Tools of Audiology

Math and acoustics applied to the clinical instruments of hearing.

This book takes the physics of sound, the biology of hearing, and the mathematics behind them into the audiology clinic, and walks through the tools an audiologist uses to characterise a patient’s auditory system and to intervene when something is wrong.

Each chapter pairs one clinical tool with the physics it probes. The audiogram is pure-tone psychophysics applied to threshold detection. Tympanometry is acoustic-impedance measurement at the eardrum. Otoacoustic emissions are the cochlear amplifier’s signature, recovered with a probe microphone. Hearing aids are real-time DSP shaped by compression theory and feedback control. Cochlear implants replace the cochlea’s transduction with direct electrical stimulation. Every instrument is an applied physics problem, and this book treats it as one.

Chapters

1. Chapter 1What is audiology?The field, the toolkit, the map of this book
2. Chapter 2The audiogramPure-tone audiometry: dB HL, air and bone, masking, configurations
   1. 2.1Pure-tone audiometry
   2. 2.2Decibels: SPL, HL, SL
   3. 2.3Air and bone conduction
   4. 2.4Masking and audiogram configurations
3. Chapter 3Speech audiometrySRT, WRS, speech-in-noise, articulation index
   1. 3.1Speech reception threshold and word recognition
   2. 3.2The speech banana and the audibility map
   3. 3.3Speech in noise: HINT, QuickSIN, AI / SII
4. Chapter 4Tympanometry and the middle earAcoustic admittance, tympanograms, acoustic reflex
   1. 4.1Acoustic immittance: impedance, admittance, the probe
   2. 4.2The tympanogram and the Jerger types
   3. 4.3The acoustic reflex and what it localises
   4. 4.4Eustachian tube dysfunction and the C-tympanogram
5. Chapter 5Otoacoustic emissionsTEOAE, DPOAE, and the cochlear amplifier as clinical signal
   1. 5.1The cochlear amplifier as clinical signal source
   2. 5.2Transient-evoked OAEs and newborn screening
   3. 5.3Distortion-product OAEs and the DP-gram
6. Chapter 6Evoked potentialsABR, ASSR, CAEP — signal averaging from the EEG floor
   1. 6.1Signal averaging and the EEG noise floor
   2. 6.2The auditory brainstem response (ABR)
   3. 6.3ASSR and CAEP: frequency-specific and cortical responses
7. Chapter 7Hearing aidsDSP, WDRC, directional processing, feedback cancellation
   1. 7.1The hearing-aid DSP pipeline
   2. 7.2Wide-dynamic-range compression
   3. 7.3Directional microphones and noise reduction
   4. 7.4Feedback cancellation and frequency lowering
8. Chapter 8Real-ear measurement and verificationProbe-tube mics, REIG/REAR, NAL-NL2 and DSL targets
   1. 8.1The probe-tube microphone and the REUR
   2. 8.2REIG and prescription targets
   3. 8.3Verification protocol and clinical practice
9. Chapter 9Cochlear implantsElectrode arrays, processing strategies, electric hearing
   1. 9.1The electrode array and current spread
   2. 9.2Processing strategies: CIS, ACE, FSP
   3. 9.3What electric hearing sounds like
10. Chapter 10Bone-conduction devicesBAHA, transcutaneous and percutaneous, skull-vibration modes
    1. 10.1Skull vibration and the bone-conduction route
    2. 10.2Device classes: BAHA, Attract, Osia, Bonebridge
    3. 10.3Candidacy, outcomes, and closing the book
11. GlossaryTerms used in this book
12. Chapter HHistoryA chronological narrative
13. Chapter SStudySpaced-repetition review
14. BibliographySources and further reading