Acta Oto-Laryngologica. 2014; 134: 1151–1157
ORIGINAL ARTICLE
Exploring the clinical approach to the bimodal fitting of hearing aids and cochlear implants: results of an international survey
FANNY W. A. C. SCHERF & LAURE P. ARNOLD POSTER PRESENTATION AT THE 12TH INTERNATIONAL CONFERENCE ON COCHLEAR IMPLANTS AND OTHER IMPLANTABLE AUDITORY TECHNOLOGIES, ESPO 2012, AMSTERDAM, THE NETHERLANDS, SFORL 2012, PARIS, FRANCE Advanced Bionics Clinical Research Department International, Stäfa, Switzerland
Abstract Conclusions: The results show that the fitting of a contralateral hearing aid (HA) in the non-implanted ear of cochlear implant (CI) recipients is now well established as standard clinical practice. However, there is a lack of experience in HA fitting within the CI centres and the use of published bimodal fitting procedures is poor. The HA is often not refitted after CI switch-on and this may contribute to rejection. Including a bimodal fitting prescription and process in the CI fitting software would make applying a balancing procedure easier and may increase its implementation in routine clinical practice. Objective: This survey was designed to investigate and understand the current approach to bimodal fitting of HAs and CIs across different countries and the recommendations made to recipients. Methods: Clinicians working with HAs and/or CIs were invited to participate in an international multicentre clinical survey, designed to obtain information on the various approaches towards bimodal hearing and CI and HA device fitting. Forty-one questions were presented to clinicians in experienced CI centres across a range of countries and answers were collected via an online survey. Results: In all, 65 responses were obtained from 12 different countries. All clinicians said they would advise a CI user to wear a contralateral HA if indicated. However, a significant number (45%) had either never fitted HAs before or had less than 1 year of experience. In general, there were no specific criteria for selecting candidates to fit with an HA. A strategy to balance the HA with the CI was not used as a standard practice for any of the adults and was used in only 12% of the children. Only half the respondents were aware of the bimodal literature. The majority of professionals (18/30) did not refit the HA after CI switch-on. However, if users complained of sound quality or loudness issues or had poor test results, a follow-up session was provided. The main benefit reported by recipients was improvement in overall sound quality.
Keywords: Cochlear implant fitting, hearing aid fitting, binaural hearing, loudness balancing, clinical practice, contralateral ear, residual hearing
Introduction As cochlear implant (CI) criteria widen, more candidates with usable residual hearing in the contralateral ear are being considered for cochlear implantation. To avoid asymmetrical auditory deprivation, the provision
of bilateral stimulation of the auditory system should be considered to be standard practice [1,2]. For some, bilateral cochlear implantation is indicated, but for others – where a second implant is not the preferred option due to too much hearing remaining in the contralateral ear, funding restrictions, or
Correspondence: Fanny Scherf, Advanced Bionics Clinical Research Department International, Stäfa, Switzerland. Tel: +32 2 300 80 89. Fax: +32 2 468 19 82. E-mail: [email protected]
(Received 25 January 2014; accepted 25 March 2014) ISSN 0001-6489 print/ISSN 1651-2251 online 2014 Informa Healthcare DOI: 10.3109/00016489.2014.914244
1152
F. W. A. C. Scherf & L. P. Arnold
personal reasons – a hearing aid (HA) fitted to the contralateral ear is the most appropriate way of achieving binaural input [3]. There are a number of benefits associated with providing binaural hearing: speech perception in noise is improved due to spatial release from masking and the headshadow effect, localization is improved, sound quality is better and music is more enjoyable [4–7]. In the early days of cochlear implantation, candidates for CI were often profoundly deaf in their contralateral ear and continued use of the HA in the non-implanted ear was commonly not recommended. It was thought that the use of a contralateral HA in the very deaf ear may interfere with the input from the CI and be detrimental to performance. However objective evidence from Ching et al. in 2001 and 2006 did not support this view [5,8]. They found that when using a specialized fitting procedure, there was no indication of significantly poorer performance under bimodal aided conditions (CI with a HA on the nonimplanted ear) compared to unilateral CI conditions. Furthermore, the bimodal benefits seemed not to be influenced by the amount of residual hearing or the duration of use of bimodal hearing devices. Based on this evidence, the fitting of a contralateral aid to all unilateral CI recipients with usable residual hearing in the non-implanted ear began to be considered. Recent reviews of published studies conclude that there is now good evidence to show the benefits of fitting a contralateral aid to unilateral CI recipients [3,9]. Bimodal device fitting is now recommended as the standard of care, in the absence of contraindications, in all adults and children who received a unilateral CI and have residual hearing in the nonimplanted ear [2]. However, the challenge remains as to how clinicians can optimally fit these two independently working systems? A number of bimodal fitting approaches have been published [10–12] but only Ching et al. described the procedure in detail [11]. The method uses the National Acoustic Laboratories non-linear version 1 HA fitting prescription, which is adapted to the CI with frequency shaping and loudness balancing at two different inputs [8]. While in the original study a significant advantage was shown from the use of the balancing procedure, further studies have not been able to show that the HA fitting method described by Ching et al. provides additional benefits over a well-fitted HA under routine standard clinical procedures [13]. Most reported studies do use some method of loudness balancing, as recommended by the international consensus, but the procedures used are not consistent across studies [12,14–16]. Further evidence has suggested that, as long as the HA has been refitted after CI activation for comfort, a further
complex fitting procedure is not necessarily needed [13]. Although several fitting approaches and recommendations concerning bimodal fitting are described in the literature, they do require time, expertise and additional equipment to be implemented effectively. Surveys of adult CI users show that the majority (51%) still discontinue their HA use after implantation, possibly due, in part, to poor basic HA fitting standards [17,18]. This survey sought to investigate and understand the current approach to bimodal fitting and the recommendations made to recipients and to investigate what is actually happening in daily clinical practice. Material and methods Clinicians working with HAs and/or CIs were invited to participate in an international multicentre clinical survey designed to obtain information on the various approaches towards bimodal hearing and device fitting. Forty-one questions in English were presented to clinicians in experienced CI centres, across a range of countries, and answers were collected via an online survey taking 15–20 min to complete. The survey was devised by Advanced Bionics specifically for this study and had not been used before. The survey was divided into seven parts: Profile, General information, Counseling, User feedback, Bimodal fitting, Evaluation of bimodal fitting, Future of bimodal practice and General comments. Questions were divided into closed-set responses with open-ended sections when required. Subject demographics are shown in Table I. Sixtyfive responses were obtained from 12 different countries from both within and outside Europe. The largest group was from Belgium, who made up 35% of the respondents. Most respondents were aged between 31 and 40 and 61% of them were audiologists. In all, 49% of the 65 respondents had between 3 and 10 years of experience of CI programming and 71% had between 3 and 15 years of experience; 37% had never fitted HAs before and 45% had less than 1 year of HA fitting experience. Not all respondents answered all questions. Results General information and profiles The average percentage of unilateral CI users using a contralateral HA across all centres was similar for adults and children at 32% and 26%, respectively. All clinicians said that they would advise an adult or
Exploring the clinical bimodal approach
1153
Table I. Subject demographics. Characteristic
Adult (n = 35)
Paediatric (n = 30)
All (n = 65)
22
18
40
Education Audiologist ENT
4
5
9
HA acoustician
2
2
4
Engineer
3
0
3
Speech pathologist
2
4
6
PhD student, neuroscience
1
1
2
Audiology assistant
1
0
1
Belgium
11
12
23
Denmark
1
0
1
France
1
2
3
Germany
6
0
6
Israel
1
1
2
Country
Italy
3
2
5
Netherlands
7
1
8
Spain
4
2
6
UK
1
0
1
India
0
6
6
Morocco
0
3
3
South Africa
0
1
1
ORIGINAL ARTICLE
Exploring the clinical approach to the bimodal fitting of hearing aids and cochlear implants: results of an international survey
FANNY W. A. C. SCHERF & LAURE P. ARNOLD POSTER PRESENTATION AT THE 12TH INTERNATIONAL CONFERENCE ON COCHLEAR IMPLANTS AND OTHER IMPLANTABLE AUDITORY TECHNOLOGIES, ESPO 2012, AMSTERDAM, THE NETHERLANDS, SFORL 2012, PARIS, FRANCE Advanced Bionics Clinical Research Department International, Stäfa, Switzerland
Abstract Conclusions: The results show that the fitting of a contralateral hearing aid (HA) in the non-implanted ear of cochlear implant (CI) recipients is now well established as standard clinical practice. However, there is a lack of experience in HA fitting within the CI centres and the use of published bimodal fitting procedures is poor. The HA is often not refitted after CI switch-on and this may contribute to rejection. Including a bimodal fitting prescription and process in the CI fitting software would make applying a balancing procedure easier and may increase its implementation in routine clinical practice. Objective: This survey was designed to investigate and understand the current approach to bimodal fitting of HAs and CIs across different countries and the recommendations made to recipients. Methods: Clinicians working with HAs and/or CIs were invited to participate in an international multicentre clinical survey, designed to obtain information on the various approaches towards bimodal hearing and CI and HA device fitting. Forty-one questions were presented to clinicians in experienced CI centres across a range of countries and answers were collected via an online survey. Results: In all, 65 responses were obtained from 12 different countries. All clinicians said they would advise a CI user to wear a contralateral HA if indicated. However, a significant number (45%) had either never fitted HAs before or had less than 1 year of experience. In general, there were no specific criteria for selecting candidates to fit with an HA. A strategy to balance the HA with the CI was not used as a standard practice for any of the adults and was used in only 12% of the children. Only half the respondents were aware of the bimodal literature. The majority of professionals (18/30) did not refit the HA after CI switch-on. However, if users complained of sound quality or loudness issues or had poor test results, a follow-up session was provided. The main benefit reported by recipients was improvement in overall sound quality.
Keywords: Cochlear implant fitting, hearing aid fitting, binaural hearing, loudness balancing, clinical practice, contralateral ear, residual hearing
Introduction As cochlear implant (CI) criteria widen, more candidates with usable residual hearing in the contralateral ear are being considered for cochlear implantation. To avoid asymmetrical auditory deprivation, the provision
of bilateral stimulation of the auditory system should be considered to be standard practice [1,2]. For some, bilateral cochlear implantation is indicated, but for others – where a second implant is not the preferred option due to too much hearing remaining in the contralateral ear, funding restrictions, or
Correspondence: Fanny Scherf, Advanced Bionics Clinical Research Department International, Stäfa, Switzerland. Tel: +32 2 300 80 89. Fax: +32 2 468 19 82. E-mail: [email protected]
(Received 25 January 2014; accepted 25 March 2014) ISSN 0001-6489 print/ISSN 1651-2251 online 2014 Informa Healthcare DOI: 10.3109/00016489.2014.914244
1152
F. W. A. C. Scherf & L. P. Arnold
personal reasons – a hearing aid (HA) fitted to the contralateral ear is the most appropriate way of achieving binaural input [3]. There are a number of benefits associated with providing binaural hearing: speech perception in noise is improved due to spatial release from masking and the headshadow effect, localization is improved, sound quality is better and music is more enjoyable [4–7]. In the early days of cochlear implantation, candidates for CI were often profoundly deaf in their contralateral ear and continued use of the HA in the non-implanted ear was commonly not recommended. It was thought that the use of a contralateral HA in the very deaf ear may interfere with the input from the CI and be detrimental to performance. However objective evidence from Ching et al. in 2001 and 2006 did not support this view [5,8]. They found that when using a specialized fitting procedure, there was no indication of significantly poorer performance under bimodal aided conditions (CI with a HA on the nonimplanted ear) compared to unilateral CI conditions. Furthermore, the bimodal benefits seemed not to be influenced by the amount of residual hearing or the duration of use of bimodal hearing devices. Based on this evidence, the fitting of a contralateral aid to all unilateral CI recipients with usable residual hearing in the non-implanted ear began to be considered. Recent reviews of published studies conclude that there is now good evidence to show the benefits of fitting a contralateral aid to unilateral CI recipients [3,9]. Bimodal device fitting is now recommended as the standard of care, in the absence of contraindications, in all adults and children who received a unilateral CI and have residual hearing in the nonimplanted ear [2]. However, the challenge remains as to how clinicians can optimally fit these two independently working systems? A number of bimodal fitting approaches have been published [10–12] but only Ching et al. described the procedure in detail [11]. The method uses the National Acoustic Laboratories non-linear version 1 HA fitting prescription, which is adapted to the CI with frequency shaping and loudness balancing at two different inputs [8]. While in the original study a significant advantage was shown from the use of the balancing procedure, further studies have not been able to show that the HA fitting method described by Ching et al. provides additional benefits over a well-fitted HA under routine standard clinical procedures [13]. Most reported studies do use some method of loudness balancing, as recommended by the international consensus, but the procedures used are not consistent across studies [12,14–16]. Further evidence has suggested that, as long as the HA has been refitted after CI activation for comfort, a further
complex fitting procedure is not necessarily needed [13]. Although several fitting approaches and recommendations concerning bimodal fitting are described in the literature, they do require time, expertise and additional equipment to be implemented effectively. Surveys of adult CI users show that the majority (51%) still discontinue their HA use after implantation, possibly due, in part, to poor basic HA fitting standards [17,18]. This survey sought to investigate and understand the current approach to bimodal fitting and the recommendations made to recipients and to investigate what is actually happening in daily clinical practice. Material and methods Clinicians working with HAs and/or CIs were invited to participate in an international multicentre clinical survey designed to obtain information on the various approaches towards bimodal hearing and device fitting. Forty-one questions in English were presented to clinicians in experienced CI centres, across a range of countries, and answers were collected via an online survey taking 15–20 min to complete. The survey was devised by Advanced Bionics specifically for this study and had not been used before. The survey was divided into seven parts: Profile, General information, Counseling, User feedback, Bimodal fitting, Evaluation of bimodal fitting, Future of bimodal practice and General comments. Questions were divided into closed-set responses with open-ended sections when required. Subject demographics are shown in Table I. Sixtyfive responses were obtained from 12 different countries from both within and outside Europe. The largest group was from Belgium, who made up 35% of the respondents. Most respondents were aged between 31 and 40 and 61% of them were audiologists. In all, 49% of the 65 respondents had between 3 and 10 years of experience of CI programming and 71% had between 3 and 15 years of experience; 37% had never fitted HAs before and 45% had less than 1 year of HA fitting experience. Not all respondents answered all questions. Results General information and profiles The average percentage of unilateral CI users using a contralateral HA across all centres was similar for adults and children at 32% and 26%, respectively. All clinicians said that they would advise an adult or
Exploring the clinical bimodal approach
1153
Table I. Subject demographics. Characteristic
Adult (n = 35)
Paediatric (n = 30)
All (n = 65)
22
18
40
Education Audiologist ENT
4
5
9
HA acoustician
2
2
4
Engineer
3
0
3
Speech pathologist
2
4
6
PhD student, neuroscience
1
1
2
Audiology assistant
1
0
1
Belgium
11
12
23
Denmark
1
0
1
France
1
2
3
Germany
6
0
6
Israel
1
1
2
Country
Italy
3
2
5
Netherlands
7
1
8
Spain
4
2
6
UK
1
0
1
India
0
6
6
Morocco
0
3
3
South Africa
0
1
1
