Auditory Event-Related Potentials to Words: Implications for Audiologists by James Jerger, Jeffery Martin and Katherine Fitzharris of the School of Behavioral Sciences, University of Texas at Dallas represents a rather fresh approach to the interpretation of late auditory evoked potentials elicited in response to word stimuli. The authors note that they hope to motivate audiologists to consider the many possible uses of auditory evoked potentials (AEP) to better assess and manage their patients with a variety of auditory difficulties. Before discussing the book’s content, several preliminary comments on the book’s esthetics and organization are offered.
Perhaps one of the most striking features of this book is the generous use of color illustrations. Utilization of distinct colors for various AEP traces and topographic mapping allows the reader to easily observe key concepts presented by the authors. One could say that the illustrations, as well as the book’s print, are “easy on the eyes.” There are seven chapters distributed over 159 pages followed by a useful reference list. The sequencing of the chapters is logical, making the presentation of information easy to follow. End of chapter summaries provide concise capsules of the key information covered in the chapter.
This book is Jerger and his colleagues’ account of much of the AEP work they have conducted over the past 10-15 years at the University of Texas at Dallas (UTD). As they note in the foreword, this book “offers no test batteries, no recipes, no steps in diagnosis. We simply present many illustrations based on studies carried out at the UTD, comment on them, and ask the readers to reflect on how word recognition testing might be more deeply mined by audiologists.”
This statement and comments throughout the book reveal two underlying themes: 1) There are some new AEP approaches that can provide insight as to the assessment of higher order auditory and cognitive functions and 2) audiologists should embrace AEPs for their ever-increasing clinical value. Their points are indeed timely, as it appears the audiology community may be retreating from, rather than advancing toward, the clinical use of AEPs.
The authors begin the book with an overview of the late potentials. The use of various stimuli, including clicks, tones and words are discussed, along with recording techniques and resultant waveforms. The authors use a 1600 – 1800 msec time window in displaying their waveforms. This allows them to display both the more classical N1 and P2 potentials, as well as the newer PN (processing negative) (300 – 800 msec) and LPC late positive component (300 – 1000 msec). The nature of each of these four AEP components, and in particular their role in revealing how we process and understand words, are discussed. This early section of the book also provides considerable basic information on topographic mapping, including its acquisition and interpretation in response to word stimuli.
The midsection of the book addresses an intriguing topic – dichotic listening and its electrophysiologic response. It is surprising that more investigation has not been done in this area, given the copious amount of literature on behavioral measures and responses during dichotic listening. The authors provide valuable insights into the electrophysiology of dichotic listening, making relevant comparisons to behavioral findings. They also outline implications for possible use of these electrophysiological approaches in the clinical domain. They provide impressive displays of the electrophysiologic expression of the right ear advantage and the effect of switching attention between ears. Also portrayed from a clinical view of electrophysiology is the abnormal left ear deficit often noted in the pediatric population with central auditory processing disorder.
The final section of the book takes aim at attention. This section profiles the role attention plays in everyday listening situations and how it may or may not interact with audition. The authors provide useful insights for utilizing AEPs (primarily PN and LPC) to isolate attention effects from other brain processes. The authors acknowledge that isolating attention is no easy task and presents many challenges –especially when recorded in response to complex acoustic stimuli such as words.
Also, in this final segment of the book, the authors discuss the value of looking concurrently at patterns of both electrophysiologic and behavioral results –especially in the clinical domain. The authors also lend insights on the use of individual and group data for both research and applied situations. Finally, they provide words of wisdom on the interactions between cognition and hearing, and how AEPs can be of value in measuring these two important processes in our communication.
In summary, Auditory Event Potentials to Words accomplishes the goals set forth early in the book. The authors provide a myriad of waveforms and insightful comments. This book teaches us a considerable amount about the late potentials and their use in the lab and clinic. It should also serve to motivate audiologists and others to think about, investigate, and apply AEPs to better serve those with dysfunction of the peripheral and central auditory systems.
I highly recommend this book for both students and professionals. It provides a unique and updated view of AEPs in a very readable manner, facilitating learning through the use of outstanding graphics, clear writing and logical organization. Authors Jerger, Martin and Fitzharris are to be congratulated!
Frank Musiek, Ph.D.
Another valuable contribution to hearing professionals by James Jerger and colleagues.