Central Auditory System Activity And Development In Children Who Use Cochlear Implants Microform

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).

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.

This volume will provide an important contemporary reference on hearing development and will lead to new ways of thinking about hearing in children and about remediation for children with hearing loss. Much of the material in this volume will document that a different model of hearing is needed to understand hearing during development. The book is expected to spur research in auditory development and in its application to pediatric audiology.

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 auditory system to interpret sounds. As the first successful device to restore neural function, the cochlear implant has served as a model for research in neuroscience and biomedical engineering. Implants and other auditory prostheses are discussed in the context of historical treatment, engineering, psychophysics, and clinical issues as well as their implications for speech, cognition, behavior, and the long-term effects on recipients .

This book will move the field of pediatric cochlear implantation forward by educating clinicians in the field as to current and emerging best practices and inspiring research in new areas of importance, including the relationship between cognitive processing and pediatric cochlear implant outcomes. The book discusses communication practices, including sign language for deaf children with cochlear implants and the role of augmentative/alternative communication for children with multiple disabilities. Focusing exclusively on cochlear implantation as it applies to the pediatric population, this book also discusses music therapy, minimizing the risk of meningitis in pediatric implant recipients, recognizing device malfunction and failure in children, perioperative anesthesia and analgesia considerations in children, and much more. Cochlear Implants in Children is aimed at clinicians, including neurotologists, pediatric otolaryngologists, audiologists and speech-language pathologists, as well as clinical scientists and educators of the deaf. The book is also appropriate for pre-and postdoctoral students, including otolaryngology residents and fellows in Neurotology and Pediatric Otolaryngology.

The contributors to this volume have provided a detailed and integrated introduction to the behavioural, anatomical, and physiological changes that occur in the auditory system of developing animals. Edwin W Rubel is Virginia Merrill Bloedel Professor of Hearing Sciences at the Virginia Merrill Bloedel Hearing Research Center at the University of Washington, Arthur N. Popper is Professor and Chair of the Department of Zoology at the University of Maryland, while Richard R. Fay is Associate Director of the Parmly Hearing Institute and Professor of Psychology at Loyola University of Chicago. Each volume in this series is independent and authoritative; taken as a set, the series will be the definitive resource in the field.