Clinical Audiology Semester 1 Comprehensive Revision Notes

CAC Assessment Overviews

• Clinical Audiology (CAC) OSCE Details:

  • Date: Wednesday, June 17.

  • Structure: Two stations, with a duration of $10$ minutes per station.

  • Focus: The stations will exclusively feature paediatric patients. Candidates are expected to explain their clinical reasoning out loud during the assessment.

  • Preparation: Review Patrick’s pediatric case study lecture for pedagogical framing.

  • Equipment/Personnel: Because real children cannot be used, stations may include an examiner and a person acting as the child, or a head model to simulate the pediatric physical environment.

  • Scope: Focuses on technical skills, communication, and management. Advanced vestibular skills like VHIT (Video Head Impulse Test) are not expected to be performed on children in this assessment.

• CAC Written Exam Details:

  • Date: Friday of the second week of the exam period.

  • Structure: $2$ hour exam worth a total of $120$ marks. The aim is approximately one mark per minute ($1$ mark/$1$ minute).

  • Content: Everything covered in Semester 1 is assessable. The exam builds upon foundational clinical reasoning and justification processes learned in APA (Audiological Practice A) and APB (Audiological Practice B) from the previous year.

  • Format: Case-based application. There are no multiple-choice questions.

  • Resources: Practice exams are available, but answer keys are not provided. Students are encouraged to use the provided worksheets and TBL (Team-Based Learning) workbooks for revision.

Vestibular Assessment and Interpretation

• Key Assessments and Functions:

  • VHIT (Video Head Impulse Test): Measures semicircular canal function at high frequencies, which correlates to day-to-day head movements. Normal gain typically falls at or above $0.7$ to $0.8$.

  • cVEMP (Cervical Vestibular Evoked Myogenic Potential): Measures the function of the saccule and/or the inferior vestibular nerve. It involves recording an output or reflex from electrodes placed on the sternocleidomastoid muscles.

  • oVEMP (Ocular Vestibular Evoked Myogenic Potential): Predominantly measures the utricle and/or the superior vestibular nerve function.

  • Dix Hallpike: A maneuver used specifically for detecting Benign Paroxysmal Positional Vertigo (BPPV) in the posterior semicircular canal.

• Case History and Differential Diagnosis:

  • ‘So Stoned’ Approach: A structured questioning method used during case history to aid in the differentiation of vestibular pathologies.

  • Importance: Case history informs clinical decisions regarding test prioritization and interpretation of findings in the context of specific conditions (e.g., M'eni(e)re’s, Vestibular Neuritis).

Case Study: John (58 and 85 Years Old)

• Scenario A: John (58 Years Old):

  • Symptoms: Unsteadiness and dizziness following IV antibiotic treatment; unilateral tinnitus; mild-to-moderate high-frequency sensorineural hearing loss (SNHL) which is significantly worse in the left ear.

  • Test Results Interpretation:

    • VHIT: All canal gain values are below $0.7$ (anterior and posterior) and below $0.8$ (horizontal), indicating high-frequency semicircular canal dysfunction.

    • oVEMP: Shows no repeatable response. A small peak appearing near a latency of $10$ ms must be scrutinized; in this case, it was identified as an artifact, not a true N10 response.

    • cVEMP: Absent responses bilaterally.

  • Summary: Bilateral vestibular hypofunction/dysfunction likely caused by ototoxicity from IV antibiotics.

  • Management:

    • Physiotherapy for vestibular rehabilitation (focusing on vision and proprioception compensation strategies).

    • ENT (Ear, Nose, and Throat) specialist referral for medical investigation due to the asymmetrical hearing loss and unilateral tinnitus.

    • Tinnitus counseling and hearing aid discussion.

    • Review of PTA (Pure Tone Audiometry) in $6$ to $12$ months.

• Scenario B: John (85 Years Old):

  • Symptoms: Unsteadiness over the last $10$ years; mild-to-moderate high-frequency SNHL.

  • Test Results Interpretation:

    • The patient exhibits semicircular canal function but absent VEMP responses.

    • Age Considerations: VEMP responses often decrease or disappear around age $60$ to $65$. In an $85$-year-old, absent bilateral VEMPs with otherwise normal vestibular findings are often considered ‘inconclusive’ rather than indicative of true end-organ pathology.

  • Management:

    • Discussion of hearing aids and symmetrical SNHL review every $12$ months.

    • Referral to general physiotherapy for strength, conditioning, and falls prevention (musculoskeletal vs. neurological focus).

Pediatric and Special Population Testing (OAEs, Corticals, ASSR)

• Otoacoustic Emissions (OAEs):

  • Measure outer hair cell function.

  • Limitations: OAEs are generally not performable or reliable in the presence of middle ear pathology (Type B tympanometry) because the pathology prevents the elicitation or recording of the response.

  • Clinical Use: Used to exclude no less than a mild-to-moderate hearing loss (< 30 to $40\text{ dB HL}$), provided tympanometry is normal (Type A).

  • Pressurized OAE: Can be attempted in patients with Type C tympanometry.

• Cortical Auditory Evoked Potentials (Corticals/Sera):

  • HearLab: An objective tool used to estimate hearing thresholds and verify aided hearing levels.

  • Clinical Applications: Useful for adults with inconsistent behavioral responses (non-organic tendencies) or for aided infants ($6$ months+) to determine if speech sounds are reaching the brain.

  • Infant Diagnostics: Corticals are NOT part of the standard initial infant diagnostic battery (which uses ABR/ASSR). Corticals require the patient to be awake/alert, while standard diagnostic ABR requires the infant to be asleep.

• Auditory Steady-State Response (ASSR):

  • Generally requires the patient to be asleep for accurate threshold estimation.

Case Study: Swesha (2-Month-Old Infant)

• Patient Context: Concern over noise exposure; high-frequency tympanometry performed.

• Test Interpretation:

  • ABR (Left Ear): Clear Wave V present at $20\text{ dB nHL}$, indicating normal mid-to-high frequency hearing in the left ear.

  • Tympanometry: Infants under $6$ months require a $1,000\text{ Hz}$ probe tone because their ear canals are cartilaginous (not a hard-walled cavity). A peak at $1,000\text{ Hz}$ indicates normal middle ear function.

  • OAEs: Present in the right ear with a Signal-to-Noise Ratio (SNR) > 6\text{ dB} across frequencies, excluding a hearing loss greater than mild-to-moderate, unless Auditory Neuropathy Spectrum Disorder (ANSD) is present.

  • Management: Reassurance for parents; behavioral testing review (VRA) at approximately $9$ months of age.

Case Study: Doreen (Cortical Testing and Consistency Checks)

• Patient Context: Medical engineer, SNHL, referred for Sera (cortical) testing due to medical panel review requirements.

• Consistency Checks:

  • Speech Audiometry: Speech curves are extremely difficult to exaggerate. If the speech curve matches the audiogram configuration and the Half Peak Level (HPL) is within $10\text{ dB}$ of the average of $1,000\text{ Hz}$ and $2,000\text{ Hz}$, the results are consistent.

  • Max Point Check: Calculated by averaging $1,000\text{ Hz}$ and $2,000\text{ Hz}$ thresholds and adding $30\text{ dB}$.

• Cortical Waveforms:

  • The P1-N1-P2 complex is tracked. As intensity increases, latency decreases (earlier) and amplitude increases.

  • Supra-thresholds: Cortical thresholds are often ‘supra-threshold,’ meaning the objective response appears at a level $10$ to $15\text{ dB}$ higher (worse) than the true behavioral threshold.

Clinical Populations: Non-Organic Hearing Loss and ANSD

• Non-Organic Hearing Loss (Pseudohypacusis):

  • Signs: Inconsistent thresholds, lack of shadowing/cross-hearing, and speech results that are ‘too good’ for the pure-tone thresholds.

  • Impact of OAEs: Present OAEs in the presence of a reported moderate-to-severe hearing loss provide objective evidence of non-organic behavior (or ANSD).

• Auditory Neuropathy Spectrum Disorder (ANSD):

  • Characterized by present OAEs (normal cochlear outer hair cell function) but absent or abnormal ABR (neural dyssyncrony).

  • Associated Conditions: Friedreich’s Ataxia is a genetically inherited condition frequently associated with ANSD.

Case Study: Hattie (Stenger Test and Friedreich's Ataxia)

• Stenger Test Principles:

  • Based on the Stenger Phenomenon: when two tones of the same frequency are presented to both ears, only the louder tone is perceived.

  • Requirement: An inter-aural difference of at least $20\text{ dB}$ at a specific frequency.

  • Setup: Present a tone at $10\text{ dB}$ above the better ear's threshold and $10\text{ dB}$ below the poorer ear's reported threshold simultaneously.

  • Interpretation:

    • Negative Stenger: The patient responds. This indicates truthfulness (true hearing loss in the poorer ear).

    • Positive Stenger: The patient DOES NOT respond. This indicates they heard the tone in the poorer ear but chose not to respond because they are faking the degree of loss in that ear.

  • Threshold Estimation: Keep the tone at $10\text{ dB}$ SL in the better ear. Increase the level in the poorer ear until the patient stops responding. The true threshold in the poorer ear is approximately the level at which they stopped responding minus $15\text{ dB}$.

Case Study: MJ (Clinical Practice and Practical Considerations)

• Scenario: $45$-minute appointment, patient has wax occlusion, history of ear infections, and cataracts.

• Priorities:

  • Tympanometry: Perform first. If it is flat with small volumes, it confirms wax occlusion.

  • Transducer Choice: Headphones are preferred over inserts if the canal is occluded to avoid pushing wax further in. However, one must check for collapsing canals.

  • Masking Rules: Apply masking if the air-bone gap exceeds $10\text{ dB}$. If thresholds are inconsistent, prioritize the frequencies with the most significant gaps (e.g., $250\text{ Hz}$ or $1,000\text{ Hz}$).

Questions & Discussion

• Q: Is the OSCE just peds or will there be adults?

• A: For the Semester 1 OSCE, it is strictly pediatric patients. No adults.

• Q: Do we do OAEs in the OSCE?

• A: You have $10$ minutes. Consider the likelihood of completing OAEs in that timeframe alongside other tasks and the availability of equipment (e.g., Titan units).

• Q: Can wax prevent OAEs?

• A: Yes, if it is completely occluding the canal.

• Q: What is the specific latency for P1-N1-P2?

• A: N1 is generally expected around $100\text{ ms}$, though there is a broad range in electrophysiological testing. Seek a repeatable P1-N1-P2 pattern.

• Q: At what age do VEMP responses diminish?

• A: They can begin to decrease from age $60$ to $65$.

Below are full detailed revision notes based strictly on the lecture transcript (no external information added). These notes condense the lecturer's explanations, exam advice, reasoning processes, and case discussions into a structured format. Based on the CAC Revision Lecture.

CAC Revision Lecture Notes

Introduction

• Final CAC lecture of Semester 1.

• Purpose:

  • Revise all CAC content covered throughout the semester.

  • Integrate knowledge from:

    • CAC

    • APA

    • APB

    • Other previous coursework

  • Focus on applying knowledge and clinical reasoning.

• Students were encouraged to:

  • Ask questions.

  • Participate in discussion.

  • Use revision resources provided.

• Additional support available through:

  • Ed Discussion

  • Drop-in revision session.

Assessment Revision

CAC OSCE

Format

• Held on Wednesday of Week 2 of exam period.

• Two stations.

• 10 minutes per station.

• Students move between rooms.

• Complete a set of tasks at each station.

Content

• Both stations involve paediatric patients.

• No adult cases.

• Students must:

  • Perform appropriate audiological tasks.

  • Explain reasoning as they proceed.

• Questions will be asked during the station.

Important points

• Real children are not used.

• An examiner is present.

• Another person may act as the child when required.

• Tasks are designed around expected student capabilities.

• Assessment may include:

  • Technical skills

  • Communication

  • Clinical management

  • Clinical reasoning

Not included

• No adult vestibular testing.

• No expectation to perform VHIT on children.

• Students should focus on appropriate paediatric test batteries.

Lecturer's advice

• Be confident in your skills.

• Think realistically about what can be completed in 10 minutes.

• Consider likely paediatric audiology tasks.

• Review Patrick's paediatric case studies lecture.

Written Examination

Format

• Friday of Week 2 of exam period.

• 2 hours.

• 120 marks.

Content

• All CAC Semester 1 material examinable.

• Builds upon:

  • APA

  • APB

  • Previous clinical reasoning knowledge.

Style

• Case-based.

• Similar format to practice exam.

Revision resources

• Practice exam.

• Topic worksheets.

• TBL workbooks.

• Kahoot repository.

• Revision drop-in session.

Exam technique

• Approximate rule:

  • 1 mark = 1 minute.

• Move on if spending too long.

• Dot points acceptable unless specifically instructed otherwise.

• Must provide sufficient detail and context.

• Be specific in terminology:

  • Example:

    • Not just "neuropathy"

    • Specify:

      • Auditory neuropathy

      • Peripheral neuropathy

      • Sensory neuropathy, etc.

Vestibular Revision

Key Concept

The most important aspect is integrating:

1. Case history

2. Differential diagnosis

3. Test results

4. Management planning

The case history guides:

• Test selection

• Prioritisation

• Differential diagnosis

• Interpretation of findings.

Vestibular Assessments

VHIT

Measures:

• High-frequency semicircular canal function.

Represents:

• Day-to-day head movement function.

Interpretation:

• Reduced gain values indicate dysfunction.

cVEMP

Measures:

• Saccule function and/or

• Inferior vestibular nerve function.

Method:

• Electrodes on sternocleidomastoid muscles.

• Records vestibular reflex responses.

oVEMP

Measures:

• Utricle function and/or

• Superior vestibular nerve function.

Dix-Hallpike

Used to identify:

• Posterior canal BPPV.

Vestibular Case: John (58 years)

History

• Unsteadiness

• Dizziness

• Following IV antibiotics

• Unilateral tinnitus

• Mild–moderate high-frequency SNHL

• Left ear significantly worse

Test Interpretation

VHIT

• Reduced gains across canals.

• Indicates:

  • Bilateral high-frequency semicircular canal dysfunction.

oVEMP

• No repeatable responses.

• Indicates:

  • Bilateral utricular dysfunction.

Important lesson:

• Apparent "blips" must occur at expected latency.

• Incorrect latency = artefact.

Overall Conclusion

Evidence of:

• Bilateral vestibular dysfunction
  or

• Bilateral vestibular hypofunction.

Most likely cause:

• Ototoxicity from IV antibiotics.

Management

Physiotherapy

Purpose:

• Compensation strategies.

Focus:

• Vision

• Proprioception

Since vestibular function is severely reduced.

ENT Referral

Because of:

• Asymmetrical hearing loss

• Unilateral tinnitus

Requires conservative medical investigation.

Audiological Management

• Hearing needs discussion

• PTA monitoring

• Tinnitus counselling

• Follow-up

Review timeframe:

• Usually 6–12 months

• Often 12 months if stable.

Vestibular Case: John (85 years)

History

• Unsteadiness over 10 years

• Mild–moderate high-frequency SNHL

Interpretation of VEMPs

Important consideration:

• VEMP responses decline with age.

Typically:

• Reduction from approximately 60–65 years onward.

Therefore:

• Bilaterally absent VEMPs in older adults may be inconclusive.

Not necessarily true vestibular dysfunction.

Reasoning:

• Semicircular canal function remained present.

• Bilateral absent VEMPs in an elderly patient may simply reflect age-related limitations.

Management

Hearing Management

• Hearing needs discussion

• Audiology review

Physiotherapy

Could include:

• Falls prevention

• Balance training

• Strength and conditioning

• Sensory integration activities

Examples:

• Walking in a straight line

• Uneven surface activities

May involve:

• General physiotherapy

• Vestibular rehabilitation.

OAEs

Infant with Type B Tympanogram

Would OAEs be performed?

Answer

No.

Reason:

• Middle ear pathology reduces ability to record OAEs accurately.

• OAEs unlikely to be measurable.

Adult with Inconsistent Thresholds

Would OAEs be useful?

Answer

Yes.

Reason:

• Useful for investigating non-organic hearing loss.

• Can help exclude hearing loss greater than mild–moderate.

Particularly useful when:

• Tympanometry is normal.

Which OAE?

DPOAEs

Used to:

• Exclude greater than mild–moderate hearing loss.

Type C Tympanogram + Normal Hearing

Theoretical answer:

• Yes, OAEs could be performed.

• Pressurised OAEs possible.

Clinical answer:

• Usually unnecessary.

• Not routinely part of the test battery when:

  • Hearing is normal.

  • Patient is consistent.

Exception:

• Investigation of auditory neuropathy.

OAE Interpretation Principles

Present OAEs

Suggest:

• Outer hair cell function present.

Can exclude:

• Hearing loss greater than mild–moderate.

Exception

Auditory neuropathy.

Present OAEs do NOT exclude auditory neuropathy.

Cortical Testing

Infant with Hearing Aids

Would corticals be performed?

Yes.

Reason:

• Can assess aided speech sound detection.

• Used with systems such as HearLab.

• Useful for hearing aid verification.

Adult with Inconsistent Thresholds

Yes.

Reason:

• Objective

• Frequency-specific

• Useful when behavioural testing is unreliable.

Infant Diagnostic Test Battery

No.

Reason:

• Infant diagnostic testing usually performed while infant sleeps.

• Corticals require infant to be awake.

• Auditory pathways not sufficiently mature in young infants.

Typical infant battery includes:

• ABR

• ASSR

• Tympanometry

• OAEs.

Infant Case: Swesha (2 months)

Findings

ABR

Wave V present at:

• 20 dBnHL

Interpretation:

• Normal hearing in left ear mid-high frequencies.

Tympanometry

Use:

• 1000 Hz probe tone.

Reason:

• Infant ear canal is not a hard-walled cavity.

• High-frequency probe tone provides more reliable information.

226 Hz tympanometry is not reliable in young infants.

OAEs

Present in right ear.

Interpretation:

• Outer hair cell function present.

• Hearing loss greater than mild–moderate can be excluded.

BUT:

• Auditory neuropathy cannot be excluded.

ASSR

Not necessary.

Reasons:

• Child awake.

• Existing results already suggest hearing is good.

Doreen Case (Corticals)

Audiogram

Summary:

• Bilateral mild–severe SNHL.

Speech Results

Consistent with audiogram.

Evidence:

• Appropriate speech curve.

• Appropriate half-peak level relationship.

Therefore:

• Not suggestive of non-organic hearing loss.

OAEs

Not expected.

Reason:

• Hearing thresholds worse than mild–moderate range.

Cortical Interpretation

Method

Threshold-seeking procedure.

At each frequency:

• Ascending and descending levels used.

Look for:

• P1–N1–P2 waveform.

As intensity decreases:

• Latency increases.

• Amplitude decreases.

Threshold identified where response remains detectable.

Important Principle

Cortical thresholds are:

Supra-threshold estimates

Meaning:

• Usually approximately 10–15 dB poorer than true behavioural thresholds.

Clinical Populations Revision

Topics included:

• Non-organic hearing loss

• APD

• Ototoxicity

• Sound intolerance

• Auditory Neuropathy Spectrum Disorder (ANSD)

Worksheets recommended for revision.

Hattie Case

Additional Information to Obtain

• Tympanometry

• OAEs

• Family history

• Timeline of hearing loss

• Progression of hearing loss

• Vestibular symptoms

• Noise exposure history

• Speech testing

Key History

Family history of:

Friedreich's Ataxia

Implication:

• Raises suspicion of auditory neuropathy.

Additional test:

ABR

Recommended because auditory neuropathy is associated with Friedreich's Ataxia.

Stenger Test

Frequency Selection

Choose:

• Frequency with largest discrepancy.

In Hattie's case:

• 250 Hz chosen.

Reason:

• Largest threshold difference.

Although any frequency with >20 dB interaural difference could be used.

Purpose

Used when:

• Non-organic unilateral hearing loss suspected.

Interpretation

Example from lecture:

• Patient stops responding at 25 dB.

Estimated threshold:

• 25 – 15 = 10 dB HL.

Indicates:

• Actual hearing threshold much better than reported.

Supports non-organic component.

CAC Revision Notes – Part 2

(Continuation from Hattie case onward. Strictly based on the transcript. No external information added.)

Hattie Case Continued

Why Hattie May Not Have Non-Organic Hearing Loss

Additional information revealed:

• Family history of Friedreich's Ataxia (FA).

• FA is genetically inherited.

• Many patients with FA present with auditory neuropathy.

Because auditory neuropathy can cause:

• Inconsistent behavioural responses.

• Variable hearing test results.

Students were encouraged to think beyond simply assuming non-organic hearing loss when responses appear inconsistent.

Stenger Test Revision

Selecting the Test Frequency

General rule:

• Any frequency with >20 dB interaural difference can be used.

Preferred approach:

• Choose the frequency with the largest discrepancy.

In Hattie's case:

• 250 Hz was suggested because it had the largest gap.

Performing the Stenger

Setup

Better ear:

• Present stimulus 10 dB above threshold.

Poorer ear:

• Present stimulus 10 dB below threshold.

Example provided:

• Better ear threshold = 10 dB HL.

• Present at 20 dB HL.

• Poorer ear threshold = 45 dB HL.

• Present at 35 dB HL.

Procedure

• Present tones simultaneously.

• Increase level systematically.

• Observe whether the patient responds.

Example

Patient responds at:

• 0 dB

• 5 dB

• 10 dB

• 15 dB

• 20 dB

Patient stops responding at:

• 25 dB

Interpretation:

• Patient begins hearing the tone in the "poor" ear.

Estimated true threshold:

• 25 – 15 = 10 dB HL

Therefore:

• Actual hearing is much better than originally reported.

Considering Auditory Neuropathy

After additional results were provided, students were encouraged to consider:

• Speech results poorer than expected.

• Presence of OAEs.

• Family history of Friedreich's Ataxia.

These findings collectively suggested:

• Possible auditory neuropathy rather than purely non-organic hearing loss.

Key point:

• Present OAEs can still occur in auditory neuropathy because outer hair cell function remains intact.