Notes for Chapter 1 p.25 35
Hair cells / frequency moving
The physical shape of the hair cells on the chlea changes as the frequency changes.
-One end vibrates at a low frequency.
-The other end of the vibrations only move during the hig
311 2. 25. 14
Audiogram sometimes separate or same chart
- Chart threshold results from hearing test frequency in Hz across top then intensity in
dB on side. Quiet on top loud on bottom.
- Audiometric can only go to 110 dB so no response means you went as
Air conduction vs. Bone conduction
Air conduction pathway is the process of going through the sound comes in through the
outer ear, the middle ear, then the inner ear then into the auditory Nerve pathwayhow we do a
lot of our hearing. Its the most efficie
Middle Ear Functions
When sound frequencies hit the eardrum, it makes the eardrum start to vibrate back and forth.
Malleus, which is physically attached to the eardrum, will begin to move.then incus.then the
In the oval windoware holes into the co
A Frequency Problem
Freq = 8 Hz
- We have 4 cycles in a cycle (where is stops in the given) How many cycles per
- Each cycle take a 4th
Period = 1/2sec or .125sec (measured in seconds)
There are 4 cycles in a second (.5) to get to 1 ful
311 Fundamentals of hearing
Central Auditory Nervous System
Brainstem, Thalamus, and the Auditory Nerve
Auditory nerve: even when sound is coming into to one cochlea. Its traveling up
both sides of the brainstem, it goes up to both thalamus into the audit
o Early intervention (of ANY kind!) is key!
o 1-3-6 goals
o Screened by 1 month in hospital
o Diagnosed by 3 months
o Intervention implemented by 6 months
- ABR (BEAR)
o Brainstem /thalamus function
IS BC outside normal limits? (Is there SNHL?)
Is AC 11+DB away from BC? (Is there conductive HL?)
Yes + Yes => Mixed HL
-Sensorineural usually a cochlea problem than nerve system problem
- If BC is outside of normal limits on the
The study of sound
What we hear!?! We need 3 things to make sound happen.
1) Energy Source
3) Vibrating Object
Sound needs a medium cant travel through a vacuum
Air pressure and temperature affects how sound moves (travels) through the
Hearing Tests Basics of testing
How does sound get into the ear?
Basics where and how?
Testing in a sound booth: there is a window a layer of form to keep out the sound and 2
Top 3 for air conductio