Hearing Loss Flashcards

1
Q

Describe the process of sound transduction

A
  • SOund waves enter the external auditory canal and bounce off the tympanic membrane.
  • The tympanic membrane thn moves the malleus, incus and stapes
  • When the STAPES FOOTPLATE moves, the pressure in the fluid filled inner ear changes and that triggers a travelling wave in the basilar membrane of the cochlea
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2
Q

Inside the cochlea, hair cells are found where?

A

Organ of corti which rests on basilar membrane

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3
Q

High frequency sounds displace the the basilar membrane where

A

Near the base of the cochlea

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4
Q

As frequency decreases, the point of maximal membrane displacement moves in what direction?

A

Toward the apex

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5
Q

What stimulates electrical activity along the auditory nerve?

A

The distortion of stereocilia on hair cells causes depolarization of the cell and that results in electrical activity along the auditory nerve

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6
Q

Causes of conductive hearing loss?

A

Transmission of sound through the air is blocked.

You can mimic this by sticking your finger in your ear. Thus, anything blocking the external auditory canal causes it.

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7
Q

Cuases of conductive hearing loss

A
  • wax
  • foreign object
  • otitis externa
  • tympanic membrane perforation
  • otitis media with effusion
  • otosclerosis
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8
Q

Sensorineural heaing loss

A

Disorders of the cochlea, cochlear nerve, central pathways

  • can be congenital
  • Presbyacusis (age related hearing loss)
  • viral infxn
  • ototoxic drugs
  • trauma
  • meniere’s
  • vestibular schwannoma
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9
Q

What is otosclerosis

A

bony overgrowth of the stapes

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10
Q

Meniere’s disease symptoms

A

-vertigo, fluctuating sensorineural hearing loss, tinnitus

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11
Q

What causes Meniere’s

A

Decreased reabsorption of endolymphatic fluid causes hydrops (fluid build-up) which causes rupture of the membrane separating the endolymph from the perilymph. These two fluids have very different compositions and their mixture produces a sudden change in vestibular pressure and electric firing properties.

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12
Q

In the early stages of meniere’s, symptoms remit between attacks and patients may be symptom free for a year or more.

A

Eventually hearing loss persists and worsens

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13
Q

Tx of menieres

A
  • low salt diet and diuretics

- vestibular sedatives when the pt has an attack

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14
Q

Conductive hearing loss audiogram

A

fairly equal threshold elevation for each frequency.

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15
Q

Otosclerosis audiogram

A

Can result in a much greater threshold elevation in the lower frequencies

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16
Q

Middle ear effusion audiogram

A

Greater elevation of thresholds in the higher frequencies

17
Q

Sensorineural hearing loss audiogram

A

usually the higher the frequency the worse the hearing

18
Q

Noise induced hearing loss generally shows a selectively greater loss at what frequency

A

4,000 hz

19
Q

Meniere’s disease audiogram

A

Hearing thresholds elevated in the lower frequencies…hearing usually worse at lower than higher

20
Q

In perforation of the tympanic membrane, the degree of hearing loss depends on

A

The size of the hole

21
Q

Growth of abnormal bone around the otic capsule is called

A

otosclerosis…..leads to fixation of the stapes

22
Q

Otosclerosis is often accompanied by what type of hearing loss

A

sensorineural

23
Q

At what age range does otosclerosis generally start

A

20’s and 30’s and is BILATERAL (prob means I don’t have it)

24
Q

Family history for otosclerosis

A

usually

25
Q

Tumor of the cerebellar pontine angle?

A

Often a vestibular schwannoma (acoustic neuroma

26
Q

Meningiomas also occur in the angle between the cerebellum and the pons BUT>

A

They usually present with sensorineural hearing loss but no vertigo