Principles of Hearing
Aid Audiology
Principles of Hearing
Aid Audiology
Maryanne Tate
a11
I I Springer-Science+Business Media, B. v.
First edition 1994
© Maryanne Tate 1994
Originally published by Maryanne Tate in 1994
ISBN 978-0-412-49070-5 ISBN 978-1-4899-7152-4 (eBook)
DOI 10.1007/978-1-4899-7152-4
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Contents
Foreword ix
Acknowledgements X
PART ONE Fundamental Sciences 1
1 Acoustics 3
1.1 Physical properties of sound 3
1.2 The measurement of sound 10
1.3 The audiometer 14
1.4 The psychological properties of sound 17
1.5 Summary 18
References 19
Further reading 19
2 Anatomy and physiology of the ear 20
2.1 Anatomy of the ear 20
2.2 The physiology of hearing 32
2.3 Summary 39
Further reading 40
3 Medical aspects of hearing loss 41
3.1 Introduction 41
3.2 Pathology of the outer ear 42
3.3 Pathology of the middle ear 46
3.4 Pathology of the inner ear 50
3.5 Other conditions of the ear 57
3.6 Summary 59
References 60
Further reading 60
4 Speech and intelligibility 61
4.1 The speech chain 61
vi Contents
4.2 The vocal tract 63
4.3 Speech-reading 64
4.4 Speech sounds 65
4.5 Hearing loss and speech perception 70
4.6 Hearing loss and speech production 71
4. 7 Summary 72
Further reading 72
5 The hearing aid system 73
5.1 The basic components of a hearing aid 73
5.2 Elementary electricity and electronics 84
5.3 Signal processing 86
5.4 Summary 93
References 94
Further reading 94
PART TWO The Practice of Hearing Aid Audiology 95
6 The assessment procedure 97
6.1 Pre-selection management 97
6.2 Otoscopy 101
6.3 Tuning fork tests 103
6.4 Principal audiometric tests 106
6.5 Understanding audiograms 117
6.6 Room requirements for audiometry 122
6.7 Summary 123
References 124
Further reading 125
7 Hearing aids and their performance 126
7.1 Introduction 126
7.2 Types of hearing aid system 127
7.3 Specification and performance 132
7.4 Hearing aid standards 139
7.5 Measuring methods 142
7.6 Power sources 146
7.7 The National Health Service provision of hearing aids 149
7.8 Summary 152
References 153
Further reading 153
8 Selection and fitting 155
8.1 The choice of a hearing aid system 155
8.2 Hearing aid fitting 163
Contents vii
8.3 Summary 171
References 171
Further reading 172
9 Earmoulds 173
9.1 Making the impression 173
9.2 Earmoulds 178
9.3 Summary 185
References 185
Further reading 186
10 Evaluation 187
10.1 Introduction 187
10.2 Insertion gain measurement 187
10.3 Functional gain measurement 190
10.4 Speech audiometry 191
10.5 Subjective evaluation 197
10.6 Summary 199
References 199
Further reading 200
11 Client management and rehabilitation 201
11.1 The rehabilitation process 201
11.2 Practical aspects of rehabilitation 207
11.3 Assistive devices for the hearing impaired 213
11.4 Management practices 214
11.5 Improving communications 217
11. 6 The role of other specialists 219
11.7 Summary 220
References 220
Further reading 221
PART THREE Special Aspects of Hearing Aid Audiology 223
12 Assessment and management of special problems 225
12.1 Tinnitus 225
References for section 12.1 232
Further reading for section 12.1 232
12.2 Impedance audiometry 232
Further reading for section 12.2 240
12.3 Specialized audiometric tests 240
References for section 12.3 246
Further reading for section 12.3 246
12.4 Non-organic hearing loss 246
viii Contents
References for section 12.4 249
Further reading for section 12.4 250
12.5 Automatic audiometry 250
References for section 12.5 252
Further reading for section 12.5 252
13 Paediatric provision 253
13.1 The effect of hearing loss in children 253
13.2 Habilitation of hearing impaired children 259
13.3 Summary 264
References 264
Further reading 265
Appendix Glossary 266
Index 277
Foreword
Both for those in training towards qualification in hearing aid audiology
and for those simply wishing to revise and update their knowledge,
it is a perennial problem to acquire one book which provides com-
prehensive and up-to-date material on hearing aid audiology. Principles
of Hearing Aid Audiology meets the need for a text book which deals not
only with the foundation sciences of hearing aid audiology but also the
many and varied aspects of audiological practice where the objective
is the rehabilitation of the hearing impaired through hearing aid
prescription and fitting. In bringing together all the material contained
in this book, Maryanne Tate has drawn on her considerable experience
in the training of hearing aid audiologists as well as in dealing with the
hearing impaired themselves. As a result, this book has total relevance
to the needs of the many professional groups whose work brings them
into contact with the hearing impaired.
The very practical nature of hearing aid audiology is fully recognized
so that the purely theoretical aspects are presented and explained with
a view to supporting hearing aid audiology in practice. With so many
audiology text books emanating from the USA, Principles of Hearing Aid
Audiology will, I am sure, be greatly welcomed by readers in the UK.
Undoubtedly, this book will feature prominently on any list of recom-
mended reading in audiology and, at the same time, will serve as a
very useful work of reference.
Barry Downes, LLB, FSHAA
Registrar of the Society of
Hearing Aid Audiologists, 1988-1993
Acknowledgements
Many colleagues and friends have helped and encouraged me to write
this book. Dr Mark Lutman (Institute of Hearing Research, Nottingham)
provided both critical comments and encouragement when I needed
them in the early stages, and I am particularly grateful for the contri-
butions of:
Dr Loraine Lawrence, S.C.M.O. Audiological Medicine, Tameside
Area Health Services
Mr Joseph Rumble, Consultant Oral Surgeon, North Middlesex
Hospital
Mr Peter Grimaldi, Consultant ENT Surgeon, StMary's Hospital, Isle
of Wight
Mr Robert Rendell, Training Officer, Hidden Hearing Ltd, and Re-
gistrar of the Society of Hearing Aid Audiologists
Dr Derek Tate, Associate Head of Centre for Design, Manufacture
and Technology, University College Salford.
I appreciate the assistance given by Roy Sands (Special Projects
Manager, Rayovac UK Ltd) and Julian Parmenter (Technical Sales
Manager, Duracell UK Ltd) with regard to battery specifications. I
should also like to express my sincere thanks to all those who read and
commented on part, or all, of the manuscript, especially Neville Browne
(Director, The London Otological Centre), Keith Attenborough (Pro-
fessor of Acoustics, The Open University), Barry Downes (Managing
Director, SieTech Hearing Ltd), David Gaszczyk (Audiologist, BMI
Healthcare), John Millership and Alan Hall (Hearing Aid Audiologists,
Amplivox and Ultratone Ltd).
Finally my thanks must go to Dorothy Rothwell who word-processed
the manuscript and tolerated my many revisions without complaint,
John Beeton and other colleagues and friends who helped me in many
ways, and to all those friends and family who endured my preoccupa-
tion throughout 1992 and 1993, especially my children Kerry, Joanne,
Christopher and Russell.
