Updates in Auditory Electrophysiological Measures: Embracing Our Past and Marching Toward Our Future

In the four decades since clinical auditory brainstem response (ABR) systems first came on the market in the 1980s, the field has seen radical changes in the footprint, portability, and computing power of auditory electrophysiological systems, not to mention increased automation and stimulus selection in these systems, a proliferation of different variants of auditory electrical potentials, and the advent of universal hearing screenings. This has greatly expanded the number of ABRs performed worldwide each day and importance of ABRs in clinical medicine as objective measures of auditory function. With these changes, some approaches to auditory electrophysiology and nomenclatures have remained steadfast, some have advanced significantly, and others have fallen to the wayside (for better or for worse). This special issue on auditory electrophysiology seeks to highlight the latest advances, while also paying homage to our past, given that an “advance” really cannot be fully appreciated without an understanding of where the advance advanced from.

In seeking out contributors to this special edition, we turned to our field's educators in auditory electrophysiology—those with the dual charge of teaching future clinicians and scholars about the past and present of such methods and their future promise, while also carrying out productive research agendas that propel the field forward. Contributors were asked to focus on new electrophysiological measures, new approaches to old techniques, and more generally how techniques developed in the laboratory might translate to new diagnostics and/or treatment. To help capture the field's evolution and current state of art, we enlisted contributors from across the globe who span in rank and experience from newly minted PhDs and recently appointed assistant professors to professors emeriti.

This special edition commences with a historical overview of auditory evoked potentials by Akshay R. Maggu, Ph.D., who introduces the electrophysiological tools most often used in our clinics and laboratories, and stimulates an appreciation for the complex histories and promising futures of these methods. Next, Frank E. Musiek, Ph.D., CCC-A, and Jane A. Baran, Ph.D., CCC-A/SLP, provide a compelling argument for the continued and increased use of the ABRs and middle latency responses in the audiology clinic for neuroauditory diagnostic purposes.

The special issue then turns its focus to two works that serve as tutorials of new approaches to electrophysiological measures, written as practical guides that draw from the authors' experiences in the field. Natàlia Gorina-Careta, Ph.D., Carles Escera, Ph.D., and their colleagues provide a guide to recording the frequency following response (FFR) to speech sounds in neonates. Next, together with our developmental psychology colleagues, we (Ashley Parker, Ph.D., and Erika Skoe, Ph.D.) share our experiences and tips for collecting ABRs and FFRs in home-based settings in children—both typically developing and with autism spectrum disorder—and adults, providing both original data and practical guidelines.

The next two articles represent examples of ongoing work to develop improved electrophysiological methods for clinical diagnosis and treatment. Wafaa Kaf, M.D., M.Sc., Ph.D., and colleagues present original research on a current hot topic in the field, cochlear synaptopathy, a pathology first discovered in a rodent model, that has generated significant new interest in cochlear and brainstem potentials in the past decade. This original article by Kaf and colleagues spotlights electrocochleography and ABRs to fast click rates as potential clinical measures of noise-induced synaptopathy, and it highlights how such techniques might be paired with the Apple's iPhone Health App to evaluate the risk of synaptopathy, helping to illustrate how future advances in our field are likely to go hand in hand with technological advances to consumer technology. Then, Vijayalakshmi Easwar, Ph.D, Steven J. Aiken, Ph.D, and their team describe their work on the envelope following response (EFR) and showcase the many complexities that must be considered when selecting a speech stimulus to use in clinical applications. While their focus is on the EFR, the major takeaway from this work—that stimulus selection is not trivial—has implications for the other auditory electrophysiological techniques featured throughout this issue.

This special issue of Seminars in Hearing concludes with two articles that highlight new approaches to automating electrophysiological responses analysis and what doors such automation might open for clinical diagnostics and assessment. Both of these articles center on machine learning, a type of artificial intelligence, that can analyze data by finding patterns within. Spencer Smith, Ph.D., Au.D., first reviews how machine learning has recently been used in hearing sciences and then shares two example datasets from his laboratory that have utilized such machine learning methods to analyze subcortical AEP data. In this last article of the special issue, Fuh-Cherng Jeng, M.D., Ph.D., and Yu-Shiang Jeng, B.S., provide a step-by-step tutorial, including a practice dataset and detailed overviews of different machine learning approaches, to help researchers and clinicians alike gain hands-on experience implementing machine learning models.

We are excited to share this diverse collection of articles, tutorials, guidelines, perspectives, and original research with readers of Seminars in Hearing. We hope that this special edition will have something for everyone and that we have achieved our goal of curating an information-packed but approachable set of articles that both seasoned professionals and newcomers to the field will enjoy reading.

In today's technological age, what is innovative today may be outdated tomorrow. So, we consider this special issue as a time capsule for the moment, one that respectively addresses the past while looking promising toward our future.

Publication History

Article published online:
26 October 2022