Hair Cell Micromechanics and Otoacoustic Emissions

Hair Cell Micromechanics and Otoacoustic Emissions

RATING: (4 of 5 ears)
EDITORS: Charles I. Berlin, Linda J. Hood, and Anthony Ricci
PUBLISHER: Singular Publishing Group, distributed by Delmar
ISBN: 0-7668-6190-2
COST: $77.95

REVIEWER: Donald A. Vogel, MS, Coordinator of Audiology, Lenox Hill Hospital/Manhattan Eye, Ear & Throat Hospital, New York, New York

SYNOPSIS: Hair Cell Micromechanics and Otoacoustic Emissions is a collection of papers from one day's lectures honoring Peter Dallos and his work on cloning prestin, a protein responsible for assisting in hair cell motility. This razor-sharp edition discusses details and physiologic make-up regarding cochlear hair cells. Edited by Charles Berlin, Linda Hood and Anthony Ricci, the book leads the reader through laboratory research to clinical practice applications. It is a successful edition of eight chapters covering areas from molecular level structures to genetics through efferent function, finally culminating with a section about clinical applications. An accompanying 15-minute long CD-ROM helps to further illustrate concepts of the book.

REVIEW: The book's first chapter, written by Peter Dallos, Ph.D., surveys the history of cochlear hair cell science and reviews outer and inner hair cell types. The chapter clarifies for the reader the relationship between cochlear amplification and OHC function and examines the isolation and identification of the protein prestin as the independent molecular motor responsible for OHC electromotility.

W.E. Brownell, Ph.D., writes about the origins of outer hair cell electromotility in the book's second chapter. This and the following chapter by Anthony Ricci, Ph.D., are natural complements to Dallos' paper. In this section, the reader will understand the evolution of mammalian hair cell electromotility, hair bundle movement and fast component adaptation. Although the Brownell chapter reviews the evolution of outer hair cells, its true strengths lie in the descriptive sections mapping out the structures and chemical functions of the outer hair cells. Reading Dr. Ricci's work, the third chapter uncovers even more facts about hair cell mechanics. Helpful in clarifying this complicated work are the discussion and questions of the chapter section called "Future Directions."

The fourth and fifth chapters of this work are papers reviewing laboratory level studies. The first, by K. J. Rennie, Ph.D., demonstrates the effects of chemical inhibitors on hair cells. Although this chapter is of significant value to the student of cochlear physiology, it is helpful in educating the clinical audiologist regarding type I hair cells and afferents. The second paper of these two chapters is by Richard Bobbin, Ph.D., and colleagues. Here, the results of the experiments yield evidence of induced movement of cell stalks. Understanding that cellular level mechanisms are present and ultimately may affect the amplitude of some OAEs is the important point to this chapter.

Rounding out the scientific bases of this book, chapter six covers genetic aspects of hair cell derived hearing loss unique to Usher Syndrome. Drs. Sevtap Savas and Bronya Keats map the chromosomal regions in which the genes responsible for Usher Syndrome are present. For the clinician, this understanding is intended to assist in counseling, diagnosis confirmation and the development of genetic therapy.

Although the core of this book is about hair cell mechanics, it is in the final two chapters that the reader will discover the most clinically relevant information. In chapter seven, Drs. Hood and Berlin discuss applications of otoacoustic emissions. At this point, they review the relationship between efferent function and OAEs. Particular relevance is placed on the discussions regarding suppression of emissions as they relate to normal OAEs, age, hearing in noise, cochlear hearing loss and neural disorders. Not to be missed here is the concomitant understanding of how measurements of OAEs are objective and powerful clinical tools whose usefulness goes beyond the applications currently employed by most audiologists.

The reader is now brought to the final and culminating chapter of the book in which Dr. Berlin and colleagues create a blueprint for employing the "Triage Trio." This protocol is described as using three objective clinical applications, tympanometry, middle ear reflexes and OAEs to generate six combinations of results, which in turn directs the clinician to various diagnostic and management categories. The chapter reviews cochlear electroacoustic events and ends with four case histories demonstrating how identical audiograms can be the result of various and complex physiologic states.

Supplementing the text of the book is a CD-ROM which delivers 5 succinct lectures by Dr. Berlin. Employing the CD-ROM as another dimension for presentation of the concepts and applications set forth in the book, Dr. Berlin continues to demonstrate his fine abilities to instruct and eloquently communicate.

CRITIQUE: Hair Cell Micromechanics and Otoacoustic Emissions is replete with highly detailed explanations of hair cell motility and the chemical and genetic forces behind it. It is an excellent guide for the scientist and clinician seeking a better understanding of hair cell mechanics. This book's highly focused collection of scientific works successfully makes the argument toward the goal of expanding clinical applications. Although the body of the book is about hair cell mechanics and the heart is otoacoustic emissions, the reader will find that the soul is in the discussion of how OAEs can be utilized in the clinic. The innovative concepts presented here are worthy not just for scientific information's sake, but as valuable tools necessary to expand the audiologist's prominence in the clinical arena. This book demonstrates that, audiologically, we live in an exciting time as we are able to witness the emergence and development of such sensitive tools capable of assisting the clinician in diagnosing more than just conductive and/or sensorineural involvements of the auditory system.