language centers and aphasia Flashcards
what is language
reading, writing, speaking, comprehension
wernicke’s area function
- recognition of spoken and written language
- creates a plan for speech
angular gyrus function
processes text and numbers into something we can process
broca’s area function
- generates motor program for larynx, tongue, cheek, lip muscles for phonation
- transmits info to primary motor cortex for action
dominant hemisphere
left in 95% of right handed people and 60% of left handed people
inferior parietal lobule function
integrate sensory information of different modalities (tactile, auditory, visual)
cranial nerves involved in speech and hearing
- CNV (trigeminal)
- CNVII (facial)
- CNVIII (vestibulocochlear)
- CNIX (glossopharyngeal)
- CNX (vagus)
- CNXI (accessory)
- CNXIII (hypoglossal)
CNV (trigeminal) function in speech and hearing
- sensory: face sinuses, teeth
- motor: muscles of mastication
muscles of mastication
- masseter
- temporalis
- lateral pterygoid
- medial pterygoid
CNVII (facial) function in speech and hearing
motor: muscles of the face
CNVIII (vestibulocochlear) function in speech and hearing
sensory: inner ear
CNIX (glossopharyngeal) function in speech and hearing
- motor: pharyngeal musculature
- sensory: posterior part of tongue, tonsil, pharynx
CNX (vagus) function in speech and hearing
motor: heart, lungs, bronchi, gastrointestinal tract
CNXI (accessory) function in speech and hearing
motor: sternocleidomastoid and trapezius muscles
CNXIII (hypoglossal) function in speech and hearing
motor: muscles of the tongue
because speech is voluntary, it is part of the ?
pyramidal system
is speech voluntary
yes
visual information in the right peripheral field is processed in the ?
left hemisphere
visual information in the left peripheral field is processed in the ?
right hemisphere
most people are ? dominant for language
left
what does it mean to be left dominant for language
language is perceived and produced by the left hemisphere
speech in response to hearing
- information transmitted via arcuate fasciculus
- interpretation of words in wernicke’s area
- reception of sound signal by auditory area 41
- activation of broca’s area for word formation
- to motor cortex that control speech muscles
arcuate fasciculus
a bundle of axons that connects Broca’s and Wernicke’s areas
hearing to speech pathway
reading out loud pathway converts ? to ?
graphemes; phonemes
graphemes
written symbol that represents a sound
phoneme
smallest unit of sound within a word
reading out loud can improve ?
memory
production effect
pronouncing words can create a memorable experience
reading out loud pathway
-visual images transmitted via retinogeniculate pathway to lateral geniculate nucleus of the thalamus
- travel to visual cortex (calcerine sulcus) via geniculocalcarine tract (visual processing)
- info from subdominant to dominant hemisphere via corpus callosum
- visual picture from occipital lobe to angular gyrus (phonological processing)
- angular gyrus to wernickes area (language comprehension)
- auditory passage to broca’s motor area via arcuate fasciculus (speech pattern production)
- pattern to primary motor cortex for muscle activation
orthographic processing
recognizing whether each letter string in a sentence represents a real or pseudoword
phonological processing
conversion of graphemes to phonemes
aphasia
an acquired communication disorder that causes problems with speaking, listening, reading, writing
aphasia causes
- stroke
- head injury (tbi)
- brain tumors
- infection
- dementia
- occlusion of the middle cerebral artery
types of aphasia
- wernicke’s aphasia
- broca’s aphasia
- conduction/associative aphasia
wernicke’s aphasia
- issues with speech comprehension
- comprehension and expression are equally impaired
- unable to understand written or spoken language
- normal grammar, syntax, rate, intonation but cannot meaningfully express themselves
- have anosognosia and paraphasias
broca’s aphasia
- issues with speech production
- output to the primary motor cortex vocalization muscles
- loss of ability to produce language, or speech is labored and non-fluent
middle cerebral artery 4 segments
- M1 sphenoid/horizontal segment
- M2 lateral/insular segment
- M3 opercular segment
- M4 cortical segment
M1 sphenoid/horizontal segment
- ICA to bifurcation
- originates at the terminal bifurcation of the internal carotid artery
- courses laterally parallel to the sphenoid ridge
- terminates at the genu adjacent to the limen insulae or at the main bifurcation
M2 lateral/insular segment
- sylvian fissure
- originates at the genu/limen insulae or the main bifurcation
- courses posterosuperiorly in the insular cleft
- terminates at the circular sulcus of insula, where it makes a right angle to hairpin turn
M3 opercular segment
- outside lateral fissure
- originates at the circular sulcus of the insula
- courses laterally along the frontoparietal operculum
- terminates at the external/superior surface of the Sylvian fissure
M4 cortical segment
- cortigal segments
- originates at the external/top surface of the Sylvian fissure
- courses superiorly on the lateral convexity
- terminates at their final cortical territory
cortical branches
- all frontal gyri, postcentral gyrus, inferior parietal lobe
- supplied by cortical branches of MCA
deep branches from M1
lateral lenticulostriate arteries supply the external capsule, lentiform nucleus, caudate
anosognosia
lack of awareness of their communication problems
paraphasias
substitutes one word for another
pathopathophysiology
motor/expressive aphasia
conduction/associative aphasia
- connection between wernicke’s and broca’s area is compromised/damaged
- intact auditory comprehension, fluent speech, but poor speech repetition
- conduit d’approche
conduit d’approche
repetitive effort to find the correct word
dysarthia
- speech disorders caused by impaired control of the muscles responsible for speech
- caused by damage in the tracts that connect motor neurons to speech muscles
? disruption causes mild or transient dysarthria
unilateral
? disruption causes persisting dysarthria
bilateral
upper motor neurons (type of nervous system and location of nuclei)
- CNS
- motor cortex
lower motor neurons (type of nervous system and location of nuclei)
- PNS
- pons and medulla
speech dysarthria can be classified by ?
location of lesion causing the disorder
agnosia
- inability to recognize objects, people, shapes, sounds, or smells
- no significant memory loss
auditory agnosia
- inability to differentiate or recognize sounds
- damage in the auditory association areas
- speech comprehension is severely compromised
- language skills (reading, writing, speaking) are retained
