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![5521 Ruffin Road
San Diego, CA 92123
e-mail: info@pluralpublishing.com
website: http://www.pluralpublishing.com
Copyright 2019 © by Plural Publishing, Inc.
Typeset in 11/13 ITC Garamond Std by Achorn International Inc.
Printed in the United States of America by McNaughton & Gunn
All rights, including that of translation, reserved. No part of this publication may be reproduced,
stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical,
recording, or otherwise, including photocopying, recording, taping, Web distribution, or
information storage and retrieval systems without the prior written consent of the publisher.
For permission to use material from this text, contact us by
Telephone: (866) 758-7251
Fax: (888) 758-7255
e-mail: permissions@pluralpublishing.com
Every attempt has been made to contact the copyright holders for material originally printed in
another source. If any have been inadvertently overlooked, the publishers will gladly make the
necessary arrangements at the first opportunity.
Library of Congress Cataloging-in-Publication Data
Names: Kramer, Steven J., author. | Brown, David K. (Professor of audiology),
author. | Jerger, James, contributor. | Mueller, H. Gustav, contributor.
Title: Audiology : science to practice / Steven Kramer, David K. Brown ; with
contributions by James Jerger, H. Gustav Mueller.
Description: Third edition. | San Diego, CA : Plural Publishing, [2019] |
Includes bibliographical references and index.
Identifiers: LCCN 2017057249| ISBN 9781944883355 (alk. paper) |
ISBN 1944883355 (alk. paper)
Subjects: | MESH: Hearing—physiology | Hearing Disorders | Audiology |
Hearing Tests—methods
Classification: LCC RF290 | NLM WV 270 | DDC 617.8—dc23
LC record available at https://lccn.loc.gov/2017057249](https://image.slidesharecdn.com/38347-250424184356-342354bd/85/Audiology-Science-to-Practice-Steven-Kramer-8-320.jpg)
![AUDIOLOGY: SCIENCE TO PRACTICE
4
Audiology is a discipline that focuses on the
study of normal hearing and hearing disorders.
Additionally, audiology includes the assessment
and treatment of vestibular (balance) disorders.
More precisely, audiology is a health care profes-
sion devoted to identification, assessment, treat-
ment/rehabilitation, and prevention of hearing
and balance disorders, and understanding the
effects of hearing loss on related communication
disorders. An audiologist is a professional who
has the appropriate degree and license in his or
her state to practice audiology, and who is, typi-
cally, certified by a professional board. Audiolo-
gists are the experts who understand the effects
of hearing loss on communication and how to
best improve a patient’s ability to hear.
Audiologists work with many other profes-
sionals and support personnel. The medical ex-
pert in hearing disorders is the physician. The
medical specialty related to the ear is called
otology, which is practiced by appropriately
trained and certified otologists, also called neuro-
otologists, otolaryngologists, or ear, nose, and
throat (ENT) specialists. Audiologists also work
closely with speech-language pathologists, who
are certified and/or licensed professionals who
engage in prevention, assessment, and treatment
of speech and language disorders, including
those who have hearing loss. In addition, many
audiologists are part of interdisciplinary teams,
especially when it comes to the assessment and
treatment of pediatric patients, as well as pa-
tients with implantable devices, cystic fibrosis,
cleft palate, or balance problems, to name a few.
PROFESSIONAL ORGANIZATIONS
The American Academy of Audiology (AAA) is the
professional organization for audiologists. In 1988,
AAA (often referred to as “triple A”) was founded
in order to establish an organization devoted en
tirely to the needs of audiologists and the interests
oftheaudiologyprofession(http://www.audiology
.org). Originally, AAA focused on transitioning
audiology to a doctoral level profession, which
became a reality by 2007. Membership in AAA
quickly skyrocketed, and, today, AAA has a mem-
bership of more than 12,000 audiologists (Amer-
ican Academy of Audiology [AAA], n.d. a). Prior
to the formation of AAA, the American Speech-
Language-Hearing Association (ASHA) was, and
still remains, a professional organization for au-
diologists and speech-language pathologists. The
ASHA was established in 1925 as the American
Academy of Speech Correction, and went through
several name changes including the American So-
ciety for the Study of Disorders of Speech (1927),
the American Speech Correction Association
(1934), the American Speech and Hearing Asso-
ciation (1947), and in 1978 became the American
Speech-Language-Hearing Association (American
Speech-Language-Hearing Association [ASHA],
n.d.). In its early years, ASHA focused on speech
disorders; however, during World War II, with
service personnel returning with hearing losses,
ASHA expanded its mission to include assessment
and treatment of those with hearing disorders.
The AAA and ASHA are both strong advo-
cates for the hearing impaired and related services
by audiologists, both at the state and national lev-
els. The AAA and ASHA each have professional
certifications for audiologists: American Board of
Audiology (ABA) Certification through AAA, and
the Certificate of Clinical Competence in Audiol-
ogy (CCC-A) through ASHA. In addition, each of
these organizations can award accreditation to
academic programs that meet a set of standards;
the Accreditation Commission for Audiology Edu-
cation (ACAE) associated with AAA, and the Com-
mission on Academic Accreditation (CAA) associ-
ated with ASHA.
Audiologists may also choose to join other
professional organizations. The Academy of Dis-
pensing Audiologists (ADA) was established in
1977 to support the needs of audiologists who
dispense (sell) hearing aids. The ADA later
changed its name to the Academy of Doctors of
Audiology (ADA) (http://www.audiologist.org),
and expanded its focus to any audiologists in
private practice or those who wished to estab-
lish a private practice. The Educational Audiol-
ogy Association (EAA) (http://www.edaud.org),
formed in 1983, is a professional membership
organization of audiologists and related profes-
sionals who deliver a full spectrum of hearing
services to all children, particularly those in ed-
ucational settings. Many audiologists are also](https://image.slidesharecdn.com/38347-250424184356-342354bd/85/Audiology-Science-to-Practice-Steven-Kramer-22-320.jpg)
![AUDIOLOGY: SCIENCE TO PRACTICE
8
setting. These are, we believe, hallmarks of a ro-
bust and growing profession with a remarkable
history. (p. 380)
REFERENCES
American Academy of Audiology [AAA]. (n.d.). Acad-
emy Information. Retrieved from http://www.audi
ology.org/about-us/academy-information
American Speech-Language-HearingAssociation [ASHA].
(n.d.). History of ASHA. Retrieved from http://www
.asha.org/about/history
Jerger, J. (2009). Audiology in the USA. San Diego, CA:
Plural.
Jerger, J., DeConde Johnson, C. (2014). A brief his-
tory of audiology in the United States. In S. Kramer
(Ed.), Audiology: Science to Practice (2nd ed.). San
Diego, CA: Plural.
Martin, F. N., Clark, J. G. (2015). Introduction to
Audiology (12th ed.). Boston, MA: Pearson Educa-
tion, Inc.
National Center for Hearing Assessment and Man-
agement (n.d.). State EDHI Information. Retrieved
from http://www.infanthearing.org/states_home
SYNOPSIS 1–1
l
l Audiology is a discipline that focuses on the study of normal hearing and
hearing disorders, as well as vestibular (balance) assessment and rehabilitation.
Audiology in the United States had its beginnings around the time of World
War II.
l
l An audiologist is a licensed professional who practices audiology, and is an
expert on the effects of hearing loss on communication and psychosocial
factors. Otology is the discipline primarily related to medical assessment and
treatment of hearing and balance disorders, and is the specialty practiced by
otologists.
l
l The American Academy of Audiology (AAA) and the American Speech-Language-
Hearing Association (ASHA) are the two main professional organizations serving
their audiologist members. The AAA was founded in 1988, and is entirely run
by and for audiologists.
l
l The national student organization for future doctoral level audiologists is
called the Student Academy of Audiology (SAA). Most doctoral audiology
programs have local chapters of SAA. Many undergraduate programs encourage
undergraduates to enroll in student chapters.
l
l Audiology became a doctoral level profession by 2007, and today the AAA has
more than 12,000 members.
l
l Some key historical milestones in audiology include development of immittance
measures (early 1970s), auditory brainstem response (ABR) measures (late
1970s), approval for audiologists to dispense hearing aids (1979), otoacoustic
emission measures (1980s), digital hearing aids become the dominant type
(1990s), and legislation allowing OTC hearing aids (2017).](https://image.slidesharecdn.com/38347-250424184356-342354bd/85/Audiology-Science-to-Practice-Steven-Kramer-26-320.jpg)
![AUDIOLOGY: SCIENCE TO PRACTICE
10
Audiology continues to gain notoriety in the labor
market, and has been highly recommended as a
top career choice with an excellent employment
outlook. In fact, Time Magazine (2015) ranked
audiology as the number one profession, out of
40 professions, based on job stress, salary, and
job outlook. CareerCast (2015, 2017) has ranked
audiology in the top four professions (out of 200
occupations) for having the least stressful job,
behind medical sonographer, compliance officer,
and hair stylist. The U.S. Bureau of Labor Sta-
tistics (2017) estimates that the average growth
rate for all occupations between 2014 and 2022
will be 7%; however, audiology’s projected job
growth is estimated to be 29%. The job market
outlook for audiologists is quite strong, and the
need is expected to grow substantially in the fu-
ture (Windmill Freeman, 2013).
EDUCATION AND
PROFESSIONAL CREDENTIALS
Today, the entry-level degree to practice clinical
audiology is a professional doctorate, referred to
as the Doctor of Audiology (AuD). The AuD is
a 3- to 4-year graduate degree composed of a
comprehensive curriculum with about 2000 to
3000 hours of clinical experiences, precepted
(supervised) by licensed and/or certified audiol-
ogists. The AuD is the entry level clinical doc-
toral degree, different from the research doctor-
ate (PhD) that has been available in audiology
and hearing sciences since its inception for those
interested in research and/or an academic posi-
tion. The move from a clinical master’s degree
in audiology to a professional doctoral degree
began in the late 1980s, and was a guiding force
in the establishment of the American Academy
of Audiology (AAA). The first AuD program be-
came available in 1993 at Baylor College of Med-
icine in Houston (which subsequently closed its
AuD program). In 1993, ASHA endorsed a plan
to transition to the clinical doctoral degree, and
by 2007 the AuD became required (a master’s
degree was no longer adequate) to practice audi-
ology. As of 2017, there were 75 audiology clin-
ical doctoral programs in the country (American
Academy of Audiology [AAA], n.d.).
Students entering audiology clinical doctoral
programs come from a variety of disciplines, such
as speech and hearing, psychology, education,
engineering, music, physics, computer science,
neuroscience, medicine, nursing, and business to
name a few. Audiology is a scientific discipline
and requires a relatively strong science founda-
tion and an ability to meet the challenges of a
rigorous curriculum. Most AuD programs expect
students to have some preparation in physical,
life, social, and behavioral sciences, as well as
statistics.
The curricula for AuD programs are quite
similar across programs, and are partially driven
by the professional accreditation standards, as
well as specific requirements for professional cer-
tification. A list and links to doctoral programs can
be found on the AAA website (www.audiology
.org) and the American Speech-Language-Hearing
(ASHA) website (www.asha.org). There are, how-
ever, differences across programs in the number
of faculty, the breadth of academic courses, the va-
riety and amount of clinical experiences, and the
amount of research available to students. While
most programs have a similar core of courses, a
program may have strengths in one or more areas,
or may provide more advanced preparation in
some areas, such as hearing aids, electrophysiol-
ogy, vestibular assessment, cochlear implants, tin-
nitus, business practice, and/or rehabilitation. As
part of an AuD program, students are required
to have clinical experiences that are precepted
by an audiologist or other relevant professional.
Some AuD programs have an on-campus clinic
where students begin their clinical experiences,
and then obtain additional clinical experiences in
community hospitals, clinics, or other agencies.
Other AuD programs may rely solely on the com-
munity resources for the clinical experiences.
The final year of the AuD program is called
an externship, which is usually the equivalent to
a year’s full-time clinical experience at a clinical
site approved by the AuD program. Externships
are established through specific affiliation agree-
ments developed between the externship site
and the AuD program’s institution. An externship
site agrees to have an on-site preceptor who will
take an active role in further educating and men-
toring the extern during the final year of his or](https://image.slidesharecdn.com/38347-250424184356-342354bd/85/Audiology-Science-to-Practice-Steven-Kramer-28-320.jpg)
Audiology: Science to Practice Steven Kramer
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- 6. Editor-in-Chief for Audiology BradA. Stach, PhD
- 7. AUDIOLOGY Science to Practice ThirdEdition Steven Kramer, PhD David K. Brown, PhD With contributions by James Jerger, PhD H. Gustav Mueller, PhD
- 8. 5521 Ruffin Road SanDiego, CA 92123 e-mail: info@pluralpublishing.com website: http://www.pluralpublishing.com Copyright 2019 © by Plural Publishing, Inc. Typeset in 11/13 ITC Garamond Std by Achorn International Inc. Printed in the United States of America by McNaughton & Gunn All rights, including that of translation, reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, including photocopying, recording, taping, Web distribution, or information storage and retrieval systems without the prior written consent of the publisher. For permission to use material from this text, contact us by Telephone: (866) 758-7251 Fax: (888) 758-7255 e-mail: permissions@pluralpublishing.com Every attempt has been made to contact the copyright holders for material originally printed in another source. If any have been inadvertently overlooked, the publishers will gladly make the necessary arrangements at the first opportunity. Library of Congress Cataloging-in-Publication Data Names: Kramer, Steven J., author. | Brown, David K. (Professor of audiology), author. | Jerger, James, contributor. | Mueller, H. Gustav, contributor. Title: Audiology : science to practice / Steven Kramer, David K. Brown ; with contributions by James Jerger, H. Gustav Mueller. Description: Third edition. | San Diego, CA : Plural Publishing, [2019] | Includes bibliographical references and index. Identifiers: LCCN 2017057249| ISBN 9781944883355 (alk. paper) | ISBN 1944883355 (alk. paper) Subjects: | MESH: Hearing—physiology | Hearing Disorders | Audiology | Hearing Tests—methods Classification: LCC RF290 | NLM WV 270 | DDC 617.8—dc23 LC record available at https://lccn.loc.gov/2017057249
- 9. Contents Preface ix Contributors xi PARTI Perspectives on the Profession of Audiology 1 1 The Discipline of Audiology 3 Professional Organizations 4 Development of the Profession of Audiology 5 References 8 2 Audiology as a Career 9 Education and Professional Credentials 10 What Do Audiologists Do? 11 Membership Demographics and Work Settings 14 References 16 PART II Fundamentals of Hearing Science 17 3 Properties of Sound 19 Simple Vibrations and Sound Transmission 20 Frequency 22 Phase 25 Amplitude 27 Intensity and Pressure 28 Decibels 31 Audibility by Frequency 37 Wavelength 37 Complex Sounds 39 Resonance 41 Acoustics of Speech 43 Filtering 46 Psychoacoustics 49 References 55 v
- 10. AUDIOLOGY: SCIENCE TOPRACTICE vi 4 Anatomy of the Auditory System 57 General Orientation to the Anatomy of the Auditory and Vestibular Systems 58 Outer Ear 63 Middle Ear 64 Inner Ear 68 The Sensory Organ of Hearing 69 Auditory Neural Pathways 75 References 80 5 Functions of the Auditory System 81 Air-to-Fluid Impedance Mismatch 82 Functions of the Outer Ear 82 Functions of the Middle Ear 83 Functions of the Inner Ear 87 Tuning Curves 93 Role of the Outer Hair Cells 96 Frequency Coding 98 Intensity Coding 100 Summary of the Auditory Transduction Process 102 References 104 PART III Clinical Audiology 107 6 Audiometric Testing 109 The Audiometer 110 Transducers 113 Air Conduction Versus Bone Conduction Testing 116 The Test Environment 117 Procedures for Obtaining Pure-Tone Thresholds 120 Examples of How to Establish Thresholds 121 Variables Influencing Thresholds 123 Techniques for Testing Infants and Toddlers 124 References 128 7 Audiogram Interpretation 129 The Audiogram 130 Describing Audiograms 138 Sample Audiograms with Descriptions 143 Additional Factors to Consider 143 References 150 8 Speech Audiometry 151 Speech Testing Equipment and Calibration 152 Speech Threshold Measures 154 Suprathreshold Speech Recognition 156 Most Comfortable and Uncomfortable Loudness Levels 161 Procedures for Suprathreshold Speech Recognition 161
- 11. vii CONTENTS Steps for ObtainingWord Recognition Score (WRS) 166 Interpreting Word Recognition Scores 168 Speech-in-Noise Tests 171 Variations with Young Children or Difficult-to-Test Populations 172 References 174 9 Masking for Pure-Tone and Speech Audiometry 177 Interaural Attenuation 178 Maskers 179 Central Masking 180 When to Mask for Air Conduction Pure-Tone Thresholds 181 When to Mask for Bone Conduction Pure-Tone Thresholds 182 Applying the Rules for Pure-Tone Masking 182 How to Mask for Air Conduction Pure-Tone Thresholds (Plateau Method) 186 How to Mask for Bone Conduction Thresholds (Plateau Method) 190 Summary of the Step-by-Step Procedures for Masking with the Plateau Method 193 Masking Examples 196 Masking for Speech Testing 206 References 209 10 Outer and Middle Ear Assessment 211 Otoscopy 212 Immittance 213 Tympanometry 216 Probe Tone Frequency 225 Wideband Acoustic Immittance 226 Acoustic Reflex Threshold Measurement 231 Interpretations of Acoustic Reflex Thresholds 233 Examples of ART Interpretations 237 Acoustic Reflex Decay 239 References 241 11 Evoked Physiologic Responses 243 Otoacoustic Emissions (OAEs) 244 Auditory Brainstem Response (ABR) 251 Neurodiagnostic ABR 255 Threshold ABR 256 Auditory Steady-State Response (ASSR) 258 References 261 12 Disorders of the Auditory System 263 Describing Auditory Disorders 264 Outer Ear Disorders 265 Middle Ear Disorders 270 Acquired Cochlear Disorders 277 Neural Disorders 289 Central Auditory Disorders 291 Nonorganic (Functional) Hearing Loss 294 Tinnitus 295 References 300
- 12. AUDIOLOGY: SCIENCE TOPRACTICE viii 13 Screening for Hearing Loss 303 Historical and Current Practice Guidelines 304 Hearing Identification Programs 306 Screening the Hearing of School Age Children 312 Screening the Hearing of Adults 313 Screening Outcomes and Efficacy 313 References 317 14 Hearing Aids 319 H. Gustav Mueller Who Dispenses Hearing Aids 320 Current Hearing Aid Usage Trends 321 Assessment of Hearing Aid Candidacy and Treatment Planning 324 Selection 327 Fitting Strategies 329 Basic Hearing Aid Styles 332 Hearing Aid Programming 338 Prescriptive Fitting Methods 339 Hearing Aid Verification 340 Hearing Aid Orientation 342 Validation of Hearing Aid Benefit 342 Summary 346 References 346 15 Implantable Devices 347 Specialized Heaing Aids and Auditory Implants 348 Bone-Anchored Implant (BAI) 348 Middle Ear Implant (MEI) 352 Cochlear Implant (CI) 354 CI Evaluation 356 References 358 16 Vestibular System 361 Anatomy and Physiology of the Vestibular System 362 Central Pathways Involved in Balance and Movement 367 Vestibular Disorders 371 Assessing Vestibular Disorders 375 References 382 Glossary 383 Index 407
- 13. Preface This textbook providesan introductory, yet com- prehensive look at the field of audiology. It is designed for undergraduate students, beginning audiology doctoral students, graduate speech- language pathology students, and other profes- sionals who work closely with audiologists. It is expected that the knowledge obtained in this textbook will be applicable to the readers’ future education or clinical practices. For some, it may help them decide to go into the profession of audiology. Fromsciencetopractice,thistextbookcovers anatomy and physiology, acoustic properties and perception of sounds, audiometry and speech measures, masking, audiogram interpretations, outer and middle ear assessments, otoacoustic emission and auditory brainstem responses, hear- ing screening, hearing aids, and cochlear and other implantable devices. Where appropriate, variations in procedures for pediatrics are pre- sented. Beginning students also have a lot of in terest in knowing about some common hearing disorders, and this book provides concise de- scriptions of selected auditory pathologies from different parts of the auditory system, with typical audiologic findings for many of the more com- monly found ear diseases and hearing disorders to help the student learn how to integrate in- formation from multiple tests. Also included is a separate chapter on the vestibular (balance) sys- tem, for those who wish to learn more about this important aspect of audiology. In addition, there are two chapters describing the profession of audiology, including its career outlook, what it takes to become an audiologist, as well as what audiologists do and where they practice. As a special addition, James Jerger, a legend in audi ology, and University of Arizona share their perspectives on the history of audiology in the United States; these can be found throughout the various chapters as set-aside boxes (Historical Vignettes). Although this textbook is intended for read- ers with little or no background in audiology, it is not a cursory overview. Instead, it presents a comprehensive and challenging coverage of hear ing science and clinical audiology, but written in a style that tries to make new and/or difficult concepts relatively easy to understand. The ap- proach to this book is to keep it readable and to punctuate the text with useful figures and tables. Each chapter has a list of key objectives, and throughout the chapter key words or phrases are italicized and included in a Glossary at the end of the textbook. In addition, most of the chapters have strategically-placed reviews (synopses) that can serve as quick refreshers before moving on, or which can provide a “quick read” of the en- tire text. Having taught beginning students for a number of years, the authors have learned a lot about how students learn and what keeps them motivated. After getting the students interested in the profession of audiology, information about acoustics is presented so that they have the tools to understand how the ear works and how hear- ing loss is assessed (which is what they really want to know) and these areas form the bulk of the text. Of course, the order of the chapters can be changed to suit any instructor. FEATURES AND ADDITIONS TO THIS EDITION This third edition of Audiology: Science to Prac- tice has been extensively revised from the previ- ous edition. This edition represents a collabora- tion with a new co-author, David Brown, whose ix
- 14. AUDIOLOGY: SCIENCE TOPRACTICE x long-time teaching experience and expertise in audiology and hearing science provided an op- portunity to again update and expand the text- book in order to be useful to a wider audience. We also incorporated some of the feedback re- ceived through a survey of faculty who were cur- rent or interested users of the textbook. This edition has four new chapters: (1) Outer and Middle Ear Assessment, that now includes a new section on otoscopy, more information on the use of different immittance probe-tone frequen cies, and a well-developed section on the use of wideband acoustic immittance (reflectance); (2) Evoked Responses, with more information and examples on the use of OAEs, ABRs, and ASSRs for assessing neural pathologies and auditory sensitivity; (3) Implantable Devices, that covers cochlear implants, bone-anchored hearing aids, and other implantable devices; and (4) Vestibu- lar System for those choosing to include a more comprehensive coverage of vestibular anatomy, physiology, disorders, and assessment. Another substantive change includes a revision of the chapter on Hearing Aids to make it more appro- priate for the undergraduate student or others who want an overview of this impor tant part of audiology. The chapter on Disorders of the Audi- tory System now has figures that include clinical data from a variety of audiology tests, including immittance, speech, and special tests, so that the student can begin to learn to integrate basic au- diologic test results for the different disorders. This edition has systematically reviewed each of the chapters from the previous edition to ex- pand, update, and reorganize the material to make it even more useful to the student new to audiology, and at the same time continuing to be more comprehensive than one might find in other introductory texts on audiology. Refer- ences and figures have been updated, including photos of new hearing instruments and ampli- fication devices, and some new figures on the anatomy of the auditory and vestibular systems. This edition retains the features that worked well in previous editions, including an easy-to-read format, key learning objectives, and synopses within each chapter with bulleted highlights for review. The chapters are now organized in a more traditional sequence beginning with in- formation about the profession of audiology, followed by acoustics, anatomy/physiology, and clinical audiology. Stylistically, this edition now has some set-aside boxes with ancillary informa- tion that are interspersed throughout the text- book, including much of Dr. Jerger’s historical account of audiology in the United States. We are excited about all the improvements in this edition that will help beginning students gain an even stronger foundation about audiology concepts. This edition also comes with a PluralPlus companion website which includes lecture out- lines in slide format that can be used in teaching audiological concepts, the full text of Dr. Jerger’s essay on the history of audiology, and more.
- 15. Contributors David K. Brown,PhD Associate Professor Director, AUD SIMLab School of Audiology Pacific University Hillsboro, Oregon Cheryl D. Johnson, EdD Adjunct Assistant Professor Disability and Psychoeducational Studies College of Education University of Arizona Tucson, Arizona James Jerger, PhD Distinguished Scholar-in-Residence School of Behavioral and Brain Sciences The University of Texas at Dallas Dallas, Texas Steven Kramer, PhD Professor School of Speech, Language, and Hearing Sciences San Diego State University San Diego, California H. Gustav Mueller, PhD Professor Department of Hearing and Speech Sciences Vanderbilt University Nashville, Tennessee xi
- 17. To the childrenwith hearing impairments on my school bus many years ago, who inspired me to pursue a career in audiology; To my past, present, and future students, who have always made my work enjoyable, challenging, and rewarding; To my wife, Paula, for her support and sacrifices during the writing of this text; To my colleagues who provide me with an exciting place to work, and for their camaraderie and continued support during the revision of this textbook. —Steven Kramer To my mentors and teachers who spent time answering my questions, may I spend as much time with my students as you did with me; To my colleagues, who shared their knowledge with me; To my students throughout the years who challenged me to learn more; To my family and especially my wife, Dianne, who gave up and put up with so much during the writing of this book. I promise I will be home for dinner soon! —David Brown
- 19. Perspectives on the Professionof Audiology P A R T I WELCOME to the fascinating world of audiology! In the rst part of this textbook, we will provide you with some informa- tion about the profession of audiology. We hope this part provides you with an appreciation for the rewarding aspects of being involved with the profession of audiology. In Chapter 1, you will learn about audiology and its professional or- ganizations. Chapter 1 also includes an overview of the development of the pro- fession, with contributions by Dr. James Jerger, a pioneer and continuing contrib- utor to audiological research. You will also nd some of Dr. Jerger’s historical perspectives interspersed throughout the textbook as set-aside boxes (Historical Vignettes). An extended version of this historical perspective by Jerger and De- Conde Johnson, from the second edition, is available on the companion website. In Chapter 2, you will learn about what is required to become an audiologist, the kinds of settings where audiologists prac tice, and the kinds of activities that might ll their work week. You will become fa- miliar with the varied paths you might take within audiology and the extensive scope of practice that denes the skills
- 20. of audiologists. Chapter2 also presents some current demographic trends in au- diology, as summarized from surveys regularly conducted by our professional organizations. For those interested in speech-language pathology, nursing, op tometry, rehabilitation counseling, or other related elds, we know that you will interact with people who have hear- ing loss and with audiologists, and the in- formation in this textbook will, undoubt- edly, be of use to you. We hope many of you will become intrigued by the possibil- ity of joining the profession of audiology.
- 21. 3 After reading thischapter, you should be able to: 1. Dene audiology and understand how audiology relates to other disciplines. 2. List some professional and student organizations related to audiology. 3. Become aware of professional websites’ resources to learn more about the profession. 4. Discuss how and when audiology as a profession rst began, and describe key events that transpired over the years as the profession evolved. The Discipline of Audiology 1
- 22. AUDIOLOGY: SCIENCE TOPRACTICE 4 Audiology is a discipline that focuses on the study of normal hearing and hearing disorders. Additionally, audiology includes the assessment and treatment of vestibular (balance) disorders. More precisely, audiology is a health care profes- sion devoted to identification, assessment, treat- ment/rehabilitation, and prevention of hearing and balance disorders, and understanding the effects of hearing loss on related communication disorders. An audiologist is a professional who has the appropriate degree and license in his or her state to practice audiology, and who is, typi- cally, certified by a professional board. Audiolo- gists are the experts who understand the effects of hearing loss on communication and how to best improve a patient’s ability to hear. Audiologists work with many other profes- sionals and support personnel. The medical ex- pert in hearing disorders is the physician. The medical specialty related to the ear is called otology, which is practiced by appropriately trained and certified otologists, also called neuro- otologists, otolaryngologists, or ear, nose, and throat (ENT) specialists. Audiologists also work closely with speech-language pathologists, who are certified and/or licensed professionals who engage in prevention, assessment, and treatment of speech and language disorders, including those who have hearing loss. In addition, many audiologists are part of interdisciplinary teams, especially when it comes to the assessment and treatment of pediatric patients, as well as pa- tients with implantable devices, cystic fibrosis, cleft palate, or balance problems, to name a few. PROFESSIONAL ORGANIZATIONS The American Academy of Audiology (AAA) is the professional organization for audiologists. In 1988, AAA (often referred to as “triple A”) was founded in order to establish an organization devoted en tirely to the needs of audiologists and the interests oftheaudiologyprofession(http://www.audiology .org). Originally, AAA focused on transitioning audiology to a doctoral level profession, which became a reality by 2007. Membership in AAA quickly skyrocketed, and, today, AAA has a mem- bership of more than 12,000 audiologists (Amer- ican Academy of Audiology [AAA], n.d. a). Prior to the formation of AAA, the American Speech- Language-Hearing Association (ASHA) was, and still remains, a professional organization for au- diologists and speech-language pathologists. The ASHA was established in 1925 as the American Academy of Speech Correction, and went through several name changes including the American So- ciety for the Study of Disorders of Speech (1927), the American Speech Correction Association (1934), the American Speech and Hearing Asso- ciation (1947), and in 1978 became the American Speech-Language-Hearing Association (American Speech-Language-Hearing Association [ASHA], n.d.). In its early years, ASHA focused on speech disorders; however, during World War II, with service personnel returning with hearing losses, ASHA expanded its mission to include assessment and treatment of those with hearing disorders. The AAA and ASHA are both strong advo- cates for the hearing impaired and related services by audiologists, both at the state and national lev- els. The AAA and ASHA each have professional certifications for audiologists: American Board of Audiology (ABA) Certification through AAA, and the Certificate of Clinical Competence in Audiol- ogy (CCC-A) through ASHA. In addition, each of these organizations can award accreditation to academic programs that meet a set of standards; the Accreditation Commission for Audiology Edu- cation (ACAE) associated with AAA, and the Com- mission on Academic Accreditation (CAA) associ- ated with ASHA. Audiologists may also choose to join other professional organizations. The Academy of Dis- pensing Audiologists (ADA) was established in 1977 to support the needs of audiologists who dispense (sell) hearing aids. The ADA later changed its name to the Academy of Doctors of Audiology (ADA) (http://www.audiologist.org), and expanded its focus to any audiologists in private practice or those who wished to estab- lish a private practice. The Educational Audiol- ogy Association (EAA) (http://www.edaud.org), formed in 1983, is a professional membership organization of audiologists and related profes- sionals who deliver a full spectrum of hearing services to all children, particularly those in ed- ucational settings. Many audiologists are also
- 23. 1. The Disciplineof Audiology 5 associated with the American Auditory Society (AAS) (http://www.amauditorysoc.org) and/or the Academy of Rehabilitative Audiology (ARA) (http://www.audrehab.org). Additionally, there is a national student organization for those inter- ested in audiology, called the Student Academy of Audiology (SAA) (http://saa.audiology.org). The SAA is devoted to audiology education, stu- dent research, professional requirements, and networking of students enrolled in audiology doctoral programs. Undergraduate students who are potentially interested in pursuing a career in audiology may also join SAA (Undergraduate As- sociate). Most university programs have a local chapter of SAA that is part of the national SAA. Undergraduate programs may also have a chap- ter of National Student Speech Language Hear- ing Association (NSSLHA). A wealth of informa- tion about the field of audiology and a career as an audiologist can be found on the above- mentioned websites. DEVELOPMENT OF THE PROFESSION OF AUDIOLOGY1 Prior to World War II, persons with hearing disor- ders received services by physicians and hearing aid dispensers (Martin & Clark, 2015). Audiology in the United States established its roots in 1922 with the fabrication of the first commercial audi- ometer (Western Electric 1-A) by Harvey Fletcher and R. L. Wegel, who were conducting pioneer- ing research in speech communication at Bell Telephone Laboratories (Jerger, 2009). These au- diometers were used, primarily, for research and in otolaryngology practices. Audiology as a profession began around the time of World War II, mostly because of returning service personnel who developed hearing prob- lems from unprotected exposures to high-level noises. Initially, returning armed-service person- nel were seen by otologists and speech-language pathologists, but clinical services for those with hearing loss soon evolved into a specialty prac- tice in the United States that became known as 1 Includes contributions by James Jerger and Cheryl De- Conde Johnson (adapted with permission). the field of audiology. While the effects of exces- sive noise on hearing have been recognized vir- tually since the beginning of the industrial age, it was not until World War II that the United States military began to address the issues of hearing conservation with a series of regulations defin- ing noise exposure as a hazard, setting forth con- ditions under which hearing protection must be employed, and requiring that personnel exposed to potentially hazardous noise have their hear- ing monitored. The introduction of jet aircraft Historical Vignette The first genuine audiologist in the United States was, undoubtedly, Cordia C. Bunch. As a graduate student at the University of Iowa, late in World War I, Bunch came under the influence of Carl Seashore, a psy- chologist who was studying the measure- ment of musical aptitude, and L. W. Dean, an otolaryngologist. Together, they stimu- lated Bunch’s interest in the measurement of hearing. Over the two decades from 1920 to 1940, Bunch carried out the first systematic studies of the relation between types of hearing loss and audiometric pat- terns. Bunch’s pioneering efforts were pub- lished in a slender volume entitled Clinical Audiometry, which is now a classic in the field. In 1941, Bunch accepted an offer from the School of Speech at Northwestern University to teach courses in hearing test- ing and hearing disorders, as part of the education of the deaf program. While at Northwestern University, Bunch mentored a young faculty member in speech science, Raymond Carhart. In 1942, Bunch unex- pectedly died at the age of 57. In order to continue the course in hearing testing and disorders, the Northwestern administra- tion asked Raymond Carhart to teach the course. The rest, as they say, is history, as Carhart became another one of the early pioneers of the field.
- 24. AUDIOLOGY: SCIENCE TOPRACTICE 6 into the Air Force and the Navy in the late 1940s, generating high levels of noise, was an impor tant factor driving interest in hearing protection. Early studies of the effects of noise on the audi- tory system were carried out in the 1940s and 1950s at the Naval School of Aviation Medicine, in Pensacola, Florida. Similar research programs were established at the Navy submarine base in Groton, Connecticut, and at the Navy Electronics Laboratory in San Diego, California. After World War II, audiology-specific educational programs were developed in universities to prepare profes- sionals for clinical work, as well as becoming the stage for further research efforts that would de- fine the practice of audiology. In the early years, audiology focused on rehabilitation, including lipreading (now called speechreading), auditory training, and hearing aids. During the late 1960s and early 1970s, there was a focus on the development of several objec- tive measures of the auditory system: Immittance (known then as impedance) blossomed into tests called tympanometry, used for assessing middle ear disorders, and acoustic reflex thresholds, used for differentiating/documenting conductive, sensory, and neural losses. The immittance test battery is now standard in basic hearing assess- ments. The mid to late 1970s brought our atten- tion to the clinical use of evoked electrical poten- tials, especially the auditory brainstem response (ABR), which provided an objective evaluation of the auditory system that was unaffected by sedation. The ABR continues to be used as a spe- cialty test for neurologic function, and even more importantly for both newborn hearing screening and follow-up hearing threshold assessment. In the late 1970s, otoacoustic emission (OAE) test- ing was developed as another objective measure of the auditory system, and became an accepted part of clinical practice by the late 1980s. The clinical applicability of OAE testing was the pri- mary impetus for states in the United States to adopt universal newborn hearing screening pro- grams. Marion Downs of the University of Col- orado, undoubtedly, had the greatest impact on the testing of pediatrics and, ultimately, the con- cept and realization of universal hearing screen- ing of all newborns. Dr. Downs founded the first screening program in 1962 and never ceased to push for newborn hearing screening. According to the National Center for Hearing Assessment and Management (NCHAM) at Utah State Uni- versity, all states and territories of America now have an Early Hearing Detection and Interven- tion (EHDI) program (National Center for Hear- ing Assessment and Management, n.d.). The development of better-designed hear- ing aids and procedures for hearing aid fittings was also an important step forward in treating those with hearing loss. During the early 1950s, the transistor was developed and its value in the design of wearable hearing aids was immediately apparent. An even greater impact on hearing aid design and miniaturization was the advent of dig- ital signal processing, and by the 1990s, digital hearing aids were becoming the standard. Other important advances in hearing aids included mi- crophone technology and better/smaller batter- ies. It is interesting to point out that prior to 1977, ASHA considered it unethical for audiologists to dispense hearing aids, except in the Veteran’s Hospitals. However, through the continuing in- Historical Vignette Attempts to exploit the residual hearing of severely and profoundly hearing-impaired persons has a history much longer than audiology. Long before there were audi- ometers and hearing aids, educators of the deaf were at the front lines of auditory training, using whatever tools were avail- able. Alexander Graham Bell, inventor of the telephone and founder of the AG Bell Association, took a special interest in the possibilities of auditory training because of his wife’s hearing loss. He was a strong proponent of the aural approach and lent his considerable reputation to its promul- gation in the last quarter of the nineteenth century. Another early supporter of system atic training in listening was Max Goldstein, who founded the world-famous Central In- stitute for the Deaf in St. Louis.
- 25. 1. The Disciplineof Audiology 7 terests and activities of audiologists directed to- ward dispensing of hearing aids throughout the 1970s, ASHA changed its perspective in 1979, and hearing aid dispensing soon became a large part of audiology practices. At the time of this writing (August 2017), the U.S. Congress passed legisla- tion allowing hearing aids to be sold over-the- counter (OTC) for adults with mild to moderate degrees of hearing loss, and established about a three-year time window to develop regulations and implementation. Cochlear implants (CI) were another mile- stone in audiology, beginning with the first im- plants in the 1960s. Subsequently, there was a 30-year, slow-but-steady, convincing of the pro- fession that cochlear implants were able to pro- duce remarkable results in adults and children, and now cochlear implants are well accepted in the audiology community. The progress of co- chlear implants over the past three decades has been truly remarkable. The early CI systems were essentially aids to speechreading and few users could maintain a conversation without the aid of visual cues. However, as the number of electrodes increased and speech-coding strat- egies became more sophisticated, performance in the auditory-only condition improved several- fold. It is now quite reasonable to expect that a person with a cochlear implant will be able to converse, even on the telephone. Thirty years ago, few people would have predicted that this level of performance would ever be attainable. There has also been a relatively long history in the area of vestibular disorders and testing. Bradford (1975) describes some of the early his- tory in this area that includes the early descrip- tions of nystagmus (reflexive eye movements) by Purkinjie (1820), discovery of the cerebellar and labyrinthine sources of vertigo by Flourens (1828), and the development of caloric testing by Barany (1915). Pioneering work in establishing the clinical use of electronystagmography (ENG) was done by Alfred Coats (e.g., Coats, 1975), Baloh and colleagues (e.g., Baloh, Sills, Honru- bia, 1977), and Barber and colleagues (e.g., Bar- ber and Stockwell, 1980). With advances in tech- nology in the past decade, the electrode-based ENG method evolved to an infrared video cam- era method for recording eye movements (VNG) during the vestibular exam. Other advancements include the development of rotary chair testing that rotates the whole body with head fixed in place, and posturography with a platform that allows for tilting the body in different directions. One of the more recent clinical developments is the recording of vestibular evoked myogenic potentials involving the ocular muscles (oVEMP) or the cervical muscles (cVEMP) in response to loud sounds, which have been shown to be use- ful for assessing the saccule and utricle, which are sensory organs of the vestibular system. Over the last 70+ years, audiology has evolved (often in parallel) along at least the fol- lowing eight distinct paths: l l Development of auditory diagnostic tests (behavioral and physiologic) l l Hearing aids and rehabilitation/treatment l l Pediatrics l l Auditory processing disorders (APDs) l l Hearing conservation l l Audiology in the educational (school) systems l l Tinnitus evaluation and therapy l l Development of vestibular tests and rehabilitation The reader is referred to some of the comment boxes throughout this textbook for overviews of these paths. A more complete historical account of audiology in the United States has been pub- lished by Jerger (2009). In addition, Jerger and DeConde Johnson have an expanded chapter on the development of these paths in the second edition of this textbook, which is also available in this textbook’s companion website. As Jerger and DeConde Johnson (2014) concluded, . . . it is interesting to observe the degree to which these paths have interacted. We see the fruits of progress in the diagnostic path reflected in the development of APD testing, the impact of advances in electroacoustics and electrophysiol- ogy on universal screening procedures, the influ- ence of cochlear implant advances on auditory training, and the influences of all on intervention with amplifica tion, hearing conservation, tinni- tus therapy, and audiology in the educational
- 26. AUDIOLOGY: SCIENCE TOPRACTICE 8 setting. These are, we believe, hallmarks of a ro- bust and growing profession with a remarkable history. (p. 380) REFERENCES American Academy of Audiology [AAA]. (n.d.). Acad- emy Information. Retrieved from http://www.audi ology.org/about-us/academy-information American Speech-Language-HearingAssociation [ASHA]. (n.d.). History of ASHA. Retrieved from http://www .asha.org/about/history Jerger, J. (2009). Audiology in the USA. San Diego, CA: Plural. Jerger, J., DeConde Johnson, C. (2014). A brief his- tory of audiology in the United States. In S. Kramer (Ed.), Audiology: Science to Practice (2nd ed.). San Diego, CA: Plural. Martin, F. N., Clark, J. G. (2015). Introduction to Audiology (12th ed.). Boston, MA: Pearson Educa- tion, Inc. National Center for Hearing Assessment and Man- agement (n.d.). State EDHI Information. Retrieved from http://www.infanthearing.org/states_home SYNOPSIS 1–1 l l Audiology is a discipline that focuses on the study of normal hearing and hearing disorders, as well as vestibular (balance) assessment and rehabilitation. Audiology in the United States had its beginnings around the time of World War II. l l An audiologist is a licensed professional who practices audiology, and is an expert on the effects of hearing loss on communication and psychosocial factors. Otology is the discipline primarily related to medical assessment and treatment of hearing and balance disorders, and is the specialty practiced by otologists. l l The American Academy of Audiology (AAA) and the American Speech-Language- Hearing Association (ASHA) are the two main professional organizations serving their audiologist members. The AAA was founded in 1988, and is entirely run by and for audiologists. l l The national student organization for future doctoral level audiologists is called the Student Academy of Audiology (SAA). Most doctoral audiology programs have local chapters of SAA. Many undergraduate programs encourage undergraduates to enroll in student chapters. l l Audiology became a doctoral level profession by 2007, and today the AAA has more than 12,000 members. l l Some key historical milestones in audiology include development of immittance measures (early 1970s), auditory brainstem response (ABR) measures (late 1970s), approval for audiologists to dispense hearing aids (1979), otoacoustic emission measures (1980s), digital hearing aids become the dominant type (1990s), and legislation allowing OTC hearing aids (2017).
- 27. 9 After reading thischapter, you should be able to: 1. Understand the academic and clinical requirements that are needed to become an audiologist: Know the basic difference between an AuD and PhD. 2. Know the legal requirements to practice audiology: List two pro- fessional certications that are available to audiologists. 3. Describe various paths/specialties that audiologists might follow to dene their careers. 4. Describe the general activities of audiologists and how they might spend their time in any given week. 5. Describe the types of settings in which audiologists typically work. 6. List four to six activities that are within an audiologist’s scope of practice. 7. Discuss why some activities within an audiologist’s scope of practice might diminish in importance, or disappear in the future. 8. Give an estimate of the number of audiologists there are in its professional organizations and describe the general member- ship demographics. 9. Access the professional websites of AAA and ASHA to nd AuD programs and to learn more about the profession. Audiology as a Career 2
- 28. AUDIOLOGY: SCIENCE TOPRACTICE 10 Audiology continues to gain notoriety in the labor market, and has been highly recommended as a top career choice with an excellent employment outlook. In fact, Time Magazine (2015) ranked audiology as the number one profession, out of 40 professions, based on job stress, salary, and job outlook. CareerCast (2015, 2017) has ranked audiology in the top four professions (out of 200 occupations) for having the least stressful job, behind medical sonographer, compliance officer, and hair stylist. The U.S. Bureau of Labor Sta- tistics (2017) estimates that the average growth rate for all occupations between 2014 and 2022 will be 7%; however, audiology’s projected job growth is estimated to be 29%. The job market outlook for audiologists is quite strong, and the need is expected to grow substantially in the fu- ture (Windmill Freeman, 2013). EDUCATION AND PROFESSIONAL CREDENTIALS Today, the entry-level degree to practice clinical audiology is a professional doctorate, referred to as the Doctor of Audiology (AuD). The AuD is a 3- to 4-year graduate degree composed of a comprehensive curriculum with about 2000 to 3000 hours of clinical experiences, precepted (supervised) by licensed and/or certified audiol- ogists. The AuD is the entry level clinical doc- toral degree, different from the research doctor- ate (PhD) that has been available in audiology and hearing sciences since its inception for those interested in research and/or an academic posi- tion. The move from a clinical master’s degree in audiology to a professional doctoral degree began in the late 1980s, and was a guiding force in the establishment of the American Academy of Audiology (AAA). The first AuD program be- came available in 1993 at Baylor College of Med- icine in Houston (which subsequently closed its AuD program). In 1993, ASHA endorsed a plan to transition to the clinical doctoral degree, and by 2007 the AuD became required (a master’s degree was no longer adequate) to practice audi- ology. As of 2017, there were 75 audiology clin- ical doctoral programs in the country (American Academy of Audiology [AAA], n.d.). Students entering audiology clinical doctoral programs come from a variety of disciplines, such as speech and hearing, psychology, education, engineering, music, physics, computer science, neuroscience, medicine, nursing, and business to name a few. Audiology is a scientific discipline and requires a relatively strong science founda- tion and an ability to meet the challenges of a rigorous curriculum. Most AuD programs expect students to have some preparation in physical, life, social, and behavioral sciences, as well as statistics. The curricula for AuD programs are quite similar across programs, and are partially driven by the professional accreditation standards, as well as specific requirements for professional cer- tification. A list and links to doctoral programs can be found on the AAA website (www.audiology .org) and the American Speech-Language-Hearing (ASHA) website (www.asha.org). There are, how- ever, differences across programs in the number of faculty, the breadth of academic courses, the va- riety and amount of clinical experiences, and the amount of research available to students. While most programs have a similar core of courses, a program may have strengths in one or more areas, or may provide more advanced preparation in some areas, such as hearing aids, electrophysiol- ogy, vestibular assessment, cochlear implants, tin- nitus, business practice, and/or rehabilitation. As part of an AuD program, students are required to have clinical experiences that are precepted by an audiologist or other relevant professional. Some AuD programs have an on-campus clinic where students begin their clinical experiences, and then obtain additional clinical experiences in community hospitals, clinics, or other agencies. Other AuD programs may rely solely on the com- munity resources for the clinical experiences. The final year of the AuD program is called an externship, which is usually the equivalent to a year’s full-time clinical experience at a clinical site approved by the AuD program. Externships are established through specific affiliation agree- ments developed between the externship site and the AuD program’s institution. An externship site agrees to have an on-site preceptor who will take an active role in further educating and men- toring the extern during the final year of his or
- 29. 2. Audiology asa Career 11 her program, prior to entering the profession as an audiologist. Externships are located through- out the country, and in many cases the location where one completes the externship may be dif- ferent than the location where the AuD program resides. Most externship placements require the student to apply for an available position, in- terview, and wait to see if they are offered the position. In the best-case scenario, the student may be in a position to choose among more than one offer. Currently, the externship is part of the AuD program, and a designee of the program maintains regular contact with the extern site re- garding the extern’s progress, performance, and professionalism. Upon completion of the AuD degree, includ- ing all the clinical rotations and externship re- quirements relevant for the state in which one chooses to practice, and upon passing a national examination in audiology (currently offered through Praxis), the student is eligible to apply for a license to practice audiology in that state. Some states may also require a separate license or exam to be qualified to dispense hearing aids. In addition to the legal requirement of having a state license, most audiologists choose to obtain professional certification through AAA and/or ASHA. But do not think that the education and training is over after obtaining a license and cer- tification; there are mandatory continuing educa- tion hours that must be fulfilled to maintain the license and certification throughout one’s profes- sional career. For those who wish to continue their education and obtain a research doctorate (PhD), the AuD can be an excellent foundation and a valuable asset in an academic position. WHAT DO AUDIOLOGISTS DO? Audiologists are typically educated and clinically trained as “generalists” in the areas of diagnostic assessment of patients with hearing and balance disorders, and nonmedical treatment of hearing loss, primarily through the fitting of hearing aids or other implantable devices (e.g., cochlear im- plants). Although many employment settings in- volve a wide range of activities and populations, there are many areas within the field of audiology in which an audiologist may choose to concen- trate, and many audiologists choose to be involved in more than one of these areas. Some examples of different areas within the discipline of audiol- ogy (not necessarily mutually exclusive) include: l l Pediatric audiologist: Interested and skilled in special audiological techniques of assessment and treatment of infants and children; good at counseling and working SYNOPSIS 2–1 l l Audiologists have been ranked as one of the top career choices with a projected need for more audiologists in the coming years. Audiology has also been ranked as one of the least stressful jobs. l l A professional doctorate (AuD) is required to practice clinical audiology. The AuD is obtained by successfully completing a 3- to 4-year clinical doctoral degree program, passing the national examination in audiology, and obtaining an audiology license from the state in which he or she resides. l l The AuD is different from the PhD; the latter being an academic, research-focused doctoral degree for those interested in an academic or research position. An externship is the nal year of an AuD program, and is usually a full-time, 12-month position at a clinical site that has a formal afliation with the university’s AuD program. Externs are typically selected by the clinical site, and require site-specic applications and interviews. Externships can be from states other than the state in which the program resides.
- 30. AUDIOLOGY: SCIENCE TOPRACTICE 12 with families and referral agencies. Often works in a facility primarily serving children, such as a children’s hospital. l l Geriatric audiologist: Interested and skilled in assessment and treatment of elderly patients; knowledgeable with the Medicare system; typically works in a veteran’s hospital or university clinic. l l Hearing aid dispensing audiologist: Engages in the fitting and selling of hearing aids as part of their audiology practice; typically works in a private practice, but may also work in a medical or university setting. l l Cochlear implant audiologist: Part of a team that determines cochlear implant candidacy; trained in the “mapping” of the patient’s device and monitoring its use. May also provide auditory rehabilitation for patients who have received an implant. An additional certification for cochlear implants is available through ABA (http:// www.boardofaudiology.org/cochlear -implant-specialty-certification) l l Auditory implant specialist: Part of a team that determines auditory implant candidacy for patients who may benefit from this form of implantable device (i.e., transcutaneous and percutaneous implants, etc.), trains patients in the care and use of these devices, and monitors their function. l l Educational audiologist: Provides hearing assessment and hearing aid management of children in schools; part of a team that provides input to the child’s educational plan and needs as they relate to their hearing abilities; may also engage in the evaluation of auditory processing disorders; works in a school district, often as an itinerant that services several schools. l l Vestibular (balance) audiologist: Provides balance system assessment and rehabilitation to children and adults. Often works in a hospital or clinic as part of a team with physicians, physical therapists, and optometrists specializing in individuals with disorders of the vestibular system including falls, imbalance, dizziness, and spatial disorientation. l l Intraoperative monitoring specialist: Skilled in evoked potentials in a variety of modalities; high level of knowledge in neurology and anatomy; assists surgeons in the operating room; often contracts with hospitals. Additional certification is needed through the American Board of Neurophysiologic Monitoring and/or the American Board of Registration of Electroencephalographic and Evoked Potential Technologists. l l Military audiologist: An enlisted audiologist (Army, Navy, or Air Force) who performs assessment and treatment of armed services personnel, recruits, and their families; establishes appropriate hearing conservation programs to monitor noise levels of enlisted personnel; works in a community-based military hospital. l l Industrial (hearing conservation) audiologist: Specializes in consulting with industrial companies with potentially excessive noise levels to establish appropriate hearing conservation programs to monitor noise levels, assess hearing, and educate employees and employers about protecting their hearing; contracts with companies. l l Academic audiologist: Clinically educated and credentialed faculty member who is part of a university audiology program; may teach, conduct research, and precept students in a university-based clinic. l l Research audiologist: Engages in hearing research, usually of an applied nature; often funded by grants in a university or hospital setting; may also work in private research institutes or in companies that develop test equipment or hearing aids. l l Forensic audiologist: Specializes in legal cases related to hearing loss and issues related to environmental or industrial noise; gives occasional depositions or testimony in legal cases; usually done outside of a regular job as an audiologist.
- 31. 2. Audiology asa Career 13 l l Animal audiology: Specializes in the assessment of hearing in animals (emphasis on canines), including the use of auditory brainstem responses (ABR). Works closely with veterinarians to evaluate hearing in the more than 80 breeds with genetic hearing loss and other dogs with age- or noise-related deafness. Usually done as a portion of an audiologist’s regular job. May also engage in fitting animals with hearing aids. Specialty training and certificate are available (http://www.fetchlab.org). Audiologists provide a variety of services to meet the needs of persons with hearing and bal- ance problems. As mentioned earlier, audiologists are involved with identification (screening), as- sessment, treatment, and prevention. Audiologists might wear different hats or many hats, such as those of a diagnostician, therapist, counselor, con- sultant, preceptor, team leader, advocate, business person, researcher, and/or teacher. An audiolo- gist’s role as a teacher might involve being an AuD student’s preceptor, providing in-service training sessions, or case study presentations to other hos- pital staff, medical students, residents, and fellows. They might develop brochures and workshops for consumers and industry on the effects of hearing loss or its prevention and treatment. They might lead aural rehabilitation group therapy sessions with adults, or auditory habilitation therapy ses- sions with children who have hearing loss. They might be asked to provide input on treatment plans for those receiving cochlear implants, oto- toxic medications, vestibular disorders, tinnitus, head injury, speech-language disorders, and/or a child’s school-based educational plan. Audiol- ogists must be able to assess and treat patients of all ages, including, for example, newborns and patients with a variety of disabilities, and must be culturally and linguistically sensitive in their selection of tests, counseling, and treatment. Audiologists working in hospitals or clinics spend a good deal of their time planning, per- forming, and interpreting diagnostic tests; usually this is followed by some patient counseling, con- sulting with the physician, writing a report for the patient’s chart, and filling out the billing informa- tion. In many cases, the audiologist seeks addi- tional services for the patient. Most patients who come to an audiologist for hearing problems will receive a basic audiological assessment, including pure-tone audiometry, speech tests, immittance tests, and otoacoustic emissions. When appropri- ate, advanced tests may be scheduled, such as au- ditory brainstem response (ABR) or assessment of auditory processing disorders. In addition, audiol- ogists are often involved with vestibular (balance) testing, tinnitus assessment, and facial nerve test- ing. Audiologists must keep up with technological advances and learn to incorporate new equipment and tests into their practice. Audiologists are experts in hearing aid fit- tings. They determine hearing aid candidacy, per- form hearing aid fittings, and verify and validate the hearing aid fitting and benefits (outcome mea- sures). They remove ear wax (cerumen manage- ment) when appropriate, make ear impressions, order hearing aids from a selected manufacturer, handle the sales transaction, and provide the nec- essary orientation, counseling, and follow-up ser- vices. Audiologists also are knowledgeable about other assistive listening devices, such as FM or infrared amplifying devices, personal listening devices, amplified telephones, Bluetooth technol- ogy, and/or alarms for those who are deaf. In many situations, audiologists are part of specialty teams consisting of physicians, nurses, and speech-language pathologists, working with patients who have cleft palate, cystic fibrosis, childhood hearing loss, or those being fit with cochlear implants or other implantable devices. Many audiologists are also involved with new- born hearing screening and work closely with pediatric nurses and trained volunteers or other hearing screening staff. Audiologists use established and emerging technologies as tools to facilitate their patient care; however, it is important to realize that au- diologists are the most knowledgeable of all pro- fessionals regarding the effects of hearing loss on communication, and how to improve the quality of life for individuals and families who are deal- ing with hearing loss. Counseling, treatment, and extended rehabilitation are very important and
- 32. AUDIOLOGY: SCIENCE TOPRACTICE 14 rewarding aspects of an audiologist’s role. The human characteristics that are important skills for audiologists are described thoroughly by DeBonis and Donohue (2007) and include such things as listening, respect for the client’s beliefs, understanding the feeling of the patient and how the hearing loss impacts the patient’s life, clinician- patient interaction styles, and collaboration with the patient and other professionals. The AAA and ASHA have each developed a document called the scope of practice that de- scribes services that are considered appropriate for audiologists. These documents are available on the respective websites (www.audiology.org; www.asha.org), and are periodically updated to reflect changes in the profession. Although the scope of practice defines the wide range of ac- tivities in which audiologists may engage, it does not imply that all audiologists have the necessary knowledge and skills to perform all the activities. Therefore, an audiologist should only perform those activities that he or she feels adequately trained to do, or obtain the necessary training should something unfamiliar be required as part of one’s job. In addition to all the activities men- tioned in the preceding sections, here are some other activities considered within the scope of practice: l l Otoscopic examination of the external ear l l Screening of speech, language, orofacial, and cognitive disorders l l Identification of high-risk factors associated with hearing, speech, or balance problems l l Cerumen (ear wax) management (consult state licensure limitations) l l Perform and interpret tests of sensory and motor evoked potentials, including intraoperative monitoring (NIOM), electromyography of facial nerve function (ENOG), and vestibular evoked myogenic potentials (VEMP) l l Perform tests of vestibular function, including videonystagmography (VNG) or electronystagmography (ENG), balance platform testing (posturography), and rotary chair testing l l Evaluation of auditory processing disorders l l Cochlear implant mapping l l Noise measurements and consultations regarding environmental modifications that might impact hearing and communication l l Tinnitus evaluation and treatment l l Design and conduct audiologic research On a final note, the audiology scope of practice will change over time, or some activities will take on less importance as new techniques emerge, current techniques go by the wayside, or other specialists reclaim the turf. For example, the use of ABR to diagnose 8th cranial nerve tu- mors has been supplanted, to a large extent, by improved imaging techniques, such as contrast computerized tomogram (CT) and magnetic res- onance imaging (MRI) scans. However, the use of ABR to determine auditory thresholds is on the rise due to the increasing need to determine out- comes of newborn hearing screening programs and any necessary infant follow-up for suspected hearing loss. As another example, some audiolo- gists are involved with intraoperative monitoring (by virtue of their experience with ABR record- ing), often involving evoked potential measures of spinal nerves during back surgery; and it is conceivable that this type of work may be sub- sumed by other specialists in the future. MEMBERSHIP DEMOGRAPHICS AND WORK SETTINGS Windmill and Freeman (2013) reported that there were about 16,000 licensed audiologists in the United States, of whom about 12,800 were involved with providing patient care. According to a recent survey by ASHA (American Speech- Language-Hearing Association, n.d.), at the end of 2016 there were 13,118 ASHA certified audiolo- gists (and 162,473 speech-language pathologists). Males comprised 14.9% of audiologists (com- pared with 3.07% of speech-language patholo- gists). Age is relatively evenly distributed among ASHA members who are less than 35 years (30%), 35 to 44 years (28%), 45 to 54 years (20%), and older than 55 years (23%). Only about 7.9% of audiologists and speech-language pathologists
- 33. Other documents randomlyhave different content
- 34. A good idea,approved Barnabas. By the light of the moon he scraped the ashes off the big slab of stone that was set in the floor of the chimney, and he was about to pry the stone itself loose when something seemed to occur to him. He straightened up, and glanced toward the door. What is the matter? asked Nathan. I'm thinking of Simon Glass, Barnabas answered. Why, I forgot all about him, exclaimed Nathan. He and what was left of his party must have turned back. I didn't see them at the fort. But I did, lad, declared Barnabas. Glass marched in with the Rangers, and that young Godfrey was close behind him. Yes, I seen 'em both, corroborated Atwood. I was watching the Indians all the time, and Colonel Butler, said Nathan. So Glass has arrived then? But you don't think he'll give us any more trouble? Barnabas only shook his head. McNicol, he said, stand yonder by the door, an' keep your ears to the wood. Watchin' won't come amiss. The man went to his post, and Barnabas stooped down and lifted the slab. He dropped to his knees, dug rapidly into the dirt with a knife, and lifted out a flat tin box, much rusted. He forced the lid open and handed Nathan a packet of papers sealed with green wax. The lad pressed it reverently to his lips. I won't look at them, he declared. The seal shall remain unbroken until I find my father, or until I am satisfied that he is dead.
- 35. It would bewise to learn the contents, lad, said Barnabas. Nathan shook his head. My father's secret is sacred to me, he replied. If he is alive, he would wish me to guard it, I know. But the papers must not be lost. Will you keep them for me? BARNABAS HANDED NATHAN A PACKET OF PAPERS Barnabas readily—even eagerly—assented. The packet was not large, and he thrust it deep down into one of his wide-topped boots. It's just damp enough not to crackle, he said, as he dropped the slab back into place, and cunningly strewed the ashes over it again— a wiser bit of forethought than he knew. Now, he added. We'll be off—
- 36. Hist, men! McNicolinterrupted, in a whisper. Come hither, quick! The three joined the Scotchman at the door, but they did not need to ask what he meant. The forest was alive with whispering voices—with the passage of feet over dry twigs and rustling grass. A light danced among the thick foliage. It was too late for retreat, and, as the little band crouched behind the shadowy doorway, they beheld a startling sight. By twos and threes a group of Tories and Indians glided into the glade, close to the spring. The two foremost held a shrinking man between them, and as they came nearer, one said aloud, in a familiar voice that made Nathan shudder: Is this the place, you rebel dog? It's Captain Stanbury's cabin, muttered the prisoner, who had evidently been made to serve as an unwilling guide. You know what you'll get if you're lying, Simon Glass—for it was he—replied with an oath. Come, men, he added. God help us! whispered Barnabas. There's no escape unless we kin keep hid. But they're comin' to the cabin, an' Colonel Butler's promise won't count with such fiends. They'll kill every man of us in cold blood. Low as the words were spoken, they reached the ears of the enemy, and a creaking noise made by McCollum's heavy boots completed the betrayal. There are rebels here! roared Simon Glass. Don't let a blasted one escape! Surround the cabin! It's all up, cried Barnabas. Give 'em a volley, an' remember the massacre. Now—fire!
- 37. Four muskets flashedand roared, and, as the echo fled down the valley, the night rang with yells of rage and agony. There was no time to look for the result of the volley through the drifting smoke. Barnabas instantly slammed the door shut, and dragged the heavy table against it. Down, all of you, he shouted. Stick to the floor. Nathan, you guard the rear wall, an' watch through the cracks of the logs. McNicol, you an' Atwood take the two ends. I'll tend to the open winder here in front. The three crawled to their posts of duty, and for a time the silence outside was broken only by an occasional moan of pain. The wary enemy had taken to cover at once, until they could learn the strength of their assailants. Did you kill Glass? McNicol whispered across the room. He ain't in sight, replied Barnabas. He moved his head just as I fired. The Tory with him is lyin' dead here on the grass, an' the prisoner is beside him—he's better off, for he'd a been tomahawked anyway. An' there's a wounded Indian dragging hisself past the spring. I won't waste powder on the wretch. Glass must have learned where we were bound, and followed us here for revenge, said Nathan. It's either that or a deeper motive, Barnabas answered, and even as he spoke a hot fire was opened on the cabin from three sides. The fusillade lasted for several minutes, the bullets tearing through the crevices or burying themselves in the thick logs, but by crouching flat all escaped harm. As the fire slackened the enemy boldly showed themselves here and there in the moonlight, but they learned a lesson in prudence when McNicol shot two of their number from a loophole, and Atwood picked off a third. Barnabas kept blazing away at the gleam of a torch some distance off in the wood, where a part of the enemy was
- 38. probably assembled. Asnearly as could be judged, the besieging force numbered nearly a score. It's a bad lookout, said Atwood, we can't count on help from any of the settlers. More likely the shooting will bring the whole party from the fort, replied Barnabas. We might make a dash by the rear if there was a winder. The enemy ain't showed up on that side yet. They're here now, whispered Nathan. I see the bushes moving— Bang! the lad's musket cracked, and with a screech an Indian fell dead. Two more who had been reconnoitering the rear of the cabin bounded into the woods. That's the way to do it, said Barnabas. Load quickly, men, an' don't all let your muskets get empty at once. An interval of silence followed, lasting perhaps ten minutes, and then a harsh voice from the forest called for a truce. Only one kin come near, shouted Barnabas. What do you want, Glass, if that's you? I'm willing to make fair terms, replied the Tory, who was careful to keep hidden. Come out and give up your arms, and not one of you shall be hurt. We'd sooner surrender to a rattlesnake than to you, Simon, Barnabas answered. We're goin' to hold the cabin, an' that's our last word. Glass accepted the ultimatum with a torrent of profanity and threats, and a moment later the firing recommenced. For some minutes the bullets rained against the logs, while the besieged, flattened on the floor, kept watch at loopholes and crevices for any of the enemy who might expose themselves. The plucky little band
- 39. well realized thattheir fight was desperate and well-nigh hopeless, but not a word or sign of fear betrayed what they felt. Presently the firing ceased, and now there were indications that the foe intended to make a combined rush. So certain of this was Barnabas that he summoned Nathan and his companions to the front wall. But for at least once in his life the old woodsman was outmatched. The Indians and Tories advanced only to the edge of the clearing, whence they let drive a straggling volley, and while this diversion was going on, three torches were thrown from the rear upon the roof of the cabin. A strong breeze happened to be blowing, and with amazing rapidity the flames took hold and spread. The roof was soon burned through in patches, and now the loft floor caught fire. Clouds of suffocating smoke rolled to the lower room, and a shower of sparks and blazing embers made the situation unbearable. It's all up with us here, cried Barnabas, an' there's nothin' left to do but die fightin'. Come, men, let's open the door, give the devils a volley, an' make a rush. Each one for hisself arter that, an' mebbe one or two of us kin reach the woods.
- 40. CHAPTER XI IN WHICHGODFREY PLEADS FOR THE CONDEMNED PRISONERS Without waiting for an answer, Barnabas jerked the table away and swung the door partly open. The enemy were on the watch and immediately opened a hot fire. Two bullets struck Reuben Atwood, and he fell dead across the threshold. The others dodged back into the heat and smoke, and just at the critical moment the firing ceased in response to a loud command. It's the Tory colonel hisself, exclaimed Barnabas, as he peeped through a crevice. He's just arrived, an' there's lots of Royal Greens along with him. Colonel Butler, he added loudly, we'll surrender, providin' you spare our lives. Come out first, and then we'll talk, the officer shouted back after a brief pause. There was hope in the words, and Barnabas and his companions lost no time in scrambling to their feet. Half-choked, and sweating from every pore, they stepped over Atwood's dead body and staggered across the clearing. At sight of the three figures there was a loud murmur of astonishment.
- 41. Where's the rest?demanded Simon Glass, as he roughly stripped the prisoners of their muskets. We're all here but one, Barnabas answered, pointing to the doorway, an' he's dead. I'll send you to join him, snarled Glass, and with that he presented a gun to the old man's head. But before he could fire, Colonel Butler knocked the weapon aside. You ruffian! he exclaimed. Would you shoot a prisoner in cold blood? He deserves it, remonstrated Glass, in an injured tone. Why, this is the leader of the rebel band that attacked my party a couple of days ago, killed four of us, and stole our horses. I have nothing to do with that affair, snapped Colonel Butler. When I want you to play executioner I'll tell you. Don't interfere again! With a scowl Glass slunk away, and for a few moments the officer scrutinized his three captives in silence. The upper part of the cabin was now wrapped in flames, and the red glare made the scene as light as day. Tories and Indians stood grouped in a half-circle, the former with cold, pitiless faces, while the latter looked ferociously at the prisoners under their painted cheeks as they gripped their blood- stained tomahawks and edged nearer with fiendish anticipation. Godfrey, who had been with the attacking party, was standing to the rear, and his face alone expressed pity. He blushed as Nathan discovered him and gave him a quick glance of contempt and defiance. You can't expect mercy, Colonel Butler finally said. Within a few hours after the surrender you are found here with arms in your possession—a direct violation of my terms. And you took the offensive, firing deliberately on a part of my force.
- 42. That's right, Colonel,chimed in Glass. They shot first. We've six dead here. We were compelled to fire, sir, said Barnabas. We had no way to retreat, an' that ruffian yonder told his men not to let one of us escape. Exactly, assented Glass. But my object was to take you prisoners. I saw you and your men recover the arms you had hidden in the woods, and I was justified in following to discover your purpose. At this Godfrey started to come forward, but changed his mind and stopped. His face was pale and haggard. Man, you lie, cried McNicol, turning to the one-eyed Tory. You never saw us get the guns, and you didn't even know we were here till you reached the cabin. And had we surrendered at the first, every one of us would have been massacred in cold blood. I know you well, you dirty traitor. Colonel, don't believe that rebel, retorted Glass, with a glance of fury at McNicol. The affair happened just as I said. Hang the affair! testily exclaimed the officer. He moved aside for a moment to converse in a whisper with Captain Caldwell, of the Royal Greens, and then turned to the prisoners. My duty is very simple, he said. There is but one question at stake. You were found bearing arms in violation of my terms. You have brought your fate on yourselves, and now— Sir, would our lives have been safe anywhere in this valley without fire-arms? interrupted Barnabas. Colonel Butler bit his lip with rage. You rebel dog, he cried, do you dare to assert that I can't enforce my own commands? But
- 43. enough. Captain Caldwell,a platoon of your men, please. Stand the prisoners out and shoot them. Nathan turned pale. Barnabas and McNicol heard the sentence without moving a muscle. A file of the Royal Greens stepped forward, bringing their musket butts to earth with a dull clatter. But just as several Tories laid hold of the victims to place them in position, an unexpected interference came from Godfrey Spencer. Colonel Butler, he exclaimed, let me speak to you before this goes any further. Stop, you fool, muttered Glass, trying to push the lad back. Let me go, Godfrey whispered fiercely. If you don't, I'll tell all. What do you want to say? asked Colonel Butler. Oh, it's you, Lieutenant Spencer! Sir, I beg you to spare these men, pleaded Godfrey. With justice to yourself, you can waive the question of their bearing arms, since their object in coming to the cabin to-night was in no wise contrary to the terms of the surrender. We came for the same purpose, and the meeting was accidental. Simon Glass has lied deliberately, and I can vouch for it that he would have shot the prisoners at once, had they given themselves up. Glass ground his teeth with rage, and had looks been able to kill, the lad must have fallen dead. I can't understand this hurried march of your little detachment from the Jersies to Wyoming, replied Colonel Butler. You told me you were sent by Major Langdon, and now I infer that this cabin was connected with your mission; also, that the prisoners marched from the Jersies with the same purpose in view. I would like a further explanation.
- 44. That I can'tgive, sir, Godfrey answered firmly. Perhaps you can? and the Colonel turned to Barnabas. The old man shook his head. It's a private matter, sir, he replied, an' my lips are sealed. But what this young lieutenant says is all true. Colonel Butler looked puzzled and vexed. Whom did Major Langdon put in command of the party? he sharply inquired of Godfrey. Simon Glass, sir. And why were you—an officer of rank—sent along as a subordinate? I don't know, sir. I don't even know fully the object of the expedition. Glass, you can explain this mystery, exclaimed the Colonel, losing patience. Sir, would you have me betray my trust? demanded Glass, with well-feigned indignation. You saw my papers yesterday. You know that they are signed by Major Langdon, and that I am acting under his orders. And under mine as well, sir, replied the Colonel, with a frown. There can be no independent commands while I have control here. Come, we'll drop the question of Major Langdon's authority. I want you to do some work for me to-morrow. You are just the man for it, and you can have the force you led out of the fort when my back was turned. I am at your service, sir, Glass replied in a mollified tone.
- 45. The Colonel nodded.You may as well camp here for the balance of the night, and start early in the morning. Scour the whole upper part of the valley, and burn every cabin and house to its foundations. A wicked smile showed how well pleased the ruffian was with his orders. How about the prisoners, sir? he asked carelessly. The sentence stands, Colonel Butler replied grimly. I will give them a few hours to prepare for death. Hang or shoot them at daybreak. I can't entertain your appeal, he added, to Godfrey. Your arguments do not mitigate the fact that these rebels were found in arms. I must do my duty. In spite of Glass's angry and threatening looks Godfrey made a second attempt to save the prisoners, but Colonel Butler cut him short in a manner that forbade further appeal. The officer was in an ugly mood, for his natural curiosity to solve the mystery connected with the cabin had been baffled. But matters of more importance demanded his immediate presence at the fort, and without delay he marched off at the head of the Royal Greens. Glass's first act after the departure of Colonel Butler was to search Nathan thoroughly from head to foot, and the lad submitted with an air of surprise that was more feigned than real; by this time he had an inkling of what it all meant. The ruffian could hardly conceal his disappointment when he failed to find what he wanted. He proceeded to search McNicol and Barnabas—luckily omitting the latter's boots—and then he reviled the prisoners with the most bitter taunts and insults his brutal mind could invent. Nathan lost his temper and answered back, thereby receiving a cruel blow in the face; but Barnabas and McNicol stoically endured
- 46. the shower ofabuse. None of the three showed any sign of fear, though they knew they were to die in the morning, and their courage might well have won admiration and pity from a more chivalrous foe. But Simon Glass's half-dozen Tory comrades—who numbered among them the survivors of the squadron of dragoons— were as brutal and degraded as himself. The rest of the force were Indians, and mercy or pity could have been better expected from a pack of panthers than from these blood-thirsty Senecas. The ruffian finally wearied of his pastime and walked toward the cabin, which was now nearly consumed. After watching the dying blaze for a moment he returned. How soon will those ruins be cool? he asked of one of his companions. I should judge in about two or three hours, the man replied. Glass looked pleased. We'd better be turning in, he continued, for we must take an early start in the morning. We'll hang the rebels before we go. Bring them over yonder now. He led the way to a thicket of low bushes that stood on the near bank of the spring. In the centre of the thicket were three saplings, and to these the prisoners were secured in a sitting position, with their arms fastened behind them and their backs turned to one another. Having seen that the work was done thoroughly, Glass departed. You'd better be praying, you rebels, he said, in a sneering tone, for your necks will stretch at the first light of dawn. The night was very warm and the Tories and Indians stretched themselves in groups amid the thick grass that carpeted the clearing. A sentry was posted on guard at the thicket, and as he paced to and fro with loaded musket the upper part of his body was visible to the captives. They could see no others of the party for the
- 47. bushes, but thesilence indicated that all were asleep. Godfrey had kept in the background after Colonel Butler's departure, either for the purpose of shunning Glass or to avoid those he had vainly tried to befriend. There was no hope of escape, and for a while the wretched little group talked in whispers, each nobly endeavoring to cheer and comfort the others. None had rested much on the previous night, and finally Barnabas and McNicol fell asleep. Nathan was now alone with his thoughts, and in the face of death his fortitude almost deserted him, and his mind yielded to bitter anguish. He lived the past over again—his boyhood days here in the valley, his years at college in Philadelphia, and then the string of terrible events that had begun with the loss of his father on Monmouth battle-field. But amid the conflicting thoughts that distressed him the memory of Godfrey's strange words was uppermost. What can it mean? the lad asked himself. Is it possible that Major Langdon sent Simon Glass here to find and steal these papers? He heard my father tell me where they were, but why would he want to get them? It is a deep mystery—one too incredible to be true! Vainly the lad puzzled himself, and at last he fell into a restless sleep. A couple of hours later he awoke with a start, realizing at once where he was, and dreading to find that dawn had come. The moon was far down and under a bank of clouds, and the cabin had long ago burnt itself out to the last spark. But, from the direction of the ruins, floated a dull noise and the sound of low voices. Barnabas, are you awake? Nathan whispered. Yes, lad, muttered the old man, and as he spoke McNicol opened his eyes and twisted his cramped body.
- 48. Before more couldbe said the bushes rustled, and a dusky figure shouldering a musket crept softly into the thicket. Godfrey— for it was, indeed, he—put a finger to his lips. Hush! he whispered. I've come to save you. All are sleeping, except Glass and four of the Indians. They're poking about in the ashes of the cabin, and we must get away before they return. I am going with you, for my life is equally in danger. He stooped down with a knife in one hand, and quickly severed the cords that held the prisoners. Now come, he added. Look where you step, and don't even breathe loudly. Nathan and his friends rose, trembling with joy, and almost doubting the reality of their good fortune. But they knew by what extreme caution safety must be won, and as noiselessly as shadows they trailed their sore and stiffened bodies behind Godfrey to the farther edge of the thicket. The young officer had thought out his plans beforehand, and with a warning gesture he stepped into the spring at the point where it became a narrow rivulet, and brawled its course swiftly across the lower corner of the clearing. The others followed, and the murmur of the waters drowned what slight noise was unavoidable. Now came the critical moment. With anxious hearts the fugitives waded slowly down the stream, crouching low beneath the fringe of tall grass that concealed, on both sides, the sleeping forms of Tories and Indians. On and on they went amid unbroken silence, and at last the dense foliage of the wood closed over them like an arch. They had safely passed the limits of the camp. They waded twenty yards further, and then stepped on land. Godfrey handed his musket to Barnabas. You know the country, he whispered. Lead as you think best. We'll make a wide detour back of the fort, Barnabas replied, an' then come around to the river at the lower end of the valley.
- 49. On a brisktrot they started toward the northwest, and as they hurried along the forest trails that the old woodsman chose, Godfrey briefly told what all were anxious to know. I got awake a bit ago, he said, and heard Glass instructing four of the worst Indians to tomahawk you people just before daylight. They were to kill me at the same time, and pretend it was done by mistake. That was to be Glass's revenge for what I said to- night. I remained perfectly still, pretending to be asleep, and when Glass and the Indians went over to the cabin, I decided all at once what to do. I told the sentry I had been ordered to relieve him, and he handed over his musket without a word. He was asleep in two minutes, and my way was clear. Barnabas and McNicol warmly thanked the lad, and Nathan impulsively clasped his hand. I hope we are friends again, Godfrey, he said. I will never forget what you did to-night. I will do more, if I ever get the chance, Godfrey answered. But I can't explain now—wait until we are certain of freedom. By this time the fugitives were a mile from the enemy's camp, and before they had gone twenty yards further a faint outcry behind them told them that their escape was discovered. All now depended on speed, for it was certain that the Indians, by the aid of torches, would follow the trail with the unerring keenness of blood-hounds. Barnabas led the little party at a steady pace, taking them several miles to the rear of the fort before he turned parallel with the river. Now they headed for the lower end of the valley, and for nearly three hours, while they traversed the lonely and gloomy forest, they heard no sound but the chirp of night-birds and the distant cries of prowling wild animals.
- 50. I can't keepthis up much longer, panted Nathan. The Indians may be close behind, but for my part I believe they've lost the trail. Mebbe so, lad, replied Barnabas, though the quietness ain't an indication of it. We're all badly winded, but the river ain't far off now. Onct we git across, or find a boat— The rest of the sentence was drowned by one blood-curdling whoop that rang with awful shrillness through the silent wood. Another and another followed, and the glimmer of a torch was seen coming over a knoll at a furlong's space behind the fugitives. The Senecas are hot on the trail! cried Barnabas, an' their keen ears have heard us. On for the river! It's our last chance!
- 51. CHAPTER XII IN WHICHA MYSTERIOUS ISLAND PLAYS A PART Barnabas was right in guessing the river to be near, and the fugitives could not have approached it at a better time or place, though they had little idea of the good fortune in store for them. If they thought about the chances at all, as they ran desperately before the screeching Indians, it was to realize what little likelihood there was of finding a boat, or of safely gaining the farther bank by swimming. But when they had plunged through a slope of water-birches, and straggled breathlessly down to the pebbly shore of the Susquehanna, a welcome sight at once met their eyes. Almost directly opposite, and twenty yards out in the stream, a big flat-boat was drifting leisurely with the current. Over the high gunwales rose two or three heads, and a voice demanded sharply: Who's yonder? Friends! cried Barnabas. Fugitives from the enemy! The redskins are hot upon us. Cover the bank with your guns while we come aboard. Splash! went Barnabas into the water, and his companions after him. With sturdy strokes they swam diagonally down-stream, caught the stern of the flat, and hauled themselves on board. As they
- 52. dropped low onthe bottom, yells and musket-shots split the air, and bullets rained like hail against the thick timbers. From the shelter of the elevated bulwark the occupants of the flat returned a cool and effective fire, and when Nathan ventured to peep through a loop-hole he saw two Indians prostrate on the beach and a third struggling in agony in shallow water. During the lull that followed the first volley from both sides, the boat drifted over a course of rapids, and the swifter current swung it well toward mid-stream. With a few parting shots the baffled foes disappeared, and a peaceful calm fell on river and wood. The escaped prisoners were surprised to find Morgan Proud and Abel Cutbush on board the flat. The latter's wife and child were with him, and another member of the party was a negro named Cato. Mrs. Cutbush was a hardy type of the colonial women of the time, and her six-year-old daughter, Molly, had not even whimpered during the brief fight. It's a good thing we happened to be here, said Proud, when he had gleaned their thrilling story from the fugitives, and it's all owin' to chance, too. I waited a bit after you left, and as no one came along I pushed down to Wilkesbarre. The people had all fled except Cato here, and Cutbush and his family, and they were tryin' to tinker up this old flat—the only boat left. I helped 'em to stop the leaks and rig bulwarks on both sides, and about an hour ago we got started. There's a couple of other parties ahead of us, but we aren't likely to ketch up with 'em. This old craft is heavy, and it draws a heap of water. I'm thinking we'll stick now and then. We'll pull through all right, cheerfully replied Barnabas. Now that them redskins have turned back the danger is about over, for the enemy will have enough plunderin' and burnin' to do right here in the valley to keep 'em busy. How are you off for weapons? We brought just one with us.
- 53. We have twoextra muskets, said Cutbush, and as Cato ain't much on shootin', his'll make up the number your party will want in case of a possible attack. There's food aboard, and as for ammunition— He pointed to a keg of powder and a quantity of bullets in one corner of the flat. By this time the boat had drifted between the abrupt mountains that closed the lower end of the Wyoming Valley, and there was a certainty of good current and depth for some miles ahead. All through the night the men of the party took turns at sleeping and at guiding the flat by means of long poles and a rudder. No hostile shot or yell broke the quiet, and at last the morning sun kissed the blue water into ripples and stained the hoary mountain peaks with gold. Danger was behind, and hope and safety in front. While Mrs. Cutbush prepared the frugal breakfast, aided by Molly and Cato, Barnabas and Nathan found time to sit in the bow of the flat, where they were presently joined by Godfrey. The lad looked haggard and worried. I'm ruined, he said, as he sat down beside his companions. I feel that I've nothing left to live for. Not that I regret what I did last night. Don't think it. But I shall be branded as a deserter—and worse. I can never go back to Major Langdon, and if I am caught I will be shot or hanged as a traitor. I wish I had never been sent on this wretched business. Your mission was not legitimate war, replied Nathan. Explanations will surely right you. But why worry about the matter at all? You are safe, and can share our fortunes. And after the fiendish acts you saw done at Wyoming by a British force— Stop! Godfrey said, sadly. I am still true to my cause, Nathan —as much as you are to yours. Let us not discuss that matter. We can at least be friends while we are together.
- 54. How could webe otherwise, after your noble deed? replied Nathan. Then you have no ill-feeling? asked Godfrey. I was afraid you blamed me for that night in Philadelphia. It was Major Langdon who found the note, and he made me go along. I have always wished I could explain. Well, it's all right now, said Nathan. And it was all right then, he added to himself, remembering his reckless flight through the town. There is something else I want to speak about, continued Godfrey. Have you got those—those papers safe? Yes, I have them, Nathan exclaimed, eagerly. Can you explain the mystery about them? Godfrey shook his head. It is a mystery, he replied, and a deep one. I only know this. The day after the battle of Monmouth, while our army was at Middletown, Major Langdon sent Simon Glass and a squad of dragoons to Wyoming to get those papers. I don't know why I was sent along, and I never knew until last night that the papers were the property of your father. And Glass—who is the worst ruffian I ever knew—has tried his best to get all of your party killed ever since he learned you were bound for the same place. That's why he was so savage with me last night, when I appealed to Colonel Butler to spare your lives. I've had an idea of what was going on for some time past, said Barnabas. I seen a mighty ugly look in Major Langdon's eyes when he stood over Captain Stanbury on the battle-field. That's when he overheard about the papers, but what in the name of creation did he want with them? Could your father have known him before, lad— over in England?
- 55. I don't know,replied Nathan. I never heard him speak of Major Langdon. In fact, I don't know anything about my father's past. But I believe the secret to this mystery lies over the sea, and I'll tell you why. He went on to relate the visit of Mr. Noah Waxpenny to the Indian Queen, and how he had asked information concerning both Richard Stanbury and Major Langdon. This was new to Godfrey and Barnabas, and all three discussed the matter earnestly, but without coming any nearer a solution. We've got to have patience, an' wait, said Barnabas. That's the only thing to do. The papers are safe, anyway, an' this fellow from London may clear up the mystery if we run across him. Or your father may turn up, lad— Perhaps Godfrey knows something about him, exclaimed Nathan. Did the British carry off any prisoners after the battle of Monmouth? Not that I know of, replied Godfrey. I saw or heard of none; but then I was in front during the retreat. My father is alive, declared Nathan. I am sure of it. I hope so, said Godfrey. Speaking about those papers, he added, I feel a good bit worried. If Glass gets it into his head that you have them—as he probably will, when he has dug over the ruins of the cabin—he is sure to follow you up. It's hardly likely, replied Barnabas. An' then he can't ketch us anyway, pervidin' the currents and depth of water hold good. No, lad, I think we're done with Simon Glass, as far as this expedition is concerned. There, Mrs. Cutbush has got breakfast ready. She's calling us.
- 56. Barnabas and thetwo lads found no further opportunity that day to discuss the mystery of Major Langdon and the papers. It was a day of hard and unremitting toil. There had been a long spell of dry weather, and, as the river gradually widened, its channel became more and more obstructed by grass-bars, shallows, and outcropping ledges. Doubtless the preceding boats had found a ready passage, but the abandoned flat that Proud and Cutbush had tinkered up under the spur of necessity was broad, heavy, and leaky. Cato was constantly kept busy bailing water, and rudder and poles were of little aid to navigation. Every few minutes all of the party except Mrs. Cutbush and Molly were compelled to get out, and by their united strength drag the craft over the shallows. By ten o'clock that night less than twelve miles had been covered, and the exhausted men could proceed no further. They encamped on a patch of sand and scrub in mid-channel, and took turns at guard mounting until morning. Mrs. Cutbush and her daughter slept in the flat, on a comfortable bed of dried grass, that was protected from the damp planks by an underlayer of pine boughs. We're about thirty miles below Wilkesbarre, now, said Barnabas, as the journey was resumed after breakfast, an' it's a good twenty miles yet to the main river, where we'll strike deep water an' the shelter of the lower forts. If I thought the wadin' and haulin' was to last another day I'd suggest we take to footin' it on shore. It would be a wise plan, agreed Godfrey. At the speed we've been making, a force of Tories and Indians could have overhauled us twice over, and they may do it yet. You don't know Simon Glass. Don't I? Barnabas interrupted grimly. I reckon I do. But honestly, lad, I believe he's given up the chase. It's best to take precautions though, an' that's why I spoke of walkin'.
- 57. It won't beeasy for me, declared Proud, shaking his head. I've got a sprained ankle. And my little gal, who ain't no light weight, would have to be carried, added Cutbush. I've been down the river twice before, said Nathan, and I'm pretty sure that the lower part of the North Branch is deeper than up here. Several others suddenly remembered the same fact, from past experience, and so it was decided to stick to the flat. Godfrey alone favored a land journey, and he could not hide his apprehension at the choice. If they knew Simon Glass as I do, he said to himself, they wouldn't lose any time in getting below the forts. However, after three hours' repetition of the previous day's labors, the channel actually did become deeper and less obstructed. In consequence the current was more sluggish, but the flat drifted steadily on for mile after mile, and there was a fair prospect of reaching the main river that evening. Early in the afternoon a magnificent buck with large antlers burst out of the woods on the south bank, about a quarter of a mile below, plunged precipitately into the water, and swam for the opposite shore. Something scared it, said Nathan. A bear or a wolf, replied Barnabas. Or a man, Godfrey suggested uneasily. Barnabas did not answer. He thoughtfully watched the animal until it mounted the bank and disappeared, and after that an extra wrinkle or two remained on his furrowed brow. During the afternoon
- 58. he scanned bothshores intently, and furtively examined the muskets to see that all were loaded. The sun faded in a haze of gold and purple, and the shroud of night fell on lonely mountain and river. There was no moon, and through the blackness the flat gurgled on its watery way. An hour after dark a misty object loomed out of mid-stream. It was an island, and as the upper point drew near, Cutbush gave the rudder a twist that sent the flat into the channel on the left. It's the proper course, he explained, and the one that we boatmen take. T'other side is full of rocks and shallows. But there's a bit of rapids below, said McNicol, if my ears don't deceive me. They're no account, replied Cutbush. There's a clean passage through toward the shore side. He swung the boat further to the left, and it glided silently along within fifty yards of the bank, and three times that distance from the island. I've got my bearin's exactly now, said Barnabas. That's what they call Packer's Island acrost from us, an' a mile or so down yonder on the right is the settlement of Northumberland, where the North an' West Branches meet. We'll be on the main river in half an hour. I want to stop at all the forts on the way down, said Nathan, because the soldiers may have had late reports from the army, and can tell me if my father— Look out, sir, Godfrey eagerly interrupted, turning to Cutbush. We're running straight into a little island. Don't you see it?
- 59. The men weregrouped in the stern at the time, and Godfrey's warning cry, coming so suddenly, startled and confused Cutbush. The result was that he sharply twisted the rudder the wrong way, sending the flat farther toward the shore, and in a direction where the depth of the channel was very doubtful. Cutbush did not discover his mistake until the others called his attention to it. Then he saw what they meant. Close ahead a triangular promontory of rock and timber jutted in a gradual slope some forty yards beyond the normal line of the bank, and thirty feet straight out from its apex lay the island to which Godfrey had reference. The location was an odd one, and it was a decidedly queer-looking island—a long, narrow cluster of bushy pine trees, pointing up and down stream, and thickly fringed at its base with bushes that seemed to grow straight out of the water. It's risky to try that passage, said Barnabas, pointing to the thirty-foot channel between island and promontory, whither the flat was now steadily drifting. We may find shoals there. I give the rudder a wrong turn without thinkin', muttered Cutbush. But it's not shoals I'm afraid of. If we float down yonder I won't have time to steer for the rift through the falls, and they're only fifty yards below. As he spoke he tried to rectify his mistake, and the first two sweeps of the rudder veered the nose of the flat away from the bank. The third swung it broadside across stream, and in this position it bore down on the little island, with a slight diagonal trend toward the wider and safer channel on the outer side. But there was hardly time for this movement to take effect, and the danger of striking was so apparent that Cutbush let go of the rudder—which was as good as useless while the flat was turned broadside—and snatched up one of the poles. He drove it in off the stern, leaned after it till he almost stood on his head, and then rose up with both arms wet to the elbow.
- 60. The pole won'ttouch! he exclaimed. There's easy twelve foot of water here. Twelve foot of water! cried Barnabas; an' that island only ten yards below! It ain't nateral, man! We're going to strike the island, said Nathan. Try again. No, it's all right, interposed Barnabas. We're movin' slow, an' there ain't any gravel beach as I can see to stick on. The rear end will strike easy, an' then the flat will swing out toward the far channel. So Cutbush dropped the pole and the boat drifted on broadside with the current, its occupants calmly waiting the moment of collision. As the distance decreased from ten yards to five, Barnabas craned his neck forward, and shaded his eyes to peer over the lower bulwark. It's queer, he muttered. I've been here before, an' I don't mind seein' that— Just then a startling thing happened. The whole island was seen to lurch visibly to one side, and at the same instant something flashed and glittered amid the fringe of bushes. Look! Godfrey whispered, hoarsely. Down for your lives, men! yelled Barnabas. It's a trap! Keep low, an' don't let 'em get aboard. The entire party dropped like a flash, and grabbed their muskets. A terrible instant of silence followed, broken by a howl from Cato and a whimper of fright from Molly, who was lying flat on the bottom in her mother's arms. Then a volley of shots rang out from the fiendishly contrived ambuscade, and more than one ball tore through the thick bulwark.
- 61. But happily noone was hurt, and Barnabas, McNicol, and Nathan at once fired through the three loopholes at which they were posted. A yell of agony blended with another fusillade from the unseen foe, and now a quicker current drove the heavy flat broadside against the mysterious little island. There was a crash of timber meeting timber and a sound of branches smiting the water. Then, with shrill and blood-curdling yells, four painted Indians scrambled over the bulwark and dropped into the boat. At the same instant a little one-eyed man, holding a musket high overhead in one hand, pulled himself aboard at the bow.
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