Language Centres and Aphasia Flashcards
what is language
reading, writing, speaking and understanding words
what does Wernicke’s area do
permits recognition of spoken and written language and creates plan of speech
angular gyrus function
processes text and numbers into a form we can speak
where is wernicke’s area found
around the auditory cortex of the sylvian fissure
what is the sylvian fissure
where the temporal and parietal lobes meet
what does Broca’s area do
generates motor program for larynx, tongue, cheek and lip muscles to create movement for phonation
transmits that to primary motor cortex for aciton
where is Broca’s area found
pars triangularis of the inferior frontal gyrus
is speech part of the extrapyramidal or pyramidal system and why
pyramidal because speech is a voluntary action
which seven cranial nerves are needed for speech
- V: trigeminal
- VII: facial
- VIII: vestibulocochlear
- IX: glossopharyngeal
- X: vagus
- XI: spinal accessory
- CII: hypoglossal
trigeminal - sensory or motor
sensory and motor
trigmeninal nerve relation to speech
controls muscles of mastication
facial - sensory or motor
sensory and motor
facial nerve relation to speech
controls muscles of facial expression
vestibulocochlear - sensory or motor
sensory
vestibulocochlear relation to speech
hearing
glossopharyngeal - sensory or motor
sensory and motor
glossopharyngeal relation to speech
- contributes to pharyngeal movement
- taste
vagus - sensory or motor
sensory and motor
vagus nerve relation to speech
- contributes to movements of the pharynx and larynx
- serves a sensory function for pharynx, larynx, trachea, bronchi and lungs
spinal accessory - sensory or motor
motor
spinal accessory relation to speech
controls neck muscles thus indirectly influences position of larynx
hypoglossal - sensory or motor
motor
hypoglossal relation to speech
controls tongue movements
two cochlear nuclei
dorsal and ventral
what does the ventral pathway control
direction of sound
ventral pathway
Cochlear nerve → ventral nucleus → superior olivary nucleus → nucleus of lateral lemniscus → inferior colliculus → medial geniculate nucleus of thalamus → primary auditory cortex
what does the dorsal pathway control
auditory pathway
quality of sound
dorsal pathway
auditory pathway
Cochlear nerve → dorsal cochlear nucleus → dorsal acoustic stria → inferior colliculus → medial geniculate nucleus of thalamus → primary auditory cortex
do both dorsal and ventral pathways decussate
auditory pathway
yes
what does the reading out loud pathway do
converts graphemes to phonemes
grapheme
written symbol that represents a sound
phoneme
smallest unit of sound within a word
production effect
reading out loud can improve memory - pronouncing words can create a memorable experience
reading out loud pathway
- Visual images → retinogeniculate pathway → lateral geniculate nucleus of the thalamus → geniculo-calcarine tract (optic radiation) → visual cortex (calcarine sulcus) for visual processing
- Orthographic processing occurs in area 19 of the visual association area, and involves recognising whether each letter string in a sentence represents a real or pseudoword
- Transfer from subdominant to dominant hemispheres via the splenium of the corpus callosum
- The visual picture: the occipital lobe → angular gyrus for phonological processing → Wernicke’s area for language comprehension → arcuate fasciculus → Broca’s area for speech pattern production → primary motor cortex for muscle activation
Aphasia
an acquired communication disorder that causes problems with any or all of the following: speaking, listening, reading and writing
causes of aphasia
- stroke (most common, ischemia of brain region due to occlusion of middle cerebral artery)
- head injury
- brain tumours
- infection
- dementia
wernicke’s aphasia
issues with speech comprehension
broca’s aphasia
issues with speech production
wernicke’s aphasia presentation
- comprehension and expression are equally impaired
- unable to understand written or spoken language
- normal grammar, syntax, rate and intonation but cannot express themselves meaningfully
- tendency to talk excessively
- tend to have anosognsia (lack of awareness) of their symptoms
- substitutes one word for another - paraphasias
broca’s aphasia presentation
- loss of ability to produce language
- speech is laboured and non fluent
conduction/association aphasia
connection between wernicke’s and brocca’s areas is damaged or compromised - therefore an acquired condition
conduction/association aphasia presentation
- intact auditory comprehension
- fluent speech
- marked inability to repeat words or sentences
dysarthria
- motor speech disorder caused by damage in the tracts that connect motor neurons to speech muscles
- damage to upper and lower motor neurons
- classified depending on location of lesion
where do upper motor neurons have their nuclei
in the motor cortex
where do lower motor neurons have their nuclei
pons and medulla
agnosia
- inability to recognise objects, people, shapes, sounds or smells
- no significant overall memory loss
auditory agnosia
inability to differentiate or recognise sounds
auditory agnosia cause
damage in the auditory association areas
auditory agnosia presentation
- speech comprehension is severely compromised
- language skills (reading, writing) are retained
