BOOK
Auditory Processing Of Temporal Fine Structure: Effects Of Age And Hearing Loss
(2014)
Additional Information
Book Details
Abstract
The book is concerned with changes in the perception of sound that are associated with hearing loss and aging. Hearing loss affects about 7% of the population in developed countries, and the proportion is increasing as the average age of the population increases. The audiogram is the most widely used diagnostic tool in audiology clinics around the world. The audiogram involves measuring the threshold for detecting sounds of different frequencies. Sometimes the audiogram is the only diagnostic tool that is used. However, hearing problems are not completely characterized by the audiogram. Two individuals with similar audiograms may show very different abilities in the detection and discrimination of sounds at above-threshold levels. Also, a person may have hearing difficulties despite having an audiogram that is within the range conventionally considered as ‘normal’. One factor that may influence the discrimination of sounds, especially the ability to understand speech in background sounds, is sensitivity to temporal fine structure (TFS).This monograph reviews the role played by TFS in masking, pitch perception, speech perception, and spatial hearing, and concludes that cues derived from TFS play an important role in all of these. Evidence is reviewed suggesting that cochlear hearing loss reduces the ability to use TFS cues. Also, the ability to use TFS declines with increasing age even when the audiogram remains normal. This provides a new dimension to the changes in hearing associated with aging, a topic that is currently of great interest in view of the increasing proportion of older people in the population.The study of the role of TFS in auditory processing has been a hot topic in recent years. While there have been many research papers on this topic in specialized journals, there has been no overall review that pulls together the different research findings and presents and interprets them within a coherent framework. This monograph fills this gap.
Table of Contents
| Section Title | Page | Action | Price |
|---|---|---|---|
| Contents | vii | ||
| Preface | xi | ||
| List of Abbreviations | xiii | ||
| Chapter 1. Processing of Sound in the Auditory System and Neural Representation of Temporal Fine Structure | 1 | ||
| 1.1 Introduction and Overview | 1 | ||
| 1.2 The Representation of Signals in Terms of ENV and TFS | 2 | ||
| 1.3 Analysis of Sound in The Cochlea | 4 | ||
| 1.3.1 Basic structure of the cochlea | 4 | ||
| 1.3.2 The travelling wave and tuning | 4 | ||
| 1.3.3 Nonlinearity of input–output functions | 8 | ||
| 1.3.4 Suppression on the BM | 9 | ||
| 1.3.5 Responses of the BM to complex sounds | 10 | ||
| 1.4 The Hair Cells and Transduction in the Cochlea | 10 | ||
| 1.5 Responses of Single Neurons in the Auditory Nerve | 13 | ||
| 1.5.1 Spontaneous activity | 13 | ||
| 1.5.2 Tuning curves and iso-rate contours | 14 | ||
| 1.5.3 Rate versus level functions | 15 | ||
| 1.5.4 Phase locking | 16 | ||
| 1.6 Effects of Hearing Loss on the Processing of Sounds | 18 | ||
| 1.6.1 Effects of cochlear hearing loss on the active mechanism | 19 | ||
| 1.6.2 Effects of cochlear hearing loss on phase locking to narrowband sounds | 20 | ||
| 1.6.3 Effects of cochlear hearing loss on phase locking to broadband sounds | 22 | ||
| 1.7 Possible Ways in Which Hearing Loss and Ageing Might Affect the Neural Coding of TFS | 24 | ||
| 1.7.1 Changes in the relative phase of responses at different points along the basilar membrane | 25 | ||
| 1.7.2 Mismatch between place and temporal information | 26 | ||
| 1.7.3 Complexity of TFS information | 27 | ||
| 1.7.4 Loss of central inhibition | 28 | ||
| 1.7.5 Relative strength of ENV and TFS coding | 28 | ||
| 1.7.6 Reduced number of synapses or neurons | 28 | ||
| 1.7.7 Increased temporal jitter in the transmission to higher neural levels | 29 | ||
| Chapter 2. The Role of TFS in Masking | 31 | ||
| 2.1 Introduction | 31 | ||
| 2.2 Detection Cues in Masking | 32 | ||
| 2.3 The Detection of Signals in Fluctuating Maskers | 33 | ||
| 2.3.1 The concept of dip listening | 33 | ||
| 2.3.2 Masking release for a narrowband fluctuating masker | 35 | ||
| 2.3.3 The role of TFS in comodulation masking release | 37 | ||
| 2.4 The Role of TFS in the Ability to Hear Out Partials in Complex Sounds | 40 | ||
| 2.5 The Role of TFS in Masking for Hearing-Impaired Listeners | 43 | ||
| 2.6 Conclusions | 44 | ||
| Chapter 3. The Role of TFS in Pitch Perception | 47 | ||
| 3.1 Introduction | 47 | ||
| 3.2 The Perception of Pitch for Sinusoids | 48 | ||
| 3.2.1 Mechanisms of pitch perception | 48 | ||
| 3.2.2 The perception of musical intervals by subjects with normal hearing | 49 | ||
| 3.2.3 The perception of musical intervals by subjects with impaired hearing | 50 | ||
| 3.2.4 The perception of pitch and musical intervals by hearing-impaired subjects with dead regions | 50 | ||
| 3.2.5 The frequency discrimination of sinusoids by normal-hearing people | 53 | ||
| 3.2.6 The frequency discrimination of sinusoids by hearing-impaired people | 56 | ||
| 3.2.7 The effect of age on frequency discrimination | 58 | ||
| 3.2.8 The detection of frequency modulation by subjects with normal hearing | 61 | ||
| 3.2.9 The detection of frequency modulation by subjects with impaired hearing | 63 | ||
| 3.2.10 The effect of age on frequency modulation detection | 65 | ||
| 3.3 The Role of TFS for Perception of Pitch for Complex Sounds | 66 | ||
| 3.3.1 TFS and pitch perception for normal-hearing listeners | 66 | ||
| 3.3.2 TFS and pitch perception for hearing-impaired listeners | 75 | ||
| 3.4 Conclusions | 77 | ||
| Chapter 4. The Role of TFS in Speech Perception | 81 | ||
| 4.1 Introduction | 81 | ||
| 4.2 Types of Vocoder Processing and their Pitfalls | 83 | ||
| 4.2.1 The importance of the number of channels | 83 | ||
| 4.2.2 The effect of the method of envelope extraction | 84 | ||
| 4.2.3 Processing to disrupt TFS cues while preserving ENV cues | 85 | ||
| 4.2.4 Processing to disrupt ENV cues while preserving TFS cues | 86 | ||
| 4.3 The Role of ENV and TFS for Speech Perception | 89 | ||
| 4.3.1 Studies using ENV speech | 89 | ||
| 4.3.2 Studies using TFS speech | 94 | ||
| 4.3.3 Studies examining the correlation between speech perception and the ability to use TFS | 98 | ||
| 4.4 Conclusions | 102 | ||
| Chapter 5. The Influence of Hearing Loss and Age on the Binaural Processing of TFS | 103 | ||
| 5.1 Introduction: Binaural Cues for Localisation and Signal Detection | 103 | ||
| 5.2 Effects of Hearing Loss and Age on Localisation and Lateralisation | 106 | ||
| 5.2.1 Effects of hearing loss | 106 | ||
| 5.2.2 Effects of age | 109 | ||
| 5.3 The Effects of Hearing Loss and Age on the Perception of Binaural Pitches | 116 | ||
| 5.4 The Effects of Hearing Loss and Age on MLDs | 118 | ||
| 5.4.1 Effects of hearing loss | 118 | ||
| 5.4.2 Effects of age | 121 | ||
| 5.5 Impact of Impaired Binaural TFS Processing on Spatial Hearing for Speech | 123 | ||
| 5.6 Conclusions | 137 | ||
| Chapter 6. Overview, Conclusions and Practical Implications | 139 | ||
| 6.1 Overview o fChapters1–5 | 139 | ||
| 6.2 Relevance of Impaired TFS Processing for Hearing Aids | 142 | ||
| 6.2.1 Compensating for the effects of impaired TFS processing | 142 | ||
| 6.2.2 Exploiting reduced TFS sensitivity to increase battery life | 142 | ||
| 6.2.3 Exploiting reduced TFS sensitivity in the design of systems to reduce acoustic feedback | 143 | ||
| 6.2.4 Choosing compression speed based on sensitivity to TFS | 144 | ||
| 6.3 Acoustical Requirements of Places Where Hearing-Impaired and Older People Meet and Dine | 147 | ||
| 6.4 The Use of Background Sounds in Broadcasting and Films | 148 | ||
| 6.5 Conclusions | 149 | ||
| References | 151 | ||
| Index | 179 |