Central Auditory Implants

Cochlear implants are currently the standard treatment for profound sensorineural hearing loss. In the last decade, advances in auditory science and technology have not only greatly expanded the utility of electric stimulation to other parts of the auditory nervous system in addition to the cochlea, but have also demonstrated drastic changes in the brain in responses to electric stimulation, including changes in language development and music perception. Volume 20 of SHAR focused on basic science and technology underlying the cochlear implant. However, due to the newness of the ideas and technology, the volume did not cover any emerging applications such as bilateral cochlear implants, combined acoustic-electric stimulation, and other types of auditory prostheses, nor did it review brain plasticity in responses to electric stimulation and its perceptual and language consequences. This proposed volume takes off from Volume 20, and expands the examination of implants into new and highly exciting areas. This edited book starts with an overview and introduction by Dr. Fan-Gang Zeng. Chapters 2-9 cover technological development and the advances in treating the full spectrum of ear disorders in the last ten years. Chapters 10-15 discuss brain responses to electric stimulation and their perceptual impact. This volume is particularly exciting because there have been quantum leap from the traditional technology discussed in Volume 20. Thus, this volume is timely and will be of real importance to the SHAR audience.

For many years or decades, cochlear implants have been an exciting research area covering multiple disciplines which include surgery, engineering, audiology, speech language pathology, education and psychology, among others. Through these research studies, we have started to learn or have better understanding on various aspects of cochlear implant surgery and what follows after the surgery, the implant technology and other related aspects of cochlear implantation. Some are much better than the others but nevertheless, many are yet to be learnt. This book is intended to fill up some gaps in cochlear implant research studies. The compilation of the studies cover a fairly wide range of topics including surgical issues, some basic auditory research, and work to improve the speech or sound processing strategies, some ethical issues in language development and cochlear implantation in cases with auditory neuropathy spectrum disorder. The book is meant for postgraduate students, researchers and clinicians in the field to get some updates in their respective areas.

Cochlear implants have instigated a popular but controversial revolution in the treatment of deafness. This book discusses the physiological bases of using artificial devices to electrically stimulate the brain to interpret sounds. As the first successful device to restore neural function, the cochlear implant serves as a model for research in neuroscience and biomedical engineering. These and other auditory prostheses are discussed in the context of historical treatments, engineering, psychophysics and clinical issues as well as implications for speech, behavior, cognition and long-term effects on people.

Today cochlear implants are the most successful of all prostheses of the nervous system. They are used in individuals who are deaf or suffer from a severe hearing deficiency caused by loss of cochlear hair cells. Auditory brainstem implants provide stimulation of the cochlear nucleus and are used in patients with an auditory nerve dysfunction, a deformed cochlea which does not allow cochlear implantation, or traumatic auditory nerve injury. In this volume different aspects of cochlear implantation such as the role of neural plasticity, the interaction with the development of the auditory system, and the optimal time of implantation in children (sensitive periods) are discussed in detail. Further, the processors and the algorithms used in modern cochlear implants are described The second part is devoted to auditory brainstem implants. It describes surgical techniques, methods for intraoperative testing as well as speech processing. It also deals with electrical stimulation of neural tissue and the neurophysiologic basis for cochlear and brainstem implants. The publication provides the latest scientific and clinical knowledge on cochlear and brainstem implants and is highly recommended to audiologists, otolaryngologists and also neurosurgeons.

Cochlear Implants: Audiologic Management and Considerations for Implantable Hearing Devices provides comprehensive coverage of the audiological principles and practices pertaining to cochlear implants and other implantable hearing technologies. This is the first and only book that is written specifically for audiologists and that exhaustively addresses the details involved with the assessment and management of cochlear implant technology. Additionally, this book provides a through overview of hybrid cochlear implants, implantable bone conduction hearing technology, middle ear implantable devices, and auditory brainstem implants. Key Features: Each chapter features an abundance of figures supporting the clinical practices and principles discussed in the text and enabling students and clinicians to more easily understand and apply the material to clinical practice.The information is evidence based and whenever possible is supported by up-to-date peer-reviewed research.Provides comprehensive coverage of complex information and sophisticated technology in a manner that is student-friendly and in an easily understandable narrative form.Concepts covered in the narrative text are presented clearly and then reinforced through additional learning aids including case studies and video examples.Full color design with numerous figures and illustrations. Cochlear Implants is the perfect choice for graduate-level courses covering implantable hearing technologies because the book provides a widespread yet intricate description of every implantable hearing technology available for clinical use today. This textbook is an invaluable resource and reference for both audiology graduate students and clinical audiologists who work with implantable hearing devices. Furthermore, this book supplements the evidence-based clinical information provided for a variety of implantable hearing devices with clinical videos demonstrating basic management procedures and practices.

Infants with early-onset severe to profound deafness are deprived of auditory stimulation until they receive a cochlear implant. Auditory input is achieved by electrical stimulation of the auditory nerve. I asked: (1) Does early-onset deafness impact the central auditory pathways? (2) Will the duration of early-onset deafness affect the system's ability to respond to electrical stimulation? (3) Can the pathways change in response to chronic stimulation? and (4) If plasticity exists, is it limited by the age at implantation?In answer to the questions posed, I found, first, that most children at initial device activation had recognizable ECAP and EABR responses (89% and 94%, respectively) but only 32% had detectable EMLRs. Second, initial ECAP and EABR wave latencies and amplitudes had no significant relationship with age at implantation whereas EMLR detectability was better, wave latencies shorter, and wave amplitudes larger in children implanted at ≥5 years compared to their younger peers. Thus, early-onset deafness and its duration influence thalamocortical responses but not auditory nerve or brainstem responses. Third, significant decreases in latencies and increases in amplitudes of all responses and increased EMLR detectability were found with ongoing implant use reflecting activity-dependent changes along the central auditory pathways promoted by implant use. Fourth, the ECAP and EABR changes were not significantly related to the age at implantation and showed some similarities to changes in the normal acoustically evoked brainstem response. Increases in EMLR detectability tended to be more subtle in children implanted between 8--17 years than changes in younger children. Age and/or duration of deafness therefore affect thalamo-cortical responses more strongly than responses from more peripheral areas.Electrically evoked potentials of the auditory nerve (ECAP), brainstem (EABR) and thalamo-cortex (EMLR), were collected repeatedly in 50 children with early-onset deafness (5.4 +/- 4.0 years); recordings were made at implant surgery, initial device activation and at regular times over the first year of implant use. Responses were also collected from 31 children (6.3 +/- 3.0 years at implantation, 5.3 +/- 2.9 years of implant experience) and in 11 adults (implanted at 42.5 +/- 7.5 years, 4.5 +/- 2.9 years of implant use).

They also detail their children's experiences with the implants after surgery, and their progress with language acquisition and in school.".