Auditory System and Speech Processing Quiz

Hearing Measurement Lecture 1

• The lecture covers audiometric measurement for Speech Language Pathologists (SLPs) and Audiologists (AUDs)
• The goals of the course are to provide a foundation for understanding audiometric results for SLP students and a basis for more advanced training for AUD students
• An understanding of basic principles and techniques will be developed, including the basic tests, how to perform them, the information each test provides, and how to interpret the information.
• Diagnoses can be physiological or rehabilitative
• Physiological diagnoses deal with what may be wrong, such as conditions that might be better treated with surgery than a hearing aid.
• Rehabilitative diagnosis involves strategies for helping people overcome obstacles and limitations
• Assessment and rehabilitation of receptive communication are the primary focus of the course.
• The course differentiates between physiological and rehabilitative diagnosis.

Types of Diagnosis

• Physiological diagnosis focuses on the body level (structure and function).

• Aspects of physiological diagnosis include normal/abnormal status, site of lesion, cause, and prognosis.

• Rehabilitative diagnosis concentrates on the person level (activities and participation).

• Considerations include if there is a problem or not and the person's capacity to perform daily tasks, along with speech understanding issues and strategies for mitigating impairment and overcoming limitations.

Physiologic Perspective

• Different types of hearing loss call for different treatment options

Rehabilitative Perspective

• Hearing loss is often a normal part of aging (presbycusis)
• Hearing loss is not always a medical concern.
• Hearing impairments often affect communication and negatively impact daily life.

Audiological Diagnosis

• Audiological diagnosis involves examining body and person factors.

Making Sense of Audiological Data

• The course covers several aspects of testing including audiograms, tympanograms, and other measures to asses hearing issues.
• Various graphs and charts are used to show data

Topics

• Pure-tone air and bone-conduction measures are covered
• Audiometric masking, speech testing, issues like pseudohypoacusis, hyperacusis, and tinnitus are also discussed
• Hearing loss prevention methods are detailed in the lecture
• Topics include the immittance battery, otoacoustic emissions, paediatric assessments, electrophysiological measures, and hearing aids and implants.

Course Format

• Lectures and integrated lab demonstrations are included, as are readings with a workbook, case quizzes, hands-on lab experiences, a midterm examination, and in-class tests.

Grading

• The course utilizes case study quizzes, lab reports, and a midterm exam to assess student learning.
• The specifics of quiz and exam weights are outlined.

Case Quizzes

• The course includes short case study quizzes (~5-10 minutes) administered in class.
• Each quiz contains a clinical audiogram and 3 multiple-choice questions that assess understanding of the loss, possible cause, and appropriate follow-up.

Lab Structure

• There are 9 groups of 4 and 1 of 3. Each group receives assignments and is responsible for issues
• Group assignments will be made next week
• A member of each group leads the session (TA led)

Tests

• A midterm exam covers the first half of the course material (including behavioral measures).
• The second half of the course covers physiology, hearing aids, and implants; three specific in-class tests assess learning in that subject matter.
• In-class tests are structured to cover these topics.
• A final exam is not included.

Activity Limitations in Audiology

• The primary limitation is trouble hearing or understanding speech, usually due to more than just the loudness of the speech itself.

Loss of Tuning on Basilar Membrane

• The energy flow characteristics in the basilar membrane are crucial in maintaining auditory processing.

Details Don't Seem to Matter For Speech

• Correct letter order and sequence is not the only aspect of understanding language. The key is the initial and final words to form well-formed words

Information in Speech: Features

• Sounds like /b/, /a/, /d/, and /i/ are measured and characterized based on glottal pulses

But what is the "real" feature? Formants?

• Formants, isolated from speech, are sufficient for speech understanding. The important structures in spoken language are the sound shapes

What is the “real” feature? Another Look at Formants

• Speech Recognition in studies using primarily formants was successful

Across-Frequency Shape (Formants)

• This topic outlines the shapes across frequency, covering the critical components of speech processing (formants).

Information in Speech: the Beginning

• Initial studies on speech emphasized the importance of the wide range of frequencies in speech recognition

1/3rd Octave-Band Importance Function (ANSI S3.5)

• The specific frequency bands and their significance with regards to human hearing measurement are outlined.

Information in Speech

• The lecture reviews speech characteristics

Importance of 0-800 Hz and other frequency bands

• Studies cover the frequency ranges and their significance

General Finding and conclusions

How Does This Relate to Hearing Measurement?

• Fletcher's work on essential frequencies and their relationship to 1 mm on the basilar membrane
• Features and octaves for speech sounds.
• Audiograms and their relationships to certain speech sounds and features.

The Audiogram was Designed for This

• Audiograms are standard tools for measuring hearing

Quick Summary

• Speech perception requires processing a wide range of frequencies
• Comparison across different frequencies is the essential part of speech understanding

Formants vs. Harmonics

• Formants are crucial features in understanding speech

Mouth Movements

• Mouth movements and characteristics in speech processing

Wide Patterns, Not Local Frequency Details

• The auditory system processes sounds in narrow frequency channels, with specific differences being important

Tonotopicity persists from cochlea to cortex (PAC)

• Tonotopicity persists from the cochlea to the cortex with tonal stimulation (in chinchillas).

An simple auditory processing schematic

• Detailed schematic relating auditory processing to anatomical structures in the auditory pathways

Across frequency processing must be above the cortex! (PAC)

• Across-frequency processing crucial outside the cortex (PAC)

Across-Frequency Integration – Association Cortex

• The planum temporale (association cortex) plays a role across-frequency integration

planum temporale processes across-frequency changes

• The planum temporale processes across-frequency changes (like duration, harmonic complexes, and the like) across tasks requiring this integration.

Speech sounds are processed in the brain, not the ear

• Speech sounds are processed in the brain based on formant patterns in the frequency spectrum.

The Detail Puzzle

• The ear has precise within-channel information and temporal resolution for challenging hearing environments and sound discrimination

Auditory Chimeras (Smith et al., Nature, 2002)

• Visual depictions of hybrid species illustrate the importance of speech sound processing

Shape Across-Frequency versus Details

• Illustrative figures illustrating speech and music processing (using chimera/hybrid examples)

The Brain is for Speech The Ear is for Music

• Summarizes the respective roles of the brain and ear in speech and music processing.

Seems Like a Lot of Trouble just for Music!

• Funny, whimsical statement about music complexity

What happens in noise when the details are missing?

• There is a breakdown/failure in sound processing

And when the details are present...

• Results in the proper output and breakdown in noise processing.

Sound is All Around Us

• A general observation regarding sounds and their prevalence in the environment.

Details are required for disentangling and tracking voices

• Auditory scene analysis (using examples of unraveling audio information)

The Healthy Ear

• Overview of the healthy ear characteristics

Consequences of Hearing Loss

• Hearing loss impacts fine details encoding
• OHC damage affects frequency tuning and precision

Disentangling/Tracking Sounds is Called “Scene Analysis"

• Hearing loss affects both audibility and scene analysis.

Understanding Speech Perception

• Speech contains "shape" information, crucial for understanding and is best analyzed by audibility across frequencies.

Understanding Speech Perception

• Fine details are essential for hearing in noisy situations, including tracking and distinguishing sounds.

Going beyond English...

• Linguistic diversity influences hearing studies, given that there are multiple languages that use features not common in English

Diagnosis of Speech Limitations (overview)

• Speech understanding limitations are often primarily due to audibility.

Part Two: Physiologic Diagnosis (overview)

• Audiologist points of entry and characteristics regarding health

Diagnosis of Impairment - The Non-Impaired System

• The use of audiograms and other tests to assess the non-impaired system.

Understanding Structure and Function

• Overview of factors that affect auditory function.

The Outer Ear

• The specifics of the outer ear, structures, and functions are described.

Outer Ear Effects

• The outer ear affects the hearing response from the environment.

Role o Middle Ear

• The role of the middle ear

MAP and MAF (overview)

• MAP and MAF (in dB SPL) across different frequencies are detailed.

Human Hearing and detailed figures

• Illustrates characteristics and differences/variations between various sounds and noise.

In the Cochlea

• Describes the physical and structural components of the cochlea

The Travelling Wave

• The travelling wave characteristics, depicting how the sound waves move through the cochlea.

Basilar Membrane Pulled Upwards

• Basic drawing/diagram of BM pulling upwards

Tip Links Open Ion Channels

• Structures associated with hair cells

Action Potential is Generated

• Describes how action potentials are generated in auditory structures

How Frequency Selective?

• A method by which frequency is tested (measured)

Role of Outer Hair Cells

• Specific energy functions by outer hair cells

Neural Tuning Curves

• The curves associated with neural responses across frequencies

Cochlear Nerve Responses to Pure Tones

• Response data for cochlear nerves related to frequency.

Introduction to Diagnosis

• Overview of introduction to diagnosis.

Diagnosis is Detective Work

• Examples of diagnostic processes and information/observations gathered

Types of Assessment Overview

• General overview related to types of assessment.

Assessment Types

• Specific types of assessments.