Control Of Cerebral Speech Flashcards
What are the 4 main stages of speech production
Conceptualism
Formulation
Articulation
Self monitoring
Conceptualism
Decide what to say
Formulation
Select appropriate words and organise in grammatical form
Articulation
Plan, co ordinate and initiate movement to produce speech
Self monitoring
Auditory and somatosensory feedback for correction
What is the left hemisphere specialised for
Phonetic, word and sentence processing
Left hemisphere
activated not only by auditory signals but by visual lights with linguistic significance
Broca’s area
-early recognition of dominance of left brain hemisphere in speech and language production
-3rd convulsion of the inferior gyrus of the frontal lobe
Broca’s aphasia
Brocas aphasia: non fluent & agramattic verbal output, effortful &halting speech. Problems with articulation, word finding, repetition, production, and comprehension of complex sentences.
Wernickes area
- Surrounds the posterior part of the lateral fissure, located at the junction of the parietal, temporal and occipital lobes.
- Part of neural system that processes speech sounds and associates sounds with concepts.
UNDERSTANDING LANGUAGE
Wernickes aphasia
Wernicke aphasisa- fluent speech, produced at a normal rate but ‘empty’. Speech content is unintelligible due to frequent errors in word choice/retreiaal. Poor comprehension of language hence no awareness of errors
Wernickes model
Visual cortex
Receives written words as visual stimulation
Wernickes model
Angular gyrus
Transforms visual representations into an auditory code
Wernickes model
Motor cortex
Word is pronounced
Respiratory system
- Movement of air in and out of lungs
- Diaphragm, external intercostal and scissors muscles.
Phonation (larynx)
- Keep food/liquids out of airways and sound source.
- Muscles stabilise the larynx, control opening/closing of the glottis and tension in vocal folds.
Articulation/resonance
- Modification and amplification of sounds
- Tongue, lips, checks, larynx, pharynx, soft palate etc muscles.
Dysarthria
- disturbance in speech muscle control due to paralysis, paresis, weakness, slowness
- can affect all speech processes
-collection of motor speech symptoms that reflect the component of the motor system
How many types of dysarthria is there
7
Apraxia of speech
- Disturbance in motor planning/ programming of sequential movements for volitional speech production- inability to transform an intact linguistic representation into a coordinate sequence of muscle contraction
- No problem with comprehension and NOT caused by muscle weakness/paralysis.
How is apraxia caused
- Caused by lesions to Broca’s area, anterior insular cortex, basal ganglia, supplementary motor area, somatosensory cortex, supramarginal gyrus. Concomitant with aphasia.
- Acquired (TBI, stroke, infections, neuro degeneration) or congenital (childhood apraxia of speech)
- Islands of luent intelligible speech (automatic phrases) interrupted by periods of effortful, off target groping for speech sounds. Low speech rate, hesitation, difficulty initiating speech.
Vegetative breathing
- Inspiration> diaphragm + intercostal muscles, 40%
- Expiration> mostly passive, 60%
- Vocal folds (larynx) are abducted:trachea is unobstructed
- Mostly involuntary nervous control (brain stem)
Forced breathing
- Phonation is a form of forced breathing requiring voluntary overdoing of vestige respiration.
- Vocal folds adduct> airway constrict > increase in expiratory subglottic pressure> audible vibration
- Frequency and intensity of sound produced determined by subglottic pressure and rate of airflow.
Breathing and speech
- Relaxation pressure~pulmonary pressure, thus deep inspiration the subglottic pressure decreases with time
- relaxation pressure is altered via muscle contraction to a subglottic pressure suitable for speech:
-initially contraction of external intercostal muscles is maintained to counter elastic recoil
-the contraction of expiratory muscles decrease lung volume
What is needed to vibrate the vocal folds
Sustained and increased subglottic pressure needed to vibrate the vocal folds- modifications to vegetative breathing
Inspiration- rapid (10%) and deep
Expiration- slow (90%)and deep
