Disorders of the Ear Flashcards
1
Q
Example of conductive hearing loss
A
otosclerosis
2
Q
Otosclerosis: disease process
A
- osteodystrophy of endochondral bone leading to bone remodeling
- effects otic capsule bone (temporal bone), where stapes footplate articulates w/ the vestibule
- slowly progressive so hearing loss occurs gradually
3
Q
Otosclerosis: inheritance
A
- autosomal dominant, 40% penetrance
- can also affect inner ear function
4
Q
Otosclerosis: treatment
A
- hearing aids
- surgical replacement (stapedectomy, most common): >90% improve, 1% with severe hearing loss
- observation
5
Q
Sensorineural hearing loss: disease process
A
- occurs when there is damage to inner ear
6
Q
Sensorineural hearing loss: 3 categories
A
- sensory: damage to hair cells
- neural: damage or loss of auditory neurons
- strial: damage or degeneration of stria vascularis
- *most patients have components of each**
7
Q
Sensorineural hearing loss: examples
A
- DFNB1
- noise induced hearing loss
- auditory neuropathy
8
Q
DFNB1: disease process
A
- autosomal recessive SNHL due to mutation in GJB2 that encodes connexin 26
- accounts for 50% of congenital, autosomal recessive nonsyndromic hearing loss
9
Q
DFNB1 treatment
A
- cochlear implantation effective in most patients
10
Q
Noise induced hearing loss: prevelance
A
- most common cause of preventable SNHL
- common diagnosis for workman’s compensation
11
Q
Noise induced hearing loss: cause
A
- most frequently occurs from exposure through years >90dB
- can result from single exposure to very loud noise
12
Q
Noise induced hearing loss: disease process
A
- initial damage occurs at post-synaptic structures and afferent fibers innervating inner hair cells
- later there is loss of hair cells and auditory neurons and fibers
13
Q
Auditory neuropathy: clinical presentation
A
- absent ABR with intact otoacoustic emissions
14
Q
Auditory neuropathy: cause and treatment
A
- DFNB9: mutation in otoferlin
- treatment: excellent results with cochlear implantation
15
Q
Auditory neuropathy: otoferlin (DFNB9)
A
- otoferlin is a calcium sensitive protein involved in synaptic vesicle release from hair cells
- otoferlin mutation hair cells are present and function except fail to release glutamate to activate auditory nerve
