Rehabilitation of unilateral profound sensorineural hearing loss with a bone anchored hearing aid

224 Pages·2010·1.71 MB·English

Rehabilitation of unilateral profound sensorineural
hearing loss with a bone anchored hearing aid

Katrise Mary Eager
Bachelor of Speech Pathology, University of Queensland, 1996
Postgraduate Diploma of Audiology, University of Queensland, 1997

This thesis is presented for the degree
of
Masters of Medical Science - Research

The University of Western Australia
School of Surgery
2009
ABSTRACT

The long-term outcomes of subjects fitted with a bone anchored hearing aid
(BAHA) for a unilateral profound sensorineural hearing loss (UPSHL) are still
evolving. Previous studies have focused on the comparison between short-
term outcomes obtained with hard-wired contralateral routing of signal (CROS)
hearing aids and those obtained with BAHA devices. Published results on
subjects who have worn their BAHA devices for UPSHL for more than twelve
months are limited.

This study explored the long-term outcomes of adults fitted with a BAHA for
UPSHL. The aims were firstly to examine subjects’ pre-operative and post-
operative speech perception in quiet and noise, as well as administer two
standardised questionnaires, the Abbreviated Profile of Hearing Benefit
(APHAB) and the Glasgow Hearing Aid Benefit Profile (GHABP). The second
aim was to evaluate the responses of implanted subjects following the pre-
operative test protocols using a supplementary questionnaire, the Single Sided
Deafness Questionnaire (SSDQ). The third aim was to monitor the subjects’
implant or repair issues. In addition, questionnaire results were compared to
subjects who underwent pre-operative assessment but were not implanted.

All subjects had a UPSHL resulting from various aetiologies including vestibular
schwannoma or other skull base tumour removal, viral infections, cochlear
trauma, idiopathic sudden hearing loss, and Meniere’s disease. There was a
significant difference between the implanted groups’ pre- and post-operative
outcomes measures, indicating a treatment effect from the fitting of the BAHA
device. No significant changes were found with the non-implanted groups’ long-
term outcome measures in regards to their perceived hearing difficulties. No
significant correlations were found between outcome measures and gender,
age of fitting, length of deafness, or ear affected for either group.

The implanted subjects’ responses on the SSDQ revealed depreciation over
time in overall usage and satisfaction rates. However, these rates remained
high when compared to other reported studies. The overall outcome results

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revealed that the BAHA remains one of the treatment methods of choice for
hearing rehabilitation with this subject group. Further studies comparing the
BAHA to wireless frequency modulated (FM) contralateral routing of signal
(CROS) systems, as well as the fitting of FM systems compatible with the BAHA
to this subject group of UPSHL are warranted to ascertain respective
advantages of these different treatment options.

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TABLE OF CONTENTS
Abstract ............................................................................................................. ii
Table of Contents ............................................................................................. iv
Acknowlegements ........................................................................................... ix
List of Figures ................................................................................................. xii
List of Tables .................................................................................................. xiv
Abbreviations .................................................................................................. xv
Glossary ....................................................................................................... xviii
Chapter 1: Introduction .................................................................................... 1
1.1 Unilateral profound sensorineural hearing loss (UPSHL) .............................. 3
1.1.1 Types of hearing loss ................................................................ 4
1.1.2 Audiological test battery ............................................................ 6
1.2 Incidence of UPSHL ................................................................................. 13
1.2.1 Incidence of congenital UPSHL .............................................. 14
1.2.2 Incidence of acquired UPSHL ................................................. 14
1.3 Congenital causes of UPSHL ................................................................... 15
1.4 Acquired UPSHL ...................................................................................... 16
1.4.1 Trauma ................................................................................... 16
1.4.2 Metabolic ................................................................................ 17
1.4.3 Neoplasms .............................................................................. 17
1.4.4 Infections ................................................................................ 19
1.4.5 Ototoxicity ............................................................................... 19
1.4.6 Immunological ......................................................................... 20
1.4.7 Idiopathic ................................................................................ 20
1.5 Loss of binaural hearing cues ................................................................... 21
1.5.1 Head shadow effect ................................................................ 23
1.5.2 Binaural summation ................................................................ 24
1.5.3 Binaural squelch ..................................................................... 25
1.5.4 Binaural redundancy ............................................................... 25
1.5.5 Localising sound ..................................................................... 26

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1.6 Studies on unilateral hearing loss ............................................................. 27
1.7 Quality of life aspects and outcome measures ......................................... 29
1.7.1 Abbreviated Profile of Hearing Aid Benefit (APHAB) .............. 32
1.7.2 Glasgow Hearing Aid Benefit Profile (GHABP) ....................... 33
1.7.3 Single Sided Deafness Questionnaire (SSDQ) ....................... 34
1.8 Summary .................................................................................................. 35
Chapter 2: Traditional options for UPSHL .................................................... 37
2.1 Transcranial hearing aids ......................................................................... 37
2.2 Contralateral routing of signal (CROS) hearing aids ................................ 38
2.3 Frequency modulated (FM) systems ........................................................ 42
2.4 Monitoring hearing loss ............................................................................ 43
Chapter 3: The bone anchored hearing aid (BAHA) .................................... 46
3.1 Background information on the BAHA ...................................................... 46
3.1.1 Surgical procedure .................................................................. 46
3.1.2 Direct bone conduction ........................................................... 50
3.1.3 BAHA sound processors ......................................................... 52
3.1.4 Post surgical complications and management ........................ 58
3.2 Use of BAHA in hearing rehabilitation ...................................................... 61
3.3 Application of BAHA with UPSHL ............................................................. 63
3.3.1 How the BAHA works with UPSHL ......................................... 65
3.3.2 Background studies ................................................................ 65
3.3.3 Recent studies ........................................................................ 69
Chapter 4: Purpose of the study .................................................................... 72
Chapter 5: Material and methods .................................................................. 74
5.1 Subject selection ...................................................................................... 74
5.1.1 Subject inclusion criteria ......................................................... 74
5.1.2 Subject recruitment ................................................................. 76
5.1.3 Study ethical approval ............................................................. 76
5.2 Test equipment ......................................................................................... 77
5.2.1 General test equipment ........................................................... 77
5.2.2 BAHA test equipment .............................................................. 78

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5.2.3 BAHA setting protocols ........................................................... 78
5.3 Test protocols ........................................................................................... 79
5.3.1 Pure tone audiometry testing .................................................. 80
5.3.2 Immittance audiometry testing ................................................ 80
5.3.3 Speech audiometry under headphones .................................. 81
5.3.4 Free-field speech testing set up .............................................. 81
5.5.5 Free-field speech testing ......................................................... 82
5.3.6 Single word testing in quiet ..................................................... 83
5.3.7 Sentence testing in noise ........................................................ 84
5.3.8 Protocols for implanting subjects and post-surgical fitting of
sound processor .................................................................................... 85
5.3.9 Questionnaire administration .................................................. 86
5.3.10 Data analysis ......................................................................... 87
Chapter 6: Results .......................................................................................... 88
6.1 Subjects .................................................................................................... 88
6.1.1 General subject characteristics ............................................... 89
6.1.2 Implanted subject characteristics ............................................ 90
6.1.3 Non-implanted subject characteristics .................................... 92
6.1.4 Subject implantation and BAHA device ................................... 95
6.2 Speech testing in quiet via free-field testing ............................................. 97
6.2.1 Pre-operative speech results of Group A ................................ 97
6.2.2 Pre-operative speech results of Group B/C ............................ 98
6.2.3 Post-operative results of Group A ........................................... 99
6.2.4 Post-operative results of Group B/C ..................................... 101
6.3 Speech testing in noise .......................................................................... 101
6.3.1 Pre-operative results of Group A ........................................... 101
6.3.2 Pre-operative results of Group B/C ....................................... 102
6.3.3 Post-operative results of Group A ......................................... 103
6.3.4 Post-operative results of Group B/C ..................................... 104
6.4 Abutment and repair issues .................................................................... 105
6.5 Questionnaires ....................................................................................... 109

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6.5.1 Implanted subjects APHAB results ....................................... 109
6.5.2 Non-implanted subjects – APHAB results from initial and
repeated surveys ................................................................................. 110
6.5.3 Implanted subject GHABP results ......................................... 111
6.5.4 Non-implanted subjects – GHABP results from initial and
repeated surveys ................................................................................. 112
6.5.5 Alternative aids and employment .......................................... 113
6.5.6 SSDQ .................................................................................... 113
Chapter 7: Discussion .................................................................................. 117
7.1 Subjects .................................................................................................. 117
7.1.1 Subject selection ................................................................... 117
7.1.2 Hearing loss group classification ........................................... 119
7.1.3 Implantation uptake of the subject group .............................. 119
7.1 4 Implanted subject numbers ................................................... 122
7.2 Speech testing ........................................................................................ 123
7.2.1 Speech testing in quiet .......................................................... 124
7.3 Speech-in-noise testing .......................................................................... 127
7.3.1 Testing in S0:N0 condition .................................................... 135
7.3.2 Testing in S0:N90/S0:N270 conditions ................................. 136
7.4 Abutment and device issues ................................................................... 138
7.4.1 Post-operative skin infections and complications .................. 138
7.4.2 Repair issues ........................................................................ 139
7.4.3 Abutment removal and discontinued usage of BAHA ........... 141
7.5 Questionnaires ....................................................................................... 143
7.5.1 APHAB .................................................................................. 143
7.5.2 GHABP .................................................................................. 145
7.5.3 SSDQ .................................................................................... 147
7.5.4 BAHA outcome measures with non-implanted subjects ........ 151
7.6 Limitations to the study ........................................................................... 152
7.7 Future studies ......................................................................................... 153
Chapter 8: Conclusions ................................................................................ 156

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Chapter 9: References .................................................................................. 159
Chapter 10: Appendices ............................................................................... 179
Appendix I ....................................................................................................... 180
Appendix II ...................................................................................................... 181
Appendix III ..................................................................................................... 183
Appendix IV..................................................................................................... 184
Appendix V ..................................................................................................... 187
Appendix VI .................................................................................................... 190
Appendix VII.................................................................................................... 193
Appendix VIII................................................................................................... 195
Appendix IX..................................................................................................... 197
Appendix X ..................................................................................................... 198
Appendix XI .................................................................................................... 199
Appendix XII.................................................................................................... 200

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ACKNOWLEDGEMENTS

I am grateful to the following people and organisations who have helped me
over the last four and half years in order to produce this Masters thesis.

I would like to thank my supervisors, Associate Adjunct Professor, Dr Robert
Eikelboom and Professor Marcus Atlas, for all their help and guidance with this
project. They have supported me both professionally and personally since the
inception of this thesis, which has been greatly appreciated. Additionally, Dr
Eikelboom, kindly did all the statistical analysis for this study. I would also like
to thank Associate Adjunct Professor, Paul Davis, who gave audiological advice
about the study and its content.

The study was funded by the Ear Sciences Institute Australia (ESIA), Nedlands,
Western Australia. I wish to thank the Institute for its continued interest and
financial support, and to Gemma Upson who has supported the study through
access to the clinical services at the Lions Hearing Clinic-Implant Centre at
Nedlands, Western Australia.

Thank you to Entific Medical System’s distributor, Shine Medical, for the loan of
test equipment during the initial years of the study. Jodie Oakley and Chris
Broadbent at Cochlear Limited, Australia kindly allowed the use of equipment
for testing procedures, loan devices and provided technical advice regarding
aspects of the bone anchored hearing aid.

I would like to thank the audiologists, Roberta Marino and Gemma Ivey at Lions
Hearing Centre-Implant Centre, Nedlands, Western Australia, as well as Celene
McNeill, Erica Caiuby and Monique Mainey from the Healthy Hearing & Balance
Care, Bondi Junction, New South Wales for subject data collection that was
used in this study, but most importantly for giving me great support and
providing important feedback during the whole process.

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The technical support and equipment design involved student and staff at Lions
Ear & Hearing Institute (LEHI), later ESIA. Mark Gallop, research officer, for the
development of the on-line data collection website. The University of Western
Australia, Engineering students who did vacation work on this project, Jennifer
Hubble and Gabrielle van der Linde, and University of Western Australia,
Nedlands, WA.

I would like to thank the subjects recruited from the clinical caseloads of the
Lions Hearing Clinic-Implant Centre and Healthy Hearing & Balance Care, who
gave generously of their time to allow this study to be completed.

Cathy Sucher and Gae Di Francesco who tirelessly read drafts of my thesis,
and provided sound audiological advice and editing skills.

A big thanks to my sister, Zoë Pozza who helped edit the final draft.

Finally, and most importantly, I want to thank my husband, Alan and my sons,
Patrick and Angus for being understanding and patient when I was not able to
fulfil my responsibilities as a wife and mother when working on this study.

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