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At least 19 recordsLinked to original sources
PubMed1998

Loudness perception with pulsatile electrical stimulation: the effect of interpulse intervals.

The effect of interpulse intervals on the perception of loudness of biphasic current pulse trains was investigated in eight adult cochlear implantees at three different stimulus levels encompassing the psychophysical dynamic range. Equal-loudness contours and thresholds were obtained for stimuli in which two biphasic pulses were presented in a fixed repetition period (4 and 20 ms), and also for single-pulse/period stimuli with rates varying between 20 and 750 Hz. All stimuli were of 500-ms duration, and the phase durations of each pulse were 100 microseconds or less. The results of these experiments were consistent with predictions of a three-stage model of loudness perception, consisting of a peripheral refractory effect function, a sliding central integration time window, and a central equal-loudness decision device. Application of the model to the data allowed the estimation of neural refractory characteristics of the subjects' remaining peripheral neural population. The average neural spike probability for a 50-Hz stimulus was predicted to be about 0.77, with an associated neural refractory time of 7.3 ms. These predictions did not vary systematically with level, implying that the effect of increasing current level on loudness results more from recruitment of neurons than from any increase in average spike probability.

Adult↗
PubMed1996

[Direct loudness scaling in diagnosis of tinnitus. A contribution to loudness perception in tinnitus].

We used free-field audiometry to investigate the loudness perception of unilateral high-frequency tinnitus in 16 "normal-hearing" ears by comparing the results with loudness scaling in 20 normally hearing ears without any tinnitus. Narrow-band noise signals at four different frequencies from 500 to 4000 Hz were employed. The parameters used included the slope m of the loudness function and the level Lm (corresponding to the loudness perception of "medium loud") as well as the suitability of fit (delta FIT). The results showed that in subjects with tinnitus the slope of the mean loudness level tended to decrease at 4000 Hz. The dynamic range of ears affected by tinnitus was restricted for stimulation with noise signals at 1000, 2000 and 4000 Hz. The parameters of delta FIT fitted to the loudness functions were increased in the whole frequency range of 500-4000 Hz, indicating that loudness scaling was not as reliable for normal hearing ears when influenced by tinnitus. Tinnitus masking was based on the finding that external sound could change tinnitus loudness. Our results showed that the loudness perception of external sound was influenced by tinnitus. This change in loudness perception seemed to be not restricted to the frequency range of the tinnitus.

Adult↗
PubMedDate not supplied

Loudness perception is influenced by long-term hearing aid use.

The aim of this study was to explore possible differences in the perception of loudness between long-term hearing aid full-time users and non-users. Categorical loudness scaling using pure-tone stimuli was carried out by hearing-impaired subjects. The mean levels of loudness categories at one frequency (hearing threshold: 50-75 dB HL) in a group of 18 hearing aid users (daily use < or = 15 hours per day) were compared with the corresponding levels found in 18 hearing-impaired non-users with the same distribution of hearing thresholds. The results show that, for hearing losses of 50-75 dB HL, the mean level rated as 'loud' by long-term full-time users of hearing aids is 4.5 dB above the mean level of the corresponding category rated by non-users. This difference is statistically significant (P<0.05). No significant differences were found for the lower categories. Among those subjects who had been wearing hearing aids for at least six months, no significant correlation was found between the levels of the 'loud' category and the length of time that hearing aids had been used.

Adult↗
PubMed1997

The contour test of loudness perception.

OBJECTIVE: This article presents the underlying rationale, normative data, and reliability data for a test of loudness perception (the Contour Test) that was devised for use in clinical hearing aid fitting. The Contour Test yields data describing the sound level required for each of seven categories of loudness ranging from very soft to uncomfortably loud. DESIGN: Two experiments are described. Experiment 1 yielded norms for the test. The subjects were 23 male and 22 female normal-hearing listeners. Test stimuli included warble tones at six frequencies and broad band speech. Experiment 2 assessed the reliability of the test results. Ten hearing-impaired listeners responded to the test at two frequencies on two occasions separated by several days. Both experiments also evaluated the effect of using different stimulus increment sizes on the measured levels of loudness categories. RESULTS: Based on the data from experiment 1, norms for each category of each stimulus are reported in terms of mean level and typical between-subject variation in responses. Data are provided in HA-12 cm3 coupler levels as well as in hearing levels (dB HL). The shape of the loudness growth function for warble tones was somewhat different from that for speech. When data were expressed in HL, there were no differences in mean loudness category levels across warble tone test frequencies. Thus, test frequencies were combined and equations were generated to describe the upper and lower limits of typical normal performance for warble tone stimuli. These equations can be used to construct a template for clinical comparison of normative values to patient loudness growth curves. Experiment 2 provided information about the test-retest variability of data yielded by the Contour Test. Reliability appears to be similar to that of the few other category scaling tests described in the literature. Most test-retest differences were 6 dB or less. Although a moderate variation in test increment size did not significantly affect the loudness category levels for young normal-hearing listeners, levels corresponding to loudness categories were significantly higher when larger increments were used with elderly hearing-impaired listeners. CONCLUSIONS: Evidence from this and other research indicates that standardized measurement of loudness perception is an achievable goal for clinical practice. The Contour Test appears to offer a viable approach to clinical measurement of loudness perception: It has good patient acceptance and combines fairly rapid administration with acceptable reliability. Details of test procedures and scoring sheets for manual administration can be downloaded from the Internet at www.ausp.memphis.edu/harl. However, it is important to keep in mind that the application of loudness perception data for narrowband stimuli (such as warble tones) to hearing aid prescription is complicated by the need to account for the effects of loudness summation across bandwidth. There is a need for additional research to establish an empirical link between clinically measured loudness perception and optimal amplification characteristics.

Adolescent↗
PubMed2001

Verifying loudness perception after hearing aid fitting.

During the verification phase of a hearing aid fitting, clinicians often want to assess the extent to which loudness perceptions for amplified sounds are similar to those typical of normal hearers. This type of verification calls for a criterion for "normal" loudness perception of sounds presented in a sound field. This research sought to answer several questions about the parameters of a valid "normal" criterion for a verification procedure using the Contour test of loudness perception. Loudness data were obtained from 30 listeners with normal hearing. Results indicated that a loudness growth function obtained with earphone listening is not an appropriate normative reference for hearing aid fitting verification. Instead, the normative data should be based on sound field listening. Results also indicated that the same normative function could be used to assess both unilateral and bilateral fittings. Further, it is likely that the same normative function can be used for most frequency responses that are likely to be used in feasible fittings. Finally, it was found that a previously published normative function obtained using an automated test procedure was not faithfully replicated using a carefully executed fully manual test procedure. We concluded that, until a replicable normative function is established, practitioners will need to generate their own local norms to perform postfitting verification of loudness normalization.

Adult↗
PubMed1998

Disturbances of loudness perception.

This article reviews information on some auditory disorders that have in common a disturbance in loudness perception. The perceptual disturbances in these disorders have interchangeably been labeled "hyperacusis," "dysacusis," or "phonophobia." Our question concerns whether the loudness disturbances associated with these auditory disorders are sufficiently different as not to justify the equivalence implied by the labelling. Emphasis is placed on those articles that have given clear accounts of the phenomenology of the disturbed perceptual experience and have offered testable hypotheses about the mechanisms underlying it. Hypotheses about the origins of disturbed loudness perception are compared with independent experimental and clinical evidence on those mechanisms. The disturbances of loudness perception that occur in cochlear hearing loss, facial nerve paralysis and stapedectomy, and in more "central" disorders are phenomenologically different, have different underlying mechanisms, and merit different labels that most of them do not currently receive.

Facial Paralysis↗
PubMed1984

Magnitude estimation of loudness. II: Loudness perception in presbycusic listeners.

Because clinical methods most commonly used for assessing loudness are indirect measures that require one normal or near normal ear, loudness perception has not been studied thoroughly in listeners with symmetrical hearing loss. In this investigation, loudness perception was studied in three groups of listeners: normal listeners, listeners with asymmetrical sensorineural hearing loss, and individuals with bilaterally symmetrical hearing impairment due to presbycusis. In Experiment 1, a Magnitude Estimation of Loudness (ME) technique was compared to Alternate Binaural Loudness Balance ( ABLB ) results for subjects with asymmetrical hearing impairment. Results indicate that ME and ABLB measurements produce similar evidence of abnormally rapid growth of loudness in asymmetrically impaired listeners. In Experiment 2, loudness growth in individuals with normal hearing or with presbycusic hearing impairment was determined from ME measurements. Although presbycusic subjects tended to have steeper loudness functions than normal subjects, the differences did not reach statistical significance except at 6000 Hz, suggesting that, as a group, presbycusic listeners display little, if any, recruitment of loudness.

Adult↗
PubMed2001

Loudness perception and late auditory evoked potentials in adult cochlear implant users.

In clinical routine the adjustment of speech processors in cochlear implant users is based on the patients' subjective statements about the loudness of specific electrical stimuli. From hearing patients it is known that the latencies and amplitudes of late auditory evoked potentials (LAEP) which are generated within the auditory cortex correlate with the loudness perception of acoustical stimuli. The aim of this study was to investigate the correlation between LAEP and loudness perception in adult cochlear implant users. We investigated 8 adult subjects who had been provided with a 22 electrode Cochlear Implant (nucleus CI24M) at least 6 months prior to the investigation. All subjects showed open speech understanding. Electrical pulse trains of 300 ms duration presented at a single electrode served as stimuli. Electrically LAEP morphologies were similar to normal hearing subjects. In all subjects and each intracochlear electrode position LAEP were well identifiable down to low loudness sensations. Both amplitudes and latencies depended on the loudness perception. The best correlation was observed for the N1 deflection. The results show that LAEP can be used for estimation of both hearing thresholds and most comfortable levels.

Adult↗
PubMed2004

Fine structure of hearing threshold and loudness perception.

Hearing thresholds measured with high-frequency resolution show a quasiperiodic change in level called threshold fine structure (or microstructure). The effect of this fine structure on loudness perception over a range of stimulus levels was investigated in 12 subjects. Three different approaches were used. Individual hearing thresholds and equal loudness contours were measured in eight subjects using loudness-matching paradigms. In addition, the loudness growth of sinusoids was observed at frequencies associated with individual minima or maxima in the hearing threshold from five subjects using a loudness-matching paradigm. At low levels, loudness growth depended on the position of the test- or reference-tone frequency within the threshold fine structure. The slope of loudness growth differs by 0.2 dB/dB when an identical test tone is compared with two different reference tones, i.e., a difference in loudness growth of 2 dB per 10-dB change in stimulus. Finally, loudness growth was measured for the same five subjects using categorical loudness scaling as a direct-scaling technique with no reference tone instead of the loudness-matching procedures. Overall, an influence of hearing-threshold fine structure on loudness perception of sinusoids was observable for stimulus levels up to 40 dB SPL--independent of the procedure used. Possible implications of fine structure for loudness measurements and other psychoacoustic experiments, such as different compression within threshold minima and maxima, are discussed.

Auditory Threshold↗
PubMedDate not supplied

The acoustic reflex threshold: not predictive for loudness perception in normally-hearing listeners.

The working hypothesis of an ongoing study is that the quick and reliable procedure of acoustic reflex threshold (ART) determination in conjunction with measurements of HTL may yield accurate estimates of loudness. The aim of this study was to investigate whether differences in loudness in normally-hearing subjects are reflected in the ARTs and to collect normal material with respect to pure-tone elicited ART and loudness categories. Categorical loudness scaling (CLS) and ART measurements were performed at frequencies of 0.5, 1, 2 and 4 kHz in 60 normally-hearing subjects (HTL<20 dB HL, 26 males, 34 females, aged 21-63 years) with no history or sequelae of middle ear disease. Subjects reporting disturbing tinnitus were excluded. The results show that the ART is not a predictor of individual loudness perception for normally-hearing subjects. Using a numerical scale (HTL=0, 'very soft'=5, 'soft'=15, 'OK'=25, 'loud'=35, 'very loud'=45 and 'too loud'=50) loudness for pure tones grows almost linearly at approximately 0.4 arbitrary loudness units per dB below the 'loud' category. Above the 'loud' category the slope is around 1 unit per dB. The median ART was 85 dB HL at frequencies of 0.5, 1, 2 and 4 kHz. No differences in loudness perception across frequencies were found.

Adult↗
PubMed2004

A revised model of loudness perception applied to cochlear hearing loss.

We previously described a model for loudness perception for people with cochlear hearing loss. However, that model is incompatible with our most recent and most satisfactory model of loudness for normal hearing. Here, we describe a loudness model that is applicable to both normal and impaired hearing. In contrast to our earlier model for impaired hearing, the new model correctly predicts: (1) that a sound at absolute threshold has a small but finite loudness; (2) that, for levels very close to the absolute threshold, the rate of growth of loudness is similar for normal ears and ears with cochlear hearing loss; (3) the relation between monaural and binaural threshold and loudness; (4) recent measures of equal-loudness contours. Like the earlier model, the new model can account for the loudness recruitment and reduced loudness summation that are typically associated with cochlear hearing loss.

Cochlea↗
PubMed1999

Dynamic frequency change influences loudness perception: a central, analytic process.

Three experiments showed that dynamic frequency change influenced loudness. Listeners heard tones that had concurrent frequency and intensity change and tracked loudness while ignoring pitch. Dynamic frequency change significantly influenced loudness. A control experiment showed that the effect depended on dynamic change and was opposite that predicted by static equal loudness contours. In a 3rd experiment, listeners heard white noise intensity change in one ear and harmonic frequency change in the other and tracked the loudness of the noise while ignoring the harmonic tone. Findings suggest that the dynamic interaction of pitch and loudness occurs centrally in the auditory system; is an analytic process; has evolved to take advantage of naturally occurring covariation of frequency and intensity; and reflects a shortcoming of traditional static models of loudness perception in a dynamic natural setting.

Acoustics↗
PubMed1999

Further evaluation of a model of loudness perception applied to cochlear hearing loss.

This paper describes further tests of a model for loudness perception in people with cochlear hearing loss. It is assumed that the hearing loss (the elevation in absolute threshold) at each audiometric frequency can be partitioned into a loss due to damage to outer hair cells (OHCs) and a loss due to damage to inner hair cells (IHCs) and/or neurons. The former affects primarily the active mechanism that amplifies the basilar membrane (BM) response to weak sounds. It is modeled by increasing the excitation level required for threshold, which results in a steeper growth of specific loudness with increasing excitation level. Loss of frequency selectivity, which results in broader excitation patterns, is also assumed to be directly related to the OHC loss. IHC damage is modeled by an attenuation of the calculated excitation level at each frequency. The model also allows for the possibility of complete loss of IHCs or functional neurons at certain places within the cochlea ("dead" regions). The parameters of the model (OHC loss at each audiometric frequency, plus frequency limits of the dead regions) were determined for three subjects with unilateral cochlear hearing loss, using data on loudness matches between sinusoids presented alternately to their two ears. Further experiments used bands of noise that were either 1-equivalent rectangular bandwidth (ERB) wide or 6-ERBs wide, centered at 1 kHz. Subjects made loudness matches for these bands of noise both within ears and across ears. The model was reasonably accurate in predicting the results of these matches without any further adjustment of the parameters.

Audiometry, Pure-Tone↗
PubMedDate not supplied

The clinical relationship between acoustic reflexes and loudness perception.

Speech-elicited acoustic reflexes and three measures of subjective loudness perceptions were administered to 10 normal ears and to 20 ears with confirmed sensorineural hearing loss. Most notable was the comparison between loudness discomfort level and the acoustic reflex, revealing a limited relationship. The use of the acoustic reflex as a clinical predictor of loudness discomfort is questioned.

Adult↗
PubMed1998

Loudness perception and frequency discrimination in subjects with steeply sloping hearing loss: possible correlates of neural plasticity.

Loudness functions and frequency difference limens (DLFs) were measured in five subjects with steeply sloping high-frequency sensorineural hearing loss. The stimuli were pulsed pure tones encompassing a range of frequencies. Loudness data were obtained using a 2AFC matching procedure with a 500-Hz reference presented at a number of levels. DLFs were measured using a 3AFC procedure with intensities randomized within 6 dB around an equal-loudness level. Results showed significantly shallower loudness functions near the cutoff frequency of the loss than at a lower frequency, where hearing thresholds were near normal. DLFs were elevated, on average, relative to DLFs measured using the same procedure in five normally hearing subjects, but showed a local reduction near the cutoff frequency in most subjects with high-frequency loss. The loudness data are generally consistent with recent models that describe loudness perception in terms of peripheral excitation patterns that are presumably restricted by a steeply sloping hearing loss. However, the DLF data are interpreted with reference to animal experiments that have shown reorganization in the auditory cortex following the introduction of restricted cochlear lesions. Such reorganization results in an increase in the spatial representation of lesion-edge frequencies, and is comparable with the functional reorganization observed in animals following frequency-discrimination training. It is suggested that similar effects may occur in humans with steeply sloping high-frequency hearing loss, and therefore, the local reduction in DLFs in our data may reflect neural plasticity.

Acoustic Stimulation↗
PubMed1990

Is there an auditory analogue to Fechner's paradox in binaural loudness perception?

In binocular brightness perception a phenomenon called Fechner's paradox can be observed. This paradox implies non-monotonicities in the psychometric functions of binocular brightness. Lehky (1983) proposed a model that describes such non-monotonicities. He suggested that Fechner's paradox also exists in binaural loudness perception. However, until now no sufficient data have been collected to test this hypothesis. Therefore, an experiment was conducted in which 36 psychometric functions were obtained using binaural stimuli in the range of intensities in which Fechner's paradox supposedly occurs. As a result, no significant non-monotonicities were found. However, it is shown that jnds derived from the psychometric functions contradict predictions derived from the limited binaural additivity model of Gigerenzer and Strube (1983).

Adult↗
PubMed2000

Relative loudness perception of low and high frequency sounds in the open and occluded ear.

A comparison of published equal loudness contours indicates that different shapes are obtained at a comfortable level when the measurements are done in an occluded ear than when they are done in an open ear, even though all measurements are expressed as dB SPL at the eardrum. This paper presents the result from a loudness balancing test which confirms this observation. Eleven normal-hearing listeners balanced the level of a 500- and a 3000-Hz octave band babble-noise to the level of a 1500-Hz octave band babble-noise. The balancing test was completed in open and occluded ears using a loudspeaker and a hearing aid receiver, respectively. A probe tube microphone was used to measure the actual levels presented near the individual's eardrum. The results show that an average of 10 dB higher level was selected for the 500-Hz octave band when listening with the occluded ear than when listening with the open ear. A large range of factors is discussed, but no physical explanation for the discrepancy was found. The findings could have consequences for psychoacoustic experiments and for the use of loudness measurements for hearing aid prescription.

Auditory Threshold↗