[SLP10415] Constitutional Factors in Stuttering

Constitutional Factors

Basic physiological tendency believed to contribute to personality, temperament, and etiology of specific mental and physical disorders

Hereditary Factors, Congenital & Early Childhood Factors, Brain Structure and Background

Factors under Biological background

Hereditary Factors according to Gregor Mendel

• Each parent in a breeding pair has equal contribution to the genetic makeup of the offspring — their children will inherit some traits of the parents

• concept of dominant and recessive traits

Hereditary Factors according to Charles Darwin

Trait have been passed down but variations in these characteristics express themselves slightly differently in each person

do not work alone

For a number of inherited disorders, genes _ ____ _____ _____

Family studies, twin studies, adoption studies

3 Approaches to the study of heredity

Persistent Stuttering

stuttering that lasts for years after the onset or beyond the age of natural recovery

Genetic predisposition

there is an increased chance or likelihood that a person will develop a disease based on the genetic makeup

Males

Who tend to be at more risk to develop persistent stuttering?

Females

Who tend to recover from stuttering more easily?

Concordance

If one twin has a condition, the other twin also has the condition

Identical Twins (Monozygotic twins)

Have 100% of identical genes

Fraternal Twins (Dizygotic twins)

Only 25% of identical genes

Identical twins

Shows more concordance and have a higher probability that both twins have stuttering

Discordance

If one twin has a condition, the other twin does not have the condition

Environment

____ must interact with the genes to produce the behavior in question

Genetics: Higher

A _____ stuttering among biological relatives than adoptive family members

Heredity

Heredity and environment play a role in the occurrence of stuttering, but ____ plays a slightly stronger role

Genes

Segments of DNA that determine various individual traits

chromosome 1, 7, 9, 12, 13, 15, 16, and 18

Chromosomes of genes found with stuttering (8)

Motor control and emotional regulation

A characteristic/genetic mutation of one of these chromosomes

Chromosome 9

Chromosome associated with persisted AND recovered stuttering

Chromosome 15

Chromosome associaed with persistent stuttering

Chromosome 12

Studies in very different cultural groups have identified this chromosome to be significantly related to stuttering

DNA

Contains the “instruction book” that tells the body how to make various chemicals that determines characteristics

Congenital & Early Childhood Factors

Not all stuttering conditions can be explained by hereditary some are explained through congenital and early childhood factors 

Congenital Factors

A physical or psychological trauma that occurs at or near birth that may predispose an individual to develop stuttering

Predisposition

A susceptibility of a person to develop a condition

30%-40%

PWS who have family histories of stuttering

History of infectious diseases, anoxia at birth, childhood surgery, head injury, mild cerebral palsy, mild retardation, and intense fear

Studies revealed several factors prior to the onset of stuttering

Brain injuries; greater

Studies of young adults who had ____ _______ had ______ incidence of stuttering

Brain Structure and Function

Central nervous systems would be different or “anomalous” for those who stutter

Motor Cortex, Broca’s Area, Left Auditory association area, Wernicke’s area, Right Frontal Operculum, Right Insula

Areas of the brain involved in speech and language processing (6)

Sensory, planning, and motor areas

Density of speech and language areas studied revealed that ____, ______, and ______ ____ developed differently as opposed to non-stuttering individuals

White Matter Tracts

Responsible for conveying information from sensory centers of the brain

Right hemisphere; denser

The white matter tracts in the _____ _______ of a PWS will be ______

Reduced gray matter volume; Broca’s area, Bilateral temporal lobe areas

Both recovered and persistent stutterers had ______ ____ _____ _____ around the _____ ____ and bilateral _____ _______.

Less dense white matter tracts

PWS whose stutter persisted showed ____ _____ ____ _______ ____ connecting phonological representations of sounds to speech motor execution areas

Left hemisphere Fiber tracts

The difference between PWS and non-PWS are the ____ ________ _____ ____ that communicate between the inferior parietal cortex (sensory integration) with the ventral frontal cortex

inferior parietal cortex

sensory integration

ventral frontal cortex

motor planning

Broca’s area

Area of the brain of PWS where the cranial nerve fibers aren’t structured as effectively to conduct impulses as fast

left superior longitudinal fasciculus (SLF)

a critical pathway connecting auditory and motor areas for speech or the area responsible for providing sensory-motor integration for speech

decreased white matter integrity

PWS often show ____ _____ _____ ____ in the left superior longitudinal fasciculus (SLF)

Right hemisphere ; left hemisphere

PWS have greater activity in the ___ ______ than in their ____ _______ during fluent and stuttered spech

Left hemisphere structures

Neuroimaging studies showed a great deal of underactivation of __ _______ _______ typically active for speech, such as white matter tracts, in PWS

Statistical parametric mapping

Quantitative neuroimaging method for analyzing functional and structural brain data to identify differences in brain activity or tissue

Right hemisphere

There is a greater activity / overactivation on the ___ ____ of the brain whenever they read aloud in PWS

MRI and PET scans

Neuroimaging methods to reveal structural and functional brain differences

Left operculum

A key motor area for integrating planning and speech execution

motor planning; speech execution

For PWS, there ae usually anomalies observed in the areas involved in ___ ____ and ____ _____

Sensory Processing

Activity of the brain that interprets information coming from the senses, such as sounds arriving via the ears and the auditory nerves

Sensory-Motor Control

• All movement is carried out with sensory information used before, during, and after to improve the precision of movement

• has something to do sensory integration and being able to produce the necessary coordination and voluntary action of the muscles whenever our senses perceive sensory information

Disturbance of feedback

PWS abnormal speech as the result of ________ _ _____ in sensory processing

Proprioceptive and tactile feedback

Feedback that normal speech depends on to identify that the movement and the positioning of your articulators are correct

Altered sensory processing

A cause of stuttering due to delayed auditory feedback that have created repetitions, prolongations, and blocks in normal speakers

Central Auditory Processing

Studies conducted on how accurately and quickly PWS can identify and judge the duration of auditory signals as compared to non-stutterers

Poorer central auditory processing, less accurate at identifying under noisy conditions, poorer judging the duration of tones

According to central auditory processing studies, PWS were found to have… (3)

longer latencies and lower amplitudes

According to the brain electrical potentials reflecting auditory processing, the brainwaves of PWS may have ____ _____ and _____ ____ when listening to linguistically complex stimuli

Longer latencies

longer delays between stimuli and brain wave responses

Lower amplitudes

Dichotic Listening Test

This test simultaneously presented 2 different syllables (like “ba” and “da”) dichotically and different syllables to each ear to test laterality between PWS and non-stuttering groups

Hemispheric dominance

The hemisphere of the brain that is more active whenever we hear the speech sounds presented

Right-ear and left-hemisphere dominance

Normal speakers heard more information to this ear / hemisphere

Left-ear and right-hemisphere dominance

PWS heard more information to this ear / hemisphere

masking noise, delayed auditory feedback, frequency shifts, and alterations in other properties of the auditory signal

Factors that can create temporary fluency in PWS (4)

Delayed auditory feedback

What can create an artificial stutter for a normal speaker

Sensory-motor control

Fluent speech depends on the ______-______ ______ of the muscles that move speech structures to produce airflow, voicing, and articulation in a coordinated fashion to produce speech sounds smoothly, sequently, and at a reasonable rate

Motor sensory control

Allows the body to move in coordination

Stuttered speech

• Caused by a disruption in the smooth, sequenced muscle contractions necessary for coordinated structural movements

• A temporal disruption of the simultaneous and successive programming of muscular movements

Stored memories of past movements

When the brain plans the movements needed to produce sounds, it uses ___ ______ _ ___ ______ and their consequences

acoustic and perceptual

Identify when and how to produce the desired ____ and ____ results

Reaction time

time between the appearance of the obect on the screen and the first sound or movement made by the listener/participant

Sensory Analysis, Response Planning, Response Execution

Processing stages involved in a reaction time task

Sensory Analysis

Subject hears signal, sees image on screen senses the position of speech structures and tension of muscles

Response Planning

Subject chooses word to say, selects phonemes and muscles to use

Response Execution

Subject activates muscles in proper sequence to say “bicycle”

Slower response times

PWS have ____ ______ ____ than individuals who don’t stutter in both auditory and visual stimuli

Linguistically meaningful stimuli

Differences in reaction time were more significantly present when using this kind of stimuli

slower speech movements ; abnormal sequencing ; abnormally tense speech muscles

PWS have ___ _____ _______ and sometimes have _______ ________ and ______ ______ ______ _______ in the movement of their articulators

sensory-motor delays

PWS have ____-____ -__ caused by abnormalities in the brain pathways

Non-speech motor control and coordination

Appears to be planned and organized by areas of the brain such as the Supplementary Motor Area (SMA) which are also involved in sequential articulatory movements of speech — which were found to be slower in PWS

Significantly slower

Initiation of the sequence of taps and optimal tapping rate in PWS are ______ ____

Language development, language delay, language complexity

Language factors on stuttering (3)

Language development

The rapid language acquisition that occurs in all children between the ages 2 and 5 places high demands on brain resources

Ages 2 and 5 years old

Onset of stuttering begins during the time of sudden increase in a language development

Language Delays or disorders

May precipitate or worsen the stuttering due to the diversion of resources or attention away from compensating for the speech motor control to deal with the language problem

Language Complexity

Stuttering is influenced by linguistic factors; hence, more stuttering occurs in more complex sentences leading to poorer performances

Emotional Factors

May be an important etiological factor that triggers the onset of stuttering as it can generate emotions

Emotional arousal

May cause stuttering due to emotions

Autonomic Arousal

Denotes activation of the sympathetic nervous system, which prepares the body for action such as fight-or-flight response

Anxiety

Generally describes a state of alert, concern about a future event

Temperament

Aspects of individual’s personality, such as sensitive versus thick-skinned, that are thought to be innate, rather than learned

More sensitive or inhibited temperament

PWS tend to have a ____ ____ or _____ _____ that may be related to stuttering

RH activity

More active and in charge of emotions and affect