Clin. Otolaryngol. 1990, 15, 321-326
Hearing aids for high-frequency hearing loss J . E. DAVIES", D. G . J O H N * AND M. J . J O N E S ? Departments of Otolaryngology and Audiology, Royal Gwent Hospital, Newport, Gwen(, UK Accepted f o r publication 24 April 1989
DAVIES J. E., JOHN D. G. & JONESM. J. (1990) Clin. Otolaryngol. 15, 321-326 Hearing aids for high-frequency hearing loss This cross-over study compares the relative benefits of a standard NHS contracted hearing aid with a high-frequency emphasis commerical aid in subjects with highfrequency hearing loss. Disability questionnaires and free-field speech-in-noise (FAAF 11) tests were used to assess subjects unaided and after 6 weeks of wearing each aid. Total FAAF I1 test scores showed no significant difference with either aid, but analysis of frequency-specific subscores demonstrated less use of low-frequency information when using the high-frequency emphasis aid. Overall questionnaire responses relating to conversation showed more benefit with the high-frequency emphasis aid. Subjects generally preferred this aid, possibly due to less low-tone gain than the standard NHS aid. Keywords high frequency hearing loss disability questionnaire hearing aid FAAF II test frequency-specific subscores
Hearing aid users commonly experience difficulty with the clarity of speech in the presence of background noise. This problem is often encountered by. patients with _ high-frequency hearing loss, and may be accentuated by the relative over-amplification of low frequencies provided by standard issue hearing aids. A wide range of hearing aids is available from both the National Health Service and commercial sources. In the Department, patients may be fitted with either an aid manufactured under contract to the NHS or a non-contracted commercial aid according to individual requirements. This study compares the hearing improvement provided by a standard NHS aid (BE17) with that provided by a highfrequency emphasis commercial aid (A&M 120 HF). Assessment was by means
of free-field speech-in-noise discrimination tests and patient disability questionnaires.
Materials and methods
Thirteen successive patients with bilateral, symmetrical, high-frequency, sensorineural hearing loss participated in this study. They were referred by their general practitioners because of hearing disability, and all had a history of industrial noise exposure. None had previously worn a hearing aid. Figure 1 shows a typical pure tone audiogram obtained from one of these patients. After pure tone audiometry and acceptance into the study, the patients completed a questionnaire derived from the Social Hearing Handicap Index' and the Sanders Scales.2 This was designed to identify dis-
Correspondence: Mr J. E. Davies, Department of Otolaryngology, Royal Infirmary, 84 Castle Street, Glasgow G4OSF, UK.
32 1
322
J. E. D A V I E S e t
al.
m U
2
40
-
60
-
c L Q,
I
80 250
I
I
I
I
500
1000
2000
4000
I 8000
Frequency (Hz)
Figure 1. Typical pure tone audiogram.
ability and provide graded responses to a series of questions describing environmental and speech/conversation listening situations (Appendix 1). Each patient performed an unaided freefield, speech-in-noise discrimination test using a four auditory alternative feature (FAAF 11) m e t h ~ dThis . ~ was carried out in a non-reverberant room using a 70dB speech source positioned 1 m from the patient at 0" azimuth, and 60dB background noise provided by 2 cocktail noise sources at the same distances but 45" and 3 15" azimuths. The speech was produced from a 4-track Philips N404/15 tape recorder and the cocktail noise on a B&O Beocord 8004 HX PRO cassette deck. These sources were passed through a Kamplex AC5 audiometer into a Goodmans Mezzo SL loudspeaker (speech) and a matched pair of JAM0 CBR805 loudspeakers (noise) to obtain a + 10 dB signal-to-noise ratio. The FAAFII word lists contained 80 monosyllabic sets of words with high-
frequency emphasis, and each test was randomly chosen from the 4 word lists. Patients were randomly allocated either a BE17 or an A&M 120 H F monaural hearing aid, worn on the side of preference, and fitted with an open or vented (2 mm parallel vent) mould according to their own choice. The tone controls were set to a bass cut position. After using the first aid for 6 weeks, patients completed a second disability questionnaire (Appendix 1) with additional questions relating to general aid satisfaction (Appendix2). They also performed a second free-field, speech-in-noise test whilst wearing the aid. The aid was then changed, keeping the same mould, for a further 6 weeks before completing a third questionnaire and speech-in-noise test. Patients were allowed to keep the aid of their choice and the reasons were noted. The gain characteristics of the 2 aids were measured using a Fonix6500 2 test system.
323
Hearing aids for highfrequency loss Table 1. Mean FAAF 11 scores in each test situation
Unaided BE 17 120 HF
Mean score (%)
s.d.
66.1 67.4 62.5
11.1 13.3 8.4
Results
The patients were all male and aged between 54 and 74 (mean 65) years. All patients chose the open mould for either comfort or functional reasons. No feedback problems were experienced. The subjective responses to the questionnaires were analysed using Wilcoxon’s signed-ranks test. Both aids showed a significant improvement over the unaided situation (P
Hearing aids for high-frequency hearing loss J . E. DAVIES", D. G . J O H N * AND M. J . J O N E S ? Departments of Otolaryngology and Audiology, Royal Gwent Hospital, Newport, Gwen(, UK Accepted f o r publication 24 April 1989
DAVIES J. E., JOHN D. G. & JONESM. J. (1990) Clin. Otolaryngol. 15, 321-326 Hearing aids for high-frequency hearing loss This cross-over study compares the relative benefits of a standard NHS contracted hearing aid with a high-frequency emphasis commerical aid in subjects with highfrequency hearing loss. Disability questionnaires and free-field speech-in-noise (FAAF 11) tests were used to assess subjects unaided and after 6 weeks of wearing each aid. Total FAAF I1 test scores showed no significant difference with either aid, but analysis of frequency-specific subscores demonstrated less use of low-frequency information when using the high-frequency emphasis aid. Overall questionnaire responses relating to conversation showed more benefit with the high-frequency emphasis aid. Subjects generally preferred this aid, possibly due to less low-tone gain than the standard NHS aid. Keywords high frequency hearing loss disability questionnaire hearing aid FAAF II test frequency-specific subscores
Hearing aid users commonly experience difficulty with the clarity of speech in the presence of background noise. This problem is often encountered by. patients with _ high-frequency hearing loss, and may be accentuated by the relative over-amplification of low frequencies provided by standard issue hearing aids. A wide range of hearing aids is available from both the National Health Service and commercial sources. In the Department, patients may be fitted with either an aid manufactured under contract to the NHS or a non-contracted commercial aid according to individual requirements. This study compares the hearing improvement provided by a standard NHS aid (BE17) with that provided by a highfrequency emphasis commercial aid (A&M 120 HF). Assessment was by means
of free-field speech-in-noise discrimination tests and patient disability questionnaires.
Materials and methods
Thirteen successive patients with bilateral, symmetrical, high-frequency, sensorineural hearing loss participated in this study. They were referred by their general practitioners because of hearing disability, and all had a history of industrial noise exposure. None had previously worn a hearing aid. Figure 1 shows a typical pure tone audiogram obtained from one of these patients. After pure tone audiometry and acceptance into the study, the patients completed a questionnaire derived from the Social Hearing Handicap Index' and the Sanders Scales.2 This was designed to identify dis-
Correspondence: Mr J. E. Davies, Department of Otolaryngology, Royal Infirmary, 84 Castle Street, Glasgow G4OSF, UK.
32 1
322
J. E. D A V I E S e t
al.
m U
2
40
-
60
-
c L Q,
I
80 250
I
I
I
I
500
1000
2000
4000
I 8000
Frequency (Hz)
Figure 1. Typical pure tone audiogram.
ability and provide graded responses to a series of questions describing environmental and speech/conversation listening situations (Appendix 1). Each patient performed an unaided freefield, speech-in-noise discrimination test using a four auditory alternative feature (FAAF 11) m e t h ~ dThis . ~ was carried out in a non-reverberant room using a 70dB speech source positioned 1 m from the patient at 0" azimuth, and 60dB background noise provided by 2 cocktail noise sources at the same distances but 45" and 3 15" azimuths. The speech was produced from a 4-track Philips N404/15 tape recorder and the cocktail noise on a B&O Beocord 8004 HX PRO cassette deck. These sources were passed through a Kamplex AC5 audiometer into a Goodmans Mezzo SL loudspeaker (speech) and a matched pair of JAM0 CBR805 loudspeakers (noise) to obtain a + 10 dB signal-to-noise ratio. The FAAFII word lists contained 80 monosyllabic sets of words with high-
frequency emphasis, and each test was randomly chosen from the 4 word lists. Patients were randomly allocated either a BE17 or an A&M 120 H F monaural hearing aid, worn on the side of preference, and fitted with an open or vented (2 mm parallel vent) mould according to their own choice. The tone controls were set to a bass cut position. After using the first aid for 6 weeks, patients completed a second disability questionnaire (Appendix 1) with additional questions relating to general aid satisfaction (Appendix2). They also performed a second free-field, speech-in-noise test whilst wearing the aid. The aid was then changed, keeping the same mould, for a further 6 weeks before completing a third questionnaire and speech-in-noise test. Patients were allowed to keep the aid of their choice and the reasons were noted. The gain characteristics of the 2 aids were measured using a Fonix6500 2 test system.
323
Hearing aids for highfrequency loss Table 1. Mean FAAF 11 scores in each test situation
Unaided BE 17 120 HF
Mean score (%)
s.d.
66.1 67.4 62.5
11.1 13.3 8.4
Results
The patients were all male and aged between 54 and 74 (mean 65) years. All patients chose the open mould for either comfort or functional reasons. No feedback problems were experienced. The subjective responses to the questionnaires were analysed using Wilcoxon’s signed-ranks test. Both aids showed a significant improvement over the unaided situation (P
