptomsymptom• The issue is the source/level of the “conflict”The issue is the source/level of the “conflict”• Travis, Freund, Glauber, Travis, etc.Travis, Freund, Glauber, Travis, etc.

Empirical Evidence:Empirical Evidence:• Little empirical supportLittle empirical support——Adams 1993; Yairi 1997Adams 1993; Yairi 1997


Emotional/psychological views Emotional/psychological views (continued)(continued)

Empirical Evidence (continued):Empirical Evidence (continued):

• The best research has failed to show that people The best research has failed to show that people who stutter, as a group, are more neurotic or have who stutter, as a group, are more neurotic or have more other psychological disorders than those who more other psychological disorders than those who do not stutter. We do not think that your child do not stutter. We do not think that your child began stuttering because of any serious emotional began stuttering because of any serious emotional difficulties. (Yairi & Ambrose, 2005, p. 387)difficulties. (Yairi & Ambrose, 2005, p. 387)


Learning theoryLearning theory

The Diagnsogenic/Semantogenic theoryThe Diagnsogenic/Semantogenic theory

The diagnosis of stuttering—that is, the The diagnosis of stuttering—that is, the decision made by someone that a child is decision made by someone that a child is beginning to stutter—is one of the causes of the beginning to stutter—is one of the causes of the stuttering problem, and apparently one of the stuttering problem, and apparently one of the most potent causes. Having labeled the child’s most potent causes. Having labeled the child’s hesitations and repetitions as “stuttering,” the hesitations and repetitions as “stuttering,” the listener—somewhat more often the mother than listener—somewhat more often the mother than the father—reacts to them as if they were all the father—reacts to them as if they were all that the label implies. (Johnson, 1962, p. 2)that the label implies. (Johnson, 1962, p. 2)


Learning theory (continued)Learning theory (continued)

Empirical EvidenceEmpirical Evidence

• Many studies showing that earliest stuttering far from Many studies showing that earliest stuttering far from normal in both quantity and qualitynormal in both quantity and quality

• The “Monster” studyThe “Monster” study


Behavioral theoriesBehavioral theories

• Classical (respondent) & operant (instrumental) Classical (respondent) & operant (instrumental) conditioning of behaviorconditioning of behavior

• Classical models provide better account of Classical models provide better account of onsetonset

• Operant models offer better account of Operant models offer better account of developmentdevelopment

• Two-Factory Theory—Brutten & Shoemaker Two-Factory Theory—Brutten & Shoemaker (1967)(1967)


Behavioral theories (continued)Behavioral theories (continued)

• Empirical EvidenceEmpirical Evidence• Inconsistent results in the laboratory and Inconsistent results in the laboratory and

especially in daily environment (Siegel, 1970)especially in daily environment (Siegel, 1970)• Little explanation of reasons for increases or Little explanation of reasons for increases or

decreases in fluencydecreases in fluency• Contingent responses most likely highlight or Contingent responses most likely highlight or

distract, thereby decreasing stutteringdistract, thereby decreasing stuttering


Early reports of cerebral asymmetry Early reports of cerebral asymmetry

• Orton & Travis in 1920s–30s; handedness etc.Orton & Travis in 1920s–30s; handedness etc.• Less left-hemi dominance for speechLess left-hemi dominance for speech

Wada test, dichotic listening studies, & decreased REA for verbal Wada test, dichotic listening studies, & decreased REA for verbal stimulistimuli

• EEG studies & ERPsEEG studies & ERPs• Suppression of neural activity in cortex (right hemi for PWS)Suppression of neural activity in cortex (right hemi for PWS)

• Neuroimaging of cortical & subcortical areasNeuroimaging of cortical & subcortical areas• Structural: CAT/CT, MRI; X-ray & magnetic propertiesStructural: CAT/CT, MRI; X-ray & magnetic properties• Functional: RCBF, PET, SPECT, fMRIFunctional: RCBF, PET, SPECT, fMRI


Structural differencesStructural differencesPWS – NFSPWS – NFS

• Both right and left planum temporal larger in PWSBoth right and left planum temporal larger in PWS• Left asymmetry seen in NFS not presentLeft asymmetry seen in NFS not present

• Asymmetry for > volume of white (transmission) matter in left Asymmetry for > volume of white (transmission) matter in left hemi for NFS while PWS have more white matter in right hemi for NFS while PWS have more white matter in right hemi.hemi.

• More activity in right frontal operculum (RFO) (BA45) of PWSMore activity in right frontal operculum (RFO) (BA45) of PWS——possible possible compensationcompensation in this area—rt homologue of in this area—rt homologue of Broca’s areaBroca’s area

• Several studies suggesting change to left-hemi activity with Several studies suggesting change to left-hemi activity with fluency enhancing activities and successful treatment—a fluency enhancing activities and successful treatment—a reorganization of neural functioning.reorganization of neural functioning.


Structural differences Structural differences PWS – NFS (continued) PWS – NFS (continued)

• A loss, reversal, or reduction of asymmetry between A loss, reversal, or reduction of asymmetry between cerebral areas,cerebral areas,

• Aberrant features of white matter tract connectivity and Aberrant features of white matter tract connectivity and tract size, and tract size, and

• Abnormal patterns of perisylvian cortical folding Abnormal patterns of perisylvian cortical folding including aberrant sulcal patterns and increased including aberrant sulcal patterns and increased gyrification. gyrification.

(Ingham et al. 2007; p. 63)(Ingham et al. 2007; p. 63)


Functional differences Functional differences PWS PWS –– NFS NFS

• In comparison to fluent speakers, individuals In comparison to fluent speakers, individuals who stutter show overactivation, especially in who stutter show overactivation, especially in the right anterior insula (BA 13) as well as the the right anterior insula (BA 13) as well as the cerebellar vermins and frontal eye fields (BA 8) cerebellar vermins and frontal eye fields (BA 8)

• Anomalous right-dominant lateralization of the Anomalous right-dominant lateralization of the above areas above areas

• Additional motor and nonmotor areas of Additional motor and nonmotor areas of activation not seen in the fluent speakersactivation not seen in the fluent speakers


Functional differences Functional differences PWS – NFS (continued)PWS – NFS (continued)

• An absence of auditory activations bilaterally (BA An absence of auditory activations bilaterally (BA 21/22)21/22)

• A small level of left basal ganglia activation was A small level of left basal ganglia activation was noted in the fluent speakers (mostly in the noted in the fluent speakers (mostly in the putamen) but was not observed in those who putamen) but was not observed in those who stutteredstuttered

(Ingham et al., 2007; pp. 59(Ingham et al., 2007; pp. 59––60)60)


Dual pre-motor systems hypothesis Dual pre-motor systems hypothesis (P. Alm, 2004, 2005)(P. Alm, 2004, 2005)

• The basal ganglia are subcortical structures in the The basal ganglia are subcortical structures in the center of the brain and receive input from many center of the brain and receive input from many areas of the cerebral cortex and the limbic systemareas of the cerebral cortex and the limbic system

• The basal ganglia play a key role for the The basal ganglia play a key role for the automatization of fast motor sequences; provide automatization of fast motor sequences; provide timing cues to (SMA) for many activities, including timing cues to (SMA) for many activities, including speechspeech


Dual pre-motor systems hypothesis Dual pre-motor systems hypothesis (P. Alm, 2004, 2005) (continued) (P. Alm, 2004, 2005) (continued)

• Two premotor pathwaysTwo premotor pathways——a direct, medial a direct, medial pathway that includes the pathway that includes the basal gangliabasal ganglia, limbic , limbic system,system, and the SMA and a lateral, indirect and the SMA and a lateral, indirect pathway including the lateral premotor cortex pathway including the lateral premotor cortex and the cerebellumand the cerebellum


Dual pre-motor systems hypothesis Dual pre-motor systems hypothesis (P. Alm, 2004, 2005) (P. Alm, 2004, 2005) (continued) (continued)

• The two pathways have different dopamine The two pathways have different dopamine receptors, with the receptors, with the medialmedial system more system more impaired due to changes in dopamine & impaired due to changes in dopamine & greater emotional response via the limbic greater emotional response via the limbic system system

• A peak in dopamine receptors occurs in the A peak in dopamine receptors occurs in the basal ganglia at age 2.5 to 3.0 years. It has basal ganglia at age 2.5 to 3.0 years. It has also been suggested that the receptors are also been suggested that the receptors are different in boys.different in boys.


Dual pre-motor systems hypothesis Dual pre-motor systems hypothesis (P. Alm, 2004, 2005) (continued)(P. Alm, 2004, 2005) (continued)

• Stuttering occurs when structural or functional Stuttering occurs when structural or functional anomalies impair the anomalies impair the medialmedial system system

• Fluency-inducing conditions shift speech motor Fluency-inducing conditions shift speech motor timing to the timing to the laterallateral system, bypassing the system, bypassing the instability of the medial system.instability of the medial system.


The covert repair hypothesis The covert repair hypothesis (CRH) (CRH) (Kolk & Postma, 1997)(Kolk & Postma, 1997)

• Via internal monitoring, speakers detect errors in Via internal monitoring, speakers detect errors in phonological encoding prior to the implementation phonological encoding prior to the implementation of articulatory commandsof articulatory commands

• Planning of the Planning of the phoneticphonetic sequence is interrupted sequence is interrupted and the correct plan is reinitiated resulting in a and the correct plan is reinitiated resulting in a disfluency (for all speakers)disfluency (for all speakers)

• It is suggested that PWS possess an abnormally It is suggested that PWS possess an abnormally slow rate of phonological encodingslow rate of phonological encoding requiring more requiring more time to activate a target, resulting in a greater time to activate a target, resulting in a greater chance of errorchance of error


The covert repair hypothesis The covert repair hypothesis (CRH) (CRH) (Kolk & Postma, 1997) (Kolk & Postma, 1997)


• Detection/repair Detection/repair combined inability to select combined inability to select correct phonological target results in the correct phonological target results in the manifestation of stuttering behaviormanifestation of stuttering behavior

• Some support from several studies including Some support from several studies including Brocklehurst (2008) who found that CWS have Brocklehurst (2008) who found that CWS have difficulty organizing lexical informationdifficulty organizing lexical information


The EXPLAN modelThe EXPLAN model(Howell & Au-Yeung, 2002; Howell, 2004)(Howell & Au-Yeung, 2002; Howell, 2004)

• Elaborates the CRH with Elaborates the CRH with separateseparate linguistic and linguistic and motor systemsmotor systems

• System not linked to internal or external System not linked to internal or external monitoringmonitoring

• Internal cognitive-linguistic system that covertly Internal cognitive-linguistic system that covertly plans (PLAN) the syntactic, lexical, phonetic plans (PLAN) the syntactic, lexical, phonetic features in serial orderfeatures in serial order

• Motor process organizes and executes (EX) the Motor process organizes and executes (EX) the outputoutput


The EXPLAN modelThe EXPLAN model(Howell & Au-Yeung, 2002; Howell, 2004) (Howell & Au-Yeung, 2002; Howell, 2004)


• When linguistic system experiences When linguistic system experiences difficulty difficulty generating linguistic sequencegenerating linguistic sequence the motor system is the motor system is unable to execute fluent speechunable to execute fluent speech

• PWS have difficulties with PWS have difficulties with motor timingmotor timing, especially , especially with with increased linguistic complexityincreased linguistic complexity (some support (some support from studies of motor and syntactical abilities & from studies of motor and syntactical abilities & structural/functional neuroimaging studies)structural/functional neuroimaging studies)


Feedback modelsFeedback models((Fairbanks, 1954; Mysak, 1960)Fairbanks, 1954; Mysak, 1960)

• Cybernetic & servosystem models of Cybernetic & servosystem models of mechanical and biological systems in the 1950s mechanical and biological systems in the 1950s (e.g., Fairbanks, 1954; Mysak, 1960)(e.g., Fairbanks, 1954; Mysak, 1960)

• Interrupted/distorted feedback prevents Interrupted/distorted feedback prevents reduction of error signal to zeroreduction of error signal to zero


Feedback modelsFeedback models(Fairbanks, 1954; Mysak, 1960) (Fairbanks, 1954; Mysak, 1960)


• Many studies of delayed auditory feedback (DAF) Many studies of delayed auditory feedback (DAF)

• (Black, 1951; Lee, 1951; Neeley, 1961; Yates, (Black, 1951; Lee, 1951; Neeley, 1961; Yates, 1963) 1963)

• Few theoretical implications but some clinical Few theoretical implications but some clinical utilityutility


Evidence from the human genomeEvidence from the human genome

• The human genome is arranged into 24 distinct The human genome is arranged into 24 distinct chromosomeschromosomes

• 46 chromosomes with 22 pairs of autosomes and 46 chromosomes with 22 pairs of autosomes and 2 chromosomes that determine sex2 chromosomes that determine sex• Females are XX and males are XYFemales are XX and males are XY

• Each chromosome contains many Each chromosome contains many genesgenes, each , each with specific base sequences that encode with specific base sequences that encode instructions for making instructions for making proteinsproteins


Evidence from the human genome Evidence from the human genome (continued)(continued)

• The human genome is estimated to have The human genome is estimated to have 20,000 20,000 –– 30,000 genes 30,000 genes

• GenotypeGenotype is determined by the basic DNA of is determined by the basic DNA of an organism and an organism and phenotypephenotype provides the provides the outward nature of the organismoutward nature of the organism

• MonozygoticMonozygotic (MZ) One fertilized egg that (MZ) One fertilized egg that develops into two embryos. develops into two embryos. DizygoticDizygotic (DZ) two (DZ) two fertilized eggs that develop separately from two fertilized eggs that develop separately from two zygotes into two embryos into two embryos.zygotes into two embryos into two embryos.



• ConcordanceConcordance is the occurrence of a trait (e.g., is the occurrence of a trait (e.g., stuttering) in both members of a pair of twins. stuttering) in both members of a pair of twins. When this is not the case, the twins are said to be When this is not the case, the twins are said to be discordant. discordant.

• Stuttering follows familial patterns (Kidd et. al., Stuttering follows familial patterns (Kidd et. al., 1970s)1970s)

• Females who stuttered were likely to have a parent Females who stuttered were likely to have a parent who stuttered 19% of the time; males 67% of the who stuttered 19% of the time; males 67% of the time (Ambrose & Cox, 1997).time (Ambrose & Cox, 1997).


Evidence from the human Evidence from the human genome (continued)genome (continued)

• Felsenfeld et al. (2000): 91 twins where one or Felsenfeld et al. (2000): 91 twins where one or both stutteredboth stuttered• MZ concordant 45% ; DZ concordant 15%MZ concordant 45% ; DZ concordant 15%• 70% of variance for stuttering genetic; 30% 70% of variance for stuttering genetic; 30%

environmentalenvironmental

• Dworznski et al. (2007): longitudinal study of boys Dworznski et al. (2007): longitudinal study of boys & girls, age 2& girls, age 2––7; genetic and environmental 7; genetic and environmental influence for onset and recovery at rates similar to influence for onset and recovery at rates similar to FelsenfeldFelsenfeld



• Yairi & Ambrose (2005): strong family history best Yairi & Ambrose (2005): strong family history best predictor of persistence and recoverypredictor of persistence and recovery

• Marginally significant linkages and relatively low Marginally significant linkages and relatively low LOD scores to dateLOD scores to date• A desirable threshold for LOD scores is 3.0 A desirable threshold for LOD scores is 3.0

(indicating odds of 1,000 to 1)(indicating odds of 1,000 to 1)



• Shugart et al. (2004): chromosome 18 (LOD 1.5), Shugart et al. (2004): chromosome 18 (LOD 1.5), (68 families 226 probands of European ancestry)(68 families 226 probands of European ancestry)

• Riaz et al. (2005): chromosomes 1q (LOD 4.61) and Riaz et al. (2005): chromosomes 1q (LOD 4.61) and 12q (LOD, (46 highly inbred Pakistani families) 12q (LOD, (46 highly inbred Pakistani families)

• Viswanath et al. (2004): statistical modeling Viswanath et al. (2004): statistical modeling indicated a significant autosomal major gene indicated a significant autosomal major gene interacting with gender and affection status of the interacting with gender and affection status of the parentsparents



• Suresh et al. (2006): females ch 21 (LOD 4.5), Suresh et al. (2006): females ch 21 (LOD 4.5), males ch 7 (LOD 2.99), ch 7 also linked to males ch 7 (LOD 2.99), ch 7 also linked to specific language impairment and autismspecific language impairment and autism


Current (multifactorial) viewsCurrent (multifactorial) views

• Demands & CapacitiesDemands & Capacities

(Starkweather & Gottwald, 1990)(Starkweather & Gottwald, 1990)

• A Neurophysiological ModelA Neurophysiological Model

(De Nil, 1999)(De Nil, 1999)

• A Multifactorial-Dynamic Model A Multifactorial-Dynamic Model

(Smith 1990, 1999; Smith & Kelly, 1997)(Smith 1990, 1999; Smith & Kelly, 1997)


Demands & capacities Demands & capacities (Starkweather & Gottwald, 1990)(Starkweather & Gottwald, 1990)

• Demands:Demands: both environmental and internalboth environmental and internal

• Capacities:Capacities: • MotoricMotoric:: The ability to initiate and control coarticulatory The ability to initiate and control coarticulatory

movements smoothly, rapidly, and with minimal effortmovements smoothly, rapidly, and with minimal effort• LinguisticLinguistic:: The ability to formulate sentencesThe ability to formulate sentences• SocioemotionalSocioemotional:: The ability to produce smooth movements The ability to produce smooth movements

when under communicative or emotional stress)when under communicative or emotional stress)• CognitiveCognitive:: The ability to use metalinguistic skills.The ability to use metalinguistic skills.

Refer to Figure 3-2 for the Stuttering Diagnostic Space Refer to Figure 3-2 for the Stuttering Diagnostic Space

copyright 2010 delmar, a part of cengage learning. all rights reserved. 1 an historical perspective...

Documents

cengage learning

zeitgeist learning theory

single theory approach

single theoretical approach

theoretical protocol

maniacal promotion

wellbred spinster lady

universal procedure