one study showing high percent of stuttering children having__ ____
one study showing high percent of stuttering children having familial stuttering
stuttering higher in ___ twins
monozygotic
Recent evidence from linkage studies (Kang et al. 2010)
- -Significant linkage on chromosome ___
- -___ relevant gene mutations identified (GNPTAB, GNPTG, and NAGPA)
- -Mutations associated with __ ___ ___
- -Significant linkage on chromosome 12
- -Three relevant gene mutations identified (GNPTAB, GNPTG, and NAGPA)
- -Mutations associated with lysosomal storage disorders
MRI morphometry
Note extra___ in the __ ___ of the stutterer
MRI morphometry (Based on Foundas, et al., 2001) Note extra-gyri in the Sylvian fossa of the stutterer
Cerebral Dominance Theory
- -Proposed stuttering was caused by a …
- -Left and right hemispheres compete for control of ____
- -_____ of neural impulses from both sides of the brain disrupts speech fluency
- -Proposed stuttering was caused by a lack of cerebral dominance
- -Left and right hemispheres compete for control of speech movements
- -Asynchrony (mistiming) of neural impulses from both sides of the brain disrupts speech fluency
Differences in brain structure
- ____ area smaller in ___ for PWS
- More gyri in ____ region in PWS
- Higher ___ matter volume in RH
- Reduced __ __ __ in LH
- Deficiencies in LH __ __ volume
- *Most research done w/ adults!
- Wernicke’s area smaller in LH for PWS
- More gyri in Sylvian (LH) region in PWS
- Higher white matter volume in RH
- Reduced white matter integrity in LH
- Deficiencies in LH gray matter volume
- *Most research done w/ adults!
Recent research with kids…
- Reduced ___ ___ ___ in LH
- Persistent and Recovered CWS: lower __ __ volume in LH speech areas
- But…only CWS who persisted showed lower __ ___integrity in LH
- No differences in ___ activity and no ____ between hemispheres
- Reduced white matter integrity in LH
- Persistent and Recovered CWS: lower gray matter volume in LH speech areas
- But…only CWS who persisted showed lower white matter integrity in LH
- No differences in RH activity and no asymmetry between hemispheres
Neuro-physiologicaldifferences
- Overactivation of ___ ___
- –Especially in __
- Lower activity in ___ areas
- –Auditory suppression ___
- Anomalous RH activity and lateralization
- __ ___ of white matter
- Lower activity in ___ __ and ___
- More activation in ___ ___ __
- Overactivation of motor areas
- –Especially in RH
- Lower activity in auditory areas
- –Auditory suppression bilaterally
- Anomalous RH activity and lateralization
- Decreased connectivity of white matter
- Lower activity in basal ganglia and cerebellum
- More activation in anterior cingulated cortex
Auditory Perceptual Theory
- Proposed stuttering was caused by defective __ ___
- The speaker expects to hear sound ___ than their auditory system feeds it back
- The speaker___ or ____ trying to correct the delay
- Proposed stuttering was caused by defective auditory feedback
- The speaker expects to hear sound earlier than their auditory system feeds it back
- The speaker waits (prolongs) or repeats trying to correct the delay
Role of audition
-Speech control relevant to \_\_\_ ~Deaf individuals ~The \_\_\_\_ effect ~\_\_ \_\_ Feedback ~\_\_\_ \_\_\_ Feedback -\_\_\_\_ listening studies
-Speech control relevant to audition ~Deaf individuals ~The Lombard effect ~Delayed Auditory Feedback ~Frequency Altered Feedback -Dichotic listening studies
Sensory/Motor Dysfunction
-Most ___ part of stuttering
-____ response times (vocal or manual)
-Abnormal _____ patterns in ___, tongue, and ____ (even in fluent speech)
~~E.g., timing, muscle activation sequencing force of movements, abnormal breathing patterns, slower rate
-Most obvious part of stuttering
-Slower response times (vocal or manual)
-Abnormal movement patterns in jaw, tongue, and larynx (even in fluent speech)
~~E.g., timing, muscle activation sequencing force of movements, abnormal breathing patterns, slower rate
Brainstem Reflexes: Disorder of Movement Theory
- Proposed stutterers have reduced tolerance for…
- If the range is exceeded, …
- ___ and ___ signals of speech muscles conflict so stuttering occurs
- Proposed stutterers have reduced tolerance for a range of oral movements
- If the range is exceeded, brainstem reflex management is upset
- Afferent and efferent signals of speech muscles conflict so stuttering occurs
DIVA (Directions into Velocities of Articulators) Model
- Stuttering is due to a disorder of __ __ __
- PWS have unreliable ___ systems so they rely excessively on controlling speech via __
- Fluency is disrupted by the attempts to ___ ___ ___ after commands have been issued
- Stuttering is due to a disorder of sensorimotor speech control
- PWS have unreliable feedforward systems so they rely excessively on controlling speech via feedback
- Fluency is disrupted by the attempts to adjust speech movements after commands have been issued
Conclusions
- Is stuttering an impairment in the vocal organism itself (peripheral nervous system)?
- Or, it is a problem of vocal planning and initiation (central nervous system)?
- *Think about the ameliorating conditions
- RH overactivity may be ___
- Is stuttering an impairment in the vocal organism itself (peripheral nervous system)?
- Or, it is a problem of vocal planning and initiation (central nervous system)?
- *Think about the ameliorating conditions
- RH overactivity may be compensatory
Genetic and neurological research combined with sensory-motor dysfunctions in PWS point to a …
Genetic and neurological research combined with sensory-motor dysfunctions in PWS point to a UNSTABLE/UNRELIABLE neuromotor system for speech
- -___ of the brain is possible
- -Many children develop a ___ (Chang et al. 2008)
- -Following treatment, stronger__ __ __
- -Also, __ __ __ can increase with practice of certain behaviors
- -Plasticity of the brain is possible
- -Many children develop a workaround (Chang et al. 2008)
- -Following treatment, stronger left hemisphere activity
- -Also, gray matter volume can increase with practice of certain behaviors
