Auditory Pathways Flashcards
how is auditory information received?
by cochlear nucleus by fibers in the cochlear nerve
fibers from the cochlear nerve enter the brainstem where and then do what?
at the cerebellopontine angle and then split into ascending and descending bundles
where does the ascending bundle synapse at?
at the anterior part of the anterior cochlear nucleus
where does the descending bundle synapse at?
the posterior part of the anterior cochlear nucleus and posterior part of the posterior cochlear nucleus
what are the monaural tracts important for?
information about sounds at a single ear
what are the binaural tracts important for?
manages information about differences between sounds at both ears
central deafness is defined as damage to what?
the central pathways- everything from the cochlear nuclei up
central deafness rarely results in what?
in ipsilateral deafness–> people are not actually deaf, they are just unable to identify where the sound is coming from
what is sensorineural deafness?
damage to the cochlea or cochlear root of CN VIII
what is the presentation of sensorineural deafness?
ipsilateral deafness of structure affected
what could cause sensorineural deafness?
antibiotics, tumors, or repeated exposure to loud noises
what is conduction deafness?
obstructed or altered transmission of sound to tympanic membrane or through ossicle chain of middle ear
what could cause conduction deafness?
damage to pinna, excess ear wax, damage to tympanic membrane
what is the blood supply of the cochlea and auditory nuclei of the pons and medulla?
basilar artery
what is the blood supply of the inner ear and cochlear nuclei?
internal auditory artery
what does occlusion of the internal auditory artery result in?
monaural hearing loss with ipsilateral facial paralysis and the inability to look toward the side of the lesion
what is the blood supply of the superior olivary complex and lateral lemniscus?
short circumferential branches of the basilar artery
what is the blood supply of the inferior colliculus?
superior cerebellar and quadrigeminal arteries
what is the blood supply of the medial geniculate bodies?
thalamogeniculate arteries
what is the blood supply of the primary auditory and association cortices?
branches of M2 segment of the middle cerebral artery
the hemisphere that controls language is considered what?
the dominant hemisphere
what is broca’s area responsible for?
production of language (spoken, written, or signed)
what is wernicke’s area responsible for?
comprehension of language (spoken and signed)
what does broca’s area work with and for what reason?
the frontal lobe, which adds syntax, grammer, and higher order motor aspects of speech
what does wernicke’s area work with and for what reason?
the parietal and temporal lobe, which add lexicon (vocabulary) and attaching sounds to their meaning
what is the arcuate fasciculus?
it is a connecting network between broca’s and wernicke’s area
what is the purpose of the arcuate fasciculus?
it allows the combination of speaking coherently, understanding what is being said to us, and then responding appropriately
What is the non-dominant hemisphere responsible for?
non-verbal communication- tone of voice
what is the area analogous to broca’s responsible for?
producing non-verbal communication (how you can change your tone to cause sarcasm)
what is the area analogous to wernicke’s area responsible for?
comprehending non-verbal communication
what does a lesion in the area analogous to broca’s area cause?
motor aprosodia
what does a lesion in the area analogous to wernicke’s area cause?
sensory aprosodia
what area differentiates where and when a sound is coming from?
the primary auditory cortex
what area classifies the sound (with assistance from the primary auditory cortex along with visual and somesthetic information) as what it is?
the auditory association cortex
what is auditory agnosia?
the inability to identify something, but to still be able to perceive it
what is auditory agnosia caused by?
bilateral lesions to the anterior superior temporal lobes
what is broca’s aphasia caused by?
tumors and occlusions of the frontal M4 branches of the middle cerebral artery
what is wernicke’s aphasia caused by?
occlusion of the temporal and parietal M4 branches of the middle cerebral artery as well as hemorrhages into the thalamus
what would cause damage to both broca’s and wernicke’s area?
occlusion of the left internal carotid or proximal portion of the middle cerebral artery
what is conduction aphasia?
comprehension is normal, speech is fluent, but patient has difficulty translating what someone has said to him/her in appropriate reply (problem with repetition)
what causes conduction aphasia?
interruptions of the connections linking the broca and wernicke’s area (arcuate fasciculus)
what is transcortical motor aphasia?
similar to broca’s aphasia but repetition is maintained
what causes transcortical motor aphasia?
anterior watershed infarct
what is transcortical sensory aphasia?
similar to wernicke’s aphasia but repetition is maintained
what causes transcortical sensory aphasia?
posterior watershed infarct
what is mixed transcortical aphasia?
it is similar to global aphasia, but repetition is maintained. both brocas and wernicke’s symptoms
