Acoustics for Audiologists

Acoustics for Audiologists

RATING: (3 of 5 ears)
AUTHOR: Peter Haughton
PUBLISHER: Academic Press
ISBN: 0-12-332922-1
COST: $79.95 (hardcover)

REVIEWER: Vishakha Waman Rawool, Ph.D., Department of Communication Sciences and Disorders, Southwest Missouri State University

SYNOPSIS: The author of this book has made a successful and sincere effort to relate basic concepts in physical acoustics to clinical audiology. The book contains all basic concepts related to sound, its propagation and measurement. The book includes concepts related to audiology including hearing aids, impedance, audiometric earphones, bone conduction vibrators, microphones, loudspeakers, audiology test rooms etc. Although the information included in this text may be found scattered through other audiology books, this book can serve as a good desk reference which will allow location of information related to basic physical acoustics in a single source. The book can be used as a reference text in several audiology courses. The interesting and challenging study questions and exercises included in this text may be helpful in augmenting the basic conceptual understanding of students enrolled in audiology programs. It should be noted that the book does not include information related to physiological or psychological acoustics.

REVIEW: The author's intended audience for the book, as implied in the book title, is audiologists. The author notes that the topics included in this book are somewhat related to the syllabi of courses offered in Britain for audiology technicians, industrial audiologists, and hearing aid dispensers.

The book includes ten chapters and two appendices. Chapters One to Five include basic properties of simple and complex sounds. The topics included in these chapters are similar to those included in other basic books available on acoustics. However, additional topics included in chapter one are density, specific gravity, viscosity, viscoelasticity and properties of gases. Chapters Two and Three are related to description of vibrations and sound waves. Chapter Four discusses sound sources and consists of description of sound sources used in clinical audiology including audiometric earphones, bone vibrators and hearing aid earphones. The fifth chapter includes the topic of complex sounds, linearity, distortion, speech spectra and recovery of signals in noise. Detailed description of measurement of sounds is incorporated in Chapter Six including a discussion of sound level meters, various microphones used in hearing aid applications and measurement of noise exposure levels. Chapter Seven includes a detailed review of concepts related to impedance including impedance in electrical circuits, mechanical impedance, acoustic impedance and clinical measurement of acoustic admittance. The highlight of the chapter is an interesting table which provides explanation of tympanometric findings in various disorders. The remaining chapters are devoted to the calibration and testing of audiometric equipment, audiometric test rooms and basic electroacoustic characteristics of hearing aids. These chapters include a detailed and careful review of standards and possible shortcomings in measurements. Two noteworthy topics in these chapters are calibration of calibrators and problems in the definition and standardization of audiometric zero. Appendix A reviews concepts in supplementary mathematics and Appendix B provides information on working with decibels.

The author has included several mathematical expressions to enhance the understanding of various concepts. He correctly points to the fact that mathematical notation can provide a concise expression of the relationship between physical quantities. However, it seems that even those audiologists who may be discouraged by the mathematical aspects of physical acoustics will be able to read this book because the related text is self-explanatory. The illustrations in the book are interesting and useful in enhancing the comprehension of concepts. As an example, the influence of wind and temperature ingredients on the propagation of sounds is illustrated through the use of cartoons. Humor is included in some places which is helpful for the relatively dry topic of acoustics. For example, the section titled 'Moving bodies' opens with the following statement: "The title of this section may sound like an advertisement for the mortician...". Each chapter ends with an exhaustive list of study questions and exercises that are both interesting and challenging. "When a sound wave 'travels', what exactly is the thing that is traveling?" is an example of a study question. Calculation of reverberation time is an example of an exercise included in the text.

CRITIQUE: The majority of the information in this book is available in other audiology books used for teaching diagnostic audiology, hearing science and hearing aids. However, this book attempts to establish a relationship between basic physical concepts and clinical audiology practices which may motivate audiologists and audiology students to develop their knowledge about basic physical acoustics. Thus, this book can serve as a good reference for audiologists and a good reference text for many courses in audiology including immittance audiometry, diagnostic audiometry, hearing aids and hearing science. The study questions and exercises included at the end of each chapter may be helpful in enhancing the basic conceptual understanding of students enrolled in audiology programs.

The book includes only physical acoustics; topics related to physiological or psychological acoustics are not included. Thus, a more appropriate title for the book may be "Physical Acoustics for Audiologists." This book is probably not appropriate as a main textbook for many courses offered for audiology majors in the United States. Most university programs offer the physical acoustics course at the undergraduate level and enrollment in these courses often includes speech-language pathology students. Besides the title, the mathematic included in the book may alienate Speech-Language Pathology majors.