Auditory Evoked Potentials: Basic Principles and Clinical Applications
RATING: (4 of 5 ears)
EDITORS: Robert F. Burkard, Manuel Don, Jos J. Eggermont
PUBLISHER: Lippincott, Williams & Williams
REVIEWER: Letitia Black, PhD, Assistant Professor, Missouri State University, Springfield, MO.
SYNOPSIS: Auditory Evoked Potentials: Basic Principles and Clinical Applications is a comprehensive text that covers a range of topics, beginning with a basic overview of evoked potentials, followed by the technical recording aspects that must be understood; concluding with clinical and research applications. A chapter of laboratory exercises allows hands-on application of knowledge gained, while a chapter consisting of nine case studies walks the reader through the clinical application of auditory evoked potentials.
REVIEW: The text consists of 33 chapters, organized in eight sections and written by an expert in the area. The first two sections overview auditory evoked potentials and basic principles that must be understood. Sections three and four cover the cochlea, VIII nerve and brainstem. Section V discusses aging and intraoperative monitoring, section VI covers cortical areas, and section VII introduces myogenic and nonauditory evoked potentials. Section VIII concludes the text with laboratory exercises and case studies.
The first section, “What are Auditory Evoked Potentials?,” consists of two chapters, which cover the peripheral and central origins of auditory evoked potentials, plus the imaging techniques that measure physiologic changes that occur as a result of neural activity. Positron emission tomography, functional magnetic resonance imaging, electroencephalography, magneto encephalography, single and multi-unit electrophysiology, and optical recording of intrinsic signals are all introduced. Methodological challenges and optimal protocols for imaging techniques are also discussed.
The second section, “Technical Basics of Evoking and Recording AEPs,” consists of four chapters. Chapter three introduces the stimuli used for auditory evoked potential assessment. Chapter four looks at instrumentation and recording parameters. Chapter five covers detection and assessment of synchronous neural activity in the temporal domain. Chapter six looks at frequency domain analysis of event related potentials.
The third section, “Research and Clinical Applications I: Auditory Evoked Potentials from Cochlea to Eighth Nerve,” consists of three chapters. Chapter seven covers the anatomy and physiology of the auditory pathway, from the external ear through the auditory nerve. This chapter includes excellent scanning electron miscrographs of the mammalian cochlea, including close up views of the organ of corti. These images aid in the understanding of the anatomy and physiology of the auditory system. Chapter eight introduces the reader to otoacoustic emissions (OAEs). The different types of OAEs are covered, in addition to the clinical utility of OAEs, their usefulness in differential diagnosis, and the effects of middle ear dysfunction on the response. The many clinical applications of OAEs are discussed, including use in hearing screenings, monitoring for changes in hearing, efferent system evaluation, and identification of pseudohypacusis. Chapter nine introduces cochlear potentials, with an emphasis on their use in differential diagnosis.
The fourth section, “Research and Clinical Applications II: Auditory Evoked Potentials from Auditory Brainstem,” consists of six chapters. This section begins with chapter ten, an introduction of the anatomy and physiology of the auditory brainstem , progressing to the auditory brainstem response (ABR) and its clinical uses in chapter 11. Chapter 12 introduces the use of the ABR in screening for hearing loss and threshold prediction. Chapter 13 describes auditory neuropathy/dysynchrony, and provides explanations for possible underlying mechanisms. Also included in this chapter is information regarding the evaluation and management of the patient, with auditory neuropathy and the use of auditory evoked potentials for diagnosis. Chapter 14 introduces the use of the ABR in auditory nerve and brainstem dysfunction, emphasizing its value for differential diagnostic purposes. Stacked ABR, maximum length sequence ABR, and Auditory Steady State Responses (ASSR) are also covered. The frequency-following response is presented in chapter 15, with a brief history, response characteristics, and the effects of stimulus parameters. Clinical applications are also presented.
The fifth section, “Research and Clinical Applications III: Aging and Intraoperative Monitoring,” consists of four chapters. The neural generators for the auditory brainstem evoked potentials are presented in chapter 16. Chapter 17 discusses the use of AEPs in intraoperative monitoring and includes several color figures to enhance the readers understanding of the material being presented. Response acquisition, interpretation, and clinical applications are also discussed. This chapter additionally includes several case studies for illustrative purposes. Chapter 18 introduces the use of electrophysiological measures as indices of auditory system maturation. Peripheral and cortical maturation are discussed for both normal and pathological populations. The relationship between behavioral, structural, and electrophysiological changes is also discussed. Chapter 19 covers the effects of aging on the auditory system and the confounding effects of hearing loss on AEPs.
The sixth section, “Research and Clinical Applications VI: AEPs from Auditory Cortical Areas,” consists of seven chapters. Chapter 20 covers the organization of the thalamocortical auditory pathway in primates, while chapters 21 and 22 cover the ASSR and middle latency responses (MLR) responses respectively. Chapter 23 presents the reader with an overview of the cortical AEPs, including the MMN and the P1-N1-P2 complex. The use of cortical AEPs to index change in neural processing for populations with hearing loss and in aural rehabilitation is presented. The value of the cortical potentials as tools to assess different stages of neural processing is also covered. Chapter 24 presents a discussion of the effects of attention, cognition, dementia, memory, and mild cognitive impairment on auditory cortical potentials. Chapter 25 introduces magneto encephalography as a non-invasive tool to study the function of the auditory cortex. Effects of lesions on the auditory pathway, as well as mechanisms of reorganization of the auditory evoked field subsequent to childhood defects such as auditory atresia, are covered. Chapter 26 reviews the use of computerized source analysis to quantify sources that contribute to auditory evoked potentials and auditory evoked fields over time.
Section VII, “Research and Clinical Applications V: Myogenic and Nonauditory AEPs,” consists of five chapters that cover potentials from the vestibular, visual, and somatosensory systems. This section concludes with a chapter that addresses how multisensory convergence shapes auditory processing.
The final section of the text, section VIII, “Practical Matters: Laboratory Exercises and Case Studies,” consists of 2 chapters. Chapter 32 presents laboratory exercises that encourage practical, hands on experience while chapter 33 presents a series of case studies to allow the reader to apply knowledge and see clinical applications of evoked potentials for diagnostic purposes.
CRITIQUE: Auditory Evoked Potentials: Basic Principles and Clinical Applications is an excellent collection of chapters written by respected experts in the field. Each chapter opens with a brief introduction and key terms to acclimate the reader to the topic. The chapters close with a Myth/Reality section and an executive summary. The Myth/Reality section helps clarify topics that are often misunderstood. The executive summary focuses the reader, giving a review of the important main points covered in the chapter. The use of case studies and the inclusion of laboratory exercises encourage hands on, experiential learning, and clinical application of knowledge. Overall, the book is well organized and easy to read. Coverage of topics ranges from intermediate to advanced, making this text appropriate for graduate students in audiology and related disciplines, as well as clinicians working with auditory evoked potentials.