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Flashcards in Hearing Deck (26):
1

Pure Tone

Simple sinusoidal wave. Our voices and music and shit are not

2

2 Parameters of Sound

Frequency - pitch
Pressure Level (decibels) loudness intensity

3

Auditory Field

About 20 to 20k Hz, but conversation area greatly increased from like 300 to 3k Hz

4

3 Functions of Outer Ear

Collect sound waves
Amplify sound pressure level
Frequency filter for localization of sound elevation

5

Sound Force Amplification by ME

Pressure = F/SA and TM to oval window is 20:1 so it decreases SA. Lever effect of ossicular chain

6

5 Differences b/w IHC and OHCs

Calix shaped, close to spiral ganglion, single row, afferent, 10 type 1 neurons synapse vs. columnar, far, 3 rows, contract for frequency tuning, and have 1 type II neurons connecting about 10

7

2 Turns/Pitch Distribution

Apical turn for low freq/pitch sounds and basal turn for high

8

Rapid Succession Mech

Calcium influx triggers motor prot which drives down tip link, reducing time constant of K channel opening, repolarizing the cell, and thus allowing cycles of mechanotransduction to occur in rapid succession (high freqs)

9

Passive Tonotopy

Tonal separation dependent on physical properties of cochlea, where high freqs vibrate base and low vibrate apex where its less stiff

10

Active Tonotopy

Finer mech via OHCs contracting at their very specific range, causing a 50 dB increase

11

Frequency Preservation in Auditory Nerve

Bc auditory nerve fibers connect w/ IHC in approx 1:1 ratio, each auditory nerve fiber transmits information about only small part of audible freq spectrum. So apical nerves respond low freqs and etc

12

2 Central Auditory Pathways

Primary: messages from cochlea
Non-primary: all types of sensory messages (reticular)

13

Otoacoustic Emissions

Normal low level sounds produced by ear as part of hearing process. Can be reduced or absent in cases of certain types of hearing loss. Reflect activity of OHCs, most sensitive cells of organ of Corti so can be objective screening test in newborns (who can't directly be tested) or adults at risk of hearing loss like workers

14

Brainstem Auditory Evoked Potentials

See it going through auditory pathway (I. auditory n. II. cochlear nuclei III. Sup olive IV. lateral lemniscus V. Inf colliculus) and see if there's any latency at the points indicating a problem. Additional tests for children/babies

15

Bone-Air Gap

Means bone conduction is better than air, so there's some sort of conductive hearing loss

16

4 Treatments for OME

Antibiotics
Tympanostomy tubes
Adenoidectomy

17

Treatment for Otosclerosis

Stapedectomy and replace w/ proper functioning synthetic one

18

2 Treatments for Congenital Ear Canal Atresia

Atresia repair
Bone Anchored Hearing Aids (BAHA) - metal screw directly into bone and vibration goes to cochlea

19

Aminoglycoside Ototoxicity (3)

Dose dependent damage to hair cells, can have genetic predisposition (often through mtDNA). Starts at cells w/ greater energy requirements (high freq) and progresses from OHCs to IHCs, base to apex

20

Speech Audiogram w/ OHC Damage

Need 50 dB to just start picking up any sound, and never get 100% bc missing cells to tune to those words

21

Cochlear Implant

Electrodes that process sound turn sound into electrical signals and placed inside cochlea at same tonotopic distribution

22

2 Kinds of Noise Induced Hearing Loss

Temporary Threshold Shift (TTS)
Permanent (PTS)

23

Sign of NILH on Pure Tone Audiometry Test

Backwards check mark at end

24

Socio-acusis

Leisure noise exposure

25

Presbycusis

Hearing of loss from age, hair cells damaged first then nerve fibers. High pitch goes first.

26

Connexin 26

AR nonsyndromic, most comon cause of genetic hearing loss in children