Lec 15: Auditory Processing Disorders 2

Historical Context and the Cognition Debate in Auditory Processing

• Evolution of the Field: Twenty years ago, the management of Auditory Processing Disorder (APD) was limited. Typical advice included sitting at the front of the class, keeping noise levels low, and "hoping for the best." It has since evolved into a significant and highly debated research area.

• The Defining Debate: The central point of contention in APD has historically been the role of cognition. This refers to higher-order processing skills such as memory, learning, attention, and intelligence.

• Geographical Divergence of Thought:

  • The United States: Traditionally focused on the test batteries presented as being purely auditory.

  • Britain: A strong school of thought argued that APD did not exist as a separate entity and that children labeled with it simply had attention disorders.

  • Australia: Typically sits in the middle, conducting its own research and viewing the two sides as having merit.

• Current Consensus: The debate is no longer whether APD has cognitive components, but to what degree they must be considered during diagnosis and management. The modern view is that auditory processing and cognition are intertwined and inseparable.

Conceptual Models of Auditory Processing

• The Bottom-Up Pathway Model (American Approach):

  • Sound enters the bottom of the auditory pathway and works its way up.

  • APD is viewed as a perceptual problem occurring as sound is processed.

  • Remediation focuses on base skill development (e.g., distinguishing where two sounds originate).

• The Top-Down Model:

  • Processing is driven by the central auditory nervous system at the "top."

  • Memory, prior learning, and language skills are used to make sense of arriving sound.

  • Remediation focuses on improving attention, memory, and language to improve auditory processing functionality.

• Integrated Reality: Most experts now agree these models are not contradictory; they occur simultaneously. Auditory processing in the real world is influenced by both sensory input and cognitive interpretation.

Empirical Evidence and Departmental Research

• Study on Interaction between APD and Cognition: A study conducted within the department looked at three groups of children:

  • Control Group: Children with no reported listening difficulties.

  • Suspected Group ($105$ children): Children referred for suspected difficulties.

  • Diagnosed Groups: Out of the $105$ suspected, $73$ did not have an APD on the test battery, while $32$ were found to have a deficit.

• Findings on Cognitive Variables:

  • The control group consistently scored higher in working memory, attention skills, and non-verbal intelligence ($\text{IQ}$).

  • The children who had listening difficulties but passed the battery still performed worse cognitively than the control group.

  • Children with APD deficits generally displayed the lowest scores in attention, memory, and non-verbal intelligence.

• Literacy Correlations:

  • Dichotic Digits: Poorer scores in dichotic digits (measuring interhemispheric transfer) correlate significantly with poorer reading and literacy skills in the classroom.

  • Speech in Noise: Children who perform poorly on speech-in-noise tasks also perform poorly on reading tasks.

  • NAPLAN Correlation: Research using Sound Scout (a speech-in-noise screening) showed a strong correlation with National Assessment Program – Literacy and Numeracy ($\text{NAPLAN}$) literacy scores, though interestingly, not with numeracy scores.

APD Across the Lifespan: Aging and Dementia

• Cognitive Decline in Older Adults: There is increasing evidence of a decrease in auditory processing skills in older adults, aligning with age-related cognitive decline.

  • Subtle central auditory processing tasks can often capture flags of decline before typical dementia symptoms appear.

• Spatial Processing Deficits: A study of $85$ older adults conducted by Grace (PhD student) found that more than half ($60 \%$) had a spatial processing deficit.

• Dementia Prevention: Current research investigates whether fitting hearing aids can slow cognitive decline by strengthening auditory pathways and supporting communication.

Comprehensive Diagnostic Test Battery

• The Current Standard: The battery must go beyond simple hearing tests to include:

  • Standard Audiogram: To rule out peripheral hearing loss.

  • Extended High Frequencies: To identify potential "hidden hearing loss."

  • Auditory Brainstem Response ($\text{ABR}$): While expensive and time-consuming, it is used to rule out auditory neuropathy (where detection is possible but firing is nonsensical). Historically, early-described APD cases were likely misdiagnosed auditory neuropathy.

  • Corticals: Used to assess the maturity of the auditory pathway.

• Cognitive Screening Tools:

  • TONY-IV (Test of Nonverbal Intelligence, Fourth Edition): A picture-book based assessment where users identify patterns to fill a blank box. Non-verbal testing is preferred over verbal testing to ensure language deficits do not skew intelligence results.

  • Digispan (Digit Span): Assesses short-term memory (repeating sequences) and working memory (repeating sequences in reverse). Working memory is more strongly related to listening ability because it requires information manipulation.

  • IVA QS (Integrated Visual and Auditory Continuous Performance Test): Referred to as "The Number One" or the "boring attention test." It is a $10-20 \,\text{minute}$ task where children click only when they see or hear the number "1." It measures sustained attention, impulsivity, and focus by comparing the child against age-norms (separated by medicated vs. unmedicated status for ADHD).

  • Auditory Closure: A language screening tool assessing the ability to fill in gaps in sentences (e.g., "A spider [has] eight legs"). This helps determine if a child's listening difficulty is driven by poor language comprehension.

Management Strategy: Direct Skills Remediation

• Evidence-Based Auditory Training: Programs should ideally show both improved test scores and real-world impact. Programs mentioned include:

  • SoundStorm: A $12 \,\text{week}$ iPad-based training targeting Spatial Processing Disorder ($\text{SPD}$) using a space-themed game.

  • Sound Diverse: A newer pilot game designed for generalized listening difficulties in noise, focusing on spatial listening skills but applicable even if a classic SPD pattern is not present.

  • Acoustic Pioneer - Zoo Caper Skyscraper: An animal-based game building binaural integration (balancing the two ears). It is useful when dichotic digit scores are asymmetrical.

  • Acoustic Pioneer - Insane Airplane: Targets temporal processing skills.

  • Acoustic Pioneer - Elephant Memory Training: Developed with psychology support to target auditory memory. Strengthening memory often improves performance across all other auditory processing tasks.

• The Engagement Challenge: Clinicians face difficulty competing with high-budget games like Fortnite or Minecraft. Medical training games can be perceived as boring, leading to poor compliance without parental supervision.

Management Strategy: Environmental and Compensatory Support

• Environmental Modifications:

  • Acoustic Treatment: Using carpet, posters, and soft materials to reduce reverberation.

  • Classroom Setup: Preferencing closed classrooms (one teacher, one class) over open-plan spaces, which are both acoustically and visually noisy.

  • Reducing Source Noise: Moving children away from air conditioners, heaters, or windows.

• Compensatory Strategies for Teachers:

  • Visual Supports: Writing instructions on the board to complement verbal speech. This is considered the "biggest" and most effective strategy for the entire class.

  • Active Listening: Ensuring a clear line of sight to the teacher's face.

  • Linguistic Strategies: Simplified phrasing or asking the child to repeat what they understood (though repeating can be difficult in a large class).

• Preferential Seating: While traditionally popular, it is becoming redundant in modern flexible-learning classrooms where teachers roam and students sit in groups.

Technical Interventions: Remote Microphones and Low Gain Aids

• Remote Microphones (e.g., Phonak Roger Focus 2):

  • Function: A teacher wears a mic, and the sound is sent directly to the child's ears (bypassing noise and distance).

  • Gold Standard: The most researched management tool for APD. It provides immediate support without waiting for skill-building.

  • Benefits: Improved access to instruction, reduced stress (measured by lower salivary cortisol), maturation of corticals, and improved attention.

  • Barriers: High cost and teacher resistance (forgetting to mute at the staff room/bathroom; complaints of neck soreness).

• Low Gain Hearing Aids:

  • Advantages: Discreet, no need for a second party (teacher) to manage a mic, practical for teenagers and adults.

  • Gain Characteristics: Typically provides $5-10 \,dB$ of gain, resulting in a $2-3 \,dB$ signal-to-noise ratio ($\text{SNR}$) improvement.

  • Comparison: Less effective than a remote mic but still provides massive real-world benefits.

Questions & Discussion

• Diagnosing Toddlers: Can a clinician tell the difference between APD and attention on the phone? No. For kids aged $4-5$, most appear to have APD because their auditory, language, and memory systems are still developing. Standardized testing is generally reliable starting at age $6$, but is more comfortable at age $7$.

• Left-Handedness and Dichotic Digits: Case study of an $11$-year-old left-handed child showed reversed asymmetry (left-ear dominance). This is a reversal of the typical right-ear dominance in the chimera theory of interhemispheric transfer.

• Management Barriers: The main barrier to remote microphone uptake is the high cost of Roger systems. There is research into creating cheaper, simplified versions.

• Study Abroad Opportunity: Announcement regarding a trip to Hokkaido, Japan, from June 23rdrd to 26thth. This is a self-funded multidisciplinary trip for screening and educational work. Interested students must email Kelly.

• LMS Maintenance: Canvas and LMS were reported as offline due to cybersecurity issues, though the system may be intermittently back online. Assignment marks are expected to be released next Monday via the rubric in LMS.

AUDI90061 – Auditory Processing Disorders (Lecture 2)

Detailed notes based strictly on the lecture transcript

Introduction

This lecture builds on the previous lecture about Auditory Processing Disorders (APD).

Previously, APD was often approached as:

1. Conducting an auditory processing test battery.

2. Identifying deficits.

3. Providing limited management recommendations (e.g., sit at the front of the classroom, reduce noise, hope for improvement).

Over the past 20 years, APD has become:

• A major research area.

• A highly debated area.

• An area where substantial evidence has emerged.

The focus of this lecture is:

Cognition and Auditory Processing

What is cognition?

Examples discussed include:

• Memory

• Learning

• Attention

• Intelligence

• Higher-order processing

These are the skills that contribute to how people function and process information.

Historical Debate: Auditory Processing vs Cognition

Historically there were two opposing viewpoints.

Viewpoint 1: APD is a real auditory problem

Predominantly associated with American researchers.

Belief:

• Auditory processing deficits exist.

• Deficits occur within the auditory system.

• Audiologists should assess and manage them.

Viewpoint 2: APD is really an attention problem

Predominantly associated with researchers in Britain.

Belief:

• APD does not truly exist.

• Children labelled with APD actually have:

  • Attention problems

  • Cognitive difficulties

Therefore management should focus on cognition rather than auditory processing.

Australia's Position

Australia largely sat between these two positions.

Research over the last 15 years has helped move the discussion forward.

Current debate is no longer:

Current debate is:

Bottom-Up vs Top-Down Models

Bottom-Up Model

Concept

Sound enters the auditory pathway and moves upward.

As sound travels through the auditory system:

• Auditory processing skills are performed.

• Deficits are considered perceptual deficits.

Implications

If a child cannot determine where sounds are coming from:

• The problem is viewed as an auditory processing deficit.

• Management should target auditory processing abilities.

Top-Down Model

Concept

Processing is driven primarily by higher-level cognitive systems.

To make sense of incoming sound, individuals use:

• Memory

• Prior learning

• Language skills

• Cognitive abilities

Implications

If listening difficulties occur:

• The problem is viewed as cognitive.

• Management should target:

  • Attention

  • Memory

  • Language

Current Understanding

The two models are not mutually exclusive.

Reality lies between both models.

Auditory processing and cognition:

• Occur simultaneously.

• Interact continuously.

• Together influence listening performance in real-world situations.

Therefore:

• Assessment must consider both.

• Management must consider both.

Evidence Supporting Cognitive Contributions

Historically, opinions dominated the field.

More recently, evidence-based research has replaced opinion-based arguments.

Research Example: APD and Cognitive Skills

Three groups of children were examined:

Group 1 – Controls

Children with:

• No listening concerns

• No auditory processing concerns

Group 2 – Referred but APD Not Identified

105 children were referred.

Of these:

• 73 showed no APD deficit on testing.

Group 3 – APD Identified

• 32 children demonstrated APD deficits.

Findings

The groups differed significantly in:

• Working memory

• Attention

• Non-verbal intelligence

Pattern observed

Controls had:

• Highest cognitive performance

Children with listening concerns but normal APD results:

• Intermediate cognitive performance

Children with confirmed APD:

• Lowest cognitive performance

Interpretation

There is a strong cognitive influence on listening performance.

However:

• The contribution of cognition varies between individuals.

• One child may rely more on memory.

• Another may rely more on attention.

• Different strengths may compensate for weaknesses.

Therefore:

• There is no single cognitive profile for APD.

Non-Verbal Intelligence Findings

Children with APD deficits demonstrated:

• Lower non-verbal intelligence scores.

Children performing within normal APD limits demonstrated:

• Higher non-verbal intelligence scores.

Overall Pattern

Children with auditory processing difficulties tend to have:

• Poorer attention

• Poorer cognition

• Poorer memory

• Lower non-verbal intelligence

However:

• There is no universal cut-off.

• Cognitive skills alone do not explain all listening difficulties.

APD and Literacy

Dichotic Digits and Reading

Poorer performance on Dichotic Digits was associated with:

• Poorer reading skills

• Literacy difficulties

The deficit is unlikely to be caused simply by difficulty hearing numbers under headphones.

Instead:

• Whatever causes poor Dichotic Digits performance also appears related to literacy difficulties.

Speech-in-Noise and Reading

Children who perform poorly on speech-in-noise tasks also tend to:

• Perform poorly on reading tasks.

Sound Scouts Screening Research

Recent research demonstrated:

Strong correlation with:

• Speech-in-noise scores

• NAPLAN literacy scores

No correlation with:

• Numeracy scores

Significance

If APD were purely attention/cognition:

• Numeracy should also be affected.

Because literacy is specifically associated:

• Something beyond general cognition appears involved.

Clinical Implications

Auditory processing cannot be considered independently of cognition.

Particularly important cognitive factors:

• Attention

• Memory

Different children may have different primary drivers:

Child A

Listening difficulties mainly driven by:

• Attention

Child B

Good attention but poor listening

Driven by:

• Auditory processing difficulties

Therefore:

• Clinicians must evaluate both.

Auditory Processing Across the Lifespan

Older Adults

Evidence shows:

• Auditory processing declines with age.

• Cognitive abilities decline with age.

These declines often occur together.

Dementia Research

Research is exploring:

• Whether hearing aid use can slow cognitive decline.

Future questions include:

• Whether improving auditory processing may also influence dementia progression.

Auditory Processing and Non-Organic Hearing Loss

Some individuals previously labelled as having:

• Non-organic hearing loss

May actually have:

• Auditory processing difficulties

• Attention difficulties

• Memory difficulties

These may present as listening difficulties.

Older Adult Research Example

Study:

• 85 older adults

Finding:

• Over 60% demonstrated spatial processing deficits.

Those with spatial processing deficits showed:

• Poorer executive functioning

compared to those without deficits.

Building an APD Test Battery

Traditional APD tests are only one part of assessment.

Additional domains must also be evaluated.

Hearing Assessment

Must rule out hearing loss.

ABR

The clinic routinely performs ABR.

Purpose:

Not to diagnose APD.

Purpose:

To ensure auditory neuropathy is not missed.

Why Auditory Neuropathy Matters

Auditory neuropathy may present with:

• Normal detection of sound

• Severe listening difficulties

Historically:

Some early APD cases may actually have been auditory neuropathy cases.

Cortical Measures

Cortical measures help assess:

• Auditory pathway maturation

They are considered an important component of assessment.

Non-Verbal Intelligence Assessment

Tool Used

TONI-4

(Test of Non-Verbal Intelligence)

Why Non-Verbal?

Listening difficulties may arise from:

• Language problems

• Comprehension difficulties

Using a verbal intelligence measure could be confounded by language deficits.

A non-verbal measure avoids this problem.

Alternative Sources

Where available:

• Neuropsychology reports

• Educational psychology reports

may provide equivalent information.

This avoids unnecessary duplication.

Importance of Screening

Audiologists do not perform full:

• Language assessments

• Cognitive assessments

• Psychological assessments

Instead:

Screening tools are used.

Purpose:

• Identify concerns.

• Guide referrals.

Auditory Working Memory Assessment

Digit Span

Conducted via Sound Scouts.

Forward Digit Span

Child repeats numbers in same order.

Measures:

• Auditory short-term memory

Backward Digit Span

Child repeats numbers in reverse order.

Measures:

• Auditory working memory

Clinical Significance

Working memory is considered more closely related to listening ability than simple short-term memory.

Listening requires:

• Receiving information

• Processing it

• Manipulating it

Attention Assessment

Attention screening is underutilised clinically.

Challenges:

• Expensive

• Time-consuming

IVA-CPT Style Task

Child:

• Watches numbers on screen

• Hears numbers through headphones

Task:

• Respond to "1"

• Ignore "2"

Characteristics

• Intentionally boring

• Lasts approximately 10–20 minutes

• Measures sustained attention

Outputs

Measures:

• Hits

• False alarms

• Response patterns

• Attention components

Normative Data

Results compared to:

• Same-age peers

• Same-sex peers

Can also compare:

• Medicated vs unmedicated ADHD populations

Auditory Closure

New addition to assessment battery.

Definition

Ability to fill in missing information using context.

Example:

"A spider ___ eight legs."

Expected response:

• "has"

Purpose

Screens for language difficulties.

Strong language abilities help listeners:

• Fill in missing information

• Cope with noisy environments

Poor performance may indicate need for:

• Speech pathology referral

The Venn Diagram Concept

Listening difficulties may involve:

• Hearing

• Auditory processing

• Cognition

• Language

Any deficit in one or more domains can create listening problems.

Therefore:

APD should be viewed as a shared interdisciplinary space rather than belonging exclusively to one profession.

Proposed APD Assessment Framework

Assessment should include:

Hearing

Including:

• Extended high-frequency audiometry where possible

Auditory Processing

Assessment of auditory processing domains.

Speech-in-Noise

Assessment of listening in noise.

Language

Language screening.

Cognition

Assessment of:

• Attention

• Memory

• Intelligence

Management of APD

Three broad categories:

1. Direct skills remediation

2. Compensatory strategies

3. Environmental modifications

1. Direct Skills Remediation

Target specific deficits through training.

Goals:

• Improve test performance

• Improve real-world listening

Real-world improvement is considered most important.

Sound Storm

Targets:

• Binaural interaction/Spatial listening skills

Features

• 12-week programme

• iPad/tablet based

• Space-themed game

• Increasing difficulty

Benefits

Evidence demonstrates:

• Improved test performance

• Improved real-world listening

Limitation

Compliance.

Children may stop training due to:

• Lack of engagement

• Busy schedules

• Competing interests (e.g., Minecraft, Fortnite)

Soundiverse

Newer programme.

Targets:

• Binaural interaction/Spatial listening skills

• General listening-in-noise difficulties

Can be used even when classic SPD pattern is absent.

Gamified learning structure (15-30 mins)

Broader applicability than Sound Storm.

Acoustic Pioneer

Zoo Caper

Targets:

• Binaural integration/dichotic listening skills

Recommended for:

• Dichotic Digits deficits

• Ear asymmetry

Uses:

• Simultaneous animal sounds

Insane Earplane

Targets:

• Temporal processing skills

Evidence-based but less popular with children.

Elephant Memory

Targets:

• Visual and auditory memory skills

Observed Effects

Improvement often seen in:

• Memory measures

• Auditory processing measures

Suggesting memory deficits can negatively affect multiple APD tests.

Example Case: 11-Year-Old Child

Presenting concerns:

• Attention difficulties

• Listening difficulties

Findings:

• Poor binaural integration

• Poor attention

Management:

• Zoo Caper Skyscraper

• Remote microphone technology

Outcome:

• Improved Dichotic Digits performance

• Improved listening

• Improved real-world functioning

2. Compensatory Strategies

Aim:

• Help listeners manage difficulties

• Support teachers and families

Examples

Visual Supports

Strong recommendation:

Teachers should:

• Write instructions on board

• Use visual supports

Benefits entire class.

Active Listening Strategies

Encourage:

• Better engagement

• Better understanding

3. Environmental Modifications

Preferential Seating

Traditionally:

• Sit at front of classroom

However modern classrooms often use:

• Group seating

• Flexible layouts

making this less useful.

Classroom Acoustics

Strategies include:

• Carpets

• Posters

• Soft furnishings

Purpose:

Reduce reverberation.

Closed Classrooms

Advantages:

• Less noise

• Less visual distraction

Compared with open-plan learning spaces.

Additional Considerations

Avoid:

• Noisy air conditioners

• Heaters

• Other environmental noise sources

Remote Microphones (Roger Focus)

Described as the strongest evidence-based intervention.

How They Work

Instead of amplification:

• Teacher microphone transmits speech directly to child.

Overcomes:

• Noise

• Reverberation

• Distance

Advantages

Portable.

Works across:

• Different classrooms

• Different teachers

• Different environments

Evidence

Most APD management research focuses on Roger systems.

Benefits

Improved:

• Access to teacher instructions

• Understanding of speech

Reduced:

• Listening-related stress

(measured via salivary cortisol)

Improved:

• Cortical maturation

• Attention

• Academic outcomes

• Quality of life

Low-Gain Hearing Aids

Emerging management option.

Potentially useful for children unwilling to use remote microphones.

Still an evolving area.

Case Study: Cassie (7.5 years)

Presenting concern:

• Listening difficulties in groups

No literacy concerns.

Findings

Lisn-S Results

Poor overall.

Strongest deficit:

• Spatial listening

Dichotic Digits

Abnormal.

Classic right-ear dominance pattern.

Diotic Condition

Normal.

Suggesting:

• Attention and memory not major contributors.

Frequency Pattern

Normal.

Gaps in Noise

Normal.

Cognition

Normal:

• Memory

• Language

• Intelligence

• Attention

Interpretation

Primarily:

• Spatial processing deficit

• Binaural integration deficit

Management

• Remote microphone

• Sound Storm or similar auditory training

Case Study: Tom

Findings included:

• Attention difficulties

• Memory difficulties

• Auditory processing difficulties

Attention testing:

• Extremely poor

• Child became bored and testing ended

Interpretation

Multiple contributing factors:

• Attention

• Memory

• Auditory processing

Management

Referral

Back to:

• Psychologist

• Paediatrician

for attention/ADHD support review.

Additional Supports

• Remote microphone

• Auditory training

• Communication strategies

Key Take-Home Message

Auditory processing difficulties should not be viewed solely as an auditory problem.

Effective assessment must consider:

• Hearing

• Auditory processing

• Attention

• Memory

• Language

• Cognition

The modern APD approach is:

No two children will necessarily have the same combination of contributing factors, and management should be tailored accordingly.