Factors associated with change in the need for recovery and subjective listening effort in employees with hearing loss receiving aural rehabilitation.

OBJECTIVE: Compared to normally-hearing employees, those with hearing loss suffer from higher Need For Recovery (NFR) after work. The aims of this study are to assess the NFR of employees with hearing loss before and after aural rehabilitation and to examine to what extent change in the NFR can be explained by changes in subjective listening effort, personal adjustments, communication strategies, auditory work demands, and self-reported hearing ability. METHODS: We included patients who received aural rehabilitation in two audiological centers in the Netherlands because of hearing complaints in their work situation. Outcomes were measured by questionnaires at baseline and 3 month follow-up. The NFR before and after the rehabilitation was compared with a t test. Hierarchical multiple analyses were performed. RESULTS: In total, 60 patients (aged 22-63, working hours ≥8 per week) participated in the study, of which 50 completed the follow-up questionnaires. The NFR was significantly lower after the aural rehabilitation (M = 45.03) compared to before the aural rehabilitation (M = 51.89), t = -3.43, p < 0.01). Change in NFR could best be explained by the change in personal adjustments (R2 = 0.45, B = -1.23, p < 0.01). CONCLUSION: The NFR of employees with hearing loss can be improved by aural rehabilitation, but this study shows that current practices reduce the NFR only in part of the employees. Therefore, improving current practices should be considered and evaluated, for example by applying a different combination of rehabilitation components. Especially, interventions that affect personal adjustments may be promising to further reduce the NFR in employees with hearing loss.

Uni- and bilateral spectral loudness summation and binaural loudness summation with loudness matching and categorical loudness scaling.

OBJECTIVE: Current hearing aid prescription rules assume that spectral loudness summation decreases with hearing impairment and that binaural loudness summation is independent of hearing loss and signal bandwidth. Previous studies have shown that these assumptions might be incorrect. Spectral loudness summation was measured and compared for loudness scaling and loudness matching. DESIGN: In this study, the effect of bandwidth on binaural summation was investigated by comparing loudness perception of low-pass filtered, high-pass filtered, and broadband pink noise at 35 Categorical Units for both unilateral and bilateral presentation. STUDY SAMPLE: Sixteen hearing-impaired listeners. RESULTS: The results show that loudness differences between the three signals are different for bilateral presentation than for unilateral presentation. In specific, binaural loudness summation is larger for the low-pass filtered pink noise than for the high-pass filtered pink noise. Finally, individual variability in loudness perception near loudness discomfort level was found to be very large. CONCLUSIONS: Loudness matching is offered as a fast and reliable method to measure individual loudness perception. As discomfort with loud sounds is one of the major problems encountered by hearing aid users, measurement of individual loudness perception could improve hearing aid fitting substantially.

Correction to: Factors influencing the need for recovery in employees with hearing loss: a cross-sectional study of health administrative data.

The original publication of this article contains typographical error in Table 5, Row 2.

Factors influencing the need for recovery in employees with hearing loss: a cross-sectional study of health administrative data.

OBJECTIVE: Need for recovery is a predictor of work stress and health problems, but its underlying factors are not yet well understood. We aimed to identify hearing-related, work-related, and personal factors influencing need for recovery in hearing-impaired employees. METHODS: We retrospectively identified hearing-impaired employees (N = 294) that were referred to the Amsterdam University Medical Center between 2004 and 2019. Routinely obtained healthcare data were used, including a survey and hearing assessments. A directed acyclic graph was constructed, revealing the hypothesized structure of factors influencing need for recovery as well as the minimal set of factors needed for multiple regression analysis. RESULTS: Four variables were included in the regression analysis. In total, 46.1% of the variance in need for recovery was explained by the factors feeling that something should change at work (B = 19.01, p < 0.001), self-perceived listening effort (B = 1.84, p < 0.001), personal adaptations scale score (B = - 0.34, p < .001), and having a moderate/poor general health condition (B = 20.06, p < 0.001). Although degree of hearing loss was associated with self-perceived listening effort, the direct association between degree of hearing loss and need for recovery was not significant. CONCLUSIONS: The results suggest that the way employees perceive their hearing loss and how they cope with it directly influence need for recovery, rather than their measured degree of hearing loss. Additionally, general health condition was found to be an independent factor for need for recovery. The results should be confirmed by future, longitudinal research.

Potential Consequences of Spectral and Binaural Loudness Summation for Bilateral Hearing Aid Fitting.

Aversiveness of loud sounds is a frequent complaint by hearing aid users, especially when fitted bilaterally. This study investigates whether loudness summation can be held responsible for this finding. Two aspects of loudness summation should be taken into account: spectral loudness summation for broadband signals and binaural loudness summation for signals that are presented binaurally. In this study, the effect of different symmetrical hearing losses was studied. Measurements were obtained with the widely used technique of Adaptive Categorical Loudness Scaling. For large bandwidths, spectral loudness summation for hearing-impaired listeners was found to be greater than that for normal-hearing listeners, both for monaurally and binaurally presented signals. For binaural loudness summation, the effect of hearing loss was not significant. In all cases, individual differences were substantial.

Evaluation of Auditory Functioning and Rehabilitation Using Patient-Reported Outcome Measures.

There is lack of a systematic approach concerning how to select an adequate hearing aid and how to evaluate its efficacy with respect to the personal needs of rehabilitation. The goal of this study was to examine the applicability and added value of two widely used self-reporting questionnaires in relation to the evaluation of hearing aid fitting. We analyzed responses, pre- and postfitting, from 1,319 subjects who completed the Client Oriented Scale of Improvement (COSI) and a slightly adapted version of the Amsterdam Inventory for Auditory Disability and Handicap (in Dutch: AVAB). Most COSI responses were at or near the maximum possible score. Results show a close relation between COSI's degree of change and final ability (Spearman's rho = 0.71). Both AVAB and COSI showed a significant effect of hearing aid experience, but-in contrast to AVAB-COSI did not show a significant effect of the degree of hearing loss. In addition, a Friedman test showed significant differences between six dimensions of auditory functioning for both AVAB and COSI, although post hoc analysis revealed that for COSI, the dimension speech in quiet explained most variation between dimensions. In conclusion, the effects of hearing loss were more salient in AVAB, while both AVAB and COSI showed differences regarding hearing aid experience. Combining the advantages of both methods results in a detailed evaluation of hearing aid rehabilitation. Our results therefore suggest that both methods should be used in a complementary manner, rather than separately.

In situ Hearing Tests for the Purpose of a Self-Fit Hearing Aid.

This study investigated the potential and limitations of a self-fit hearing aid. This can be used in the "developing" world or in countries with large distances between the hearing-impaired subjects and the professional. It contains an on-board tone generator for in situ user-controlled, automated audiometry, and other tests for hearing aid fitting. Twenty subjects with mild hearing losses were involved. In situ audiometry showed a test-retest reliability (SD <3.7 dB) that compared well with the precision of diagnostic audiometry using headphones. There was good correspondence (SD <5.2 dB) with traditional pure-tone audiometry. In situ loudness scaling yielded important information about suprathreshold perception, which will have an added value for the selection of compression and the selection of maximum power output to be allowed in hearing aids.

Adjustments of the amplitude mapping function: Sensitivity of cochlear implant users and effects on subjective preference and speech recognition.

OBJECTIVE: In sound processors of cochlear implant (CI) users, input sound signals are analysed in multiple frequency channels. The amplitude mapping function (AMF) is the output compression function dictating the conversion from (acoustical) channel output levels to (electrical) current levels used for electrode stimulation. This study focused on the detectability of AMF adjustments by CI users and the effects of detectable AMF adjustments on subjective preference and performance. DESIGN: Just noticeable differences (JNDs) for AMF settings were measured for pre-processed sentences at 60 dB SPL in quiet and noise. Three AMF settings, ranging twice the JND, were used during a take-home trial period of 12 days. Subjective ratings were collected and speech recognition in quiet and noise was measured. STUDY SAMPLE: JND measurements: 17 CI users. Field experiment: 15 CI users. RESULTS: JNDs for AMF settings varied among subjects and were similar in quiet and noise. A steeper AMF in the lower part was advantageous for speech recognition in quiet at soft levels. Subjective ratings showed limited agreement with speech recognition, both in quiet and noise. CONCLUSIONS: CI users may benefit from different AMF settings in different listening situations regarding subjective preference and speech perception, especially for speech in quiet.

Selecting Appropriate Tests to Assess the Benefits of Bilateral Amplification With Hearing Aids.

The aim of this study was to investigate the effect of bilateral hearing aids (HA) in subjects with mild and moderate-to-severe hearing loss. This study was designed as a within-subject feasibility study. Bilateral HA use was assessed using different laboratory tests on speech reception, listening effort, noise tolerance, and localization. All data were evaluated with bilateral and unilateral HA fittings. Forty experienced bilateral HA users were included with hearing impairment ranging from mild to moderate-to-severe. Subjects were stratified into two groups based on the degree of hearing loss. Speech reception in noise, listening effort, and localization tests showed a bilateral benefit for the moderate-to-severely hearing-impaired subjects. A bilateral benefit was also observed for listening effort in the mildly hearing-impaired group. The assessment of listening effort shows promise as a measure of bilateral HA benefit for mild hearing impairment. Localization and speech reception in noise tests provide additional value for larger losses. The next step is to compare experienced unilateral with bilateral HA users.

Spectral loudness summation for electrical stimulation in cochlear implant users.

OBJECTIVE: This study investigates the effect of spectral loudness summation (SLS) in the electrical domain as perceived by cochlear implant (CI) users. Analogous to SLS in the acoustical domain, SLS was defined as the effect of electrode separation at a fixed overall stimulation rate. DESIGN: Categorical loudness scaling (CLS) was conducted at three overall stimulation rates using single-electrode stimuli and multi-electrode stimuli presented interleaved on two or four electrodes. The specific loudness of the pulses in the multi-electrode stimuli were equalized based on single-electrode measurements at the same overall stimulation rate. At a fixed overall stimulation rate and a fixed loudness perception, SLS was calculated as the difference in mean current between single-electrode and multi-electrode stimuli. STUDY SAMPLE: Ten postlingually deafened adult CI users. RESULTS: The amount of SLS varied between subjects and between the number and location of the stimulated electrodes in the multi-electrode configuration. SLS was significantly higher than 0 for a subset of the subjects. CONCLUSIONS: For a subpopulation of CI users, loudness models should account for nonlinear interactions between electrodes (in the perceptual domain). Similarly, SLS should be accounted for when using CLS outcomes for fitting purposes, at least in a subpopulation of CI users.

Reliability of categorical loudness scaling in the electrical domain.

OBJECTIVE: In categorical loudness scaling (CLS), subjects rate the perceived loudness on a categorical scale with alternatives. ISO 16832 describes an internationally standardized CLS procedure for the acoustical domain. This study focuses on the reproducibility of CLS following the recommendations of ISO 16832 using electrical stimuli presented to cochlear implant (CI) users. DESIGN: Repeated CLS measurements were done using single-electrode stimuli at four electrode positions. Loudness growth functions (LGFs) described loudness as a function of level (µA). LGF shapes were characterized with an exponential b parameter. The reproducibility of the b parameter and inter-session intra-subject differences in percentage dynamic range (DR) between 'Very Soft' and 'Loud - Very Loud' levels were analysed. STUDY SAMPLE: Ten CI users. RESULTS: Inter-session differences did not significantly differ between loudness categories or electrode positions. Across loudness categories the standard deviation of inter-session differences equalled 7.2%DR. The reproducibility of LGF shapes was moderate (r = 0.63). The LGFs of 43% of the measured electrodes significantly deviated from linear (nonzero b parameter). CONCLUSIONS: The reproducibility was comparable to the reproducibility for acoustical stimulation in normal-hearing and hearing-impaired listeners. CLS data for electrical stimuli are preferably fitted with a model that is flexible in describing LGF shapes.

Audiologist-driven versus patient-driven fine tuning of hearing instruments.

Two methods of fine tuning the initial settings of hearing aids were compared: An audiologist-driven approach--using real ear measurements and a patient-driven fine-tuning approach--using feedback from real-life situations. The patient-driven fine tuning was conducted by employing the Amplifit(®) II system using audiovideo clips. The audiologist-driven fine tuning was based on the NAL-NL1 prescription rule. Both settings were compared using the same hearing aids in two 6-week trial periods following a randomized blinded cross-over design. After each trial period, the settings were evaluated by insertion-gain measurements. Performance was evaluated by speech tests in quiet, in noise, and in time-reversed speech, presented at 0° and with spatially separated sound sources. Subjective results were evaluated using extensive questionnaires and audiovisual video clips. A total of 73 participants were included. On average, higher gain values were found for the audiologist-driven settings than for the patient-driven settings, especially at 1000 and 2000 Hz. Better objective performance was obtained for the audiologist-driven settings for speech perception in quiet and in time-reversed speech. This was supported by better scores on a number of subjective judgments and in the subjective ratings of video clips. The perception of loud sounds scored higher than when patient-driven, but the overall preference was in favor of the audiologist-driven settings for 67% of the participants.

Candidacy for bilateral hearing aids: a retrospective multicenter study.

PURPOSE: The goal of this study was to find factors for refining candidacy criteria for bilateral hearing aid fittings. Clinical files of 1,000 consecutive hearing aid fittings were analyzed. METHOD: Case history, audiometric, and rehabilitation data were collected from clinical files, and an extensive questionnaire on long-term outcome measures was conducted. After at least 2 years of hearing aid use, 505 questionnaires were returned. In order to compare differences in benefits between unilateral and bilateral fittings, two subgroups were composed in which most relevant variables (age, degree of hearing loss, and audiometric asymmetry) were matched for unilateral fittings (n=212) and bilateral fittings (n=477). RESULTS: The bilateral group had significantly higher benefit scores than the unilateral group for detection, speech intelligibility in reverberation, and localization, but poorer scores for comfort of loud sounds. The benefit of bilateral hearing aids was not significantly related to the level of technology of the hearing aids. CONCLUSION: The analysis of the relation between objective parameters and the subjective outcome measures showed that candidacy for a successful bilateral fitting could not be predicted from age, maximum speech intelligibility, employment, exposure to background noise, or social activities.

A prospective multi-centre study of the benefits of bilateral hearing aids.

OBJECTIVES: In this prospective study the benefits of a second hearing aid were evaluated objectively (functional tests) and subjectively (questionnaires). In addition, a battery of diagnostic tests (by headphones) was applied to determine whether the bilateral benefit could be predicted from a priori tests. DESIGN: Diagnostic tests by headphones (binaural masking level difference, interaural time difference, and speech reception thresholds per ear) were conducted to focus on binaural functioning, and free-field tests were used for unilateral and bilateral hearing aids in the same participants to analyze differences in speech intelligibility and horizontal localization. The participants were recruited from the regular patients for hearing aid fitting in eight Audiological Centers. Eventually, 214 participants participated in this study. Each of these participants was fitted with two new hearing aids and started a trial period. Before the trial period the headphone tests were conducted, after the trial period the free-field tests were conducted with one and two hearing aids, and the participants completed a questionnaire. RESULTS AND CONCLUSIONS: In a number of respects bilaterally fitted hearing aids offered a benefit relative to unilaterally fitted hearing aids (the so-called bilateral benefit), both subjectively (questionnaire) and objectively (speech perception in noise and localization). However, we found large interindividual differences and not all differences were clinically relevant. The results of the diagnostic tests showed that it was not possible to predict the bilateral benefit from a priori information based on headphone tests. At the end of the trial period 93% of the participants preferred a bilateral fitting.

Interactive fitting of multiple algorithms implemented in the same digital hearing aid.

The main purpose of this study is to examine the applicability of an adaptive and interactive optimization strategy to fine-tune three hearing-aid algorithms simultaneously: dynamic compression, temporal signal enhancement, and noise reduction. The optimal combination of these three algorithms was determined by a multidirectional pattern search with an adaptive step size. Additionally, we applied a round-robin procedure to validate the results of the optimization procedure. For both procedures the listeners were asked to compare two consecutive, differently processed sentences in continuous and fluctuating background noises on speech intelligibility. Ten hearing-impaired and four normal-hearing subjects participated. The reliability and consistency of the multidirectional pattern search was low, especially for the fluctuating noise condition. The results of the round-robin procedure did not correspond closely with the pattern search results. These findings suggest that the current implementation of a multidirectional optimization procedure has not yet proven to be applicable for the necessary individual fine tuning of complex signal processing strategies, when the objective is to maximize speech intelligibility.

International Outcome Inventory for Hearing Aids (IOI-HA): results from The Netherlands.

This paper presents data on the Dutch translation of the International Outcome Inventory for Hearing Aids (IOI-HA). The inventory was used as an additional postal tool in a nationwide study on the benefits of bilateral hearing aid fitting. Responses of 505 hearing aid users were analysed. Descriptive statistics and inter-item correlations are reported. Factor analysis resulted in the extraction of two factors. Cronbach's alpha coefficients and corrected item total correlations showed high internal consistency of the scales. Significant correlations were found between IOI Factor 2 and the Hearing Handicap and Disability Inventory and subscales of the Amsterdam Inventory for Hearing Disability and Handicap.