Hearing Loudness Research Articles

Restoring Perceived Loudness for Listeners With Hearing Loss.

Normalizing perceived loudness is an important rationale for gain adjustments in hearing aids. It has been demonstrated that gains required for restoring normal loudness perception for monaural narrowband signals can lead to higher-than-normal loudness in listeners with hearing loss, particularly for binaural broadband presentation. The present study presents a binaural bandwidth-adaptive dynamic compressor (BBDC) that can apply different gains for narrow- and broadband signals. It was hypothesized that normal perceived loudness for a broad variety of signals could be restored for listeners with mild to moderate high-frequency hearing loss by applying individual signal-dependent gain corrections. Gains to normalize perceived loudness for narrowband stimuli were assessed in 15 listeners with mild to moderate high-frequency hearing loss using categorical loudness scaling. Gains for narrowband loudness compensation were calculated and applied in a standard compressor. Aided loudness functions for signals with different bandwidths were assessed. The deviation from the average normal-hearing loudness functions was used for gain correction in the BBDC. Aided loudness functions for narrow- and broadband signals with BBDC were then assessed. Gains for a 65 dB SPL speech-shaped noise of BBDC were compared with gains based on National Acoustic Laboratories' nonlinear fitting procedure version 2 (NAL-NL2). The perceived loudness for 20 real signals was compared to the average normal-hearing rating. The suggested BBDC showed close-to-normal loudness functions for binaural narrow- and broadband signals for the listeners with hearing loss. Normal loudness ratings were observed for the real-world test signals. The proposed gain reduction method resulted on average in similar gains as prescribed by NAL-NL2. However, substantial gain variations compared to NAL-NL2 were observed in the data for individual listeners. Gain corrections after narrowband loudness compensation showed large interindividual differences for binaural broadband signals. Some listeners required no further gain reduction for broadband signals; for others, gains in decibels were more than halved for binaural broadband signals. The interindividual differences of the binaural broadband gain corrections indicate that relevant information for normalizing perceived loudness of binaural broadband signals cannot be inferred from monaural narrowband loudness functions. Over-amplification can be avoided if binaural broadband measurements are included in the fitting procedure. For listeners with a high binaural broadband gain correction factor, loudness compensation for narrowband and broadband stimuli cannot be achieved by compression algorithms that disregard the bandwidth of the input signals. The suggested BBDC includes individual binaural broadband corrections in a more appropriate way than threshold-based procedures.

Analysis of the Association between Hearing Thresholds and Loudness of Tinnitus in Patients with Noise-Induced Hearing Loss

Analysis of the Association between Hearing Thresholds and Loudness of Tinnitus in Patients with Noise-Induced Hearing Loss

Acceptable noise level in Danish adult subjects diagnosed with unilateral Ménière's disease

Objective: The acceptable noise level (ANL) test is used for quantification of the amount of background noise that subjects are willing to accept when listening to speech. Earlier studies including subjects with normal hearing and/or mixed types of sensorineural hearing losses have shown that ANL is not affected by hearing sensitivity. The purpose of this study was to investigate possible within-subject ANL differences between ears in subjects with unilateral Ménière's disease. Study design: ANL was measured in three conditions in both ears of 11 Danish adult subjects diagnosed with unilateral Ménière's disease. Both speech and noise signals were presented through earphones. The Wilcoxon signed rank test was utilized to determine if there were significant differences between ANLs measured in the unaffected and the ears affected by Ménière's disease. Spearman's rank correlation coefficient was calculated to determine if an association exists between the speech discrimination score and ANL in the affected ear. Results: Similar mean ANL results were found in the subjects’ unaffected and affected ear. No association between speech discrimination and the ANL on the affected ear was found. Conclusion: The present study showed no within-subject ANL differences owing to differences in hearing sensitivity or loudness growth patterns.

FITTING AND VERIFICATION PROCEDURE FOR DIRECT BONE CONDUCTION HEARING DEVICES

The present invention relates to a method for fitting and verification of direct bone conduction hearing devices to a patient, wherein a. in a first step the hearing threshold and loudness discomfort levels are measured directly on a titanium implant of a patient, b. in a second step these hearing threshold and loudness discomfort levels are converted to equivalent force thresholds (F HT ) and loudness discomfort levels (F LDL ) on an artificial skull force measuring device, c. in a final step the output force levels of the direct bone conduction hearing device is measured in a free sound field with the device attached to the said artificial skull force measuring device and compared to the F HT and the F LDL as the base for final adjustments of the device.

Loudness and auditory steady-state responses in normal-hearing subjects

This study evaluated the use of multiple auditory steady-state responses (ASSRs) to estimate the growth of loudness in listeners with normal hearing. Individual intensity functions were obtained from measures of loudness growth using the contour test and from the electrophysiological amplitude measures of multiple amplitude-modulated (77–105Hz) tones (500, 1000, 2000, and 4000Hz) simultaneously presented to both ears and recorded over the scalp. Slope analyses for the behavioural and electrophysiological intensity functions were separately performed. Response amplitudes of the ASSRs and loudness sensation judgements increase as the stimulus intensity increases for the four frequencies studied. A significant relationship was obtained between loudness and the ASSRs. The results of this study suggest that the amplitude of the ASSRs may be used to estimate loudness growth at least for individuals with normal hearing.

Hearing Aid Maximum Output and Loudness Discomfort: Are Unaided Loudness Measures Needed?

The purpose of this study was to evaluate a clinical protocol for setting hearing aid maximum output (MPO) in adult users. The protocol consisted of matching prescriptive targets for MPO followed by aided loudness validation and adjustment. Twenty-eight adults fit with multichannel hearing aids during the previous two years were recalled for unaided loudness measures. During the recall visit, unaided frequency-specific loudness discomfort levels were measured for frequencies between 250 and 3000 Hz. These values were converted to real-ear levels by adding individually measured real-ear dial differences. Real-ear saturation responses (RESR) were measured using a 90 dB pure-tone sweep and compared to the real-ear loudness discomfort levels. All participants completed the APHAB Aversiveness scale and Munro-Patel loudness questionnaire. A subset of participants (n = 20) completed the Profile of Aided Loudness. The average RESR-UCL difference was -5.7 dB, and the maximum difference was 15 dB. For all but one participant, the average RESR values (.5-3 kHz) were either less than or no more than 5 dB above the LDLs, and the aided APHAB Aversiveness scores were below the 80th percentile. There were no significant correlations between the scores on the loudness questionnaires and the differences between RESR and LDL values. Results suggest that unaided LDL measures may be redundant if aided loudness validation measures are completed.

Growth of loudness in listeners with cochlear hearing losses: recruitment reconsidered.

This article examines how loudness grows with increasing intensity near threshold in five listeners with hearing losses of predominantly cochlear origin. It provides evidence against the pervasive and long-held notion that such listeners show abnormally rapid loudness growth near their elevated thresholds. As in a previous study for listeners with normal hearing, loudness functions near threshold were derived from loudness matches between a pure tone and four- or ten-tone complexes using a simple model of loudness summation. This study assumed that the loudness function had the same form for any component of a complex, but a scale factor that depended on the amount of hearing loss allowed the loudness at threshold to vary with frequency. The best-fitting loudness functions had low-level local exponents [i.e., slopes of the low-level loudness function plotted as log(loudness) versus log(intensity)] that were within the normal range. At 0 dB SL, the average local exponents were 1.26 for the listeners with hearing losses compared with 1.31 for normal listeners, which indicates that loudness near threshold grows at similar rates in normal listeners and listeners with hearing losses. The model also indicated that, on average, the loudness at threshold doubled for every 16 dB of hearing loss. The increased loudness at threshold, together with somewhat enlarged local exponents around 20 dB SL, accounts for the near-normal loudness often obtained for high-SPL tones in listeners with hearing losses. Such loudness functions are consistent with the steep functions shown by classical data on loudness matches between tones for which thresholds are normal and tones for which thresholds are elevated. Thus, the present data indicate that an abnormally large loudness at an elevated threshold is likely to be a better definition of recruitment than the classical definition of it as an abnormally rapid growth of loudness above an elevated threshold.

It’s not your father’s recruitment: A new view of loudness growth in cochlear hearing loss

For over 60 years, one of the most commonly held beliefs in audiology has been that loudness grows more rapidly than normal near the elevated thresholds of listeners with cochlear hearing losses. This belief was based on the untested assumption that loudness at threshold is the same—often incorrectly assumed to be zero—in normal listeners and listeners with cochlear hearing losses. Recent tests of this assumption indicate that loudness at threshold is not zero in either group of listeners. These data also indicate that loudness near threshold grows at a normal rate in listeners with cochlear hearing losses. In other words, recruitment in the sense of a rapid growth of loudness near an elevated threshold does not occur. How, then, can intense sounds have approximately normal loudness in listeners with cochlear hearing losses? The explanation is that loudness at threshold is greater when the threshold is elevated by a cochlear loss than when it is normal. We call this softness imperception. Therefore, listeners with cochlear hearing losses not only have reduced dynamic range of audibility; they also have reduced dynamic range of loudness. Implications for the design of hearing aids will be discussed. [Work supported by NIH/NIDCD grant R01DC02241.]

What we have learned from the listening experiences in concert halls—Physical properties and subjective impressions of five concert halls in Tokyo

Since Suntory Hall and Casals Hall were opened in 1986 and in 1987, respectively, there has been a remarkable increase in classical concerts in Tokyo. From the listening experiences of various types of music in the same hall, and the same performance in different halls, many interesting features of concert hall acoustics have been found. This report summarizes the listening impressions of five concert halls in Tokyo and compares them with design policy, architecture and acoustical characteristics. Several issues, which seem to be important in the acoustical design of a concert hall such as hearing loudness, reverberation time, ceiling reflections, are discussed.

Evaluation of Relationship Between Hearing Threshold and Loudness Discomfort Level in Sensorineural Hearing Loss

The relationship between hearing level and loudness discomfort level (LDL) for narrow-band noise was evaluated in two groups of patients with sensorineural hearing loss. Group I had thresholds ranging from 25-60 dB SPL and Group II's thresholds ranged from 65-100 dB SPL. LDLs were determined for narrow bands of noise centered at 500, 1000, 2000, and 4000 Hz. The LDLs for Group II were greater than those for Group I and the differences were statistically significant. It is speculated that one reason for others not finding differences as a function of hearing level may be the absence of severe to profound hearing loss in the test populations.

Subtractive hearing loss, loudness recruitment and decruitment.

The normal relation of subjective loudness to intensity is regular, smooth, and lawful. The most frequently recognized abnormality of the loudness function is a more‐rapid‐than‐normal growth of loudness with increase of intensity: namely, loudness recruitment. A hypothesis is presented to the effect that a random loss of sensory units (“sensory unit” is defined as a nerve fiber of the auditory nerve and the sensory cells of the organ of Corti that excite it) may result in a reduction of the maximum subjective loudness. Several cases of neural and central lesions are presented, some with normal thresholds. These illustrate a less‐rapid‐than‐normal growth of loudness with intensity, which may be attributed to such a loss or block of sensory units. The condition is referred to as “decruitment.” The cases are illustrative. More observations are necessary to establish the incidence and possible localizing value of the symptom.