Auditory & Vestibular Systems

Question 1

What inner ear structure pushes on the cochlea?

This causes what to happen?

Answer 1

stapes

(cochlea is fille diwth fluid)

causes tiny hair cells to be stimulated in the organ of corti & this generates an electrical since different frequencies move different hair fibers

Question 2

What is the general auditory pathway?

Answer 2

chochlear nerve

cerebellopontine angle (lateral pons)

and then connects with various other structures

Question 3

What is the difference between conductive & sensorineural hearing loss?

Answer 3

conductive: sound waves can’t convert to nerve signals (structural problem)
sensorineural: something wrong with the nerve (chochlea disease, chochlear nerve failure, CN damage)

Question 4

What presbycusis & what is its cause?

Answer 4

age-related hearing loss

caused by degeneration of organ of corti

Question 5

What results indicate condutive or sensorineural hearing loss in both the Weber & Rinne test?

Answer 5

Question 6

The 3 semicircular canals respond to what type of stimulus?

Answer 6

rotation of the head

Question 7

What are the otolith organs? They respond to what type of stimuli? How?

Answer 7

utricle & saccule

linear motion (gravity, moving forward/backward)

via calcium oxalate crystals connected to hair cells

Question 8

Information from the vestibular nerve is sent where?

Answer 8

brainstem (beneath floor of 4th ventricle in pons/medulla) & cerebellum

Question 9

In general, what type of nystagmus is seen with left, right, torsional/rotation?

Answer 9

peripheral vestibular dysfunction

Question 10

In general, what type of nystagmus is seen with upbeat/downbeat?

Answer 10

central vestibular dysfunction

Question 11

Common causes perpheral vertigo?

Answer 11

(usually benign)

inner ear problems

BPV

vestibular neuritis

Meniere’s disease

Question 12

Common causes central vertigo?

Answer 12

brainstem or cerebellar lesion

vestibulobasilar stroke / TIA

cerebellar infarction / hemorrhage

tumor (posterior fossa)

Question 13

Difference in positional testing between central & peripheral nystagmus?

Answer 13

central: immediate nystagmus
peripheral: delayed nystagmus

Question 14

What is the common cause of BPV?

Treatment?

Answer 14

d/t calcium debris in semicircular canals (canalithiasis)

Epley maneuver can reposition otoconia

Question 15

What is labrynthitis?

Answer 15

neuropathy of vestibular portion of CNVIII

causes vertigo

usually viral or post-inflammatory

benign/self-limited

Question 16

What is Meniere’s disease?

3 classic symptoms?

Treatment?

Answer 16

endolymph fluid accumulation & swelling of the labrynthine system

1. tinnitus
2. sensorineural hearing loss
3. vertigo

avoid high salt diet (decrease swelling), avoid caffeine/nicotine (vasoconstrictors), try diuretics