Preface

The auditory system is a complex organ that perceives sound, converts it into electrical signals, and conveys these signals to the brain for interpretation. The various cells in this system are arranged to form an extremely intricate architectural structure. The functions of these cells in the auditory system are equally diverse. Their roles are mediated by a vast plethora of different protein components. Given the high complexity of the structure and function of the auditory system, it is not surprising that multiple things can and do go wrong. Malfunctions of the auditory system can affect any of its parts. The outer ear can be deformed or missing. Middle ear development can be impaired. These defects may result in conductive hearing loss. However, by far the most common defect is sensorineural hearing loss, which is due to inner ear dysfunction. This book discusses the different structures and functions of the auditory system in both normal and impaired hearing.

The first section of the book presents the basic structure of the auditory system. Chapter 1, "Structure and Physiology of Human Ear Involved in Hearing" presents the gross organization of the ear. It describes various cell types and the acellular membrane in detail. Chapter 2, "Electrophysiology and Auditory Training," discusses the recording of electrical changes collected through electrodes placed on the scalp as a tool to help in monitoring auditory intervention programs.

The second section includes three chapters related to auditory brainstem responses. Chapter 3, "Short Latency Evoked Potentials of the Human Auditory System," discusses auditory brain stem responses. Chapter 4, "Precocious Auditory Evoked Potential Recording with Free-Field Stimulus," describes a case series study of children assessed by auditory brain stem responses as well as auditory steady-state responses. Chapter 5, "Auditory Brainstem Response with Cognitive Interference in Normal and Autism Spectrum Disorder Children - Understanding the Auditory Sensory Gating Mechanism," presents findings concerning auditory brain stem responses with cognitive interference in healthy children and auditory sensory gating capacity in those with autism spectrum disorders.

The third section deals with the genetics of hearing loss. Chapter 6, "A Short Overview on Hearing Loss and Related Auditory Defects," describes different inherited deafness forms as well as the very common age-related hearing loss. Chapter 7, "Nonreceptor Protein Kinases and Phosphatases Necessary for Auditory Function," discusses those protein kinases and phosphatases variants that are known to cause hearing loss in humans or mice.

The final section defines cochlear prosthetic devices and optical wireless cochlear implants. Chapter 8, "Issues in Creation of Bio-Compatible Cochlear Signal: Towards a New Generation of Cochlear Prosthetic Devices," highlights problems and suggests solutions for the treatment of hearing loss. Finally, Chapter 9, "Hearing Restoration through Optical Wireless Cochlear Implants," presents two

new implant architectures for improving the efficiency and reliability of hearingrestoration devices.

I would like to thank Commissioning Editor Ms. Lucija Tomicic-Dromgool and Author Service Manager Ms. Sara Debeuc at IntechOpen for their help throughout the publication process.

> **Sadaf Naz,** School of Biological Sciences, University of the Punjab, Lahore, Pakistan

> > Section 1

Structure and Physiology

of the Auditory System
