Intro to Hearing Sciences & Clinical Audiology
Cultural & Ethical Frame
Acknowledgement of Gadigal land; value of Indigenous knowledge systems
Indigenous concept of “Deep Listening”
Listening with all senses; heightened awareness beyond ear-hearing alone
Commitment to culturally safe, person-centred, non-ableist practice
Respect diverse communication modes (Auslan, spoken language, lip-reading, devices)
Ask clients their preferred terminology (deaf, Deaf, hard-of-hearing, etc.)
Avoid outdated terms (e.g. “deaf and dumb”)
Why Audiology Matters for Speech Pathologists
Communication ≈ integration of speech, language, cognition and auditory access
Therapies & assessments rely on clear auditory input
Misdiagnosing articulation / phonological errors if hearing not ruled out
Oral cognitive tests unreliable if client misses stimuli
Advocacy role
Identify, screen, refer, & collaborate with audiologists
Bridge siloed services; promote holistic, trans-disciplinary care
Epidemiology & Public-Health Numbers
Prevalence
\frac16 Australians (≈17%) have measurable hearing loss
Neonates: \frac{4}{1000} fail newborn screen
Children/teens (<15 y): ≈15 % present with some impairment
Adults ≥71 y: 75\% have disabling loss (criteria for hearing-aid candidacy)
Acquired vs congenital
Majority of losses develop after infancy (noise, ageing, otitis media, genetics, trauma)
Screening landscape
Universal newborn hearing screen (UNHS) within 48 h – Australia pioneered
No mandatory follow-up screens (preschool, school-entry, adolescence, workforce, retirement)
German 2023 cohort: largest detection peak at 4–6 y despite UNHS
Consequences of under-detection
Language delay, academic impact, social isolation, cognitive load ➜ fatigue ➜ memory decline
Potential link between sensory degradation (hearing, olfaction) & dementia
Fundamentals of Sound & Physics
Sound = mechanical vibration of air particles (longitudinal pressure waves)
Demonstrated by pendulum/ball energy transfer & polystyrene tube standing waves
Measurands
Frequency (Hz), amplitude (dB SPL/HL), phase, duration
Noise dose = \text{Intensity} \times \text{Exposure Time} (regulatory safe-listening limits)
Anatomy & Physiology Review (Outer → Central)
Outer ear
Pinna focuses & filters; ear canal (~1 cm³, S-shaped) affords protection
Middle ear
Tympanic membrane (ultra-thin) converts air vibration ➜ mechanical
Ossicles: malleus, incus, stapes amplify (~20–30 dB) & impedance-match
Eustachian tube ventilates; fluid accumulation (otitis media with effusion) stiffens chain
Inner ear (cochlea)
Snail-shaped, pea-sized; fluid waves deflect basilar membrane
Tonotopic: base = high Hz, apex = low Hz ("keyboard" analogy)
Hair cells (≈15{,}000–20{,}000)
Stereocilia bend ➜ mechano-electrical transduction ➜ neurotransmitter release
Auditory nerve (VIII) preserves tonotopy (outer fibres = HF, core = LF)
Central processing (oversimplified in video)
Brainstem nuclei → midbrain → thalamus → auditory cortex
Higher-order functions: segregation, recognition, memory, linguistic decoding
Audiology: Professional Scope & Tools
Training pathway: Master’s degree (Australia & most countries)
Roles
Diagnostic assessment (behavioural & physiological)
Hearing aids, cochlear implants, bone-anchored, middle-ear & assistive tech selection & fitting
Tinnitus & vestibular evaluation/rehab
Environmental modification & counselling
Practitioner spectrum
Audiologist (Master’s) vs Audiometrist (TAFE diploma; adult, low-complexity focus)
Core clinical logic
Is there dysfunction along auditory pathway?
Anatomical site (outer/middle/inner/retro-cochlea/central)?
Reversible, medical, surgical, or compensate with devices?
Consequences & psychosocial impact; multidisciplinary intervention plan
Reliance on calibrated equipment & systematic deduction – mis-calibration → misdiagnosis
Speech Pathology ↔ Audiology Interfaces
Overlapping populations
Cranio-facial anomalies (e.g., cleft palate → 90 % OME)
Neurogenic disorders (aphasia, TBI, dementia) – high co-prevalence of HL
Voice & swallowing clients may concurrently have HL due to age or etiology
Collaboration workflow
Case history: "Last audiogram?" If >12 m or unknown → screen/refer
In-session red flags: mishears, requests repetition, abnormal articulation patterns, flat prosody
Screening tiers
No-equipment quick checks (Ling-6, whisper test)
Portable screener audiometer / tympanometer
Referral to GP ➜ audiologist for full diagnostic battery
Incorporate results into therapy goals & accommodations (visual supports, FM mics, captioning)
Devices & Lived Experience (Kate’s Story Highlights)
Progressive loss detected via school screen at 11; psychosocial isolation → suicidal ideation (21)
Coping pathway
Hearing aids + lip-reading + Auslan classes
Cochlear implant at 29 (initial "alien" sounds → neuro-plastic adaptation)
Bimodal fitting (CI + GN Resound HA) for bilateral benefit
Wireless accessories (multi-mic, phone clip) & iOS app control
Outcomes: music appreciation (Coldplay "Yellow"), localisation, parent-child communication
Take-home themes
HL journey is lifelong, dynamic, emotional
Technology helps but never fully "restores" normal hearing
Family, counselling, and environmental supports remain crucial
Ableism, Language & Inclusivity
Device-centric "fix" narrative vs Deaf cultural pride
Most audiologists do not use sign language; reasons
Adult-onset HL group (largest cohort) remains oral
Time & community immersion required for fluency
Interpreter collaboration common; baseline Auslan advocated for all health professionals
Promote dual goals
Maximise access (spoken, signed, written, visual, tactile)
Respect consumer choice & identity (Deaf, hard-of-hearing, cochlear implanted, etc.)
Prevention & Public Health
Noise-induced loss: identifiable audiometric "notch" at 3–6 kHz
Safe-listening on devices; occupational dose regulations (pub workers, musicians)
Healthy lifestyle (vascular health, diet, exercise) may slow presbycusis – not reverse it
Emerging therapies
Hair-cell regeneration drug trials (human) – partial gains ≈ CI benefit; long-term unknown
Course Content Roadmap (Audiology Blocks)
Week 4 Hearing screening vs diagnostic evaluation; intro to audiograms
Week 5 Types of HL (conductive, sensorineural, mixed); symbol conventions; Quiz 1
Week 8 Advanced diagnostics (speech audiometry, OAEs, ABR); surgical decision criteria
Week 9 Tympanometry, middle-ear pathologies; Quiz 2
Week 10 Speech-based test batteries; device candidacy & fitting rationale
Week 11 Physiological tests (OAE/ABR detail, newborn protocols)
Week 12 Comprehensive review before final exam
Practical Tips for Student Clinicians
Always check/ask for recent audiogram (<12 mo) before speech-language assessment
Use amplification systems, microphones, real-time captions in clinic/class when available
Speak facing the client; clear rate; avoid saying "never mind" – maintain conversational equity
Document hearing status & accommodations in every report/plan
Encourage families to attend audiology follow-ups; provide written referrals & rationale
Key Numerical & Formula References
Prevalence: \text{HL} \approx 17\% of general population
Newborn screen false-negative importance: majority of childhood HL diagnosed post-UNHS (4–6 y peak)
Noise dose concept: D = L \times t where L = level (dB) & t = exposure time (h)
Ossicular chain gain ≈ 20\,\text{dB} (log-pressure ratio \approx 10^{\frac{20}{20}} = 10)
Further Reading / Resources
Andrew Solomon – "Far from the Tree" (chapter on Deaf culture vs medical model)
Oliver Sacks – "Seeing Voices"
WHO World Report on Hearing 2021
AIATSIS resources on Indigenous sign languages & deep listening (Dadirri concept)
National Acoustic Laboratories (NAL) publications – noise dose & safe listening
Action Items Before Week 4
Review ear anatomy & basic acoustics (Hearing Science lectures)
Locate recent audiogram examples on Canvas; practise symbol identification
Attempt Ling-6 & whisper tests with peers to experience quick screens
Register interest in Auslan Level 1 (USYD Sign Language Society)