Auditory Processing Pathway

Question 1

3 parts of the ear?

Answer 1

1. Outer (visible)
2. Middle (filled with air)
3. Inner (filled with fluid)

Question 2

Function of the tympanic membrane?

Answer 2

soundwaves apply force, sets off vibration of malleolus

Question 3

What does the malleolus do?

Answer 3

connects to tympanic membrane

Question 4

3 bones in the ear?

Answer 4

malleolus, incus, stapes

Question 5

2 boundaries within the middle ear?

Answer 5

oval window and tympanic membrane

Question 6

What occurs at the oval window?

Answer 6

Vibration transfers mechanical wave into water waves in Inner EAR

Question 7

What is the sensory receptor of the cochlea?

Answer 7

Organ of Corti (rows outer hair cells, 1 row inner hair cells)

Question 8

What do the hair cells do after bent by the sound waves?

Answer 8

convert mechanical energy to electrical energy

Question 9

Describe the semi-circular canals

Answer 9

fluid filled
* Three-dimensional perception of position
* Sound waves do not travel in semicircular canals
* Crystal located in three semicircular canals

Question 10

What do the crystals do when head/body moves?

Answer 10

Movement of head/body causes crystals to move and provided feedback regarding position (CN 8)

Question 11

What are bipolar cells?

Answer 11

Spiral ganglion (type I) cells located in cochlea

Question 12

2 sets of fibers in the bipolar cells?

Answer 12

1. primary auditory fibers – longer & central fibers
2. peripheral process

Question 13

2 branches of the vestibulocochlear nerve?

Answer 13

1. Vestibular branch
2. Cochlear branch

Question 14

What does the inferior colliculus do?

Answer 14

essential to sound localization,
second location binaural processing

Question 15

Auditory Cortex Location?

Answer 15

Temporal Lobe
most of auditory cortex hidden view in lateral sulcus, on collection gyri known as Heschl’s gyri.

Some visible area auditory cortex extends into superior temporal gyrus

Question 16

Primary Auditory Cortex/Core region (A1)

Answer 16

superior temporal plane
Heschl’s Gyrus

Question 17

Regions of the Auditory Association Cortex (A2)

Answer 17

belt and parabelt parietal & temporal borders
Belt region – region adjacent to core region
Parabelt region – neighboring areas around to belt

Question 18

Which area is imprecise?

Answer 18

Demarcation area

Question 19

Function of auditory cortex?

Answer 19

to perceive sound
perception of pitch
where originated from (direction of the sound)
source of the sound
discernment of speech sounds

Question 20

What is a tonotopic map?

Answer 20

Core region organized tonotopically
Arranged by frequency; humans have 6 tonotopic maps (regions)
Neurons tuned to ONLY respond to specific frequencies

Question 21

Neurons that respond to info from one ear; inhibit same info to the ____ ear

Other neurons activated by info from ____ears

Answer 21

opposite; both

Question 22

What components are not as well known as the visual cortex?

Answer 22

Mechanism and component auditory cortex

Question 23

What is the left sylvian fissure important for?

Answer 23

speech production & speech recognition

Question 24

How is the left sylvian fissure described?

Answer 24

2 lane, 2 way highway

Question 25

What happens if damage occurs above/below the sylvian fissure?

Answer 25

above: parietal & frontal lobes speech production deficits below: temporal lobe– caused speech recognition deficits

Question 26

5 part Sequence from hearing to lang. comp. and memory

Answer 26

1. COchlea 2. central auditory pathway 3. primary and secondary -Auditory aka core, belt, and parabelt cortex 4. Sylvian Fissure parietal-temporal 5. Pre-Frontal Cortex

Question 27

Primary Auditory Pathway

Answer 27

-cochlear nuclei (dorsal & ventral) cross through trapezoid body -superior olivary complex (pons) – SOC – info from two ears, now have two fields -lateral lemniscus tract cross at nucleus -inf colliculus (midbrain) communicate with each other -medial geniculate (thalamus) -geniculocortical fibers (internal capsule)

Question 28

Acoustic reflex?

Answer 28

Involuntary muscle contraction of stapes in middle ear in response to loud sound Muscle contraction pulls stapes from oval window & stiffens osculation chain

Question 29

Does the coordination of head and eye movement to maintain equilibrium involve other cranial nerves?

Answer 29

YES! inferior colliculi to superior colliculi (CN III) SOC to medial longitudinal (CN IV, VI) auditory and vestibular branches of CN VIII with cerebellum

Question 30

What is involved in sound localization?

Answer 30

superior olivary complex – neurons sensitive to time & intensity differences inferior colliculi – receive binaural input in cortex, too - maybe

Question 31

How small is the timing difference for arrival of sound between the ears?

Answer 31

Can detect timing difference as small as 10 microseconds

Question 32

What are auditory evoked potentials??

Answer 32

Test completed to identify Central hearing disorders/tumors Measure with electrodes on skull Interpretation of results: Amplitude/Latency/Interpeak latency/Interaural Latency

Question 33

What are dichotic listening tasks used for?

Answer 33

Used to determine hemispheric lateralization of language

Question 34

What is the right ear advantage?

Answer 34

for perception of words = left hemisphere lateralization of language

Question 35

Causes of conductive hearing loss?

Answer 35

Ear Infection, fluid, loss Eustachian tube function, benign tumors

Question 36

Causes of sensorineural hearing loss?

Answer 36

Ototoxic drugs, aging, illness, noise exposure, tumors

Question 37

What is an acoustic neuroma?

Answer 37

benign tumor grows on CN VIII; can impact hearing & balance, diagnosed MRI

Question 38

What is labrynthitis?

Answer 38

inflammation of inner ear

Question 39

What is Meniere's disease?

Answer 39

inner ear disorder causes vertigo. Onset 1 ear but can progress to both

Question 40

Otosclerosis?

Answer 40

hearing loss due to inability of oscillating bones to freely vibrate, hereditary

Question 41

What is tinnitus?

Answer 41

ringing or buzzing in ears, unilateral or bilateral, varies in severity and consistency

Question 42

What is central hearing loss?

Answer 42

result of tumor or injury to auditory pathway or auditory cortex

Question 43

What is usher syndrome?

Answer 43

rare genetic disorder impacts hearing & vision, sometimes balance. Abnormal development hair cells.

Question 44

What is pendred syndrome?

Answer 44

genetic disorder causes early hearing loss children due to lack protein called pendrin needed to keep salt levels balanced

Question 45

Where is the planum temporale?

Answer 45

Posterior to auditory cortex within Sylvian fissure, forms the heart of Wernicke’s Area Cortical area in the brain, in the right and the left.

Question 46

Right ear advantage?

Answer 46

words are sent to both hemispheres but language processed in (L) thus word processed initially by right ear, must then proceed to (L) via Corpus Collosum

Question 47

Signs of APD?

Answer 47

difficulty understanding speech in degraded situations (non-optimal environment/loud environment) delayed, inconsistent, or inappropriate responses misunderstanding many requests for repetition problems with auditory attention and localization poor musical skills associated reading, spelling, and learning problems

Question 48

What do we know about APD?

Answer 48

-Aud processing improves with age -It’s cortical and complicated -Probably not a sensory problem -Probably more related to executive function, attention, and cognition