The Acceptable Noise Level and the Pure-Tone Audiogram.

PURPOSE: The vast majority of previous studies suggest that there is no relationship between the acceptable noise level (ANL) and pure-tone hearing thresholds reported as the average pure-tone hearing thresholds (pure-tone average). This study aims to explore (a) the relationship between hearing thresholds at individual frequencies and the ANL and (b) a measure of the slope of the audiogram and ANL. METHOD: Sixty-three Danish adult hearing aid users participated. Assessments were pure-tone audiogram and 3 different versions of the ANL test made monaurally at 2 different sessions. RESULTS: The findings show that low-frequency hearing thresholds and the slope of the audiogram are significantly related to all versions of the ANL. CONCLUSION: It is possible that previous studies have failed to discover a relationship between ANL and hearing thresholds due to the use of the broad 4-frequency pure-tone average. This has implications for our understanding of the ANL test.

Objective and Subjective Outcome of a New Transcutaneous Bone Conduction Hearing Device: Half-year Follow-up of the First 12 Nordic Implantations.

OBJECTIVE: To examine the objective and subjective outcome of a new transcutaneous bone conduction hearing device. STUDY DESIGN: Prospective, consecutive case series. PATIENTS: Twelve patients were implanted. Eight patients had a conductive/mixed (con/mix) hearing loss. Four had single sided deafness. MAIN OUTCOME MEASURES: At half-year follow-up, aided and unaided sound field hearing was evaluated by 1) warble tone thresholds, 2) pure-tone average (PTA4), 3) speech discrimination score (SDS) in quiet, and 4) speech reception threshold 50% at 70 dB SPL noise level (SRT50%). Subjective outcome was evaluated by three questionnaires: 1) International Outcome Inventory for Hearing Aids, 2) Speech, Spatial and Qualities of Hearing Scale 12, and 3) a questionnaire on frequency and duration of use. RESULTS: No major complications occurred. The mean aided PTA4 was lowered by 23dB. SDS was increased by 40% at 50dB, by 34% at 65dB, and by 12% at 80 dB SPL. SRT50% in noise improved 5.2 dB. 58% of the patients used the device daily and 83% at least 5 days a week. 50% used the device ≥ 8 hours and 75% ≥ 4  hours a day. Mean International Outcome Inventory for Hearing Aids score was 3.7, corresponding to beneficial outcome. In Speech, Spatial and Qualities of Hearing Scale 12, "quality of hearing" scored especially high. The con/mix hearing loss group showed larger benefit especially in SDS, SRT50% in noise and the subjective evaluations, whereas frequency and duration of use were similar. CONCLUSION: This study on the first 12 Nordic patients implanted with a new transcutaneous bone conduction hearing device demonstrates significant objective, as well as subjective hearing benefit. Patient satisfaction was high, as was the frequency of use.

The effect of repeated measurements and working memory on the most comfortable level in the ANL test.

OBJECTIVE: To study the effect of a large number of repetitions on the most comfortable level (MCL) when doing the acceptable noise level (ANL) test, and explore if MCL variability is related to central cognitive processes. DESIGN: Twelve MCL repetitions were measured within the ANL test using interleaved methodology during one session using a non-semantic version. Phonological (PWM) and visuospatial working memory (VSWM) was measured. STUDY SAMPLE: Thirty-two normal-hearing adults. RESULTS: Repeated measures ANOVA, intraclass correlations, and the coefficient of repeatability (CR) were used to assess the repeatability. Repeated measures ANOVA and CR indicated poor agreement between the two first repetitions. After excluding the first repetition, analyses showed that the MCL in the ANL test is reliable. A negative association was found between PWM and MCL variability indicating that subjects with higher PWM show less variability. CONCLUSIONS: The findings suggest that, after excluding the first repetition, the MCL in the ANL test is reliable. A single repetition of the MCL in the ANL test should be avoided. If an interleaved methodology is used, a single ANL repetition should be added prior to the actual testing. The findings also suggest that MCL variability is associated to PWM but not VSWM.

Prediction of IOI-HA scores using speech reception thresholds and speech discrimination scores in quiet.

BACKGROUND: Outcome measures can be used to improve the quality of the rehabilitation by identifying and understanding which variables influence the outcome. This information can be used to improve outcomes for clients. In clinical practice, pure-tone audiometry, speech reception thresholds (SRTs), and speech discrimination scores (SDSs) in quiet or in noise are common assessments made prior to hearing aid (HA) fittings. It is not known whether SRT and SDS in quiet relate to HA outcome measured with the International Outcome Inventory for Hearing Aids (IOI-HA). PURPOSE: The aim of the present study was to investigate the relationship between pure-tone average (PTA), SRT, and SDS in quiet and IOI-HA in both first-time and experienced HA users. RESEARCH DESIGN: SRT and SDS were measured in a sample of HA users who also responded to the IOI-HA. STUDY SAMPLE: Fifty-eight Danish-speaking adult HA users. DATA COLLECTION AND ANALYSIS: The psychometric properties were evaluated and compared to previous studies using the IOI-HA. The associations and differences between the outcome scores and a number of descriptive variables (age, gender, fitted monaurally/binaurally with HA, first-time/experienced HA users, years of HA use, time since last HA fitting, best ear PTA, best ear SRT, or best ear SDS) were examined. A multiple forward stepwise regression analysis was conducted using scores on the separate IOI-HA items, the global score, and scores on the introspection and interaction subscales as dependent variables to examine whether the descriptive variables could predict these outcome measures. RESULTS: Scores on single IOI-HA items, the global score, and scores on the introspection (items 1, 2, 4, and 7) and interaction (items 3, 5, and 6) subscales closely resemble those previously reported. Multiple regression analysis showed that the best ear SDS predicts about 18-19% of the outcome on items 3 and 5 separately, and about 16% on the interaction subscale (sum of items 3, 5, and 6) CONCLUSIONS: The best ears SDS explains some of the variance displayed in the IOI-HA global score and the interaction subscale. The relation between SDS and IOI-HA suggests that a poor unaided SDS might in itself be a limiting factor for the HA rehabilitation efficacy and hence the IOI-HA outcome. The clinician could use this information to align the user's HA expectations to what is within possible reach.

The acceptable noise level: the effect of repeated measurements.

OBJECTIVE: This study explores if increasing number of repetitions might improve the precision of the acceptable noise level (ANL) test. DESIGN: We measured twelve ANL repetitions, i.e. four complete ANL tests (4 × 3 repetitions), at one session using diotic presentation and a non-semantic ANL version. STUDY SAMPLE: Thirty-two normal-hearing adults. RESULTS: Small order and fatigue effects were seen. We used the coefficient of repeatability (CR) to assess the repeatability; CRs ranged between 3.9 and 7.6 dB for the four ANL tests. Using the twelve ANL repetitions we removed the variability of the ANL across subjects by normalizing the data to the individual mean ANL for the twelve repetitions. The mean normalized ANL across the subjects rapidly approached the ANL normalized to the individual mean for the 12 repetitions (0 dB), and after three repetitions the SD seemed to be stable at about 3 dB. CONCLUSIONS: The findings suggest that both order and fatigue affect the ANL. The findings also suggest that it may be more accurate to speak of an acceptable noise range than ANL. These findings have large implications for how we understand acceptable noise and it would explain a large part of the variability seen among normal-hearing and perhaps hearing-impaired subjects.

Does the acceptable noise level (ANL) predict hearing-aid use?

OBJECTIVE: It has been suggested that individuals have an inherent acceptance of noise in the presence of speech, and that different acceptance of noise results in different hearing-aid (HA) use. The acceptable noise level (ANL) has been proposed for measurement of this property. It has been claimed that the ANL magnitude can predict hearing-aid use patterns. Many papers have been published reporting on different aspects of ANL, but none have challenged the predictive power of ANL. The purpose of this study was to discuss whether ANL can predict HA use and how more reliable ANL results can be obtained. DESIGN: Relevant literature regarding the ANL was found on Medline, Embase, and Google Scholar. Additional information was found as references in the included papers and through personal contacts, for instance when attending audiology conferences. STUDY SAMPLE: Forty-five papers published in peer reviewed journals as well as a number of papers from trade journals, posters and oral presentations from audiology conventions. CONCLUSIONS: An inherent acceptance of noise in the presence of speech may exist, but no method for precise measurement of ANL is available. The ANL model for prediction of HA use has yet to be proven valid.

Acceptable noise level (ANL) with Danish and non-semantic speech materials in adult hearing-aid users.

OBJECTIVE: The acceptable noise level (ANL) test is used for quantification of the amount of background noise subjects accept when listening to speech. This study investigates Danish hearing-aid users' ANL performance using Danish and non-semantic speech signals, the repeatability of ANL, and the association between ANL and outcome of the international outcome inventory for hearing aids (IOI-HA). DESIGN: ANL was measured in three conditions in both ears at two test sessions. Subjects completed the IOI-HA and the ANL questionnaire. STUDY SAMPLE: Sixty-three Danish hearing-aid users; fifty-seven subjects were full time users and 6 were part time/non users of hearing aids according to the ANL questionnaire. RESULTS: ANLs were similar to results with American English speech material. The coefficient of repeatability (CR) was 6.5-8.8 dB. IOI-HA scores were not associated to ANL. CONCLUSIONS: Danish and non-semantic ANL versions yield results similar to the American English version. The magnitude of the CR indicates that ANL with Danish and non-semantic speech materials is not suitable for prediction of individual patterns of future hearing-aid use or evaluation of individual benefit from hearing-aid features. The ANL with Danish and non-semantic speech materials is not related to IOI-HA outcome.

Acceptable noise level: repeatability with Danish and non-semantic speech materials for adults with normal hearing.

OBJECTIVE: The acceptable noise level (ANL) is used to quantify the amount of background noise that subjects can accept while listening to speech, and is suggested for prediction of individual hearing-aid use. The aim of this study was to assess the repeatability of the ANL measured in normal-hearing subjects using running Danish and non-semantic speech materials as stimuli and modulated speech-spectrum and multi-talker babble noises as competing stimuli. DESIGN: ANL was measured in both ears at two test sessions separated by a period ranging from 12 to 77 days. At each session the measurements at the first and the second ear were separated in time by 15-30 minutes. Bland-Altman plots and calculation of the coefficient of repeatability (CR) were used to estimate the repeatability. STUDY SAMPLE: Thirty nine normal-hearing subjects. RESULTS: The ANL CR was 6.0-8.9 dB for repeated tests separated by about 15-30 minutes and 7.2-10.2 dB for repeated tests separated by 12 days or more. CONCLUSIONS: The ANL test has poor repeatability when assessed with Danish and non-semantic speech materials on normal-hearing subjects. The same CR among hearing-impaired subjects would imply too poor repeatability to predict individual patterns of future hearing-aid use.

Evaluation of long-term patient satisfaction and experience with the Baha® bone conduction implant.

OBJECTIVE: Evaluate long-term patient satisfaction with bone-anchored hearing aids (the Baha®, now referred to by Cochlear as a 'bone conduction implant') in our hospital clinic spanning the eighteen-year period from the inception of our Baha program. The researchers further wished to analyse the various factors leading to patient satisfaction/dissatisfaction with their Baha. We developed a new questionnaire to obtain a comprehensive impression of individual patient practices, general satisfaction, and experiences with their Baha in respect to time spent using Baha, sound quality, annoyance from noise disturbance, ease of communication, cosmetic appearance, and satisfaction with the Baha amongst patient relatives, an aspect not previously investigated. DESIGN: The study design was retrospective and executed as a postal questionnaire. The questionnaire was developed by the authors of this paper. STUDY SAMPLE: Patients operated on for a Baha at our hospital from 1989 to 2007. RESULTS: The response rate was 92.4%. Eighty-six percent were satisfied or very satisfied with their Baha. Ninety-one percent of respondents could communicate using their Baha in a one-on-one conversational setting. A primary factor leading to dissatisfaction, experienced by 70% of responding patients, was annoyance from wind noise. CONCLUSIONS: Baha was found to yield good overall patient satisfaction over the long-term, and it was possible to identify specific factors attributing to satisfaction/dissatisfaction.

Acceptable noise level with Danish, Swedish, and non-semantic speech materials.

OBJECTIVE: Acceptable noise level (ANL) has been established as a method to quantify the acceptance of background noise while listening to speech presented at the most comfortable level. The aim of the present study was to generate Danish, Swedish, and a non-semantic version of the ANL test and investigate normal-hearing Danish and Swedish subjects' performance on these tests. DESIGN: ANL was measured using Danish and Swedish running speech with two different noises: Speech-weighted amplitude-modulated noise, and multitalker speech babble. ANL was also measured using the non-semantic international speech test signal (ISTS) as speech signal together with the speech-weighted amplitude-modulated noise. The latter condition was identical in both populations. STUDY SAMPLE: Forty Danish and 40 Swedish normal-hearing subjects. RESULTS: In both populations ANL results were similar to previously reported results from American studies. Generally, significant differences were seen between test conditions using different types of noise within ears in each population. Significant differences were seen for ANL across populations, also when the non-semantic ISTS was used as speech signal. CONCLUSIONS: The present findings indicate that there are extrinsic factors, such as instructions, affecting the ANL results.

Comparison of two bone anchored hearing instruments: BP100 and Ponto Pro.

OBJECTIVE: This study aimed at investigating if there were differences in auditory performance, operation, or user preference between the Ponto Pro or the BP100, two bone anchored hearing instruments (BAHI) with modern sound processing technology. DESIGN: Subjects wore the devices in daily life in a crossover study for periods ranging from 25 to 63 days. A speech-in-noise test was carried out as well as measures of noise reduction and feedback suppression algorithms. User satisfaction was reported using the NSH and the GHABP questionnaires. At the end of the test, subjects selected one of the devices for permanent use. STUDY SAMPLE: Twelve first-time users of BAHIs. RESULTS: Eight subjects selected the Ponto Pro; four selected the BP100. The Ponto Pro was rated as easier to operate than the BP100, the visual appearance of the Ponto Pro was rated as nicer than that of the BP100, and speech understanding was rated higher with the Ponto Pro than with the BP100. Speech-in-noise tests showed improvements using directional microphones with the Ponto Pro. CONCLUSIONS: 67% of the subjects opted for permanent use of the Ponto Pro, which, compared to the BP100, was rated to have a nicer look, to be easier to operate, and to yield better speech intelligibility.

Simulated real-ear measurements of benefit from digital feedback suppression.

Digital feedback suppression (DFS) enables users of hearing instruments (HI) to benefit from amplification levels that normally would provoke whistling or poor sound quality. A standardized test for the measurement of DFS benefit is not available. This paper proposes and evaluates an objective method for assessment of extra feedback-free amplification (headroom) provided by a given DFS. It is shown that the whistle-free loop gain can be calculated from data obtained with simulated real-ear measurements with the modified pressure method. Test-retest trials were carried out to assess the reliability of the proposed method. Also, a method was developed for defining an appropriate gain level at which the proposed measurement should be carried out. It is concluded that the proposed method needs to be modified to provide useful information.

Real-ear measurement verification for open, non-occluding hearing instruments.

Real-ear measurements using the modified pressure method with concurrent (real-time) equalization can be inaccurate, when amplified sound leaks out of the ear canal and reaches the reference microphone. In such situations the reference microphone will detect an increased sound level and reduce the output of the loudspeaker to maintain the desired level. The risk of having errors due to leaks increases if digital feedback suppression (DFS) is used, thus achieving higher feedback-free gain levels. The following hypotheses were tested: a) using the concurrent equalization method for fitting hearing instruments with DFS may result in underestimated real-ear insertion gain (especially when using open fittings) and b) as the benefit of the DFS system increases, this error also increases. Real-ear measurements were carried out in twenty-one subjects using the modified pressure method with stored equalization as well as with concurrent equalization. The results of the study supports both hypotheses. As a consequence it is recommended to use a stored equalization method for real-ear measurements of hearing instruments with DFS and open fitting.

Learning effect when using the Danish Hagerman sentences (Dantale II) to determine speech reception threshold.

The objective of the present study was to examine the learning effect found when using the Danish sentence test, Dantale II, in our daily clinical work. Specifically, the aim was to determine the within-visit and the inter-visit learning effects when the Dantale II is presented to aided hearing-impaired listeners who have not previously completed the task. Nineteen subjects participated in the study. The within-visit learning effect after listening to 160 sentences was found to be 3.2 dB, and the inter-visit learning effect was 1.6 dB with an inter-visit period range of 14-43 days. For research evaluation of algorithms or hearing aid settings, where the differences are expected to be small, it is recommended that a pool of test subjects are regularly tested using the Dantale II speech material. Moreover, a limitation of the number of signal processing test conditions is suggested.