This chapter examines some of the reasons for hearing loss as well as the amazing technological advances made over the past 100 years that have led to the development of sophisticated prostheses permitting the deaf and hard of hearing to hear again. These range from conventional hearing aids for people who retain some hearing to cochlear and brainstem implants for those with physical damage to the cochlea and auditory nerves, as well as myriad other devices that address damage to different sections of the auditory pathway.

Chapter Contents:

• 6.1 Introduction
• 6.2 What Is Sound?
• 6.2.1 Characteristic Impedance (Z) and Sound Pressure
• 6.2.2 Sound Intensity (I)
• 6.3 How Hearing Works
• 6.3.1 The Outer Ear
• 6.3.2 The Middle Ear
• 6.3.3 The Inner Ear
• 6.3.4 Hearing Statistics
• 6.4 Hearing Loss
• 6.4.1 Causes
• 6.4.2 Diagnosis
• 6.4.3 Treatment
• 6.5 Hearing Aids
• 6.5.1 History
• 6.5.2 Hearing Aid Operation
• 6.6 Bone Conduction Devices
• 6.7 Middle Ear Implants
• 6.7.1 Piezoelectric Devices
• 6.7.2 Electromagnetic Hearing Devices
• 6.7.3 Issues with Implantable Middle Ear Devices
• 6.8 Direct Acoustic Cochlear Stimulatory Devices
• 6.8.1 Actuator Design
• 6.9 Cochlear Implants
• 6.9.1 Historical Background
• 6.9.2 How Cochlear Implants Work
• 6.9.3 Installation of the Electrode
• 6.9.4 Signal Processing and Cochlear Stimulation
• 6.9.5 Spectral Maxima Strategies
• 6.9.6 Strategies to Enhance Vocal Pitch
• 6.10 Auditory Brainstem Implants
• 6.10.1 Electrodes
• 6.10.2 Stimulus Mapping
• 6.11 References

Inspec keywords: hearing; neurophysiology; cochlear implants; ear

Other keywords: physical damage; hearing aids; hearing loss; auditory nerves; brainstem implants; sophisticated prostheses; auditory pathway; cochlear implants

Subjects: Prosthetics and other practical applications; Prosthetics and orthotics; Auditory prostheses and hearing aids