Mechanics of hearing

by [email protected]
Basics of Sound Waves

sound = pressure
- rms
  - 2x10-5 pascal vs 20 pascal
reflections
- acoustic impedance
  the middle ears
movable structure
malleus
sound propagation inside the cochlea
organs
- ihcs
- outer hair cell ohcs : amplifiers
diff freq will make cochlea vibrate in diff parts
cochlear tonotopic map
narrower,stiffer vs broader, more compliant
natural freq= sqr stiffness/mass
similar to ocean wave occurred in shallow vs deep zone
hair cells
mechanical gating
mechanical properties of bundle
- bundle stiffness, receptor potential, and displacement
phenomenological model
electromotility
- cochlear amplifier: without this, we can’t hear low freq
Otoacoustic emissons (OAEs)
Comparative studies of OAEs
- frogs, tokay gecko
  - organ: tympanum and …
  - we can actually attach mic to their ear and get freq
    peripheral
    idea: light from jellyfish - make the frog emit when stress to help sci bros

The Oddball Paradigm and Mismath Negativity

by Jamie O’Reily
keywords

ERP event related potential
The Oddball Paradigm
80% normal 20% mismatch (deviant)
Mismatch Negativity (MMN)
??
Sensory-memory Violation / Prediction Error
many researches
- predictive coding theory
  - sensory input >> phy feature abstraction >> deviance detection, …
    Confounds of the Oddball Paradigm
stimulus-specific adaption
auditory response sensitivity to physical properties of stimuli
Control Paradigms
some flip-flop, roving test that I don’t understand
Confounds of the Control Paradigms

Summary

MMN might be a sensory prediction-error signal
difference waveform acan obscure the effect
control paratigism suffer from confounds
implications for clinical and preclinical research

psychoacoustics - diagnosis tools for capd

by Sittiprapa Isarangura
(human perception of sound)

audiogram
normal hearing vs moderate hearing loss
ASHA (2005)
central auditory processing disorder (CAPD)
not caused by higher-order language or cognitive factors
Model of speech understanding & Structured test battery
- attention, memory
- auditory processing, speech processing, language processing
- dillon & cameron (2021)
test hearing loss >> audio processing tests >> psychoacoustic tasks
- ex.tests
  - auditory discrimination test
    - ref vs target (tell dif for duration, freq, intensity)
      - detailed vs rough, robotics
  - auditory temporal processing
    - gap detection
  - dichotic speech test (hear 2 sound from 2 ears)
    - dichotic cvs, digits, words, sentences
  - binaural interaction test
    - masking level difference
  - audiological assessment components
    - listening in spaialized noise-sentences (LiSN-S) test
- electrophysiologic measure
  question (not asked yet):
  I want to learn more how perfect pitch works

from your lecture
i think most people can identify the different between 2 different notes
is the perfect pitch is about training higher order processing similar to train people to recognize different words

Brain and Sound

fastest sense, critical for survival
auditory pathway
spectral processing
sound localization
- ITD & ILD
auditory scene analysis
- the basics of auditory scene analysis
  - many interesting stuffs
corticofugal modulation
- top down
- ohh that diagram is so similar to HMM
auditory corticses and connections
speech processing pathways
- diagram
brain correlates of music-evoked emotions
- cochlear nucleus and auditory pathway stuffs have tight connect to amygdala

hearing aid
cross hearing aid

one microphone (deaf ear) one speaker (good ear)
cochlear hearing aid
1-2M baht per ear

shock
closed to cach other
critical bands
stimulate
stimulate one >> stimulate many freq >> bad
high filadity stategy
channel one 80 channel two 20
12 to 22 electrode: similar

how to develop more detailed

attention and focus: learning

tone - pitch change low frequency

created on: Fri Dec 12 2025